U.S. patent application number 11/029667 was filed with the patent office on 2006-01-26 for steering system for outboard drive.
Invention is credited to Makoto Mizutani, Takahiro Oguma.
Application Number | 20060019558 11/029667 |
Document ID | / |
Family ID | 35657846 |
Filed Date | 2006-01-26 |
United States Patent
Application |
20060019558 |
Kind Code |
A1 |
Mizutani; Makoto ; et
al. |
January 26, 2006 |
Steering system for outboard drive
Abstract
A steering system for an outboard drive includes a steering
handle furnished on a watercraft, a steering device, a lever that
has first and second ends, and a sensor. The first end of the lever
is attached to the drive. The sensor senses an actual position of
the steering handle to provide a position signal to the steering
device. The steering device includes an electric motor that has an
outer casing and a ball screw extending through the outer casing.
The ball screw and the outer casing move relative to one another in
accordance with the actual position of the steering handle. The
second end of the lever is attached to the ball screw or the outer
casing. The ball screw or the outer casing steers the drive through
the lever.
Inventors: |
Mizutani; Makoto;
(Shizuoka-ken, JP) ; Oguma; Takahiro;
(Shizuoka-ken, JP) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
35657846 |
Appl. No.: |
11/029667 |
Filed: |
January 5, 2005 |
Current U.S.
Class: |
440/59 |
Current CPC
Class: |
B63H 25/10 20130101;
B63H 20/12 20130101 |
Class at
Publication: |
440/059 |
International
Class: |
B63H 20/08 20060101
B63H020/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 5, 2004 |
JP |
2004-000219 |
Jan 5, 2004 |
JP |
2004-000264 |
Jan 5, 2004 |
JP |
2001-000267 |
Claims
1. A steering system for an outboard drive comprising a steering
handle adapted to be furnished on a watercraft, a steering device,
a lever having first and second ends, the first end being attached
to the drive, and a sensor sensing an actual position of the
steering handle to provide a position signal to the steering
device, the steering device comprising an electric motor having an
outer casing and a ball screw arranged to extend through the outer
casing, the ball screw and the outer casing moving relative to one
another in accordance with the actual position of the steering
handle, the second end of the lever being attached to the ball
screw or the outer casing, the ball screw or the outer casing
steering the drive through the lever.
2. The steering system as set forth in claim 1, wherein the drive
comprises a drive unit, a steering shaft that is attached to the
drive unit and that extends generally vertically, a swivel bracket
arranged to journal the steering shaft for steering movement of the
drive unit about a steering axis, a clamping bracket adapted to be
mounted on the watercraft, a tilt pin extending generally
horizontally through the swivel bracket and the clamping bracket,
the clamping bracket supporting the swivel bracket with the drive
unit for tilt movement about a tilt axis, a support member or
support unit arranged to extend from the tilt pin or the swivel
bracket to support the ball screw, and a link unit arranged to
couple the second end of the lever with the outer casing of the
electric motor.
3. The steering system as set forth in claim 2, wherein the support
unit comprises a pair of support members attached to respective
ends of the tilt pin.
4. The steering system as set forth in claim 2, wherein the link
unit includes a link member and a connecting pin, the link member
being connected to the second end of the lever via the connecting
pin.
5. The steering system as set forth in claim 2, wherein the first
end of the lever is attached to the steering shaft.
6. The steering system as set forth in claim 1, wherein the drive
comprises a drive unit, a steering shaft that is attached to the
drive unit and that extends generally vertically, a swivel bracket
arranged to journal the steering shaft for steering movement of the
drive unit about a steering axis, a clamping bracket adapted to be
mounted on the watercraft, a tilt pin extending generally
horizontally through the swivel bracket and the clamping bracket,
the clamping bracket supporting the swivel bracket with the drive
unit for tilt movement about a tilt axis, a support member arranged
to extend from the tilt pin or the swivel bracket to support the
outer casing of the electric motor, and a link member arranged to
extend from the second end of the lever to be coupled to the ball
screw.
7. The steering system as set forth in claim 6, wherein the support
member has first and second ends coupled to respective ends of the
tilt pin, and the support member supports the outer casing of the
electric motor between the first and second ends.
8. The steering system as set forth in claim 6, wherein the link
member has a first end coupled to the second end of the lever
through a first ball joint and has a second end coupled to the ball
screw through a second ball joint.
9. The steering system as set forth in claim 1, wherein the drive
comprises a drive unit, a steering shaft attached to the drive unit
and extending generally vertically, a swivel bracket arranged to
journal the steering shaft for steering movement of the drive unit
about a steering axis, a clamping bracket adapted to be mounted on
the watercraft, and a tilt pin extending generally horizontally
through the swivel bracket and the clamping bracket, wherein the
clamping bracket supports the swivel bracket with the drive unit
for tilt movement about a tilt axis, wherein the tilt pin is
hollowed to support the outer casing of the electric motor therein,
wherein the ball screw coaxially extends through the tilt pin, and
wherein a link member is arranged to extend from the second end of
the lever to be coupled to the ball screw.
