Information
-
Patent Grant
-
6287160
-
Patent Number
6,287,160
-
Date Filed
Wednesday, October 27, 199924 years ago
-
Date Issued
Tuesday, September 11, 200122 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Morano; S. Joseph
- Vasudeva; Ajay
Agents
- Knobbe, Martens, Olson & Bear, LLP
-
CPC
-
US Classifications
Field of Search
US
- 440 53
- 440 61
- 091 167 R
- 091 170 R
- 091 173
- 091 422
- 092 61
-
International Classifications
-
Abstract
A tilt and trim arrangement for marine propulsion includes an improved construction. A swivel bracket, which carries a drive unit for pivotal movement about a steering axis includes a pair of ribs spaced apart transversely from each other. A clamping bracket is affixed to an associated watercraft and supports the swivel bracket for pivotal movement about a tilt axis. A hydraulic tilt device is provided for tilting the swivel bracket. The tilt device includes a cylinder housing, a piston slidably supported within the housing and a piston rod affixed to the piston. The cylinder housing has an upper section with a diameter that is smaller than a lower section, and the piston rod extends outwardly from the upper section. The piston rod is pivotally affixed to the ribs. The upper section of the cylinder housing is generally positioned between the ribs at least when the piston rod is fully retracted within the cylinder housing.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a tilt and trim arrangement for a marine propulsion, and more particularly to an improved tilt and trim arrangement that is reinforced against external force while remaining compact.
2. Description of Related Art
Marine outboard drives, i.e., both outboard motors and the outboard drive sections of inboard motors, have drive units mounted on an associated watercraft by a tilt and trim arrangement or bracket assembly which comprises a swivel bracket and a clamping bracket. The swivel bracket carries the outboard drive unit for pivotal movement about a generally vertically extending steering axis. The clamping bracket, in turn, is affixed to the associated watercraft and supports the swivel bracket for pivotal movement about a generally horizontally extending tilt axis.
The bracket assembly includes a hydraulic tilt device disposed between the swivel bracket and the clamping bracket so that the swivel bracket is tilted up or down relative to the clamping bracket. The hydraulic tilt device is, for example, a compound tilt and trim cylinder assembly.
The hydraulic tilt device includes a cylinder assembly having a cylinder housing which defines a cavity therein. A piston is slidably supported in the cavity. A piston rod is affixed to the piston and extends beyond the cavity. The swivel bracket has a pair of ribs spaced apart transversely from each other and a pivot pin extends between them. The piston rod is affixed on the pivot pin for pivotal movement. Meanwhile, the clamping bracket also has a pair of ribs spaced apart transversely from each other and another pivot pin extends between them. The cylinder housing is affixed on this pivot pin for pivotal movement. A powering assembly is provided for pressurizing working fluid in the cavity of the cylinder housing. The powering assembly includes an electric motor, a hydraulic pump and a reservoir, all of which are relatively bulky. With the reciprocal movement of the piston in the cavity of the cylinder housing, the piston rod extends from or contracts into the housing and the drive unit, thereby, is tilted up or down in a certain range.
Recently, outboard motors are inclined to have larger engines than before because more powerful and high speed propulsions are desired. This trend necessarily invites large sized drive units to support such large engines which are quite heavy as well as unwieldy. In addition, these outboard motors produce large thrust force. The bracket assembly accordingly must support a heavy drive unit and receive such a large thrust force. The ribs and hydraulic tilt assembly need to be bigger and have more sufficient rigidity in order to withstand the increased weight of the drive and the increased spacing necessary to receive the larger powering assembly. In fact, the bulky cylinder housing and powering assembly are likely to cause a problem as to how they are disposed in a limited space between the rigid ribs.
Some conventional bracket assemblies have a cylinder assembly and a powering assembly positioned side-by-side to each other. However, a cylinder housing of this cylinder assembly must be off-centered and hence produces a torque upon the ribs when the cylinder extends and contracts. Thus, the ribs require reinforcement and, if reinforced, they are larger, which further exacerbates the arrangement of the cylinder and powering assembly between the clamping and swivel brackets.
Other conventional bracket assemblies have a cylinder housing spaced widely from the swivel bracket. This arrangement, however, does not present a compact bracket assembly.
SUMMARY OF THE INVENTION
A need therefore exists for a compact tilt and trim arrangement for a marine propulsion with sufficiently reinforced ribs to support larger outboard motors.
In accordance with one aspect of the present invention, a tilt and trim arrangement for a marine outboard drive comprises a swivel bracket carrying a drive unit for pivotal movement about a generally vertically extending axis. The swivel bracket is provided and includes a pair of ribs spaced apart transversely from each other. A clamping bracket is adapted to be affixed to an associated watercraft and supports the swivel bracket for pivotal movement about a generally horizontally extending axis. A hydraulic tilt device is provided and includes a cylinder housing defining a cavity therein. A piston assembly is slidably supported in the cavity. A piston rod is affixed to the piston assembly and extends beyond the cavity. The cylinder housing includes a tilt section and a trim section. An outer diameter of the tilt section is smaller than an outer diameter of the trim section. The piston rod extends within the tilt section. A first pivotal connection couples the piston rod to the swivel bracket at a position generally between the ribs. Second pivotal connection couples the cylinder housing to the clamping bracket. The tilt section is generally positioned between the ribs of the swivel bracket at least when the piston rod exists almost fully within the cylinder housing.
