U.S. patent application number 13/678878 was filed with the patent office on 2013-06-20 for electrically powered surfboard.
The applicant listed for this patent is Paul MARTIN. Invention is credited to Paul MARTIN.
Application Number | 20130157526 13/678878 |
Document ID | / |
Family ID | 48481618 |
Filed Date | 2013-06-20 |
United States Patent
Application |
20130157526 |
Kind Code |
A1 |
MARTIN; Paul |
June 20, 2013 |
ELECTRICALLY POWERED SURFBOARD
Abstract
Conventional unpowered surfboards enable riders to catch and
ride waves towards a shoreline and experience the thrill and power
of ocean waves. An electric powered surfboard has been developed to
assist novice riders or riders who have suffered injuries or
impairments which limit their ability to paddle are effectively
prevented, or at least impaired from enjoying this activity. The
surfboard comprises one or more propulsion systems which each
comprise an electric motor, a drive shaft and a rotor. The rotor
may be a propeller mounted in a fin of the board, or it may be an
impellor in a water jet. The surfboard also comprises a power
control system for controlling power to the propulsion system and
comprises a speed controller and a battery as well as a cooling
system for cooling the motor and speed controller. The surfboard
may also comprise a monitoring system which comprises a power
monitor and an output device for indicating the remaining capacity
to the rider. This has the advantage of improved reliability as
well as informing the user of their use and remaining capacity to
ensure they are able to safely return to the shore.
Inventors: |
MARTIN; Paul; (Linden Park,
AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MARTIN; Paul |
Linden Park |
|
AU |
|
|
Family ID: |
48481618 |
Appl. No.: |
13/678878 |
Filed: |
November 16, 2012 |
Current U.S.
Class: |
440/2 ;
440/6 |
Current CPC
Class: |
B63B 49/00 20130101;
B63H 21/17 20130101; Y02T 70/50 20130101; B63H 21/21 20130101; Y02T
70/5272 20130101; B63B 32/10 20200201; B63J 2/12 20130101 |
Class at
Publication: |
440/2 ;
440/6 |
International
Class: |
B63H 21/17 20060101
B63H021/17; B63B 49/00 20060101 B63B049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2011 |
AU |
2011904784 |
Claims
1. An electric powered surfboard comprising: at least one
propulsion system comprising an electric motor and a rotor
assembly; a power control system for controlling power to the at
least one propulsion system comprising a speed controller and at
least one battery; and a cooling system for cooling the motor and
speed controller.
2. The electric powered surfboard as claimed in claim 1, further
comprising: a monitoring system comprising a power monitor and an
output device for indicating a remaining capacity to the rider.
3. The electric powered surfboard as claimed in claim 2, wherein
the remaining capacity is indicated as an estimate of the time
remaining determined from a predefined battery capacity.
4. The electric powered surfboard as claimed in claim 3, wherein
the estimate of the time remaining is based upon the recent power
usage levels.
5. The electric powered surfboard as claimed in claim 2, wherein
the remaining capacity is indicated as a percentage of total
capacity determined from a predefined battery capacity.
6. The electric powered surfboard as claimed in claim 2, wherein
the output device is a digital display device mounted in or on the
board.
7. The electric powered surfboard as claimed in claim 2, wherein
the output device is a remote display device in wireless
communication with the power monitor.
8. The electric powered surfboard as claimed in claim 2, wherein
the monitoring system further comprises one or more warning
indicators.
9. The electric powered surfboard as claimed in claim 8, wherein
the monitoring system comprises a temperature sensor and the one or
more warning indicators comprises an over temperature
indicator.
10. The electric powered surfboard as claimed in claim 8, wherein
the one or more warning indicators comprises a low power
indicator.
11. The electric powered surfboard as claimed in claim 8, wherein
the one or more warning indicators are provided on the top surface
of the board.
12. The electric powered surfboard as claimed in claim 1, wherein
the propulsion system the electric motor is a brushless DC motor
which is rated with a power rating in excess of 500 W.
13. The electric powered surfboard as claimed in claim 1, further
comprising a fin, and wherein the rotor assembly comprises a drive
shaft and a propeller located in the fin.
14. The electric powered surfboard as claimed in claim 13, wherein
the drive shaft exits a lower surface of the surfboard and enters a
forward edge of the fin, and the propeller is located in a cut out
portion in the rear of the fin.
15. The electric powered surfboard as claimed in claim 14, wherein
the fin further comprises a propeller guard.
16. The electric powered surfboard as claimed in claim 1, wherein
the rotor assembly comprises a drive shaft and a water jet and the
drive shaft drives an impellor in the water jet.
17. The electric powered surfboard as claimed in claim 16, wherein
the at least one propulsion system further comprises a scoop and a
thruster tube, wherein the scoop projects from the bottom surface
of the board to draw water into the water jet and the thruster tube
directs water from the water jet to the rear of the board where it
is expelled.
18. The electric powered surfboard as claimed in claim 1, wherein
the cooling system is an open loop system comprising an intake port
and an exhaust port.
19. The electric powered surfboard as claimed in claim 18, wherein
the intake port is located on a lower surface in a front half of
the board, and the exhaust port is located on a upper surface in a
rear of half of the board.
20. The electric powered surfboard as claimed in claim 1, wherein
the cooling system is a passive cooling system.
21. The electric powered surfboard as claimed in claim 20, wherein
the speed controller and electric motor are mounted in a metal heat
sink box located near a top surface of the board.
22. The electric powered surfboard as claimed in claim 1, wherein
the cooling system is a closed loop system comprising a pump and a
heat exchange region.
23. The electric powered surfboard as claimed in claim 22, wherein
the heat exchange region is located in an upper region of the
board.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to Australian
Provisional Patent Application No. 2011904784 entitled
"Electrically powered surfboard" and filed on 16 Nov. 2011, the
entire content of which is hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to surfboards. In a particular
form the present invention relates to an electrically powered
surfboard for assisting riders in riding waves.
