U.S. patent application number 17/693544 was filed with the patent office on 2022-09-29 for fixed mount electric actuator for a marine steering system, and a propulsion unit comprising the same.
The applicant listed for this patent is Marine Canada Acquisition Inc.. Invention is credited to Noam DAVIDSON, David HIGGS, Ray Tat Lung WONG.
Application Number | 20220306261 17/693544 |
Document ID | / |
Family ID | 1000006394884 |
Filed Date | 2022-09-29 |
United States Patent
Application |
20220306261 |
Kind Code |
A1 |
WONG; Ray Tat Lung ; et
al. |
September 29, 2022 |
FIXED MOUNT ELECTRIC ACTUATOR FOR A MARINE STEERING SYSTEM, AND A
PROPULSION UNIT COMPRISING THE SAME
Abstract
The propulsion unit comprises an electric actuator and a tiller
coupled the electric actuator. The electric actuator includes a
housing having a first end and second end. There is an output shaft
fully received within the housing. The output shaft includes a
coupling portion and a tiller is coupled the coupling portion of
the output shaft such that such that a line of action of the
actuator is in the same plane as the tiller.
Inventors: |
WONG; Ray Tat Lung;
(Richmond, CA) ; HIGGS; David; (Richmond, CA)
; DAVIDSON; Noam; (Vancouver, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Marine Canada Acquisition Inc. |
Richmond |
|
CA |
|
|
Family ID: |
1000006394884 |
Appl. No.: |
17/693544 |
Filed: |
March 14, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16789975 |
Feb 13, 2020 |
11273894 |
|
|
17693544 |
|
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|
62805307 |
Feb 13, 2019 |
|
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62805887 |
Feb 14, 2019 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B63H 25/10 20130101;
B63H 20/10 20130101; B63H 25/24 20130101; B63H 20/12 20130101 |
International
Class: |
B63H 25/24 20060101
B63H025/24; B63H 25/10 20060101 B63H025/10; B63H 20/12 20060101
B63H020/12; B63H 20/10 20060101 B63H020/10 |
Claims
1. An electric actuator for a marine steering system, the electric
actuator comprising: a housing having first and second ends; an
output shaft fully received within the housing, the output shaft
having first and second ends and including a coupling portion
disposed between the first end thereof and the second end thereof;
a roller screw assembly disposed within the housing near the first
end of the housing, the roller screw assembly including a plurality
of rollers and a central screw received by the rollers, the rollers
being rotatable about the central screw and the central screw
coupling to the output shaft; and a motor disposed within the
housing near the first end of the housing, the motor including a
stator and a rotor, the rotor having an axial bore which engages
with the rollers of the roller screw assembly, wherein rotation of
the rotor causes the roller screw assembly to translate axially
relative to the rotor and the output shaft to reciprocate within
the housing.
2. The electric actuator as claimed in claim 1 further including a
guide bushing disposed within the housing near the motor, the guide
bushing reciprocatingly receiving the output shaft.
3. In combination, the electric actuator as claimed in claim 1 and
a tiller, the tiller having a tiller axis and being coupled to the
output shaft such that a line of action of the output shaft is in
the same plane as the tiller axis throughout the entire steering
range.
4. In combination, the electric actuator as claimed in claim 1 and
a tiller, the tiller being coupled to the output shaft such that
the axis of the output shaft intersects the axis of the tiller
through the entire steering range.
5. The electric actuator as claimed in claim 1 further including a
guide bushing disposed within the housing near the second end of
the housing, the guide bushing reciprocatingly receiving the output
shaft.
6. The electric actuator as claimed in claim 1 further including a
guide bushing reciprocatingly receiving the output shaft, the guide
bushing having at least one aperture to enable air flow between the
first end of the housing and the second end of the housing.
7. The electric actuator as claimed in claim 1 wherein the coupling
portion of the output shaft includes a tiller extension.
8. The electric actuator as claimed in claim 1 wherein an interior
of the electric actuator is sealed.
9. The electric actuator as claimed in claim 1 wherein the motor is
concentric to the roller screw assembly.
