Information
-
Patent Grant
-
6350165
-
Patent Number
6,350,165
-
Date Filed
Wednesday, June 21, 200024 years ago
-
Date Issued
Tuesday, February 26, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Ziolkowski; Timothy J.
- Cook & Franke SC
-
CPC
-
US Classifications
Field of Search
US
- 440 900
- 440 75
- 440 83
- 475 220
- 475 230
- 475 269
- 475 302
- 475 306
- 475 311
- 475 323
- 475 317
- 475 224
- 475 316
- 475 257
-
International Classifications
-
Abstract
An inboard/outboard powered watercraft (10) incorporating a transmission (30, 80) in its vertical drive unit (24) for providing two forward speeds plus reverse. The transmission is packaged to fit within the vertical drive unit (24) by incorporating a bevel gear apparatus (44, 120). In one embodiment, the transmission (30) also includes a planetary gear apparatus (46) together with two hydraulic clutches (70, 72) and a ring gear brake (56). In a second embodiment, three hydraulic clutches (98, 100, 114) are utilized with bevel gears (94,96,106,110,112) alone to provide the two forward and reverse speeds.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of watercraft, and more particularly to the field of marine propulsion systems, and specifically to a transmission having two forward speeds and reverse for an inboard/outboard stern drive watercraft.
In conventional single speed marine drives, an engine is mechanically coupled to a propeller either directly or through a gearbox to provide a single gearing ratio. It is known that a single gear ratio connection between the engine and propeller will provide less than optimal performance for many applications. There have been efforts to improve the performance of marine propulsion systems by the use of multi-speed and hydraulically coupled transmissions. It is known that the performance of a watercraft may be improved by providing a higher gear ratio connection between the engine and the propeller for low speed operation and acceleration, and by providing a direct drive or overdrive gear ratio between the engine and the propeller for high speed operation. In this manner, the engine may be operated at a point closer to its peak power output during a wider range of operating conditions.
U.S. Pat. No. 5,711,742 issued on Jan. 27, 1998, to Leinonen, et. al., incorporated by reference herein, describes a multi-speed marine propulsion system with an automatic shifting mechanism. An automatic transmission is interposed between the engine and the inboard/outboard drive apparatus. Although providing improved performance when compared to prior art single speed propulsion systems, the device of Leinonen creates an excessively long driveline that necessitates the placement of the engine in a more forward position within the watercraft hull than may otherwise be desirable.
U.S. Pat. No. 4,820,209 issued on Apr. 11, 1989, to Newman, incorporated by reference herein, describes a marine propulsion system having a fluid coupling with a variable power output. While this system avoids the long driveline of the Leinonen apparatus, it does so at the expense of multi-speed forward gear ratios. In lieu of multi-speed gears, the device of Newman provides for a controlled slippage between the engine and the propeller in order to improve low speed watercraft operation. The hydraulic coupling and forward-reverse gearing of the Newman transmission are enclosed within a housing passing through the transom of the watercraft, which in turn connects to the vertical drive unit containing the propeller. The device of Newman fails to provide a direct mechanical connection between the engine and the propeller at a plurality of forward gear ratios.
BRIEF SUMMARY OF THE INVENTION
Thus, there is a particular need for an improved multi-speed mechanical drive transmission for a stern drive watercraft. Accordingly, a transmission for a watercraft is described herein as including: a generally horizontal input shaft rotatably supported by the vertical drive unit housing and adapted for coupling to an engine output shaft of the watercraft; a generally vertical output shaft rotatably supported by the vertical drive unit housing and adapted for coupling to a propeller gear apparatus; a bevel gear apparatus selectively connectable between the input shaft and the output shaft in one of a high forward, reverse and neutral positions for providing a high forward ratio of rotation between the input shaft and the output shaft, a reverse ratio of rotation between the input shaft and the output shaft, and neutral connection between the input shaft and the output shaft respectively; a planetary gear apparatus having a sun gear connected for rotation with a portion of the bevel gear apparatus, a planet gear having an axis of rotation connected for rotation with the output shaft, and a ring gear; a brake selectively connected between the vertical drive unit housing and the ring gear, the brake having an engaged position for providing a low forward ratio of rotation between the input shaft and the output shaft and a disengaged position for allowing independent rotation of the sun gear and the planet gear.