BACKGROUND
[0003] Conventional unpowered surfboards enable riders to catch and
ride waves towards a shoreline and experience the thrill and power
of ocean waves. However in order to catch a wave, the surfer must
first paddle through the surf zone and out to the point where the
waves begin to form crests which can be caught and ridden. Once the
rider is in a suitable position to catch an incoming wave, the
rider must quickly accelerate in order to catch the wave as it
passes the rider. Such activities are both time consuming and
exhausting, and require the rider to have considerable upper body
strength in order to pass through the surf zone to reach the waves,
and then to rapidly accelerate and actually catch a wave.
Accordingly persons who have suffered injuries or impairments which
limit their ability to paddle are effectively prevented, or at
least impaired from enjoying this activity. Similarly novice riders
often lack the necessary combination of strength and skill to catch
waves.
[0004] Whilst various powered watercraft and electric surfboards
have been developed which such persons could utilise, such
watercraft and surfboards do not typically replicate the feel and
handling characteristics of conventional surfboards, nor are they
suitably adapted to the needs of such riders. One example uses a
pod containing a battery and water jets which is fitted in the rear
section of the board. However the size and weight of this pod
adversely affect the feel and handling of board it is fitted to, or
requires the construction of a specialised board. Further for
injured, impaired or novice riders, reliability and safety is a
significant concern, and it is important that riders do not become
stranded in the surf zone or beyond and are able to safely return
to shore.
[0005] There is thus a need to provide a powered surfboard with the
feel and handling of conventional surfboards that is adapted to
assist injured, impaired, or novice riders to experience the joy of
surfing or to at least to provide such riders with a useful
alternative.
SUMMARY
[0006] According to a first aspect of the present invention, there
is provided an electric powered surfboard comprising:
[0007] at least one propulsion system comprising an electric motor
and a rotor assembly;
[0008] a power control system for controlling power to the at least
one propulsion system comprising a speed controller and at least
one battery; and
[0009] a cooling system for cooling the motor and speed
controller.
[0010] In a further aspect the electric powered surfboard further
comprises a monitoring system comprising a power monitor and an
output device for indicating a remaining capacity to the rider. In
one aspect the power monitor provides real time, or near real time
monitoring of the battery usage and remaining battery capacity. The
power monitor may also monitor and report other parameters such as
current amps, battery voltage, power, battery temperature, motor
temperature or RPMs. In one aspect the battery capacity is defined
and reported in milli-Amp hours (mAh). In one aspect the remaining
capacity is indicated as an estimate of the time remaining
determined from the predefined battery capacity. The estimate of
remaining capacity remaining time may be based upon the current
usage level or it may be based upon historical values or averages
(ie past usage). Alternatively or additionally the remaining
capacity is indicated as a percentage of total capacity determined
from the predefined battery capacity.
[0011] In one aspect the output device is a digital display device
mounted in or on the board. The display device may be mounted on
the surface of the board, within a compartment with a viewing
window. In one aspect the output device is a remote display device,
which may be worn by the user, which is in wireless communication
with the power monitor. In one aspect the monitoring system further
comprises one or more warning indicators. In one aspect the one or
more warning indicators comprises a low power indicator and/or a
low voltage indicator and/or an over temperature indicator, in
which case the monitoring system further comprises a temperature
sensor. In one aspect the one or more warning indicators are
provided on the top surface of the board. These may be via a
display device or via separate indicators, such as LEDs or other
lights.
[0012] The surfboard may comprise one, two, three or four
independent propulsion systems. In one aspect the electric motors
are brushless DC motors which are rated with a power rating in
excess of 500 W. The motors may be in-runner or out-runner
motors.
[0013] In a further aspect the rotor assembly is a drive shaft and
a propeller located in a fin. In one aspect the drive shaft exits
the lower surface of the surfboard and enters the forward edge of
the fin, and the propeller is located in a cut out portion in the
rear of the fin. In one aspect the fin further comprises a
propeller guard.
[0014] In a further aspect the rotor assembly is a drive shaft and
water jet, and the drive shaft drives an impellor in the water jet.
In one aspect the at least one propulsion system further comprises
a scoop and a thruster tube, wherein the scoop projects from the
bottom surface of the board to draw water into the water jet and
the thruster tube directs water from the water jet to the rear of
the board where it is expelled. In one aspect the jet pump is an
all plastic jet pump.
[0015] In a further aspect the cooling system is a closed loop
system, an open loop system or a passive cooling system. The
cooling system facilitates the use of high power motors, such as
those with ratings in excess of 500 W which can provide the output
required to catch waves. The cooling system may be a liquid cooling
system. In one aspect the cooling system is a closed loop system
comprising a pump and a heat exchange region. In one aspect coolant
is pumped around the speed controller and motor and then through a
heat exchange region located on an upper surface of the board where
it exchanges heat with the surrounding environment (eg seawater).
In one aspect the cooling system is an open loop system comprising
an intake port and an exhaust port. In one aspect the intake port
is located on the lower surface in the front half of the board, and
the exhaust port is located on the upper surface in the rear of
half of the board. Seawater is drawn in and passed over the speed
controller and motor before being expelled. A pump may be used. In
one aspect a passive cooling system is used. In one aspect the
speed controller and motor are mounted in a metal heat sink box
located near or flush with a surface of the board, such as the top
surface, to exchange heat with the surrounding environment (eg
seawater), or in a housing or box containing the motor and/or other
components and one or more openings in the top surface to allow
water to flow into and out of the housing and over the motor so
that the natural flow of water is used to cool the motor.