10. The electrical actuator as claimed in claim 1 wherein the
coupling portion is resilient at least in part.
11. A propulsion unit for a marine steering system, the propulsion
unit comprising an electric actuator and a tiller coupled the
electric actuator, the electric actuator including: a housing
having first and second ends; an output shaft fully received within
the housing, the output shaft having first and second ends, and
including a coupling portion disposed between the first end thereof
and the second end thereof, the tiller being coupled the coupling
portion of the output shaft such that a line of action of the
electric actuator is in the same plane as the tiller; a roller
screw assembly disposed within the housing near the first end of
the housing, the roller screw assembly including a plurality of
rollers and a central screw received by the rollers, the rollers
being rotatable about the central screw and the central screw
coupling to the output shaft; and a motor disposed within the
housing near the first end of the housing, the motor including a
stator and a rotor, the rotor having an axial bore which engages
with the rollers of the roller screw assembly, wherein rotation of
the rotor causes the roller screw assembly to translate axially
relative to the rotor and the output shaft to reciprocate within
the housing.
12. The propulsion unit as claimed in claim 11 wherein the electric
actuator further includes a guide bushing disposed within the
housing near the motor, the guide bushing reciprocatingly receiving
the output shaft.
13. The propulsion unit as claimed in claim 11 wherein the electric
actuator further includes a guide bushing disposed within the
housing near the second end of the housing, the guide bushing
reciprocatingly receiving the output shaft.
14. The propulsion unit as claimed in claim 11 wherein the electric
actuator further includes a guide bushing reciprocatingly receiving
the output shaft, the guide bushing having at least one aperture to
enable air flow between the first end of the housing and the second
end of the housing.
15. The propulsion unit as claimed in claim 11 wherein the electric
actuator further includes a pair of guide bushings which support
the output shaft on either side of the tiller to reduce side
loads.
16. The propulsion unit as claimed in claim 11 wherein the coupling
portion of the output shaft includes a tiller extension.
17. The propulsion unit as claimed in claim 11 wherein the coupling
portion is resilient at least in part.
18. The propulsion unit as claimed in claim 11 wherein the tiller
resiliently couples to the propulsion unit.
19. The propulsion unit as claimed in claim 11 wherein the electric
actuator is bolted to the propulsion unit and wherein an interior
of the electric actuator is sealed.
20. The propulsion unit as claimed in claim 11 wherein the tiller
is bolted to the propulsion unit by a bolt and there is a resilient
insert about the bolt.
21-24. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM TO PRIORITY
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/789,975 filed Feb. 13, 2020, now U.S. Pat.
No. 11,273,894, which claims priority to U.S. Provisional Patent
Application No. 62/805,307 filed Feb. 13, 2019, and U.S.
Provisional Patent Application No. 62/805,887, filed Feb. 14, 2019,
which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to an electric actuator and,
in particular, to an electric actuator for a marine steering
system, as well as a propulsion unit comprising the same.
Description of the Related Art
[0003] U.S. Pat. No. 9,944,377 which was published on Apr. 17,
2018, in the name of Davidson et al., and the full disclosure of
which is incorporated herein by reference, discloses a marine
steering system comprising a propulsion unit including a tilt tube,
a support rod received by the tilt tube, a tiller, and an electric
actuator for imparting steering movement to the propulsion unit.
The electric actuator includes a housing and an output shaft
reciprocatingly received by the housing. The output shaft is
partially threaded and has smooth surfaces. There is a motor
disposed within the housing. The motor includes a stator and a
rotor. Rotation of the rotor causes the output shaft to translate
axially relative to the rotor and causes the output shaft to
reciprocate relative to the housing. A pivot plate is pivotably
connected to the tiller of the propulsion unit. The pivot plate
rotationally constrains the housing of the electric actuator to
provide reaction torque for rotation of the rotor. There are
support arms which connect respective ends of the output shaft to
the support rod of the propulsion unit. The support arms provide
rotational constraint to the output shaft and the support arms
inhibit axial movement of the output shaft relative to the marine
vessel while the housing of the electric actuator reciprocates
linearly along the output shaft.