10. The steering system as set forth in claim 1, wherein the drive
comprises a drive unit, a steering shaft attached to the drive unit
and extending generally vertically, a swivel bracket arranged to
journal the steering shaft for steering movement of the drive unit
about a steering axis, a clamping bracket adapted to be mounted on
the watercraft, and a tilt pin extending generally horizontally
through the swivel bracket and the clamping bracket, wherein the
clamping bracket supports the swivel bracket with the drive unit
for tilt movement about a tilt axis, wherein the ball screw is
coupled to the second end of the lever, and wherein the outer
casing of the electric motor is adapted to be attached to the
watercraft or is attached to the clamping bracket.
11. The steering system as set forth in claim 10, wherein the ball
screw and the second end of the lever are coupled together through
a ball joint.
12. The steering system as set forth in claim 1, wherein the drive
comprises a drive unit, a steering shaft attached to the drive unit
and extending generally vertically, a swivel bracket arranged to
journal the steering shaft for steering movement of the drive unit
about a steering axis, a clamping bracket adapted to be mounted on
the watercraft, a tilt pin extending generally horizontally through
the swivel bracket and the clamping bracket, wherein the clamping
bracket supports the swivel bracket with the drive unit for tilt
movement about a tilt axis, wherein a support member adapted to be
attached to a transom of the watercraft or attached to the clamping
bracket to support the ball screw, and wherein a link member
arranged to extend from the second end of the lever to be coupled
to the outer casing of the electric motor.
13. The steering system as set forth in claim 12, wherein the link
member and the second end of the lever are coupled together through
a ball joint.
14. The steering system as set forth in claim 1, wherein the outer
casing of the electric motor is generally positioned at a center of
the ball screw when a steering angle is zero.
15. An outboard drive system comprising a drive unit, a steering
shaft attached to the drive unit and extending generally
vertically, a swivel bracket arranged to journal the steering shaft
for steering movement of the drive unit about a steering axis, a
clamping bracket adapted to be mounted on the watercraft, a tilt
pin extending generally horizontally through the swivel bracket and
the clamping bracket, the clamping bracket supporting the swivel
bracket with the drive unit for tilt movement about a tilt axis, a
lever having first and second ends, the first end being attached to
the steering shaft, and a steering device including an electric
motor that has an outer casing and a ball screw arranged to extend
through the outer casing, the ball screw and the outer casing
moving relative to each other, the second end of the lever being
attached to the ball screw or the outer casing, the ball screw or
the outer casing moving the steering shaft about the steering axis
through the lever.
Description
PRIORITY INFORMATION
[0001] The present application is based on and claims priority
under 35 U.S.C. .sctn. 119 to Japanese Patent Application No.
2004-000219, filed on Jan. 5, 2004, Japanese Patent Application No.
2004-000264, filed on Jan. 5, 2004, and Japanese Patent Application
No. 2004-000267, filed on Jan. 5, 2004, the entire contents of
which are expressly incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to a steering system
for an outboard drive, and more particularly relates to an improved
steering system that incorporates an electric motor for steering an
outboard drive.
[0004] 2. Description of Related Art
[0005] Many watercraft are propelled by one or more outboard motors
mounted on a transom board. A typical outboard motor has a drive
unit and a bracket assembly. The drive unit incorporates a
propulsion device (e.g., a propeller) that propels the watercraft.
The bracket assembly is mounted on the watercraft to support the
drive unit and to enable pivotal movement of the drive unit about a
steering axis. In a typical outboard motor, the steering axis is
defined by a steering shaft coupled with the drive unit and
extending vertically through the bracket assembly.
[0006] The typical watercraft includes a steering system that
incorporates a steering handle (e.g., a steering wheel). The
steering handle is operable by the operator of the watercraft. A
steering device is responsive to movements of the steering handle
and is coupled with the steering shaft to cause the steering shaft
to move in accordance with the movement of the steering handle.
[0007] In some typical systems, a hydraulically operable steering
device moves the steering shaft. Such a steering device includes a
hydraulic system that occupies a relatively large space. The
hydraulic system also includes a pipe arrangement that makes the
steering device complicated.
[0008] A steering device incorporating an electric motor can
replace the hydraulic steering device. For example, Japanese Patent
No. 2959044 discloses an electrical steering device having an
electric motor, a rack and pinion mechanism, and a link mechanism.
The electric motor drives a pinion of the rack and pinion mechanism
to axially move a rack thereof, and the link mechanism rotates the
steering shaft in accordance with the axial movement of the rack.
The drive unit can thus change its position about the steering
axis, thereby, turning the watercraft left or right.