In another embodiment, a transmission for a stern drive watercraft is described herein, the stern drive having a vertical drive unit housing disposed rearward of a transom of the watercraft, the transmission including: a generally horizontal input shaft rotatably supported by the vertical drive unit housing and adapted for coupling to an engine output shaft of the watercraft; a generally vertical output shaft rotatably supported by the vertical drive unit housing and adapted for coupling to a propeller gear apparatus; and a bevel gear apparatus selectively connectable between the input shaft and the output shaft for alternatively providing a first forward gear ratio connection, a second forward gear ratio connection, a reverse gear ratio connection, and a neutral connection between the input shaft and the output shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the present invention will become apparent from the following detailed description of the invention when read with the accompanying drawings. Similar parts appearing in multiple figures may be numbered consistently among the figures, in which:
FIG. 1
is a partial cross-sectional view of a watercraft having a stern drive apparatus.
FIG. 2
is a cross-sectional view of a first embodiment of a bevel gear transmission disposed in the vertical drive unit of the watercraft of FIG.
1
.
FIG. 3
is a cross-sectional view of a second embodiment of a bevel gear transmission disposed in the vertical drive unit of the watercraft of FIG.
1
.
FIG. 4
is a top view of the steering arm of a marine propulsion unit illustrating the routing of control wiring.
FIG. 5
is a schematic flow diagram for the pressurized hydraulic system of the transmission of FIG.
3
.
DETAILED DESCRIPTION OF THE INVENTION
A watercraft
10
is illustrated in
FIG. 1
as having a hull
12
including a transom
14
forming the rearward portion of the watercraft
10
. The watercraft
10
is powered by a marine propulsion apparatus
16
including an engine
18
disposed within the hull
12
. Engine
18
may be any known type such as a gasoline or diesel engine. Engine
18
includes an output shaft
20
for conveying mechanical energy to a propeller
22
through a vertical drive unit
24
rotatably and pivotally connected to a gimbal housing
26
. This style of marine propulsion apparatus
16
is known in the art as an inboard/outboard drive unit. The vertical and horizontal drive axes of the propeller
22
may be adjusted by pivoting/rotating the vertical drive unit
24
relative to the gimbal housing
26
. As will be described more fully with regard to FIG.
2
and
FIG. 3
, the vertical drive unit
24
utilizes a combination of bevel gears and clutches so that the ration of the speed of rotation of propeller
22
with respect to the speed of rotation of output shaft
20
may be selected to be one of two forward drive ratios, a reverse ratio, or a neutral ratio. The inventor has found that the use of bevel gears and clutches will facilitate the packaging of a multi-speed transmission to be small enough to fit within the confines of a standard vertical drive unit. By including the necessary gearing for two forward speeds and reverse within the vertical drive unit
24
, the applicant has avoided many of the disadvantages of prior art multi-speed marine transmissions.
FIG. 2
illustrates one embodiment of a transmission
30
that may be used in stern drive watercraft
10
. The transmission
30
includes a housing
32
which may form at least part of the vertical drive unit
24
of watercraft
10
. Transmission
30
includes an input shaft
34
coupled to the engine output shaft
20
. Input shaft
34
is rotatably supported by one or more thrust bearings
36
for rotation relative to housing
32
. Transmission
30
further includes a generally vertical output shaft
38
rotatably supported within housing
32
by bearings
40
,
42
. Output shaft
38
is adapted for coupling to propeller
22
through a propeller gear apparatus as is known in the art for translating the vertical rotation of output shaft
38
into the horizontal rotation of propeller
22
. Although input shaft
34
is illustrated as being generally horizontal and output shaft
38
as being generally vertical, one may appreciate that in other embodiments the components of transmission
30
may be disposed in other orientations as may be appropriate for the particular application.