SUMMARY OF THE INVENTION
[0004] There is provided an electric actuator for a marine steering
system. The electric actuator includes a housing having a first end
and second end. There is an output shaft fully received within the
housing. The output shaft includes a first end, a second end, and a
coupling portion disposed between the first end and the second end.
There is a roller screw assembly disposed within the housing near
the first end of the housing. The roller screw assembly includes a
plurality of rollers and a central screw received by the rollers.
The rollers are rotatable about the central screw and the central
screw is coupled to the output shaft. There is a motor disposed
within the housing near the first end of the housing. The motor
including a stator and a rotor. The rotor has an axial bore which
engages with the rollers of the roller screw assembly. Rotation of
the rotor causes the roller screw assembly to translate axially
relative to rotor and the output shaft to reciprocate within the
housing. There may be a guide bushing disposed within the housing
near the motor. The guide bushing may reciprocatingly receiving the
output shaft. There may be a guide bushing disposed within the
housing near the second end of the housing. The guide bushing may
reciprocatingly receive the output shaft. The coupling portion of
the output shaft may include a tiller extension. The motor may be
concentric to the roller screw assembly.
[0005] There is also provided a propulsion unit for a marine
steering system. The propulsion unit comprises an electric actuator
and a tiller coupled to the electric actuator. The electric
actuator includes a housing having a first end and second end.
There is an output shaft fully received within the housing. The
output shaft includes a first end, a second end, and a coupling
portion disposed between the first end and the second end. The
tiller is coupled to the coupling portion of the output shaft such
that such that a line of action of the actuator is in the same
plane as the tiller. There is a roller screw assembly disposed
within the housing near the first end of the housing. The roller
screw assembly includes a plurality of rollers and a central screw
received by the rollers. The rollers are rotatable about the
central screw and the central screw is coupled to the output shaft.
There is a motor disposed within the housing near the first end of
the housing. The motor includes a stator and a rotor. The rotor has
an axial bore which engages with the rollers of the roller screw
assembly. Rotation of the rotor causes the roller screw assembly to
translate axially relative to the rotor and the output shaft to
reciprocate within the housing. There may be a guide bushing
disposed within the housing near the motor. The guide bushing may
reciprocatingly receive the output shaft. There may be a guide
bushing disposed within the housing near the second end of the
housing. The guide bushing may reciprocatingly receive the output
shaft. The coupling portion of the output shaft may include a
tiller extension. The electric actuator may be bolted to the
propulsion unit and an interior of the electric actuator may be
sealed. The tiller may be bolted to the propulsion unit by a bolt
and there may be a resilient insert about the bolt. The motor may
be concentric to the roller screw assembly.
BRIEF DESCRIPTIONS OF DRAWINGS
[0006] The invention will be more readily understood from the
following description of the embodiments thereof given, by way of
example only, with reference to the accompanying drawings, in
which:
[0007] FIG. 1 is a perspective view of a propulsion unit for a
marine vessel and an electric actuator mounted on the propulsion
unit;
[0008] FIG. 2 is a top plan view of the propulsion unit and the
electric actuator of FIG. 1;
[0009] FIG. 3 is a perspective view of the electric actuator of
FIG. 1;
[0010] FIG. 4 is a sectional view of the electric actuator of FIG.
1;
[0011] FIG. 4A is an enlarged partial sectional view of the
electric actuator of FIG. 1;
[0012] FIG. 5 is a sectional view similar to FIG. 4 of another
embodiment of an electric actuator similar to the electric actuator
of FIG. 1;
[0013] FIG. 6 is a sectional view similar to FIG. 4 of yet another
embodiment of an electric actuator similar to the electric actuator
of FIG. 1; and
[0014] FIG. 7 is a sectional view similar to FIG. 4 of a further
embodiment of an electric actuator similar to the electric actuator
of FIG. 1.