[0009] In the steering device disclosed in the above-referenced
Japanese patent, the electric motor and the rack and pinion
mechanism are disposed in a relatively large body positioned within
the watercraft in front of the transom board. Thus, the steering
device occupies a significant volume of space inside the watercraft
or can interfere with other components in the watercraft.
SUMMARY OF THE INVENTION
[0010] An aspect of the present invention is recognition of the
need for an outboard drive with an improved steering system with a
simple and compact steering device for moving the steering shaft
about the steering axis. To address such a need, an aspect of the
present invention involves a steering system for an outboard drive
that comprises a steering handle adapted to be finished on a
watercraft, a steering device, a lever that has first and second
ends, and a sensor. The first end of the lever is attached to the
drive. The sensor senses an actual position of the steering handle
to provide a position signal to the steering device. The steering
device comprises an electric motor that has an outer casing and a
ball screw arranged to extend through the outer casing. The ball
screw and the outer casing move relative to one another in
accordance with the actual position of the steering handle. The
second end of the lever is attached to the ball screw or the outer
casing. The ball screw or the outer casing steers the drive through
the lever.
[0011] In accordance with another aspect of the present invention,
an outboard drive system comprises a drive unit. A steering shaft
is attached to the drive unit and extends generally vertically. A
swivel bracket is arranged to journal the steering shaft for
steering movement of the drive unit about a steering axis. A
clamping bracket can be mounted on the watercraft. A tilt pin
extends generally horizontally through the swivel bracket and the
clamping bracket. The clamping bracket supports the swivel bracket
with the drive unit for tilt movement about a tilt axis. A lever
has first and second ends. The first end of the lever is attached
to the steering shaft. A steering device includes an electric motor
that has an outer casing and a ball screw arranged to extend
through the outer casing. The ball screw and the outer casing move
relative to each other. The second end of the lever is attached to
the ball screw or the outer casing. The ball screw or the outer
casing moves the steering shaft about the steering axis through the
lever.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features, aspects and advantages of the
present invention are described below with reference to the
drawings of preferred embodiments, which embodiments are intended
to illustrate and not to limit the present invention.
[0013] FIG. 1 illustrates a top plan view of an outboard motor
mounted on a watercraft, and illustrates a steering system that is
configured in accordance with certain features, aspects and
advantages of the present invention.
[0014] FIG. 2 illustrates an enlarged top plan view of the outboard
motor with a steering device of the steering system of FIG. 1.
[0015] FIG. 3 illustrates an enlarged top plan view of a portion of
the outboard motor and the steering device, wherein the portion of
the outboard motor is partially cross-sectioned.
[0016] FIG. 4 illustrates a front elevation view of the portion of
the outboard motor and the steering device shown in FIG. 3.
[0017] FIG. 5 illustrates a side elevation view of the portion of
the outboard motor and the steering device shown in FIG. 3, wherein
a swivel bracket of the outboard motor is positioned in a tilted
down position.
[0018] FIG. 6 illustrates a side elevation view of the portion of
the outboard motor and the steering device of FIG. 3, wherein the
swivel bracket is positioned in a tilted up position.
[0019] FIG. 7 illustrates an enlarged top plan view of a portion of
an outboard motor and another steering device modified in
accordance with a second embodiment of the present invention,
wherein the portion of the outboard motor is partially
cross-sectioned.
[0020] FIG. 8 illustrates a front elevation view of the portion of
the outboard motor and the steering device of FIG. 7.
[0021] FIG. 9 illustrates an enlarged top plan view of a portion of
an outboard motor and a further steering device modified in
accordance with a third embodiment of the present invention,
wherein the portion of the outboard motor is partially
cross-sectioned.
[0022] FIG. 10 illustrates a front elevation view of the portion of
the outboard motor and the steering device of FIG. 9.
[0023] FIG. 11 illustrates an enlarged top plan view of a portion
of an outboard motor and a further steering device modified in
accordance with a fourth embodiment of the present invention,
wherein the portion of the outboard motor is partially
cross-sectioned.
[0024] FIG. 12 illustrates a front elevation view of the portion of
the outboard motor and the steering device of FIG. 11.
[0025] FIG. 13 illustrates a top plan view of an outboard motor
mounted on a watercraft, and illustrates a steering system that is
modified in accordance with a fifth embodiment of the present
invention.
[0026] FIG. 14 illustrates an enlarged top plan view of a portion
of the outboard motor of FIG. 13 and a steering device of the
steering system of FIG. 13, wherein a portion of the outboard motor
partially cross-sectioned.
[0027] FIG. 15 illustrates a front elevation view of the portion of
the outboard motor and the steering device of FIG. 13, wherein a
portion of the steering device associated with a left hand portion
of the outboard motor in the figure illustrates a variation of the
steering device of FIG. 14.