BRIEF DESCRIPTION OF DRAWINGS
[0016] A preferred embodiment of the present invention will be
discussed with reference to the accompanying drawings wherein:
[0017] FIG. 1A is a top view of an electric powered surfboard
according to an embodiment of the present invention;
[0018] FIG. 1B is a rear view of an electric powered surfboard
according to an embodiment of the present invention;
[0019] FIG. 1C is a side view of an electric powered surfboard
according to an embodiment of the present invention;
[0020] FIG. 2A is a top view of an electric powered surfboard
according to an embodiment of the present invention;
[0021] FIG. 2B is a rear view of an electric powered surfboard
according to an embodiment of the present invention;
[0022] FIG. 2C is a side view of an electric powered surfboard
according to an embodiment of the present invention;
[0023] FIG. 3 is a perspective view of fin housing a propeller and
propeller guard according to an embodiment of the present
invention;
[0024] FIG. 4 is a top view of a compartment including the speed
controller and motor according to an embodiment of the present
invention;
[0025] FIG. 5 is a top view of a closed loop cooling system
according to an embodiment of the present invention;
[0026] FIG. 6 is a side view of a closed loop cooling system
according to an embodiment of the present invention;
[0027] FIG. 7 is a schematic view of display for monitoring the
power control system according to an embodiment of the present
invention;
[0028] FIG. 8 is a block diagram of the various functional systems
according to an embodiment of the present invention;
[0029] FIG. 9 illustrates cross sectional and underside views of
several embodiments of scoops located on the underside of the
board;
[0030] FIG. 10A is a perspective view of a motor housing to allow
passive cooling of the motor;
[0031] FIG. 10B is a a top view of the motor housing of FIG.
10A;
[0032] FIG. 10C is a side view of the motor housing of FIG.
10A;
[0033] FIG. 10D is another top view of the motor housing of FIG.
10A;
[0034] FIG. 10E is an exploded top view of another embodiment of a
motor housing;
[0035] FIG. 10F is a top view of yet another embodiment of a motor
housing including a plurality of circular holes on the top surface
thereof;
[0036] FIG. 10G illustrates a top view of yet an embodiment of a
motor housing including a plurality of diamond shaped openings on
the top surface thereof;
[0037] FIG. 11A is another perspective view of a motor housing to
allow passive cooling of the motor in accordance with the
embodiment of FIG. 10A;
[0038] FIG. 11B is a side view of the motor housing of FIG.
11A;
[0039] FIG. 11 C is a reverse perspective view of the motor housing
of FIG. 11A;
[0040] FIG. 11D is perspective view of the motor housing of FIG.
11A as it is positioned with respect to a cavity in the surfboard
to receive the motor housing;
[0041] FIG. 11E is another perspective view of the motor housing of
FIG. 11A as it is installed in the cavity in the surfboard shown in
FIG. 11D;
[0042] FIG. 11F is an perspective view of the motor housing of FIG.
11A installed in the cavity in the surfboard shown in FIG. 11D;
[0043] FIG. 11G is a partial perspective view of the surfboard
showing the motor housing of FIG. 11A installed so that the top
surface thereof is flush with the top surface of the board, and
further showing a speed controller and an open housing cover for
the speed controller;
[0044] FIG. 11H is another partial perspective view as shown in
FIG. 11G, but with the speed controller housing cover closed;
[0045] FIG. 12A is a perspective view of another embodiment of a
motor housing with a motor housing cover open, and the motor
housing located flush with the top surface of the board to allow
passive cooling of the motor;
[0046] FIG. 12B is another perspective view of FIG. 12A showing the
motor housing cover closed;
[0047] FIG. 13A illustrates a perspective view of a compartment for
housing a battery and components of the power control system being
installed into a surfboard;
[0048] FIG. 13B is an enlarged perspective view of the battery of
FIG. 13A;
[0049] FIG. 14 illustrates an electronics module encased in fibre
glass resin;
[0050] FIG. 15 illustrates a side view of the rear of an embodiment
of an electric powered surfboard;
[0051] FIG. 16A is a top view of an embodiment of an electric
powered surfboard;
[0052] FIG. 16B is a top view of another embodiment of an electric
powered surfboard;
[0053] FIG. 16C is a top view of another embodiment of an electric
powered surfboard using a single propeller based propulsion
system
[0054] FIG. 17A is a top view of a flexible drive shaft and mount;
and
[0055] 17B is a perspective view of the drive shaft, fins and
propeller of embodiments of an electric powered surfboard; and
[0056] 17C is another perspective view of the drive shaft, fin and
propeller of embodiment of the electric powered surfboard of FIG.
17A.
[0057] In the following description, like reference characters
designate like or corresponding parts throughout the figures.
DESCRIPTION OF EMBODIMENTS
[0058] Embodiments of a modular electric powered surfboard 10 will
now be described. The surfboard 10 is a conventional surfboard with
a centre of mass 11 and fins 12, which includes a series of modular
components located in compartments and conduits distributed
throughout the surfboard so as to preserve the ride and handling
characteristics of the surfboard. Preferably the modules are
distributed both longitudinally and laterally to maintain the
centre of mass of the board, or to or substantially preserved). The
modules include one or more propulsion systems, a power control
system and a cooling system and may also comprises other modules
such as a monitoring system. The one or more propulsion systems
comprise an electric motor and a rotor assembly with the power
control system controlling power to the propulsion system. The
power control system comprises a speed controller and at least one
battery. The motor and speed controller are cooled by a cooling
system. FIGS. 1A, 1B and 1C, illustrate top 100, rear 110 and side
120 views of an electric powered surfboard according to an
embodiment of the invention. In this embodiment the rotor assembly
80 comprises a draft shaft and a water jet, with the drive shaft
driving an impellor in the water jet. Embodiments of an electric
powered surfboard are further illustrated in FIGS. 16A and 16B.