In accordance with another aspect of the present invention, a tilt and trim arrangement for a marine outboard drive comprises a swivel bracket carrying a drive unit for pivotal movement about a generally vertically extending axis. A clamping bracket is adapted to be affixed to an associated watercraft and supports the swivel bracket for pivotal movement about a generally horizontally extending axis. A tilt and trim device is provided and includes a housing having a tilt section and a trim section. An outer diameter of the tilt section is smaller than an outer diameter of the trim section. The tilt section defines a tilt cavity and has a tilt piston slidably movable within the tilt cavity. The trim section defines a trim cavity and has a trim piston slidably movable only within the trim cavity. An inner diameter of the tilt cavity is smaller than an inner diameter of the trim cavity. A piston rod is affixed to the tilt piston and extends beyond the tilt cavity. A first pivotal connection couples the piston rod to the swivel bracket, and a second pivotal connection couples the cylinder to the clamping bracket. Both the trim piston and the tilt piston move as a unit to move the drive unit in a trim range and only the tilt piston moves to move the drive unit in a tilt range. The swivel bracket has a pair of ribs spaced apart transversely relative to each other. The tilt section is generally positioned between the ribs at least when the piston rod exists almost fully within the cylinder.
In accordance with a further aspect of the present invention, a tilt and trim arrangement for a marine outboard drive comprises a swivel bracket carrying a drive unit for pivotal movement about a vertically extending steering axis. The swivel bracket is provided and includes a pair of ribs spaced apart transversely from each other. A clamping bracket is adapted to be affixed to an associated watercraft and supports the swivel bracket for pivotal movement about a horizontally extending tilt axis. A tilt and trim device is placed between the swivel bracket and the clamping bracket for tilting the swivel bracket. The tilt and trim device includes a cylinder housing which defines a cavity therein. A piston is slidably supported in the cavity and a piston rod is affixed to the piston. The cylinder housing has a lower section and an upper section which diameter is smaller than the lower section. The piston rod extends outwardly from the upper section and is affixed to the ribs for pivotal movement. The upper section is generally positioned between the respective ribs at least when the piston rod is fully retracted within the cylinder housing.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiment which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of this invention will now be described with reference to the drawings of a preferred embodiment which is intended to illustrate and not to limit the invention.
FIG. 1
is a side elevational view showing an outboard motor including a tilt and trim arrangement in accordance with an embodiment of the present invention. The outboard motor is illustrated as attached to the transom of an associated watercraft, which is shown partially in section and is illustrated in a fully trimmed down position.
FIG. 2
is partial side elevational view showing the outboard motor of FIG. I in a fully tilted up position.
FIG. 3
is an enlarged front elevational view showing the tilt and trim arrangement. A piston rod shown in this figure exists almost fully within a cylinder housing. Pivotal mounts of the piston rod and the cylinder housing are shown partially in section.
FIG. 4
is a perspective view showing a hydraulic tilt device of the tilt and trim assembly which unifies the cylinder housing and powering members.
FIG. 5
a cross-sectional plan view taken along the line
5
—
5
in
FIG. 3
showing a pivotal connection between the piston rod and a swivel bracket of the tilt and trim assembly. The powering members are also shown schematically with circles.
FIG. 6
is a cross-sectional plan view taken along the line
6
—
6
in
FIG. 3
showing the cylinder housing positioned between ribs. The cylinder housing and the powering members are shown schematically with circles.
FIG. 7
is a partial perspective view showing the pivotal connection between the piston rod and the ribs of the swivel bracket. The piston rod in this figure exists fully within the cylinder housing.
FIG. 8
is a cross-sectional view showing the cylinder assembly taken along its longitudinal axis and also a diagrammatic view showing a fluid circuit in connection with a cylinder assembly. Arrows laid along respective passages indicate a direction of the fluid flow for the extension of the piston rod.
FIG. 9
is a cross-sectional view showing the cylinder assembly in which a piston assembly is in a fully trimmed down position with the piston rod existing almost fully within the cylinder housing of the cylinder assembly.
FIG. 10
is a cross-sectional view showing the cylinder assembly in which the piston assembly is in a trim adjusted area.
FIG. 11
is a cross-sectional view showing the cylinder housing in which the piston assembly is in a fully trimmed up position.
FIG. 12
is a cross-sectional view showing the cylinder housing in which the piston assembly is in a fully tilted up position with the piston rod extending almost fully out the cylinder housing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
With reference initially to
FIGS. 1 through 4
, the general overall environment of an exemplary outboard motor and a tilt and trim arrangement will be described. Although the invention is described in conjunction with an outboard motor, various aspects of the tilt and trim adjustment mechanism can be used with other types of outboard drives, such as, for example, the outboard drive portion of an inboard/outboard drive. Other usages will also be readily apparent to those skilled in the art.
An outboard motor
20
is shown as attached to a transom
22
of an associated watercraft
24
. In connection with the following description, the terms “front,” “forward” and “forwardly” means at or toward the side where the clamping bracket
54
is affixed to the transom
22
of the associated watercraft
24
and the terms “rear” and “rearwardly” mean at or toward an opposite side of the front side unless stated otherwise.