[0028] FIG. 16 illustrates a top plan view of an outboard motor
mounted on a watercraft, and illustrates a steering system that is
modified in accordance with a sixth embodiment of the present
invention.
[0029] FIG. 17 illustrates an enlarged top plan view of a portion
of the outboard motor of FIG. 16 and a steering device of the
steering system of FIG. 16.
[0030] FIG. 18 illustrates a front elevation view of the portion of
the outboard motor and the steering device of FIG. 16.
[0031] FIG. 19 illustrates an enlarged top plan view of a portion
of an outboard motor and a further steering device modified in
accordance with a seventh embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0032] FIGS. 1-6 illustrate a steering system 30 configured in
accordance with certain features, aspects and advantages of one
embodiment of the present invention for an outboard motor 32. The
outboard motor 32 merely exemplifies one type of outboard drive.
The steering system 30 can be used with other types of outboard
drives such as, for example, stern drives for inboard/outboard
systems. Such applications will be apparent to those of ordinary
skill in the art in view of the description herein.
[0033] The outboard motor 32 preferably comprises a drive unit 34
and a bracket assembly 36. The drive unit 34 preferably comprises a
housing unit and a power head disposed atop the drive unit 34 and
above the housing unit. The housing unit preferably comprises a
driveshaft housing and a lower unit extending below the driveshaft
housing. The bracket assembly 36 supports the drive unit 34 on a
transom 38 of an associated watercraft 40 and places a marine
propulsion device (not shown) in a submerged position, with the
watercraft 40 resting on the surface of a body of water.
Preferably, the marine propulsion device is a propeller.
[0034] As used in this description, the terms "forward,"
"forwardly" and "front" mean at or to the side where the bracket
assembly 36 is located, and the terms "rear," "reverse," "backward"
and "rearward" mean at or to the opposite side of the front side,
unless indicated otherwise or otherwise readily apparent from the
context use. As further used in this description, the term
"horizontally" means that the subject portions, members or
components extend generally parallel to the water surface when the
watercraft 40 is substantially stationary with respect to the water
surface and when the drive unit 34 is not tilted. The term
"vertically" means that portions, members or components extend
generally normal to those that extend horizontally.
[0035] As shown in FIGS. 3 and 4, the bracket assembly 36
preferably comprises a swivel bracket 44, a clamping bracket 46, a
steering shaft 48 and a tilt pin (or pivot pin) 50. The steering
shaft 48 preferably extends generally vertically through the swivel
bracket 44 and is affixed to the housing unit through upper and
lower mount assemblies. The steering shaft 48 is pivotally
journaled within the swivel bracket 44 for steering movement about
a steering axis defined by the steering shaft 48. The steering axis
extends vertically along a center plane CP (FIGS. 2-4) that extends
vertically and fore to aft relative to the outboard motor 32. The
drive unit 34 pivots about the steering axis relative to the swivel
bracket 44 because the steering shaft 48 is affixed to the drive
unit 34.
[0036] In the illustrated embodiment, a steering lever 52
preferably is affixed to a top end of the steering shaft 48 to
extend forward. The steering lever 52 has a forward end 54 and a
rear end 55, and the steering lever 52 preferably is affixed to the
steering shaft 48 at the rear end 55 thereof. As thus constructed,
the drive unit 34 is steerable about the steering axis when the
steering lever 52 moves the steering shaft 48 right and left. In
the illustrated embodiment, a steering device 56 is provided on the
bracket assembly 36 to move the steering lever 52.
[0037] The clamping bracket 46 comprises two bracket arms 58 that
are spaced from each other to interpose the swivel bracket 44 there
between, and the respective bracket arms 58 are affixed to the
watercraft transom 38 (FIG. 2) by clamping bolts. Preferably, the
clamping bolts are previously inserted into suitable bolt holes 60
in the bracket arms 58. The tilt pin 50 extends generally
horizontally through the swivel bracket 44 and the bracket arms 58
of the clamping bracket 46 to complete a hinge coupling between the
swivel bracket 44 and the clamping bracket 46. The clamping bracket
46 thus supports the swivel bracket 44 and the drive unit 34 for
pivotal movement about a tilt axis defined by the tilt pin 50. The
tilt pin 50 preferably is pivotally affixed to the bracket arms 58
by nuts 62 shown in FIG. 3. In the illustrated embodiment, each end
portion of the tilt pin 50 extends outward beyond the nuts 62.