Transmission
30
utilizes the combination of a bevel gear apparatus
44
and a planetary gear apparatus
46
to provide a compact multi-speed drive mechanism. Bevel gear apparatus
44
is selectively connectable between the input shaft
34
and the output shaft
38
in any one of a high forward, reverse, and neutral positions for providing a high-forward ratio of rotation between the input shaft
34
and the output shaft
38
, a reverse ratio of rotation between the input shaft
34
and the output shaft
38
, and a neutral connection between the input shaft
34
and output shaft
38
respectively. The term neutral connection is used herein to describe a neutral gear where no power is transmitted between the input shaft
34
and the output shaft
38
, and wherein those two shafts are free to rotate independent of each other. The planetary gear apparatus
46
includes a sun gear
48
connected for rotation with a portion of the bevel gear apparatus
44
, a planet gear
50
having an axis of rotation
52
connected for rotation with the output shaft
38
, and a ring gear
54
. Planetary gear apparatus
46
may include one or a plurality of planet gears
50
, each having an axis of rotation
52
supported by a carrier
58
. Carrier
58
is in splined connection with output shaft
38
for concentric rotation therewith. Transmission
30
also includes a brake
56
selectively connected between the vertical drive unit housing
32
and the ring gear
54
. The brake
56
may be any style known in the art for use with ring gears, and has an engaged position for preventing the rotation of ring gear
54
relative to housing
32
and a disengaged position for allowing ring gear to rotate.
Input shaft
34
is driven by drive shaft
20
to rotate with engine
18
. In one embodiment, the speed of rotation of input shaft
34
will be the same as the speed of rotation of engine
18
. However, one may envision applications wherein a speed reducer or overdrive mechanism may be interposed between the engine
18
and transmission input shaft
34
. An input bevel gear
60
is in splined connection with input shaft
34
for concentric rotation therewith. Input bevel gear
60
forms a portion of the bevel gear apparatus
44
, together with a forward bevel gear
62
and a reverse bevel gear
64
. Forward bevel gear
62
and reverse bevel gear
64
are rotatably supported to be concentric with output shaft
38
by bearings
66
,
68
respectively. Forward bevel gear
62
is engaged with a first portion of input bevel gear
60
for rotation in a forward direction therewith. Reverse bevel gear
64
is engaged with a second portion of input bevel gear
60
on an opposed side of input bevel gear
60
from forward bevel gear
62
. Accordingly, reverse bevel gear
64
is engaged for rotation in a reverse direction with input bevel gear
60
. Forward bevel gear
62
and reverse bevel gear
64
, forming a further portion of bevel gear apparatus
44
, will be in rotation coincident with input shaft
34
and engine
18
. The relative speeds of rotation of forward bevel gear
62
and reverse bevel gear
64
will be a function of the diameter of each of these respective gears and the diameter of the input bevel gear
60
. Sun gear
48
is attached to, and preferably formed to be integral with the forward bevel gear
62
for concentric rotation therewith.
Transmission
30
further includes a forward clutch
70
connected between the forward bevel gear
62
and the output shaft
38
for selectively connecting the output shaft
38
for forward rotation with the forward bevel gear
62
. A reverse clutch
72
is connected between the reverse bevel gear
64
and the output shaft
38
for selectively connecting the output shaft
38
for reverse rotation with the reverse bevel gear
64
. Clutches
70
,
72
may be any style known in the art, and may be preferably hydraulically operated clutches, such as for example the Hydra Series provided by Yamaha Motor Corporation. Pressurized hydraulic fluid for the operation of the clutches
70
,
72
may be provided by a pump (not shown) driven by any of the components of transmission
30
that rotate coincident with engine
18
, or by a pump connected directly to the engine
18
such as a power steering pump.
Transmission
30
may be operated in a first forward (low) gear ratio mode by disengaging forward clutch
70
and reverse clutch
72
and engaging brake
56
. In this mode, output shaft
38
will be free to rotate independent of forward bevel gear
62
and reverse bevel gear
64
. The forward rotation of sun gear
48
together with forward bevel gear
62
will result in the forward rotation of carrier
58
and its attached output shaft
38
through the action of the planetary gear assembly
46
. The relative speeds of rotation of sun gear
48
and output shaft
38
(i.e. plant gear carrier
58
) will depend upon the relative sizes of the sun gear
48
, planet gear
50
and ring gear
54
. In one embodiment, the gear ratio provided by such an arrangement may be 1.33:1 lower than that provided by a standard forward single speed transmission. Transmission
30
may be shifted to a second (high) gear ratio mode by disengaging brake
56
and engaging forward clutch
70
, while reverse clutch
72
remains disengaged. In this mode, output shaft
38
will rotate together with forward bevel gear
62
at a speed determined by the relative diameters of forward bevel gear
62
and input bevel gear
60
. Sun gear
48
and carrier
58
are thereby caused to rotate together, and will accordingly cause the rotation of ring gear
54
. A reverse gear ratio mode of operation may be achieved with transmission
30
by engaging reverse clutch
72
and disengaging forward clutch
70
with brake
56
being disengaged. In this mode, output shaft
38
will rotate together with reverse bevel gear
64
. The resulting counter-rotation of carrier
58
and sun gear
48
will then be accommodated by the free turning of ring gear
54
. The speed of reverse rotation of output shaft
38
will be a function of the relative diameters of input bevel gear
60
and reverse bevel gear
64
.