DESCRIPTIONS OF THE PREFERRED EMBODIMENTS
[0015] Referring to the drawings and first to FIG. 1, there is
shown a propulsion unit 10 for a marine vessel (not shown). The
propulsion unit 10 generally comprises a mounting bracket 12 for
mounting the propulsion unit 10 to the marine vessel. The
propulsion unit includes a swivel bracket assembly 14 for steering,
trimming and tilting the propulsion unit 10 relative to the marine
vessel. The propulsion unit 10 includes an engine 16 for powering
the propulsion unit 10 and a propeller 18 for imparting a thrust to
the marine vessel. There is also an electric actuator 30 which is
mounted on the propulsion unit. In this example, and as best shown
in FIG. 2, the electric actuator 30 is mounted asymmetrically on
the propulsion unit 10. The propulsion unit shown in FIGS. 1 and 2
is an outboard engine. However, the propulsion unit 10 may be any
suitable marine propulsion unit such as, for example, an inboard
engine or a stern drive.
[0016] The electric actuator 30 is shown in greater detail in FIG.
3. The electric actuator 30 has a housing 32 which has a first end
34 and a second end 36. There is a mounting subassembly 38
extending radially relative to a longitudinal axis 110 of the
electric actuator 30. The mounting subassembly includes an aperture
40 which allows access to an interior 41 of the housing 32. There
is a seal 42 disposed about the aperture 40 so that the interior of
the housing is sealed when the electric actuator 30 is mounted to
the propulsion unit 10. The mounting subassembly 38 also includes a
plurality of threaded apertures 44a, 44b, 44c, and 44d which allow
the electric actuator 30 to be bolted to the propulsion unit 10 as
shown in FIGS. 1 and 2. Referring back to FIG. 3, the mounting
subassembly further includes dowel pins 46a and 46b which enable
the electric actuator to be aligned with the propulsion unit prior
to bolting the electric actuator 30 to the propulsion unit, as
described above.
[0017] Referring now to FIGS. 4 and 4A, the electric actuator 30
includes an output shaft 48 which is fully received and sealed
within the housing 32 when the housing is mounted to the propulsion
unit 10. This protects the output shaft from the environment and
reduces the need for advanced corrosion protection. The output
shaft 48 includes a first end 50, a second end 52, and a coupling
portion 54 disposed between the first end 50 of the output shaft 48
and the second end 52 of the output shaft 48.
[0018] As seen in FIG. 4A, the output shaft is coupled to a roller
screw assembly 56 which is disposed within the housing 32 near the
first end 34 of the housing 32. The roller screw assembly includes
a plurality of rollers arranged in an annular configuration, for
example rollers 58a and 58b, and a central screw 60. The rollers
are rotatable about the central screw in a planetary fashion but do
not translate axially relative to the central screw. Alignment of
the rollers 58a and 58b and the central screw 60 is maintained
through the use of respective interlocking gear teeth 62 and 64 on
the rollers 58a and 58b and the central screw 60. There are annular
end plates 66a and 66b which hold the roller screw assembly 56
together. The end plates 66a and 66b are free to rotate relative to
the central screw 60 and the end plates 66a and 66b are each
provided with journal bearing bores (not shown) that allow the
rollers 58a and 58b to rotate independently of the end plates 66a
and 66b.
[0019] The central screw 60 is provided with an axial through bore
68. A bolt 70 extends through the axial through bore of the central
screw, and threadedly engages the first end 50 of the output shaft
48 to couple the roller screw assembly 56 to the output shaft 48.
However, in other examples, the central screw and the output shaft
may be a unitary construction, such as in the form of a traditional
acme screw, for example.
[0020] Still referring to FIG. 4A, there is a motor 72 disposed
within the housing 32 near the first end 34 of the housing 32. The
motor 72 is a DC brushless electric motor, in this example, and
includes a stator 74 and a rotor 76. The rotor 76 is constrained
axially within the housing 32 but is able to rotate through the
provision of bearings 78a and 78b disposed at opposite ends of the
rotor 76. The rotor has a threaded axially through bore 80 which
threadedly engages the rollers 58a and 58b. Rotation of the rotor
76 relative to the roller screw assembly 56 causes the roller screw
assembly to translate axially relative to the rotor and the output
shaft 48 to reciprocate within the housing 32.