[0038] A tilt and trim adjustment device 64 (FIG. 4) preferably is
provided between the swivel bracket 44 and the clamping bracket 46
to tilt (raise or lower) the swivel bracket 44 together with the
drive unit 34 relative to the clamping bracket 46. The tilt and
trim adjustment device 64 preferably comprises a hydraulically
operated mechanism that includes a hydraulic cylinder 66, a
hydraulic piston that reciprocates within the cylinder 66, a
hydraulic pump 68 that powers the piston, and a fluid reservoir 70
that stores a working fluid such as oil. A piston rod extends
outward beyond one end of the cylinder 66. Preferably, a bottom end
of the cylinder 66 is pivotally affixed to the clamping bracket 46
while a top end of the piston rod is pivotally affixed to the
swivel bracket 44.
[0039] When the hydraulic pump 68 operates, the piston rod extends
from the cylinder 66 or retracts into the cylinder 66 in response
to the movement of the working fluid within the cylinder 66. When
the piston rod extends, the swivel bracket 44 and the drive unit 34
are tilted upward. With the piston rod retracts, the swivel bracket
44 and the drive unit 34 are tilted downward. Preferably, the drive
unit 34 moves between a fully tilted down position that is the most
lowered position of the drive unit 34 and a fully tilted up
position that is the most raised position of the drive unit 34 when
the tilt and trim adjustment device 64 is activated. Preferably, a
lower tilt range is a trim adjustment range.
[0040] The power head comprises a prime mover, which in this
embodiment is an internal combustion engine such as, for example, a
four-cycle engine or two-cycle engine. Other prime movers such as,
for example, an electric motor, can replace the engine. The power
head further comprises a protective cowling assembly. Preferably,
the protective cowling assembly defines a generally closed cavity,
and the engine is disposed within the protective cowling
assembly.
[0041] As illustrated in FIG. 1, the steering system 30 comprises a
steering handle such as, for example, a steering wheel 72, a
steering column 74, a steering position sensor 76, an electric
cable 78, a steering controller 80 and the foregoing steering
device 56. The steering column 74 preferably extends upward and
rearward from a forward bottom of a cockpit of the watercraft 40
and is supported by a journal for rotation. The steering wheel 72
is disposed atop the steering column 74 in a position so that an
operator of the watercraft 40 can turn the wheel 72. The steering
position sensor 76 is positioned at a bottom of the steering column
74 to sense an actual angular position of the steering wheel 72
when the wheel is turned by the operator. The sensor 76 senses a
pivot angle of the steering column 74 that corresponds to an amount
of the angular movement of the steering wheel 72 from a reference
position (e.g., the neutral position of the steering wheel when the
watercraft is moving straight ahead without turning). The cable 78
electrically connects the sensor 76 in the forward area of the
cockpit to the steering controller 80 positioned in the proximity
of the steering device 56. The sensor 76 provides a position signal
to the steering device 56 through the cable 78.
[0042] Alternatively, the steering controller 80 can be placed in
the cockpit, for example, in the proximity of the sensor 76. In
this variation, the electric cable 78 interconnects the controller
80 and an electric motor 84 of the steering device 56, which is
described below.
[0043] When the operator turns the steering wheel 72 clockwise or
counterclockwise, the steering column 74 rotates with the steering
wheel 72, and the steering position sensor 76 senses a position of
the steering wheel 72. A signal indicating the sensed position of
the steering wheel 72 is transmitted to the steering controller 80.
The controller 80 controls the steering device 56 to move the
steering lever 52 to the right or to the left in accordance with
the position of the steering wheel 72.
[0044] The cable 78 can be formed in a variety of configurations.
For example, electrical conductors or optical fibers can be used.
In one variation, the cable 78 is replaced by a wireless
transmitter placed at or near the sensor 76 and a wireless receiver
placed at or near the controller 80.
[0045] As illustrated in FIGS. 2-5, the steering device 56
preferably comprises the electric motor 84. The electric motor 84
has an outer casing 86 and has a ball screw 88 extending through
the outer casing 86. The outer casing 86 and the ball screw 88
together form a direct drive type motor ("a DD motor"). The outer
casing 86 includes the remainder of the motor elements such that
the outer casing 86 and the ball screw 88 together function as a
motor. The steering controller 80 is electrically connected to the
electric motor 84 to control the motor 84. The ball screw 88
comprises an elongated screw and a plurality of balls (not shown)
placed in the grooves of the screw in an area of the casing 86. The
casing 86 and the screw 88 are coupled with each other via the
balls in a known manner. The casing 86 and the ball screw 88 move
axially relative to each other when the motor 84 is activated. More
specifically, the controller 80 activates and controls the motor 84
to move the outer casing 86 or the ball screw 88 relative to one
another in response to the actual position of the steering wheel
72. The steering lever 52 converts the axial movement of the outer
casing 86 or the ball screw 88 to a pivotal movement of the
steering shaft 48. Additionally, the electric motor 84 is connected
to receive electrical power from a battery or batteries (not
shown).