One may appreciate that the size of transmission
30
may be minimized by arranging its various components as illustrated in FIG.
2
. In particular, having the output shaft
38
disposed to have its axis of rotation being perpendicular to the axis of rotation of input shaft
34
is conducive to a layout wherein input bevel gear
60
is concentric with input shaft
34
while forward bevel gear
62
and reverse bevel gear
64
are each concentric with output shaft
38
and are disposed at respective locations on the output shaft
38
corresponding to the diameter of the input bevel gear
60
. This layout provides a volume between the forward bevel gear
62
and the reverse bevel gear
64
for locating the forward clutch
70
and reverse clutch
72
, each having an axis of rotation concentric with the output shaft
38
. Furthermore, forming the sun gear
48
as an extension of the forward bevel gear
62
and disposing sun gear
48
to be concentric with the output shaft
38
on a side of the forward bevel gear
62
opposed the reverse bevel gear
64
allows the planetary gear apparatus
46
may be located proximate the bevel gear apparatus
44
. Support of output shaft
38
is accomplished by having a thrust bearing
40
located at an end of output shaft
38
above reverse bevel gear
64
, and by having a roller or ball bearing
42
located proximate the carrier
58
. An extension
74
of input bevel gear
60
is supported by one double-thrust bearing
36
. Thus, a robust, compact package is provided for connecting perpendicular input and output shafts in any of two forward speed ratios or a reverse speed ratio.
FIG. 3
illustrates a partial cross-sectional view of another embodiment of a bevel gear transmission
80
as may be used in the marine propulsion apparatus
16
of watercraft
10
. Transmission
80
includes a housing
82
rotatably supporting an input shaft
84
and an output shaft
86
through respective bearings
88
,
90
,
92
. Input shaft
84
is connected to engine output shaft
20
. Input shaft
84
may be selectively connected to first forward bevel gear
94
or reverse bevel gear
96
by the operation of the respective first forward clutch
98
or reverse clutch
100
. First forward bevel gear
94
and reverse bevel gear
96
are rotatably supported for concentric rotation about input shaft
84
by respective bearing assemblies
102
,
104
. A first output bevel gear
106
is in splined connection for concentric rotation with output shaft
86
. First output bevel gear
106
is engaged on a first side with first forward bevel gear
94
and on an opposed side with reversed bevel gear
96
. An extension
108
of first output bevel gear
106
is supported by thrust bearing
92
for corresponding support of output shaft
86
. A second forward bevel gear
110
is in splined connection with input shaft
84
for concentric rotation therewith. Second forward bevel gear
110
may be selectively engaged with output shaft
86
through second output bevel gear
112
and clutch
114
. Second output bevel gear
112
is formed to be concentric with output shaft
86
and is supported on one side by bearing
92
and on an opposed side by bearing
116
.