The outboard motor
20
generally comprises a drive unit
26
and a tilt and trim arrangement
28
. The drive unit
26
comprises a power head
30
, a driveshaft housing
32
and a lower unit
34
. The power head
30
is disposed atop the drive unit
26
and includes an internal combustion engine
38
, a top cowling
40
and a bottom cowling
42
. The engine
38
powers a propulsion device such as a propeller
44
disposed at the lowermost portion of the drive unit
26
and, therefore, the engine desirably has a crankshaft extending generally vertically, as is conventional in the art. The top and bottom cowlings
40
,
42
generally completely encircle the engine
38
so as to protect it. For instance, water is prevented from splashing over the engine
38
. The top cowling
40
is detachably affixed to the bottom cowling
42
so as to ensure access to the engine
38
for maintenance.
The driveshaft housing
32
depends from the power head
30
and supports a driveshaft which is driven by the crankshaft of the engine
38
. The driveshaft extends generally vertically through the driveshaft housing
32
. The driveshaft housing
32
also has some sections of an exhaust system through which exhaust gasses from the engine
38
pass and flow down to the lower unit
34
.
The lower unit
34
, in turn, depends from the driveshaft housing
32
and supports a propeller shaft which is driven by the driveshaft. The propeller shaft extends generally horizontally through the lower unit
34
. The propeller
44
is affixed at the end of the propeller shaft and is driven by the propeller shaft. A bevel gear transmission is provided between the driveshaft and the propeller shaft. The transmission crosses these two shafts generally normal to each other (i.e., the transmission couples together the two shafts at generally a 90° shaft angle). The lower unit
34
has also a discharge section of the exhaust system. The majority of the exhaust gasses are finally discharged to the body of water surrounding the outboard motor
20
through a hub
48
of the propeller
44
under normal running conditions.
The tilt and trim arrangement
28
comprises a swivel bracket
52
and a clamping bracket
54
. The swivel bracket
52
carries the drive unit
32
for pivotal movement about a generally vertically extending axis, i.e., an axis of a steering shaft
56
. The steering shaft
56
passes through a steering shaft housing section
58
of the swivel bracket
52
and extends beyond the top end and the bottom end of the steering shaft housing section
58
. A pair of upper mount assemblies
60
and a pair of lower mount assemblies
62
are affixed at both upper sides and lower sides of the driveshaft housing
32
. The upper and lower mount assemblies
60
,
62
include mount sections
64
,
66
and support sections
68
,
70
. The support sections
68
,
70
extend forwardly from the mount sections
64
,
66
which are affixed to the driveshaft housing
32
. The support sections
68
,
70
have bores into which the steering shaft
56
is fitted. The bores of the support sections
68
,
70
and the steering shaft
56
are joined together by spline connections. Because the steering shaft
56
is thus unified with the support sections
68
,
70
, the swivel bracket
52
supports the driveshaft housing
32
for pivotal movement about the axis of the steering shaft
56
. A steering arm
74
extends forwardly from the upper support section
68
to be steerable by an operator of the outboard motor
20
.
The clamping bracket
54
, in turn, is affixed to the transom
22
of the associated watercraft
24
with a pair of clamping sections
76
. The clamping bracket
54
supports the swivel bracket
52
for pivotal movement about a generally horizontally extending axis, i.e., an axis of a tilt shaft or pivot pin
78
. The clamping bracket
54
has a pair of ribs
80
that extend generally rearwardly from the clamping sections
76
. The ribs
80
extend generally vertically from almost the top to the bottom of the clamping bracket
54
. The ribs
80
include upper portions
81
and lower portions
82
. The distance between the upper portions
81
is greater than a distance between the lower portions
82
, as best understood from FIG.
3
. The tilt shaft
78
is pivotally supported in bores generally formed at the top ends of the ribs
80
.
The tilt and trim arrangement
28
includes a hydraulic tilt device
84
for tilting up and down the drive unit
32
about the axis of the tilt shaft
78
. The tilt movement actually includes a trim adjusting movement and a tilt movement, which is in the narrow sense of the word. That is, the drive unit
26
moves in a trim adjusted range in which the propeller
44
is generally in the body of water surrounding the outboard motor
20
to propel the associated watercraft
24
. The movement of the drive unit
26
in this range, therefore, can adjust a trim angle of the drive unit
32
. The hydraulic tilt device
84
in this range, however, must work against the thrust force, in addition to the weight of the outboard motor
20
, in order to trim up the outboard drive unit
32
. The drive unit
26
also moves in a tilt range which is higher than the trim adjusted range. The propeller
44
in this tilt range is generally (but not always) out of the body of water for storage or transportation, or simply to raise the propeller out of the water when running in shallow water or to avoid in-water articles (e.g., rocks, logs, fishing nets, etc.). The hydraulic tilt device
84
in the tilt range only works against the weight of the outboard motor
20
when raising the drive unit
32
in this range.
The hydraulic tilt device
84
generally comprises a cylinder assembly
86
and a powering assembly
87
. The cylinder assembly
86
is disposed generally between the lower portions
82
of the clamping bracket ribs
80
. Although an internal construction of the hydraulic tilt device
84
will be described later with reference to
FIG. 8
, the cylinder assembly
86
includes a cylinder housing
88
, a piston assembly and a piston rod
90
. The cylinder housing
88
has a cavity therein and the piston assembly is slidably supported in the cavity of the cylinder housing
88
. The piston rod
90
is affixed to the piston assembly and extends beyond the cavity. The longitudinal axis of the cylinder housing
86
generally is aligned in a transverse direction (i.e., side to side) with a center axis of the tilt and trim arrangement
28
as seen in FIG.