[0046] In the illustrated embodiment shown in FIG. 3, a cylindrical
motor housing 92 extends parallel to the tilt pin 50 and holds the
outer casing 86. The ball screw 88 also extends parallel to the
tilt pin 50. Preferably, the outer casing 86 is affixed to an
inside wall of the motor housing 92 at a center location by bolts
or by other suitable fixing elements such as, for example, a
bonding agent. Preferably, the motor housing 92 is sufficiently
longer than the casing 86 to protect the ball screw 88, because the
ball screw 88 in the illustrated embodiment is longer than the tilt
pin 50.
[0047] A support member or support unit preferably extends from the
tilt pin 50 to support the ball screw 88. In the illustrated
embodiment, the support unit is formed by two support members 94
that are mounted onto respective end portions of the tilt pin 50
and that generally extend forwardly from the tilt pin 50. The
respective support members 94 are positioned symmetrically relative
to the center plane CP.
[0048] Each support member 94 is generally configured as a shape of
the letter "S." A rear end of the support member 94 has an opening
through which an end portion of the tilt pin 50 extends. A forward
end of the support member 94 also has an opening through which an
end of the ball screw 88 extends. The rear end of each support
member 94 is attached to one end portion of the tilt pin 50 such
that a spacer 96 is interposed between the nut 62 and the rear ends
of the support member 94. The forward end of each support member 94
is attached to a respective end of the ball screw 88. Preferably, a
distance between the forward ends of the support members 94 is
longer than a distance between the rear ends of the support members
94, because the ball screw 88 is longer than the tilt pin 50. In
the illustrated embodiment, nuts 98 fix the rear ends of the
support members 94 onto the tilt pin 50, while nuts 100 fix the
forward ends of the support members 94 onto the ball screw 88. In
alternative embodiments, a single support member 94 of sufficient
strength may be used to support the ball screw 88. As thus
constructed, the ball screw 88 is affixed to the tilt pin 50 and
can pivot about the tilt axis when the drive unit 34 tilts up or
down.
[0049] A link unit couples the forward end 54 of the steering lever
52 with the outer casing 86 of the electric motor 84. The link unit
preferably comprises a link member 102 and a connecting pin 104. In
the illustrated embodiment, the motor housing 92 is coupled with
the link member 102 to be a part of the link unit.
[0050] The link member 102 preferably is a metal plate that
generally has a half elliptic shape. As shown in FIG. 4, a center
area 102a of the link member 102 is slightly recessed such that
both side areas 102b of the link member 102 are positioned higher
than the center area 102a when the link member 102 is positioned
above the motor housing 92. As shown in FIG. 3, the link member 102
preferably has a slot 105 in the center area 102a. The connecting
pin 104 preferably extends from the lever 52 and extends through
the slot 105 of the link member 102 to couple the lever 52 and the
link member 102 with each other. The slot 105 is loose enough for
the pin 104 to move back and forth therein. In the illustrated
embodiment, both the steering axis and an axis of the pin 104 are
positioned on the center plane CP when the drive unit 34 is not
steered. The recessed configuration of the link member 102 is
advantageous because the position of the drive unit 34 can be
lowered to lower the center of gravity of the outboard motor 30 to
increase the stability of the watercraft 40.
[0051] The motor housing 92 has two bosses 108 (FIG. 4) that extend
upward from a top surface of the motor housing 92. The link member
102 is affixed to the motor housing 92 by bolts 110 at the
respective bosses 108. The bolts 110 enable the motor housing 92
and the link member 102 to be easily and rigidly coupled together.
In one variation, the link member 102 is unitarily formed with the
motor housing 92 such that the link unit is simpler.
[0052] As thus constructed, the motor housing 92 is movable along
the ball screw 88, and the ball screw 88 is not movable because the
ball screw 88 is rigidly affixed to the tilt pin 50. The motor
housing 92 thus moves axially along the ball screw 88 accordingly
in this embodiment when the electric motor 84 is activated.
[0053] The motor housing 92 is placed in the center of the ball
screw 88 such that the center of the outer casing 86 is positioned
on the center plane CP when the steering wheel 72 is in a neutral
position (e.g., a non-turning position). Thus, the illustrated
steering device 56 is positioned symmetrically relative to the
center plane CP when the steering angle is zero. The motor housing
92 and the outer casing 86 are positioned at a reference position
that corresponds to a reference position of the steering wheel 72.
The steering angle is zero at those reference positions. The pin
104 is positioned at the forward-most end of the slot 105 under
these conditions.
[0054] When the operator turns the steering wheel 72 clockwise or
counterclockwise, the sensor 76 senses an actual position of the
steering wheel 72 and transmits a position signal to the controller
80 through the cable 78. The controller 80 activates and controls
the electric motor 84. The outer casing 86 of the electric motor 84
and the housing 92 move along the ball screw 88 to the right or to
the left as indicated by the arrow A of FIG. 2 under control of the
controller 80. The movement of the housing 92 causes the pin 104 to
move rearward within the slot 105 and causes the lever 52 turn with
a certain angle that the controller 80 indicates. For example, as
illustrated in FIG. 1, when the operator turns the steering wheel
72 clockwise as indicated by the arrow B, the lever 52 turns
counterclockwise as indicated by the arrow C, and the drive unit 34
also turns counterclockwise as indicated by the arrow D. This
position of the drive unit 34 causes the watercraft 40 to turn
right in response to the operator action.