FIGS. 2A, 2B and 2C, show top 200, rear 210 and side 220 views of
an electric powered surfboard according to another embodiment of
the invention. In this embodiment the rotor assembly 80 comprises a
drive shaft and a propeller located in the fin. Embodiments 10a 10b
10c of an electric powered surfboard are further illustrated in
FIGS. 16A, 16B and 16C.
[0059] Top 100, side 110 and rear 120 views of an embodiment of an
electric powered surfboard are illustrated in FIGS. 1A to 1C. In
this embodiment the surfboard 10 comprises a throttle 20, one or
more batteries 30, a display 40, a speed controller 50, a motor 60,
a cooling system 70, a rotor assembly 80 and a thrust tube 90. The
components may be grouped into a plurality of functional systems.
FIG. 8 illustrates a block diagram of the overall system 800
arranged into a propulsion system 810 comprising one or more
propulsion units 812, a power control system 820, a cooling system
830 and a monitoring system 840. Each propulsion unit 812 comprises
an electric motor 60 and a rotor assembly. In this embodiment the
rotor assembly comprises a water jet 83 in which an impeller 84 is
driven by a drive shaft 62 which draws water in via a scoop 82 and
propels the water out the rear of the board via thrust tubes 90.
Embodiments of an electric powered surfboard are further
illustrated in FIGS. 16A and 16B. In another embodiment, the rotor
assembly 80 comprises a drive shaft 62 and a propeller 86 located
in the fin 12. The fin 12 may be provided with a propeller guard
87. FIGS. 2A, 2B and 2C, show top 200, rear 210 and side 220 views
of an electric powered surfboard according to this embodiment of
the invention. FIG. 3 shows a perspective view of the fin and FIGS.
17B and 17C are rear perspective views of embodiments of an
electric powered surfboard.
[0060] The power control system comprises a throttle 20, one or
more batteries 30 and a speed controller 50 for providing and
controlling power to motors in the propulsion system in response to
the throttle. The cooling system provides cooling to the motors and
speed controller and the monitoring system includes a power monitor
and an output device for monitoring and reporting power usage and
remaining capacity to the rider. Preferably the output device is a
display 40, such as a LCD or LED display. The monitoring system may
also comprise one or more warning indicators. Multiple output
devices or indicators may be used such as a combination of a
display, warning lights and/or sounds. In addition to power usage
and capacity, the monitoring system may include sensors for
detecting high temperatures, low power, low voltage and/or loss of
the rider.
[0061] The propulsion system 810 is used to assist riders, and in
particular impaired or unskilled riders to conserve energy when
moving through the water, to assist them when moving though the
surf zone where waves are breaking and attempting to push the rider
back to shore, as well as provide the quick impulsive high thrust
needed to catch a passing wave. Each propulsion unit 812 includes
electric motor 60 which drives a shaft 62 which in turn drives a
rotor such as an impeller 84 in a water jet or a propeller 86 which
may be located in the fin. A combination of the two (ie a propeller
and water jets) could also be provided. These components are
distributed along and throughout the board to ensure the board's
original centre of gravity can be maintained. The choice of the
number of propulsion units 812 to include depends upon factors such
as available space, choice of motors, intended use and/or required
thrust. As will be discussed speed controllers and cooling systems
(and in particular liquid cooling systems) may be used to enable
the use of small light weight and powerful motors. Typically
between 1 and 4 propulsion systems will be used, although more
could be provided if space and battery power permits. In the case
of a single propulsion system this should be aligned along the
longitudinal centreline. In the case of multiple propulsion systems
these should be distributed to preserve symmetry about the
longitudinal centreline. Providing multiple propulsion systems
improves the redundancy of the system should one of the individual
propulsion systems fail.
[0062] Propeller systems generate approximately 40% more thrust
than water jet systems and thus a single propeller based propulsion
system can be used with the propeller located in the main central
fin. The fin provides a convenient mounting or housing for the
propeller and a guard can also be provided to both protect the
propeller and prevent injury to a rider (or others) as shown in
FIGS. 2A to 2C, and FIG. 3. In the embodiment shown in FIGS. 2A to
2C the guard in the plane of the fin, but other guard arrangements
which project radially (or laterally), and which enclose, cage or
shroud the propeller, whether fully or partially can be used. For
example a sphere shaped cage guard with (ie with apertures to allow
water flow) could be used or a circular shroud or ring around the
propeller could be used. A flexible drive shaft is used to drive
the propeller. In one embodiment a mount 64 is used to orient the
drive shaft from the motor down through the board so that the drive
shaft exits the lower surface of the board and enters the forward
end of a fin to drive a propeller. FIG. 17A illustrates a top view
of the drive shaft 62 and mount 64, and FIG. 17B illustrates a view
of the underside of a surfboard comprising multiple fins 12a-12e,
in which the drive shaft 62 exits the lower surface of the board
and enters the rear of central fin 12a to drive a propeller 86.
FIG. 17C shows another embodiment in which the underside of the
board comprises a single fin 12 which receives the drive shaft 62
to drive a propeller 86. As shown in FIGS. 2A to 2C and FIG. 16C
the single propeller based propulsion system is distributed along
the centreline. Systems with multiple propeller based propulsion
systems may also be used.
[0063] In the case of water jet systems, a single water jet may be
used. However using two water jets provides similar thrust levels
to a single propeller system and has additional redundancy should
one of the propulsion systems fail in use. For example as shown in
FIGS. 1A to 1C the two propulsion systems as distributed
symmetrically about the centreline so that they are mirrored about
the centreline.
[0064] Catching waves requires high thrust for the short duration
when the wave is passing the rider, and thus in order to assist
impaired or unskilled riders in catching waves (and thus being able
to enjoy the surfing experience) it is desirable that high power
motors are used in the propulsion system. Thus preferably electric
motors capable of providing high power are selected. In one
embodiment brushless DC motors which are rated with a power rating
in excess of 500 W were selected. However electric motors with
higher ratings such as 1000 W, 2000 W or even as high as 5000 W or
more may be used. Lower power motors such as 250 W, 300 W, or 400 W
may be used depending upon the system and the riders capabilities.