3
.
As best seen in
FIG. 3
, the cylinder housing
88
has a trunnion
92
through which a bore
94
is formed transversely. A pivot pin
96
is fitted into the bore
94
and both ends of the pivot pin
96
are journaled by openings
98
formed at both lowermost ends of the ribs
80
of the clamping bracket
54
. This coupling between the cylinder housing
88
and the lowermost ends of the ribs permits pivotal movement of the cylinder housing
88
relative to the clamping bracket
54
.
The piston rod
90
has an eyelet
100
provided with a bore
102
. The swivel bracket
52
has a pair of ribs
106
extending forwardly generally from the steering shaft housing section
58
. Another pivot pin
108
is journaled by openings
110
formed at both of the ribs
106
. The pivot pin
108
provides a pivotal coupling between the outer end of the piston rod
90
and the swivel bracket
52
. The swivel bracket ribs
106
will be described in more detail below.
The piston rod
90
extends and contracts with the reciprocal movement of the piston assembly. Pressurized working fluid within the cylinder assembly
86
produces this reciprocal movement of the piston assembly. The aforenoted powering assembly
87
is provided for powering or pressurizing the working fluid. The powering assembly
87
includes a reversible electric motor
114
, a reversible hydraulic pump
116
and a fluid reservoir
118
. Both of the electric motor
114
and the reservoir
118
are relatively bulky members. These components are placed in a fluid circuit which will be described below in reference to FIG.
8
.
As best seen in
FIG. 4
, the powering assembly
87
is unified with the cylinder assembly
86
. In the illustrated embodiment, the hydraulic pump
116
is completely unified with the cylinder housing
88
and both of the electric motor
114
and the reservoir
118
are affixed onto the cylinder housing
88
by bolts
119
at both shoulders of the combined structure. The hydraulic tilt device
84
generally has a cross-shape. That is, the cylinder housing
88
is positioned generally longitudinally or vertically so that the piston rod
90
can extend and contract along the longitudinal axis of the housing. The electric motor
114
and the reservoir
118
are supported on a transverse crosspiece and the hydraulic pump
116
is accommodated in the crosspiece, below the electric motor
114
.
The electric motor
114
is disposed between one of the swivel bracket ribs
106
and one of the clamping bracket ribs
80
, while the fluid reservoir
118
is disposed between the other one of the swivel bracket ribs
106
and the other one of the clamping bracket ribs
80
. Both of the electric motor
114
and the fluid reservoir
118
lie next to one of the upper portions
81
of the clamping bracket ribs
80
when the hydraulic tilt device
84
positions the drive unit
32
in the fully trimmed down position.
Since the electric motor
114
and the reservoir
118
, which have similar weights relative to each other, are separately disposed on the both shoulders of the cylinder housing
88
, the hydraulic tilt device
84
has good weight balance.
An upper section
122
of the cylinder housing
88
is thinner than the lower section
124
. This is because the upper section
122
includes a tilt cavity and the lower section
124
includes a trim cavity. The inner construction of the cylinder assembly
86
will be described below. As seen in
FIG. 4
, a space
130
is formed between the upper section
122
and the electric motor
114
, while another space
132
is formed between the upper section
122
and the reservoir
118
. The respective swivel bracket ribs
106
are positioned in the spaces
130
,
132
, as seen in FIG.
3
.
As best seen in
FIGS. 5 and 6
, the swivel bracket
52
includes the steering shaft housing section
58
, the pair of ribs
106
and a pair of wing-like sections
136
. The steering shaft
56
passes through a bore
138
formed in the steering shaft housing section
58
. The ribs
106
extend forwardly in parallel to each other. As seen in
FIG. 5
, the pivot pin
108
, which supports the eyelet
100
of the piston rod
94
, is journaled by the pair of openings
110
via bushings
140
. The electric motor
114
and the fluid reservoir
118
are disposed at both outer sides of the ribs
106
in the proximity thereto. Also, the ribs
106
further extend to a lower position (see FIG.
3
), and the upper section
122
of the cylinder housing
88
is disposed between the ribs
106
, as seen in FIG.
6
.
It should be noted that the upper section
122
of the cylinder housing
88
is generally positioned between the ribs
106
only when the piston rod
90
exists almost fully within the cylinder housing
88
. This can be readily understood when
FIGS. 1 and 2
are referred in comparison with each other. As seen in
FIG. 1
, when the drive unit
26
is fully trimmed down, the upper section
122
of the cylinder housing
88
is generally positioned between the respective ribs
106
. This situation is also seen in FIG.
7
. However, in
FIG. 2
, when the drive unit
26
is fully tilted up, the upper section
122
of the cylinder housing
88
is moved is completely out from a position between the ribs
109
.
As seen in
FIG. 3
, the tilt and trim arrangement
28
is additionally provided with a trim sensor
142
positioned behind the tilt shaft
78
between the swivel bracket
52
and the clamping bracket
54
. The trim sensor
142
senses a trim/tilt angle and sends a signal to a control unit. An electric connector
143
is provided for connecting both of the trim sensor
142
and the electric motor
114
to a battery placed in the hull of the associated watercraft
24
and to the control unit through cables
144
,
145
.
A tilt lock pin
146
is further provided on the swivel bracket
52
. The tilt lock pin
146
has a tilt stopper which can be seated on the top of the clamping bracket
54
to hold the drive unit
26
mechanically at the fully tilted up position when the operator turns a stopper lever.