[0055] As illustrated in FIGS. 5 and 6, the steering device 56 is
able to pivot about the tilt axis because the support members 94
are affixed to the tilt pin 50. As shown in FIG. 5, the link member
102 generally extends horizontally when the drive unit 34 is in a
tilted down position. In contrast, when the drive unit 34 is fully
tilted up as illustrated in FIG. 6, the link member 102 is inclined
and the steering device 56 is positioned lower than the tilt pin
50.
[0056] In the illustrated embodiment, the connecting pin 104
extends from the steering lever 52, and the slot 105 is located at
the link member 102. Alternatively, the connecting pin 104 can
extend from the link member 102 with the slot 105 located at the
steering lever 52. In this alternative, the pin 104 is positioned
at the rear-most end of the slot 105 when the drive unit 34 is
positioned for straight ahead movement (e.g., no turning).
[0057] The steering device 56 of the steering system 30 in the
illustrated embodiment has a simple and compact arrangement because
the electric motor 84 is disposed in the motor housing 92 that
extends along the ball screw 88 and has no rack and pinion
mechanism. The illustrated ball screw 88 is located close to the
tilt pin 50 because the ball screw 88 is supported by the tilt pin
50. This arrangement makes the portion of the steering device 56
situated within the watercraft 40 smaller than in a system using
known steering devices.
[0058] FIGS. 7 and 8 illustrate a steering system 116 modified in
accordance with a second embodiment of the present invention. The
members, components, and devices that are the same as those
described above are assigned the same reference numerals in the
embodiment of FIGS. 7 and 8 and in other embodiments described
below, and will not be described again unless required in the
context of the description of another element.
[0059] The steering system 116 of FIGS. 7 and 8 includes a steering
device 118. The steering device 118 incorporates a modified motor
housing 120 that preferably has a housing body 122 and two housing
arms 124. The housing body 122 generally extends parallel to the
tilt pin 50 and holds the outer casing 86 of the electric motor 84.
The respective housing arms 124 extend from respective ends of the
housing body 122 toward the tilt pin 50 and are affixed to the end
portions of the tilt pin 50.
[0060] Preferably, a link rod 128 connects the steering lever 52
with the ball screw 88. In this second embodiment, the steering
lever 52 does not have a slot Instead, the link rod 128 is affixed
to the lever 52 by a ball joint 130 that has a pin 132. Also, the
link rod 128 is affixed to one end of the ball screw 88 by another
ball joint 134 that has a pin 136.
[0061] Because the outer casing 86 is affixed to the tilt pin 50
via the motor housing 120, while the ball screw 88 is free to move
relative to the outer casing 86 in the second embodiment, the ball
screw 88 extends from or retracts into the housing 120. With the
movement of the ball screw 88, the steering lever 52 pivots about
the steering axis. Thus, the drive unit 34 moves clockwise or
counterclockwise to turn the watercraft 40 to the left or to the
right respectively. The ball joints 130, 134 allow the swivel
bracket 44 with the drive unit 34 to tilt up and down even though
the motor housing 120 is affixed to the tilt pin 50. Also, the ball
joints 130, 134 allow greater tolerance in the dimensions of the
components of the steering system 116. The arrangement of the
second embodiment also allows the tilt pin 50 to be shorter.
[0062] FIGS. 9 and 10 illustrate a further steering system 140
modified in accordance with a third embodiment of the present
invention. The steering system 140 incorporates a modified steering
device 141 that has a movable motor housing 92. In the third
embodiment, modified support members 142 are applied to support the
ball screw 88 on the swivel bracket 44 rather than on the tilt pin
50. The steering device 141 includes two bosses 143 that preferably
project toward the motor housing 92 from top forward ends of the
swivel bracket 44. The support members 142 are affixed to the
respective bosses 143 by bolts 144. Because the ball screw 88 is
affixed to the swivel bracket 44, the tilt pin 50 does not need to
extend outward and can be shorter in the third embodiment.
[0063] FIGS. 11 and 12 illustrate a further steering system 148
modified in accordance with a fourth embodiment of the present
invention. The steering system 148 incorporates a modified steering
device 150 that has the movable ball screw 88. The motor housing 92
preferably has bosses 152 that project toward the bosses 143 of the
swivel bracket 44. The motor housing 92 is affixed to the swivel
bracket 44 at the bosses 152 by bolts 154. The bolts 154 are
schematically shown in actual lines in the figure, although a large
part of each bolt 154 is hidden by the motor housing 92 during
normal viewing.