The combination of first forward bevel gear
94
, second forward bevel gear
110
, second output bevel gear
112
, and reverse bevel gear
96
constitute a bevel gear apparatus
120
selectively connectable between the input shaft
84
and the output shaft
86
for alternatively providing a first forward gear ratio connection, a second forward gear ratio connection, a reverse gear ratio connection, and a neutral connection between the input shaft
84
and the output shaft
86
. To obtain the first forward (low) gear mode of operation, the first forward clutch
98
is engaged, and the reverse clutch
100
and second forward clutch
114
are disengaged. In this mode, first forward bevel gear
94
rotates with input shaft
84
and is engaged with first output bevel gear
106
to drive output shaft
86
in a forward direction. The ratio of the speeds of rotation between input shaft
84
and output shaft
86
is a function of the relative diameters of the first forward bevel gear
94
and the first output bevel gear
106
. In one embodiment, this ratio may be 1.2/1. A second forward (high) gear ratio mode of operation may be obtained by disengaging first forward clutch
98
and reverse clutch
100
while engaging second forward clutch
114
. In this mode of operation, second forward bevel gear drives second output bevel gear
112
in a forward direction to rotate output shaft
86
therewith at a ratio determined by the relative diameters of the second forward bevel gear
110
and the second output bevel gear
112
. In one embodiment, this ratio may be an overdrive ratio of 0.74:1. Reverse operation of transmission
80
may be achieved by disengaging first forward clutch
98
and second forward clutch
114
while engaging reverse clutch
100
. In this mode of operation, reverse bevel gear
96
is driven to rotate with input shaft
84
, and is engaged to rotate first output bevel gear
106
and output shaft
86
in a reverse direction. The relative speeds of rotation of input shaft
84
and output shaft
86
will be a function of the respective diameters of reverse bevel gear
96
and first output bevel gear
106
.
The bevel gear apparatus
120
of the embodiment of
FIG. 3
is advantageously configured to provide a robust, compact, multi-speed transmission
80
adapted for use in a vertical drive unit
24
of an inboard/outboard marine propulsion unit
16
. First forward bevel gear
94
and reverse bevel gear
96
are disposed for concentric rotation about input shaft
84
at a distance corresponding to the diameter of first output bevel gear
106
. The space between first forward bevel gear
94
and reverse bevel gear
96
is advantageously utilized to locate first forward clutch
98
and reverse clutch
100
. The desired greater diameter of second forward bevel gear
110
permits second output bevel gear
112
to be positioned below the first output bevel gear
106
and to be concentrically supported with output shaft
86
by bearing
92
. Second forward clutch
114
may be positioned below second output bevel gear
112
along output shaft
86
in an area that is otherwise not utilized. In this manner, a two forward speed transmission
80
may be packaged in a housing
82
that is not substantially different in size than prior art single forward speed vertical drive units.
Clutches
98
,
100
,
114
may be any style known in the art and may preferably be hydraulic clutches. Pressurized hydraulic fluid may be provided for the operation of the clutches and for the lubrication of the various parts of transmission
80
by an oil pump
118
connected to input shaft
84
. As shown in schematic flow diagram
FIG. 5
, oil pump
118
may draw hydraulic fluid from a sump
119
and may have an output
120
connected to a plurality of control valves
122
,
124
,
126
for the control of respective clutches
98
,
96
,
114
. A pressure regulator
121
may be used to limit and/or control the pressure of the hydraulic fluid being supplied to the valves
122
,
124
,
126
. In one embodiment, pressure regulator
121
is used in conjunction wet slip clutches, as are known in the art, to enhance control of the watercraft
10
during slow speed operation. This is accomplished by varying the hydraulic fluid pressure below a predetermined speed, such as 10 miles per hour, and/or below a predetermined engine speed, such as 1,000 revolutions per minute. In this embodiment, pressure regulator
121
may take the form of a plurality of relief valves, with a lower pressure relief valve (such as 200 psi) being made operable during periods of slow speed operation and a higher pressure relief valve (such as 1,000 psi) being made operable during normal periods of operation. For this example, a pressure regulator
121
may be connected in fluid communication between first forward clutch
98
and pump outlet
120
. This feature improves control of the watercraft
10
during docking or other slow speed maneuvers. Any sudden acceleration will result in the clutch locking up at normal operating pressure.
The embodiment of
FIG. 3
is particularly adapted for the use of a fly-by-wire control system. The term “fly-by-wire” is meant to describe a control system wherein the shifting of transmission
80
is accomplished by the electrical control of valves
122
,
124
,
126
without the need for a mechanical connection passing through housing
82
. By using electrically controlled valves
122
,
124
,
126
such as solenoid valves or an electrically-driven rotary valve, the need for mechanical penetrations through housing
82
is eliminated. In one embodiment as illustrated in
FIG. 4
, the electrical wires used for controlling the position of valves
122
,
124
,
126
are routed out of housing
82
through the center line of a steering arm
130
attached to housing
82
along its vertical axis of rotation. By locating wires
128
along this axis of rotation, the flexing of the wires
128
during the steering of watercraft
10
is minimized.