With reference now to
FIGS. 8 through 12
, an internal construction of the cylinder assembly
86
and a fluid circuit will be described. The cylinder housing
88
is formed with an upper member
150
and a lower member
152
. The upper member
150
has a flange
154
mated with the top end of the lower member
152
and hence both members
150
,
152
are unified together at the mated portions in a suitable manner. The upper member
150
generally defines the above noted upper section or the tilt section
122
, while the lower member
152
defines the above noted lower section or the trim section
124
. An outer diameter of the tilt section
122
is smaller than an outer diameter of the trim section
124
.
The cylinder housing
88
defines a housing cavity
156
therein. The housing cavity
156
comprises a tilt cavity
160
and a trim cavity
162
. The tilt cavity
160
and the trim cavity
162
are defined in the tilt section
122
and the trim section
124
, respectively. An inner diameter of the tilt cavity
160
is smaller than an inner diameter of the trim cavity
162
.
A piston assembly
164
is slidably supported in the housing cavity
156
. The piston assembly
164
comprises a tilt piston
166
, a trim piston
168
. In this embodiment, a floating piston
170
is additionally provided between the tilt piston
166
and the trim piston
168
. The floating piston moves along with the tilt piston
166
in regular operations, but stays separately from the tilt piston
166
at a position where it is if the drive unit
26
strikes an underwater obstacle. The floating piston
170
thus memorizes the position of the tilt piston
166
before the collision to permit the drive unit
26
to return to the desired tilt/trim position, as described in greater detail below. The piston rod
90
is affixed to the tilt piston
166
and extends through and beyond the tilt cavity
160
.
The trim piston
168
has a larger diameter than a diameter of the tilt piston
166
because the trim piston
168
must work against the thrust force generated by the propeller
44
in addition to the weight of the outboard motor
20
. The tilt piston
166
in comparison only receives the weight of the outboard motor
20
. Thus, the diameter of the tilt piston
166
can be smaller than the diameter of the trim piston
168
. The inner diameter of the tilt cavity
160
thus is smaller than the inner diameter of the trim cavity
162
, and the outer diameter of the tilt section
122
is smaller than the outer diameter of the trim section
124
.
The tilt section member
150
has a circular portion
172
that protrudes into the trim section member
152
and is tightly fitted therein to seal the housing cavity
156
. A circular projection
174
extends farther into the trim cavity
162
. An outer diameter of the circular projection
174
is smaller than an outer diameter of the circular portion
172
. A pocket
176
is, therefore, formed between an outer surface of the circular projection
174
and an inner surface of the trim section member
152
. The circular portion
172
, the circular projection
174
and the other portion of the tilt section member
150
, however, all have the same inner diameters so that the tilt piston
166
and the floating piston
170
can reciprocate therein.
The trim piston
168
has a hollow
180
that can receive the floating piston
170
and the circular projection
174
. That is, the hollow
180
has a cup-like shape. An aperture
182
is provided at the bottom of the trim piston
168
.
The cooperation between the piston assembly
164
and the housing cavity
156
generally defines a first chamber
186
above the tilt piston
166
, a second chamber
188
below the trim piston
168
and a third chamber
190
between the floating piston
170
and the trim piston
168
. The second chamber
188
and the third chamber
190
can communicate with each other through the aperture
182
when the floating piston
170
moves away from the trim piston
168
.
A fluid control circuit
194
is provided outside of the cylinder housing
88
as also shown in FIG.
8
. At least some of the fluid passages and valving arrangements desirably are formed within the cylinder assembly
86
to minimize external conduits and make the trim device
84
compact.
The tilt section member
150
has a passage
196
at the top portion thereof. The passage
196
is opened to the first chamber
186
. The trim section member
152
has another passage
200
at the bottom portion thereof. This passage
200
is opened to the second chamber
188
. A third passage
202
is further provided to extend through the circular portion
172
of the tilt section member
150
and through an upper portion of the trim section member
152
. The third passage
202
communicates with the third chamber
190
.
The reversible hydraulic pump
116
is provided in the fluid circuit
194
. The hydraulic pump
116
has two ports
206
,
208
which alternatively will be an inlet port and an outlet port in response to changes of rotational directions of the hydraulic pump
116
. Both ports
206
,
208
communicate to one side of a three-way valve
210
through delivery passages
212
,
214
, respectively. The three-way valve
210
includes an expansion section
216
, a shut down section
218
and a contraction section
220
which are interchangeable by the operator in a suitable manner. The passage
196
in the tilt section member
150
and the passage
200
in the trim section member
152
are connected to the other side of the three-way valve
210
through a passage
222
and another passage
224
, respectively. The movement of the valve between these three positions can be accomplished automatically by a mechanical valve or can be an actuator mechanism to move the valve between positions, as well known in the art.
The ports
206
,
208
of the hydraulic pump
116
also communicate with the fluid reservoir
118
through passages
228
,
230
. The respective passages
228
,
230
incorporate check valves
232
which permit fluid flowing from the reservoir
118
to the hydraulic pump
116
but prevent reverse flow. The passages
228
,
230
are united together to be a single passage and then connected to the reservoir
118
. The passage
202
of the cylinder housing
88
, which communicates with the third chamber
190
, is connected to the reservoir
118
through a passage
234
. One more passage
236
is provided between the reservoir
118
and the passage
224
. A relief valve
238
is placed within the passage
236
so as to permit the fluid flowing to the reservoir
118
in the event that the fluid pressure in the passage
224
becomes higher than a preset magnitude.