The electric motors may be in-runner or out-runner type motors.
In-runner motors tend to be more compact and easier to cool than
outrunner motors. However in-runner motors also tend to be less
efficient and produce less torque than out-runner motors. Thus the
choice of motor may be dictated by the type of board the motor is
to be installed in, with in-runner motors preferred when weight
sensitivity and room are key considerations (i.e. small boards) and
out-runner motors selected for us in larger stand up boards where
there is more room or when greater efficiency is a key
requirement.
[0065] A large variety of suitable motors from a range of
manufacturers have been tested with weights ranging from 200 g up
to 800 g in mass selected to meet a desired thrust level of
efficiency. Suitable motors can be sourced from a hobby supplier
such as Hobby King (www.hobbyking.com).These include HET (High End
Technology) motors such as the 600 and 700 series can-in-run
brushless motors with rpm ratings from 400 up to 2000 KV (rpm/v) or
Scorpion brushless outrunner motors with stators in the 30-50 mm
size range and with rpm ratings from 300 to 2000 KV (rpm/v). The
motor is used to drive the rotor assembly such as a propeller or an
impeller in a jet pump which draws water up from scoops or intakes
located on the underside of the board.
[0066] The propeller may be mounted in a fin. A portion may be cut
out of the fin and a bore provided to receive the drive shaft. The
size of the propeller can be chosen based upon the size of the fin,
and can range from sizes of 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60
mm or higher to obtain the desired thrust levels of efficiency. The
propeller may be manufactured from brass or other suitable
materials. Suitable propellers may be those sold under Prop Shop
Props.TM. or ABC Prop.TM. brands sourced from model boat suppliers
(eg www.hobbysupplies.com.au).
[0067] A conventional jet pump may be used or a jet pump
manufactured from all plastic or non metal composite materials to
reduce the risk of corrosion of the jet pump. Jet pump sizes can
vary size and thrust depending on the internal impeller system
which can range from impeller size of 30 mm, 40 mm, 45 mm, 50 mm or
higher to obtain the desired thrust levels of efficiency. One
suitable jet pump is a jet power 40 mm jet unit available at
http://www.jet-drive.de/index.php?option=com_virtuemart&page=shop.browse&-
category_id=11&Itemid=17.
[0068] Water is drawn into the water jet/impeller via a scoop 82
located on the underside of the board and projects below the board.
Whilst an intake with a flat (non projecting) or a cavity (eg a
scoop is taken out of the bottom of the board) may be used to draw
water into the jet pump, it has been found that the use of a scoop
which projects into the water flow helps to ram water into the
water jet and significantly increases the efficiency of the water
jet compared to the use of a flat or cavity intake. Whilst the
scoop projects into the water, and thus may create extra drag, it
increases the volume of water reduces the amount of cavitation that
can occur when a flat intake is used. The intake may take various
configurations such as those illustrated in the sectional and
underside views shown in FIG. 9. The intake may comprise solely of
a scoop 910 which projects outward from the underside of the board
912. Alternatively a scoop 910 may be used in conjunction with a
cavity 922 in the board located forward of the scoop 910. Further
the cavity may take a range of shapes such as a half cone shape
932. Preferably the scoop has a relatively low profile and is
shaped to minimise drag and cavitation effects. In one embodiment
the inlet size has (cross sectional) dimensions of approximately 40
mm (width) by 120 mm to 160 min in length. The scoop may be
constructed from plastic or rubber or other materials with
sufficient strength to hold their shape whilst moving through the
water and which are resistant to corrosion.
[0069] A thrust tube is provided after the output of the jet pump
to direct the water to the rear of the board where it can be used
to propel the surfboard forward. Preferably the thrust tubes exit
at the rear of the board and are located in the plane of the board
as illustrated in FIG. 1C. In some cases the boards may thin
towards the rear in which case the thrust tubes may extend above
and beyond the board surface. Using a thrust tube and placing the
exhaust point in the rear helps to prevent the back end from being
pulled into the water which can occur if the exhaust point is
located a short distance from the intake point on the underside of
the board. Placing the exhaust at the rear provides for a smoother
bottom surface and thus doesn't disturb the water flow on the
bottom of the board thus helping to preserve the natural ride and
performance of the board. Rear thrust tubes allow the output to be
efficient directed and can be adjusted in length or shape to suit
individual boards and lengths. FIG. 15 illustrates a close up side
view of the rear of an embodiment of an electric powered surfboard.
A scoop 82 projects out from the underside board and draws water
into the water jet/impeller module which projects slight above the
board surface. A thrust pipe 90 is embedded in the board (extending
slightly above the top surface of the board) and projects from the
rear of the board with a slight downward inclination.
[0070] The power control system 820 comprises a throttle 20, one or
more batteries 30 and a speed controller 50 for providing and
controlling power to motors in the propulsion systems in response
to the throttle. In the case of multiple propulsion units, and thus
multiple motors, a single speed controller may be used to all of
the motors or a separate speed controller may be used to control
each motor separately. A range of brushless electric speed control
(ESC) units may be used. One suitable brushless ESC unit is the
Turnigy 120A water-cooled brushless motor controller
(http://www.hobbyking.com/hobbyking/store/.sub.--8946_Turnigy_Marine.sub.-
--120A_Brushless_Boat_ESC.html). Lower amp versions may also be
used (eg the 35 A). The throttle 20 may be provided on the surface
of the board near the front to allow the user to control power
whilst leaning on the board in a prone or paddling position. This
is the typical position the user will be in when assistance is
required. A control line 21 may send the control signals to the
speed controller where they are used to control the motor to
produce the desired thrust level. Alternatively a wireless signal
could be used to transmit throttle commands to a receiver
associated with the speed controller.