[0064] FIGS. 13-15 illustrate a further steering system 160
modified in accordance with a fifth embodiment of the present
invention. The steering system 160 incorporates a modified steering
device 162 that has the movable ball screw 88. The illustrated ball
screw 88 extends coaxially with a modified tilt pin 164 that is
hollowed. Thus, the illustrated tilt pin 164 is configured as a
pipe, and the ball screw 88 extends through the pipe. The ball
screw 88 has a center axis E that is identical to the tilt axis of
the tilt pin 164. The tilt pin 164 preferably has a relatively
large diameter so that the tilt pin 164 is also a motor housing
that holds the outer casing 86. Preferably, the steering device 162
includes collars 166 that are inserted into the tilt pin 164 to
hold the ball screw 88 therein. The collars 166 space the ball
screw 80 apart from the swivel bracket 44.
[0065] Alternatively, as shown in the left hand side of the tilt
pin 164 of FIG. 15, each bracket arm 58 of the clamping bracket 46
has a cylindrical projection or boss 168 that unitarily extends
from the bracket arm 58. Each projection 168 is inserted into an
opening 169 of the swivel bracket 44 to space the ball screw 88
apart from the swivel bracket 44.
[0066] When constructed as shown in FIGS. 13-15, the steering
device 162 in the fifth embodiment is extremely compact and does
not protrude into the watercraft.
[0067] FIGS. 16-18 illustrate a further steering system 170
modified in accordance with a sixth embodiment of the present
invention. The steering system 170 incorporates a modified steering
device 172 that has the movable ball screw 88. A motor housing 174
of the sixth embodiment is attached to the transom 38 of the
watercraft 40. A bracket 176 preferably is affixed to a portion of
the transom 38 by bolts 178 in close proximity to one side corner
of the watercraft 40. Preferably, a first end portion 180 of the
motor housing 174 is affixed to the bracket 176 via a ball joint
182. A second end portion, which is opposite to the first end
portion 180, comprises the outer casing 86. The ball screw 88
extends through the motor housing 174 and further extends outward
from the outer casing 86. An end 184 of the ball screw 88 is
affixed to a forward end 54 of the steering lever 52 via a ball
joint 186 by a pin 188. In FIG. 18, one nut 62 couples the tilt pin
50 with the clamping bracket 46. Preferably, another nut is affixed
to another side of the tilt pin 50 to couple the tilt pin 50 to
another side of the clamping bracket 46.
[0068] Because the motor housing 174 is attached to the transom 38
of the watercraft 40, the tilt pin 50 can be short enough to be
covered by the power head of the drive unit 34. The electric cable
78 in the sixth embodiment is located away from the drive unit 34.
Thus, the cable 78 does not bend and stretch much even though the
drive unit 34 tilts up and down. The life span of the cable 78 may
thus be extended.
[0069] In the illustrated embodiment, the controller 80 is attached
to the electric motor 86. As noted above, the controller 80 can be
separated from the electric motor 86 and can be placed close to the
sensor 76. In this variation, the steering device 172 can be more
compact.
[0070] FIG. 19 illustrates a further steering system 190, which is
modified in accordance with a seventh embodiment of the present
invention. The steering system 190 incorporates a modified steering
device 192 that has the movable motor housing 92. In the seventh
embodiment, two support members 194 preferably are affixed to the
transom 38 of the watercraft 40 by bolts to support the ball screw
88. The illustrated motor housing 92 is rigidly coupled with a link
member 198. The link member 198 in turn is affixed to the steering
lever 52 via a ball joint 200 that has a pin 202. The pin 202
preferably is inserted into a slot (not shown) which is disposed at
the lever 52.
[0071] The motor housing 92 does not move with the tilt movement of
the drive unit 34 because the ball screw 88 is affixed to the
transom 38. The controller 80 is affixed to the housing 92. Thus,
the electric cable 78 does not bend and stretch much even though
the drive unit 34 tilts up and down. The life span of the cable 78
in the seventh embodiment may also be extended, accordingly.
[0072] Although this invention has been disclosed in the context of
certain preferred embodiments, it will be understood by those
skilled in the art that the present invention extends beyond the
specifically disclosed embodiments to other alternative embodiments
and/or uses of the invention and obvious modifications and
equivalents thereof. It is also contemplated that various
combinations or sub-combinations of the specific features and
aspects of the embodiments may be made and still fall within the
scope of the invention. It should be understood that various
features and aspects of the disclosed embodiments can be combined
with or substituted for one another in order to form varying modes
of the disclosed invention. Thus, it is intended that the scope of
the present invention herein disclosed should not be limited by the
particular disclosed embodiments described above, but should be
determined only by a fair reading of the claims that follow.
* * * * *