As also seen in
FIG. 8
, the tilt piston
166
includes a shock absorber mechanism
250
to permit the drive unit
26
to pop up when an underwater obstacle is struck and to return to its trimmed/tilted position when the underwater obstacle is cleared. For this purpose, the shock absorber mechanism
250
has an absorber valve
252
and a return valve
254
in the tilt piston
166
. The floating piston
170
memorizes the initial trim/tilt position of the tilt piston
166
immediately before the pop up action.
In operation, at first, the drive unit
26
is fully trimmed down position as shown in FIG.
1
and the cylinder assembly
86
is in the situation shown in FIG.
9
. When a trim adjustment action is started, the expansion section
216
of the three-way valve
210
is selected so that the passages
222
,
224
communicate with the passages
214
,
212
in the directions as schematically indicated in
FIG. 8
by the arrows in the box of the section
216
. The hydraulic pump
116
is operated by the electric motor
114
to push the working fluid toward the passage
224
. The fluid flows in the passage
224
and then enters the second chamber
188
of the trim cavity
162
through the passage
200
. The fluid pushes the trim piston
168
upwardly. The piston assembly
164
moves up as a unit accordingly. The fluid in the third chamber
190
is displaced to the reservoir
118
through the passage
202
and the passage
234
. The fluid in the first chamber
186
, in turn, is also displaced by the upward movement of the piston assembly
164
to the passage
222
through the passage
196
. The fluid then returns to the hydraulic pump
116
through the three-way valve
210
and the passage
214
. Thus, the piston rod
90
extends from the first chamber
186
to lift the drive unit
26
upwardly in the trim adjusted range. The fluid displacement of the piston rod
90
which has extended from the cylinder housing
86
is compensated or filled with the fluid coming from the reservoir
118
through the check valve
232
.
The trim piston
168
can be held at any position in the trim cavity
162
as shown in
FIG. 10
by switching over the three-way valve
210
from the expansion section
216
to the shut down section
218
. The hydraulic pump
116
is of course not operated under this condition. The drive unit
26
is thus maintained at a certain trim adjusted position established by the trim device
84
.
If the operator desires to raise the drive unit
26
toward the fully trimmed up position, communication between the expansion section
216
of the three-way valve
210
, the communication line
224
, and the hydraulic pump
116
is maintained while the pump is operated. The working fluid is thus continuously supplied to the second chamber
188
and the piston assembly
164
still moves upward. The trim piston
168
is then stopped when the trim piston
168
abuts the circular position
172
of the tilt section member
150
. In this position, the hollow
180
of the trim position
168
receives the circular projection
174
. This situation is shown in FIG.
11
. At this position of the trim piston
168
, the drive unit
26
is fully trimmed up.
If the operator desires to raise the drive unit
26
further into the tilt range, the expansion section
216
of the three-way valve
210
is kept positioned in the communication line and operation of the hydraulic pump
116
is continued. Although upward movement of the trim piston
168
is now restrained at the top of the trim cavity
162
and the aperture
202
is closed by the trim piston
168
, the tilt piston
166
as well as the floating piston
170
still move upwardly as pressurized fluid continues to flow into the second chamber
188
. The fluid is supplied to the third chamber
190
through the aperture
182
in the trim piston
168
. The fluid in the first chamber
186
is displaced to the hydraulic pump
116
through the same passages involved with the trim adjusting action. The capacity of the piston rod
90
is again compensated by the fluid supplied from the reservoir
118
. The tilt piston
166
upward travel continues until the piston
166
reaches the top of the tilt cavity
160
as shown in FIG.
12
. At this position of the tilt piston
166
, the drive unit
26
is placed at the fully tilted up position as shown in FIG.
2
.
If the operator desires to lower the drive unit
26
, the three-way valve
210
is switched to the contraction section
220
and the electric motor
114
runs in reverse. With this reversed rotation of the electric motor
114
, the hydraulic pump
116
also functions in reverse. The movement of the piston assembly
164
in this reversed operation is completely reverse of the operation described above. That is, the tilt piston
166
as well as the floating piston
170
move down, without movement of the trim piston
168
, in the tilt cavity
156
, and then with the trim piston
168
when it can move in the trim cavity
162
. With this movement of the piston assembly
164
, the piston rod
90
retracts into the housing cavity
156
and the drive unit
26
is tilted down and/or trimmed down. The fluid which has compensated the fluid displacement of the piston rod
90
returns to the reservoir
11
8
through the passage
202
and the passage
234
in this downward movement.
In the event that an underwater obstacle is struck to the drive unit
26
when the drive unit
26
is at a trim adjusted position, huge pressure is generated in the first chamber
186
because the piston rod
90
is pulled instantaneously upwardly with enormous force. However, the pressure will be relieved by the shock absorber mechanism
250
. That is, the fluid in the first chamber
186
immediately passes through the shock absorber valve
252
to the space between the tilt piston
166
and the floating piston
170
. The piston rod
90
hence can extend rapidly. The floating piston
170
remains at the trim adjusted position to memorize this initial position of the tilt piston
166
. When the underwater obstacle is cleared, the fluid in the space between the tilt piston
166
and the floating piston
170
returns to the first chamber
186
through the return valve
254
. The tilt piston
166
then returns to the initial position memorized by the floating piston
170
. Accordingly, the trim adjusted position of the drive unit
26
is continuously maintained.