[0071] The throttle may be a fully proportional throttle (eg 0-100%
power) and throttle/power selection may be received through the use
of a rotatable dial or dowel, a slider, a rocker switch
(increase/decrease), or series of buttons (increase/decrease).
Alternatively or additionally buttons or other inputs may be used
to select predetermined power levels (eg 25%, 50%, 75% 100%) or
programs which provide a predefined power level for a predefined
time period (unless terminated early by a user). For example a surf
zone program which provides constant thrust at a low to moderate
power level (eg 40%) for a period of 5 minutes to allow the rider
to transit through the surf zone could be provided and/or a wave
catching program that provides 100% thrust for 30 seconds to allow
the rider to catch a wave. The buttons may be provided in large
sizes, or otherwise provided as easy to activate inputs to
facilitate ease of activation of the desired power level or
program. The speed controller may then translate these inputs into
power levels or commands to the motor or motors. The speed
controller may control how power is distributed across the motors.
For example if three propulsion units are used, more power may be
provided to the central unit. Controls to allow thrust vectoring
may also be provided.
[0072] An on off switch may be provided on the board or on a remote
device 24 such as watch which is wearable by the user to allow them
to remotely switch off the surfboard in the event that they fall
off. Alternatively a proximity based approach could be used in
which a proximity sensor detects if an appropriate device worn or
associated with the rider (eg watch, magnetic keycard, RFID tag
located in angle cuff etc). If contact is lost for a defined period
of time (eg 10 seconds) the motors can be configured to
automatically shut off. Similarly a detachable ankle cord with a
snap fit arrangement which is designed to snap apart if the rider
falls off could be utilised. The snap fit arrangement can
incorporate a sensor, such as continuity sensor which when broken
triggers an engine shut down. Similarly a gravity switch may also
be provided detect when the board is upright or upside down, so
that the motors may be shut down when the board is upside down. The
watch or remote device could also include throttle controls if
desired, although this is less preferable than on the board surface
where they are more easily accessible when riding the board.
[0073] One or more batteries 30 may be located in a compartment,
which will typically be provided in the front half of the board to
offset the motors and jets in the rear. FIGS. 13A and 13B
illustrate an embodiment of a compartment 1300 for housing a
battery 30 and components of the power control system being
installed into a surfboard. The compartment is a box with a clear
acrylic lid to allow viewing of a display 40 contained within the
compartment. The batteries may be high energy density cells having
high discharge/recharge rates such as Lithium based batteries
including Lithium polymer, lithium ion and lithium phosphate which
have high energy density and low weight characteristics. The
internal surfboard battery voltage can range from 11 V up to 50 V
depending on the desired power levels and efficiencies for the
system. The capacity of the batteries can range from 5000 mAh hours
to as many as 100,000 mAh hours of capacity in the main operating
battery system. Batteries may be joined in series to increase
capacity. An example of a suitable battery is the Turnigy 5.0
battery which has a 5000 mAh capacity. Providing two such batteries
provides 10000 mAh capacity. A waterproof recharging connector 32
may be provided on the board to allow recharging of the batteries.
Alternatively a cover for the battery compartment may be provided
to allow removal and recharging of the batteries. A battery
controller may be provided as a module in the speed controller or
as a separate module. The battery controller may control charging
and battery balancing and additional electronics may be provided to
allow recharging from 240V AC or 12V DC supply. The speed
controller receives on/off commands, input throttle requests and
sends control signals to control the power generated by the motor
or motors. The speed controller, along with other electronics may
be encased in fibre glass resin or other materials to protect them
from water. FIG. 14 illustrates an embodiment of an electronics
module (including an electronic speed controller) 50 encased in
liquid fibre glass resin.
[0074] High power electric motors and speed controllers can
generate significant heat, which if not dealt with may lead to a
failure or reduce the motor life and thus a cooling system may be
included to prevent or minimise this risk. This provides greater
reliability and thus a safer system for use by novice, impaired or
injured riders. Suitable cooling systems 830 include liquid cooled
loop systems which may be arranged as either open loop or closed
loop systems, or systems using heat sink compartments which may be
cooled by the seawater or environment surrounding the board, or
some combination of the two. Liquid cooled loop systems direct a
fluid around specific components such as the motor, speed
controller and any other electronics or heat generating parts. A
single loop or multiple loops may be used. To more efficiently cool
the motor, a jacket may be provided through which a coolant can
flow. Intermediary materials may be used to draw heat away from the
components which are then cooled. The specific choice of cooling
system used will depend upon the number, type and power of electric
motors used.
[0075] In an open loop system seawater is drawn in through one or
more intake ports and passed over the speed controller and motors
before being expelled through one or more exhaust ports. The intake
and exhaust ports may be located on any surface, with the intake
preferably being located on the lower surface to provide improved
access to seawater during normal use. The seawater may be forced
through the coolant system through active components such as pumps
or through passive design features, or a combination of the two.
For example the design and location of the intake may be chosen so
that water will be forced (or rammed) into the coolant intake
through motion of the board through the water. Additionally or
alternatively a pressure differential may be set up between the
intake and exhaust based upon their respective locations (for
example by locating the intake on the lower surface and the exhaust
on the upper surface) or as a result of heating of the water whilst
in the system. Preferably the intake port(s) are located on the
lower side in the front half of the board, and the exhaust port(s)
are located on the upper surface in the rear half of the board. The
cooling requirements are typically such that the ports have a small
diameter in the range 5-25 mm, although bigger or smaller ports may
be used as required. A mesh or grill or other filter (including a
removable filter) may be provided to prevent fouling of the intake.