While the preferred embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those of skill in the art without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.
Claims
- 1. A transmission for a stern drive watercraft, the stem drive having a vertical drive unit housing disposed rearward of a transom of the watercraft, the transmission comprising:a generally horizontal input shaft rotatably supported by the vertical drive unit housing and adapted for coupling to an engine output shaft of the watercraft; a generally vertical output shaft rotatably supported by the vertical drive unit housing and adapted for coupling to a propeller gear apparatus; a bevel gear apparatus selectively connectable between the input shaft and the output shaft in one of a high forward, reverse and neutral positions for providing a high forward ratio of rotation between the input shaft and the output shaft, a reverse ratio of rotation between the input shaft and the output shaft, and neutral connection between the input shaft and the output shaft respectively; a planetary gear apparatus having a sun gear connected for rotation with a portion of the bevel gear apparatus, a planet gear having an axis of rotation connected for rotation with the output shaft, and a ring gear; a brake selectively connected between the vertical drive unit housing and the ring gear, the brake having an engaged position for providing a low forward ratio of rotation between the input shaft and the output shaft and a disengaged position for allowing independent rotation of the sun gear and the planet gear.
- 2. The transmission of claim 1, wherein the bevel gear apparatus further comprises:an input bevel gear connected to the input shaft for rotation therewith; a forward bevel gear engaged with a first portion of the input bevel gear for rotation in a forward direction therewith; a reverse bevel gear engaged with a second portion of the input bevel gear for rotation in a reverse direction therewith.
- 3. The transmission of claim 2, further comprising:a forward clutch connected between the forward bevel gear and the output shaft for selectively connecting the output shaft for forward rotation with the forward bevel gear; and a reverse clutch connected between the reverse bevel gear and the output shaft for selectively connecting the output shaft for reverse rotation with the reverse bevel gear.
- 4. The transmission of claim 3, wherein the planetary gear apparatus further comprises:the sun gear being attached to the forward bevel gear for rotation therewith; a carrier attached to the output shaft for rotation therewith; the ring gear having an axis of rotation; the planet gear engaged between the sun gear and the ring gear and having an axis of rotation attached to the carrier for rotation therewith.
- 5. A transmission comprising:an input shaft; an output shaft; an input bevel gear connected to the input shaft for rotation therewith; a forward bevel gear engaged with a first portion of the input bevel gear for rotation in a forward direction therewith; a reverse bevel gear engaged with a second portion of the input bevel gear for rotation in a reverse direction therewith; a forward clutch connected between the forward bevel gear and the output shaft for selectively connecting the output shaft for forward rotation with the forward bevel gear; a reverse clutch connected between the reverse bevel gear and the output shaft for selectively connecting the output shaft for reverse rotation with the reverse bevel gear; a sun gear attached to the forward bevel gear for rotation therewith; a carrier attached to the output shaft for rotation therewith; a ring gear having an axis of rotation; at least one planetary gear engaged between the sun gear and the ring gear and having an axis of rotation attached to the carrier for rotation therewith; a brake having a low gear position for preventing the rotation of the ring gear about its axis of rotation and having a high gear position for allowing the rotation of the ring gear about its axis of rotation.
- 6. The transmission of claim 5, further comprising:the input shaft having an axis of rotation; the output shaft having an axis of rotation disposed perpendicular to the axis of rotation of the input shaft axis of rotation; the input bevel gear being concentric with the input shaft; and the forward bevel gear and the reverse bevel gear each being concentric with the output shaft and being disposed at respective locations on the output shaft corresponding to a diameter of the input bevel gear.
- 7. The transmission of claim 6, further comprising:the sun gear being formed as an extension of the forward bevel gear and being disposed concentric with the output shaft on a side of the forward bevel gear opposed the reverse bevel gear.
- 8. The transmission of claim 6, further comprising the forward clutch and the reverse clutch each having an axis of rotation concentric with the output shaft and being disposed about the output shaft between the forward bevel gear and the reverse bevel gear.
- 9. The transmission of claim 5 further comprising:a housing; a first bearing rotatably supporting the output shaft with respect to the housing and disposed proximate the reverse bevel gear on a side of the reverse bevel gear opposed the forward bevel gear; a second bearing rotatably supporting the output shaft with respect to the housing and disposed proximate the carrier on a side of the carrier opposed the forward bevel gear.