As described above, the diameter of the tilt section
122
is smaller than the diameter of the trim section
124
. The tilt section
122
can be well placed between the ribs
106
. Because of this, the ribs
106
can be elongated as long as possible so as to have sufficient rigidity. The ribs
106
, therefore, can withstand a relatively large thrust force and will not be distorted by such force and by the weight of the drive unit
32
. In addition, the ribs
106
and the tilt section
122
of the cylinder housing
88
do not interfere with each other. Thus, the tilt and trim arrangement
28
is kept compact.
The facets of the present invention can be applied to other marine propulsions such as outboard drive sections of inboard motors, as noted above. 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. A tilt and trim arrangement for a marine outboard drive comprising a swivel bracket carrying a drive unit for pivotal movement about a generally vertically extending axis, said swivel bracket including a pair of ribs spaced apart transversely from each other, a clamping bracket adapted to be affixed to an associated watercraft and supporting said swivel bracket for pivotal movement about a generally horizontally extending axis, a hydraulic tilt device including a cylinder housing defining a cavity therein, a piston assembly slidably disposed within said cavity, and a piston rod affixed to said piston assembly and extending beyond said cavity, said cylinder housing including a tilt section and a trim section, an outer diameter of said tilt section being smaller than an outer diameter of said trim section, said piston rod extending within said tilt section, a first pivotal connection arranged between said piston rod and said ribs so as to be disposed generally between said ribs, a second pivotal connection arranged between said cylinder housing and said clamping bracket, and a distance between the respective ribs being shorter than the outer diameter of said trim section.
- 2. A tilt and trim arrangement as set forth in claim 1, wherein said hydraulic tilt device further includes a hydraulic pump for supplying pressurized working fluid to said cavity, and an electric motor for driving said hydraulic pump, said electric motor being disposed laterally outward of said ribs.
- 3. A tilt and trim arrangement as set forth in claim 2, wherein said clamping bracket includes a pair of second ribs, one of said second ribs is spaced apart transversely from one of said first ribs to define a space therebetween, and said electric motor is positioned within said space.
- 4. A tilt and trim arrangement as set forth in claim 3, wherein another one of said second ribs is spaced apart transversely from another one of said first ribs to define a second space therebetween, and said fluid reservoir is positioned within said second space.
- 5. A tilt and trim arrangement as set forth in claim 4, wherein a distance between portions of said second ribs that define said first and second spaces is longer than a distance between the rest of the respective second ribs.
- 6. A tilt and trim arrangement as set forth in claim 2, wherein said hydraulic pump is unified with said cylinder housing.
- 7. A tilt and trim arrangement as set forth in claim 2, wherein said hydraulic tilt device additionally comprises a fluid reservoir for containing the working fluid, and the fluid reservoir is disposed laterally outward of said ribs at a side opposite said electric motor.
- 8. A tilt and trim arrangement as set forth in claim 7, wherein at least one of said electric motor and said fluid reservoir is unified with said cylinder housing.
- 9. A tilt and trim arrangement as set forth in claim 1, wherein said clamping bracket includes a pair of second ribs, said cylinder housing extends between both the second ribs and at generally equal distance from the respective second ribs.
- 10. A tilt and trim arrangement for a marine outboard drive comprising a swivel bracket carrying a drive unit for pivotal movement about a generally vertically extending axis, said swivel bracket including a pair of ribs spaced apart transversely from each other, a clamping bracket adapted to be affixed to an associated watercraft and supporting said swivel bracket for pivotal movement about a generally horizontally extending axis, a tilt and trim device including a housing having a tilt section and a trim section, an outer diameter of said tilt section being smaller than an outer diameter of said trim section, said tilt section defining a tilt cavity and having a tilt piston slidably movable within said tilt cavity, said trim section defining a trim cavity and having a trim piston slidably movable only within said trim cavity, an inner diameter of said tilt cavity being smaller than an inner diameter of said trim cavity, a piston rod affixed to said tilt piston and extending beyond said tilt cavity, a first pivotal connection arranged between said piston rod and said ribs so as to be disposed generally between the respective ribs, a second pivotal connection arranged between said cylinder and said clamping bracket, both of said trim piston and said tilt piston moving as a unit to shift said drive unit in a trim range and only said tilt piston moving in a tilt range, and a distance between the respective ribs being shorter than the outer diameter of said trim section.
- 11. A tilt and trim arrangement as set forth in claim 10, wherein said first pivotal connection is positioned generally between said ribs.
- 12. A tilt and trim arrangement as set forth in claim 10, wherein said tilt and trim device further includes a hydraulic assembly for supplying pressurized working fluid to said tilt cavity and said trim cavity, and said hydraulic assembly has at least two components disposed at either outer side of said ribs.
- 13. A tilt and trim arrangement as set forth in claim 10, wherein said trim piston has an aperture through which working fluid passes when said tilt piston moves separately from said trim piston.