Additionally the design and location of any intake or exhaust ports
may be shaped to reduce cavitation caused by water being drawn into
the intake or flowing around the ports.
[0076] In a closed loop system no input and exhaust ports are
required and liquid coolant is pumped around the speed controller
and motor and then through a heat exchange region. The heat
exchange region maybe located in an upper region (ie near the
surface) of the board where the coolant can exchange heat with the
surrounding environment such as air or seawater flowing across the
top surface of the board. Further a non corrosive high thermal
capacity (ie efficient heat exchange) coolant can be used.
[0077] An embodiment of an open loop cooling system 70 is
illustrated in FIGS. 1A to 1C. The intake 71 is located on the
underside of the board and a tube 72 passes water to the motor and
then the speed controller before being expelled through exhaust 73
located on the upper side of the board. A top view 500 and a side
view 600 of an embodiment of a closed loop cooling system are
illustrated in FIGS. 5 and 6. A pump 510 pumps a coolant around the
motor 60 after which it is directed around the speed controller 50
before being directed to the heat exchange region 540. As
illustrated in FIG. 6, the heat exchange region may be just below
the upper or top surface 610 of the board 610 whereas the motor and
speed controller may be located more centrally between the upper
surface 610 and the lower surface 620 of the board.
[0078] FIG. 4 shows a top view of a compartment which contains a
speed controller 50 and a motor 60. In this case the motor and the
speed controllers are both provided with cooling jackets which
surround the components. Such cooling jackets may be used in either
open loop or closed loop systems.
[0079] In another embodiment a passive (ie pump free) cooling
system may be used in which the flow or presence of surrounding sea
water is used to cool electronics components such as the speed
controller and motor, or housings containing such components. In
one embodiment the speed controller and motor are placed or mounted
in a metal heat sink box using thermally conductive paste which is
then sealed. The metal heat sink box is then mounted or located
near or flush with a surface of the surfboard (such as the upper
surface) to exchange heat with the surrounding environment (eg by
seawater washing over the board). FIGS. 12A and 12B illustrate an
embodiment of a metal motor housing 1200 which is located flush
with the top surface of the board to allow passive cooling of the
motor 60. FIG. 12A illustrates an open housing (ie prior to
sealing) containing the motor and electronic speed controller, and
FIG. 12B illustrates the housing with the cover 1210 in place.
[0080] In other embodiments, a housing 1000 for containing a motor
60 may be constructed with one or more openings in the top surface
to allow the seawater to penetrate into (and out of) the box to
cool the motor. This will be referred to as the motor housing
although it is to be understood that the housing may contain other
components. In these embodiments the movement of the board, or the
natural wave movement of seawater (when the board is stationary)
will naturally force flow through cooling in which seawater flows
into the box, around the can of the motor and then out of the box.
The one or more openings may a series of grills, holes, or
apertures, and may be of different sizes. FIGS. 10A to 10G
illustrate various views and embodiments of a motor housing 1000 to
allow passive cooling of the motor. FIG. 10A illustrates a
perspective view 1010 of a housing in the shape of a rectangular
box; FIG. 10B illustrates a top view 1020; and FIG. 10C illustrates
a side view 1030. The housing houses a motor 60 connected to a
shaft 62 and front drive coupling which connects the motor to the
electronic speed controller. A plurality of openings 1022 allow
water to flow in (arrows 1034), circulate and cool the motor 60,
mix with water in the rear of the housing and then exiting via an
opening (or openings) in the rear of the housing (arrows 1035). In
this embodiment the openings 1022 comprise a plurality of narrow
elongate openings (ie a grill) over the motor and a rear section
which extends from the rear of the motor to form a pool with a
large opening in the top surface to allow water to easily flow out
from the housing box. In FIG. 10B the top surface is shaded, and
portions of the motor and shaft are visible through openings 1022.
Hidden portions of the motor 60, motor coupling wires 23 and shaft
62, openings 1022 and wall 1033 are shown as dotted lines in FIGS.
10B and 10C.
[0081] In one embodiment the housing is constructed from a box 1031
with a removable top surface 1040 (ie a lid). In one embodiment the
box is constructed out of acrylic. In this embodiment the box
includes an internal wall 1033 which divides the box into a rear
section (or portion) 1032 though which water can flow via openings
in the top surface, and a front section (or portion) 1034 which
houses the front drive coupling of the motor which couples the
motor to the electronic speed controller via wiring 23 and which is
sealed to prevent the ingress of water. In other embodiments this
also houses the electronic speed controller, and may house other
electronic components and wiring. The wall 1033 contains an opening
for receiving the front portion or section of the motor so that the
motor spans the front and rear sections. The wall may act as a
mount for the motor, or other elements maybe used to securely mount
the motor in place. Once the motor is received in the opening in
internal wall 1033, the front section is sealed to prevent water
ingress in to the front section. An access panel can be provided in
the top surface of the front section to provide for simple access
to the front drive coupling so that maintenance can be performed as
required. In another embodiment the front section is not sealed and
instead the motor coupling is sealed against water ingress through
the use of sealant such as encasing the motor coupling in fibre
glass resin.
[0082] The top surface 1040 may be divided into different potions
or sections. In one embodiment these comprise a rear portion 1044
with a single large opening, a mid portion 1046 located over the
middle of the motor with openings comprises of a plurality of
narrow elongate openings to form a grill, and a front portion 1048
with no openings which covers at least the front section 1034 (ie
forward of internal wall 1033). In one embodiment the top surface
1040 is formed from a plurality of panels. FIG. 10E illustrate an
exploded top view of an embodiment of a top surface 1050 having a
separate rear panel 1052, a separate middle panel 1054 and a
separate front panel 1056. The rear panel has a single opening 1052
and the middle panel has a plurality of openings 1055. Each panel
can be separately removed to allow internal access to the box, such
as to allow for motor maintenance or replacement/upgrade as
required.