[0021] There is a guide bushing 82 disposed within the housing 32
near the motor 72. The guide bushing 82 reciprocatingly receives
the output shaft 48. As seen in FIG. 4, there is also a guide
bushing 84 disposed near the second end 36 of housing 32. The guide
bushing 84 also reciprocatingly receives the output shaft 48. There
are apertures 86a and 86b in the guide bushing to enable or
facilitate air flow between the first end of 34 of the housing 32
and a second end 36 of the housing 32 as well as through a center
of the housing.
[0022] Still referring to FIG. 4, a tiller 88 of the propulsion
unit 10 is coupled the coupling portion 54 of the output shaft 48.
The tiller has a longitudinal axis 89. The guide bushings 82 and 84
support the output shaft on either side of the tiller to reduce
side loads. The tiller 88 is coupled to the output shaft 48 such
that line of action 120 of the output shaft of the electric
actuator 30 is in the same plane as the tiller axis 89 through the
entire steering range. The axis 121 of the output shaft intersects
the axis of the tiller through the entire steering range. This
minimizes turning moment (torque couple) on the roller screw
assembly 56. This is advantageous because any torque couple causing
an overturning moment to the roller screw assembly decreases
efficiency and derates load carrying capacity. The tiller 88 is
mounted on the propulsion unit 10 by a plurality of attachment
bolts, for example attachments bolts 90a and 90b. Each said bolt is
surrounded by a respective resilient insert, for example resilient
insert 92a and 92b, which provide compliance. More specifically,
the resilient inserts function as a safeguard against shock loading
and damage to contacting surfaces.
[0023] The electric actuator 30 is also provided with manual
override mechanisms. A tool (not shown) may be inserted through
access port 94 to manually rotate the roller screw assembly 56 to
manually reposition the propulsion unit 10. A tool (not shown) may
also be inserted through access port 96 to manually rotate the
motor 72 so as to manually reposition the propulsion unit 10 at a
reduced ratio.
[0024] FIG. 5 shows another embodiment of an electric actuator 130.
The electric actuator 130 shown in FIG. 5 is generally identical to
the electric actuator shown 30 in FIGS. 1 to 4 with the notable
exception that there is a tiller extension 132 mounted on the
coupling portion 54. The tiller extension allows the electric
actuator 130 to be mounted to any propulsion unit to provide a
higher mechanical advantage. A spacer (not shown) may optionally be
employed to provide an equal tiller extension amount. The spacer
may be of resilient material to provide shock absorption. The
tiller extension 132 or the spacer provide adjustment to fit a
variety of propulsion units. For example, the electric actuator 130
may be mounted to a propulsion unit during the manufacture of the
propulsion unit, or the electric actuator may be mounted to an
in-service propulsion unit as a retrofit.
[0025] FIG. 6 shows another embodiment of an electric actuator 230.
The electric actuator shown in FIG. 6 is similar to the electric
actuator 30 shown in FIGS. 1 to 4 with the notable exception that
electric actuator 230 includes a motor 272 that is concentric to
the roller screw assembly 256. The electric actuator includes a
controller 275 and an actuator position sensor, in this example a
linear magnetoresistive absolute position sensor 277. The electric
actuator 230 further includes a brake 279 and a chamber 281 for an
additional motor and roller screw (not shown).
[0026] FIG. 7 shows a further embodiment of an electric actuator
330. The electric actuator shown in FIG. 7 is generally identical
to the electric actuator 30 shown in FIGS. 1 to 4 with the notable
exception that instead of resilient inserts 92a and 92b, the
coupling portion 354 is made of resilient material to provide
similar shock absorption.
[0027] It will be understood by a person skilled in the art that
while the electric actuators disclosed herein comprise a roller
screw assembly, in other examples, the electric actuator may
comprises any suitable screw assembly with a drive screw. It will
also be understood by a person skilled in the art that many of the
details provided above are by way of example only, and are not
intended to limit the scope of the invention which is to be
determined with reference to the following claims.
* * * * *