- 14. A tilt and trim arrangement for a marine outboard drive comprising a swivel bracket carrying a drive unit for pivotal movement about a vertically extending steering axis, said swivel bracket including a pair of first ribs spaced apart transversely from each other, a clamping bracket adapted to be affixed to an associated watercraft and supporting said swivel bracket for pivotal movement about a horizontally extending tilt axis, said clamping bracket including a pair of second ribs spaced apart transversely from each other, a tilt and trim device placed between said swivel bracket and said clamping bracket for tilting said swivel bracket, said tilt and trim device including a cylinder housing defining a cavity therein, a piston slidably disposed within said cavity, and a piston rod affixed to said piston, said cylinder housing having a lower section and an upper section, an outer diameter of said upper section is smaller than an outer diameter of said lower section, said piston rod extending outwardly from said upper section and being affixed to said first ribs for pivotal movement, said lower section being affixed to said second ribs, and said outer diameter of said lower section being longer than a distance between the respective first ribs.
- 15. A hydraulic tilt and trim assembly for a marine outboard drive comprising a swivel bracket arranged to support a drive unit for pivotal movement about a generally vertically extending axis, the swivel bracket including a pair of ribs spaced apart transversely from each other, a clamping bracket adapted to be affixed to an associated watercraft and arranged to support the swivel bracket for pivotal movement about a generally horizontally extending axis, a cylinder housing defining an inner cavity, a piston slidably disposed within the inner cavity, a piston rod affixed to the piston and extending beyond the inner cavity, a hydraulic pump arranged to supply working fluid to the inner cavity, an electric motor driving the hydraulic pump, and a fluid reservoir arranged to contain the working fluid, one of the piston rod and the cylinder housing being coupled with the ribs for pivotal movement, the other one of the piston rod and the cylinder housing being coupled with the clamping bracket for pivotal movement, a portion of one of the ribs being interposed between the cylinder housing and the electric motor when the piston rod exists generally fully within the cylinder housing, a portion of the other rib being interposed between the cylinder housing and the fluid resovoir when the piston rod exists generally within the cylinder housing.
- 16. A hydraulic tilt and trim assembly as set forth in claim 15, wherein the clamping bracket includes a pair of second ribs, the other one of the piston rod and the cylinder housing is coupled with the second ribs, and the electric motor is interposed generally between one of the first ribs and one of the second ribs.
- 17. A hydraulic tilt and trim assembly for a marine outboard drive comprising a swivel bracket arranged to support a drive unit for pivotal movement about a generally vertically extending axis, the swivel bracket including a pair of ribs spaced apart transversely from each other, a clamping bracket adapted to be affixed to an associated watercraft and arranged to support the swivel bracket for pivotal movement about a generally horizontally extending axis, a cylinder housing defining an inner cavity, a piston slidably disposed within the inner cavity, a piston rod affixed to the piston and extending beyond the inner cavity, a hydraulic pump arranged to supply working fluid to the inner cavity, and an electric motor driving the hydraulic pump, a fluid reservoir arranged to contain the working fluid, one of the piston rod and the cylinder housing being coupled with the ribs for pivotal movement, the other one of the piston rod and the cylinder housing being coupled with the clamping bracket for pivotal movement, and a portion of one of the ribs being interposed between the cylinder housing and the fluid reservoir when the piston rod exists generally fully within the cylinder housing.
- 18. A hydraulic tilt and trim assembly as set forth in claim 17, wherein a portion of the other rib is interposed between the cylinder housing and the electric motor when the piston rod exists generally fully within the cylinder housing.
- 19. A hydraulic tilt and trim assembly as set forth in claim 17, wherein the clamping bracket includes a pair of second ribs, the other one of the piston rod and the cylinder housing is coupled with the second ribs, and the fluid reservoir is interposed generally between one of the first ribs and one of the second ribs.
- 20. A hydraulic tilt and trim assembly for a marine outboard drive comprising a swivel bracket arranged to support a drive unit for pivotal movement about a generally vertically extending axis, the swivel bracket including a pair of ribs spaced apart transversely from each other, a clamping bracket adapted to be affixed to an associated watercraft and arranged to support the swivel bracket for pivotal movement about a generally horizontally extending axis, a cylinder housing defining an inner cavity, a piston slidably disposed within the inner cavity, a piston rod affixed to the piston and extending beyond the inner cavity, and a hydraulic unit arranged to supply working fluid to the inner cavity, the hydraulic unit including at least two components, one of the piston rod and the cylinder housing being coupled with the first ribs for pivotal movement, the other one of the piston rod and the cylinder housing being coupled with the clamping bracket for pivotal movement, a portion of one of the ribs being interposed between the cylinder housing and one of the components when the piston rod exists generally fully within the cylinder housing, and a portion of the other rib being interposed between the cylinder housing and the other component when the piston rod exists generally fully within the cylinder housing.
- 21. A hydraulic tilt and trim assembly as set forth in claim 20, wherein the clamping bracket includes a pair of second ribs, the other one of the piston rod and the cylinder housing is coupled with the second ribs, and each one of the components is interposed generally between one of the first ribs and one of the second ribs.
- 22. A hydraulic tilt and trim assembly as set forth in claim, 21, wherein a distance between portions of the second ribs which interpose the components is longer than a distance between the rest of the respective second ribs.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-306186 |
Oct 1998 |
JP |
|
US Referenced Citations (9)
Foreign Referenced Citations (4)
Number |
Date |
Country |
234095 |
Nov 1985 |
JP |
101295 |
Apr 1989 |
JP |
404005194 |
Jan 1992 |
JP |
230893 |
Jan 1992 |
JP |