- 10. The transmission of claim 9, wherein the first bearing comprises a thrust bearing.
- 11. The transmission of claim 10, further comprising:an extension of the input bevel gear extending about the input shaft in a direction opposed the forward bevel gear and the reverse bevel gear; a thrust bearing rotatably supporting the extension of the input bevel gear with respect to the housing.
- 12. The transmission of claim 9, wherein the housing comprises a vertical drive unit of a marine stern drive apparatus.
- 13. The transmission of claim 5, further comprising a plurality of planetary gears engaged between the sun gear and the ring gear and each having an axis of rotation attached to the carrier for rotation therewith.
- 14. The transmission of claim 5, further comprising:the input shaft having an axis of rotation; the output shaft having an axis of rotation disposed perpendicular to the axis of rotation of the input shaft axis of rotation; the input bevel gear having an axis of rotation concentric with the axis of rotation of the input shaft; the forward bevel gear and the reverse bevel gear each having an axis of rotation concentric with the axis of rotation of the output shaft and being disposed at respective locations on the output shaft corresponding to a diameter of the input bevel gear; the forward clutch and the reverse clutch each having an axis of rotation concentric with the output shaft and being disposed about the output shaft between the forward bevel gear and the reverse bevel gear; the sun gear being formed as an extension of the forward bevel gear and disposed on a side of the forward bevel gear opposed the forward clutch.
- 15. A marine propulsion apparatus comprising:an engine having an output shaft; a gimbal housing connected to the engine and rotatably supporting a drive shaft connected to the engine output shaft, the gimbal housing adapted for passing through the transom of a watercraft; a vertical drive unit rotatably and pivotally connected to the gimbal housing; an input shaft rotatably supported by the vertical drive unit and connected to the drive shaft; an output shaft rotatably supported by the vertical drive unit; a propeller connected to the output shaft; an input bevel gear connected to the input shaft for rotation therewith; a forward bevel gear engaged with a first portion of the input bevel gear for rotation in a forward direction therewith; a reverse bevel gear engaged with a second portion of the input bevel gear for rotation in a reverse direction therewith; a forward clutch connected between the forward bevel gear and the output shaft for selectively connecting the output shaft for forward rotation with the forward bevel gear; a reverse clutch connected between the reverse bevel gear and the output shaft for selectively connecting the output shaft for reverse rotation with the reverse bevel gear; a sun gear attached to the forward bevel gear for rotation therewith; a carrier attached to the output shaft for rotation therewith; a ring gear having an axis of rotation; at least one planetary gear engaged between the sun gear and the ring gear and having an axis of rotation attached to the carrier for rotation therewith; a brake having a low gear position for preventing the rotation of the ring gear about its axis of rotation and having a high gear position for allowing the rotation of the ring gear about its axis of rotation.
- 16. A watercraft comprising:a hull including a transom; an engine disposed within the hull and having an output shaft; a gimbal housing connected to the engine and rotatably supporting a drive shaft connected to the engine output shaft, the gimbal housing adapted for passing through the transom; a vertical drive unit rotatably and pivotally connected to the gimbal housing; an input shaft rotatably supported by the vertical drive unit and connected to the drive shaft; an output shaft rotatably supported by the vertical drive unit; a propeller connected to the output shaft; an input bevel gear connected to the input shaft for rotation therewith; a forward bevel gear engaged with a first portion of the input bevel gear for rotation in a forward direction therewith; a reverse bevel gear engaged with a second portion of the input bevel gear for rotation in a reverse direction therewith; a forward clutch connected between the forward bevel gear and the output shaft for selectively connecting the output shaft for forward rotation with the forward bevel gear; a reverse clutch connected between the reverse bevel gear and the output shaft for selectively connecting the output shaft for reverse rotation with the reverse bevel gear; a sun gear attached to the forward bevel gear for rotation therewith; a carrier attached to the output shaft for rotation therewith; a ring gear having an axis of rotation; at least one planetary gear engaged between the sun gear and the ring gear and having an axis of rotation attached to the carrier for rotation therewith; a brake having a low gear position for preventing the rotation of the ring gear about its axis of rotation and having a high gear position for allowing the rotation of the ring gear about its axis of rotation.
US Referenced Citations (24)