[0083] FIG. 10F illustrates a top view of an embodiment of a
housing 1060 in which the openings (apertures) are in the form of a
plurality of circular holes 1062. Similarly FIG. 10G illustrates a
top view of an embodiment of a housing 1070 in which the top
surface is a grid (or mesh) in which the openings (apertures) are
in the form of a plurality of diamond shaped openings 1072 between
the structural members forming the grid.
[0084] FIGS. 11A to 11H illustrate installation of an embodiment of
motor housing 1000 shown in FIG. 10A into a surfboard. FIGS. 11A to
11C show various views of housing constructed from acrylic. The top
surface is provided in 3 panels, with the middle panel located over
the motor and including three elongate openings (which extend along
the shaft axis) to allow water to flow in, and a rear panel with a
large central rectangular opening to allow water to flow out of the
housing. FIGS. 11D to 11F illustrate placement of the housing in a
cavity made in the surfboard which has been cut to size to receive
the housing. FIG. 11G shows the motor housing located in the
surfboard so that the top surface is flush with the top surface of
the board, along with a further metal housing for the electronic
speed controller which is located forward (to the right in FIG.
11G) of the motor housing. The speed controller circuit board is
also shown just prior to installation in the metal housing. FIG.
11G shows the completed housings for the motor and electronic speed
controller which are located flush with the top surface of the
board to allow passive cooling of these components.
[0085] Such passive or natural cooling systems provide an abundant
and endless supply of cooling liquid without the need for tubing,
piping and high-pressure water cooling jackets to cool the
brushless motor system. This increases efficiency in build times
and improves overall simplicity and reliability of the entire jet
board. In particular, this cooling system may be used effectively
with larger boards using out-runner motors where space is less of
an issue and provides an efficient and low maintenance cooling
system (although it is to be understood that passive cooling
systems can be used with in-runner motors as well).
[0086] The monitoring system 840 includes a power monitor which
provides real time, or near real time monitoring of the battery
usage and remaining battery capacity. The power monitor may also
monitor and report other parameters such as current (amps), battery
voltage, power, battery temperature, motor temperature or even
motor RPM. The battery capacity may be reported in milli-Amp hours
(mAh) or reported as a percentage of total capacity and/or
estimated time remaining based upon known battery capacity. The
remaining capacity is effectively a fuel gauge indicating to the
user how much available power there is remaining. The estimate of
remaining capacity may be based upon the difference between known
capacity and actual usage. This may be expressed as the remaining
capacity or as an estimate of the time remaining at the current
usage level. A memory may be used to store historical values or
averages of past usage to allow estimates of the remaining capacity
based upon past use. The reporting system may use a digital display
device 40. The display device may be mounted on the surface of the
board, within a compartment with a viewing window, or the display
device may be in a remote device in wireless communication with the
power monitor. An example of a display device is shown in FIG. 7 in
which the display 700 is split into 4 portions 710 720 730 and 740,
and separately reports current, temperature, power and remaining
capacity.
[0087] The monitoring system may include additional warning sensors
and indicators. These warning sensors may include temperature
sensors and low voltage or low power sensors. The display device 40
may display warnings or separate indicators such as LED's or
audible alarms may be used. Other sensors such as pressure sensors,
gravity sensors, or proximity sensors may be may be used to
determine if the rider is on the board or the board is upright, to
allow deactivation of motors in case the rider comes off the
board.
[0088] An example of a compartment including a motor, speed
controller and power monitor and display is illustrated in FIG. 4.
The speed controller 50 receives power via electrical connectors 21
from the batteries (or a battery controller) and controls motor 60
via electrical connectors 52. The temperature of the speed
controller is measured by sensor 53 and reported by display 54. A
power sensor 55 measures battery usage which is also provided to
the display for reporting instantaneous power usage and remaining
capacity. The speed controller also includes a wireless receiver 56
for receiving on/off commands from a remote device 24. A suitable
power monitor and display is the eloggerV4 and PowerPanel LCD
display manufactured by Eagletree systems. The elogger monitors the
capacity and usage of the batteries and the motor, and has inputs
for sensors such as temperature and power and can display the
results in the PowerPanel LCD display. However other
microcontrollers and displays may be used.
[0089] The electric surfboard may be constructed from a
conventionally constructed surfboard from which compartments and
conduits have been cut out to receive the various components. To
preserve the ride and handling of the assembled board, the
components are distributed throughout the board (ie both
longitudinally and laterally) so as to maintain the centre of
gravity. The components may be sealed in place or provided with
access panels as required.
[0090] The electric surfboard may be constructed by obtaining a
conventionally constructed surfboard (eg polyurethane or
polystyrene foam covered with layers of fibreglass, cloth and
polyester or epoxy resin) and cutting out compartments and conduits
for receiving various components, or the compartments and conduits
may be included during manufacture. The compartments may empty when
installed, or may be preloaded with components. A combination of
the techniques may be used. Once the various components are
inserted into the components, the compartments may then be sealed
within the board, or provided with externally accessible plates to
allow access to the components. Preferably the components are
distributed around the board to preserve the original centre of
mass and to preserve the ride and handling characteristics of the
board. Preferably the batteries are placed near the front and the
motor is toward the rear of the board.
[0091] The electric surfboard described herein is well suited to
use by impaired or unskilled riders as it allows them to conserve
energy and assists them when getting to the waves and to catch
them. The use of a cooling system allows high power motors to be
provided to assist in catching waves where rapid acceleration (ie a
short impulse) is required. High power motors can use significant
power and thus a monitoring system and displays can also be
provided to allow the rider to continuously monitor how much power
they are using and how much power is left. This is very important
to allow riders with impairments or little skill to control power
management and remaining energy levels and ensure they have
sufficient power to safely return to the shore. Various other
sensors and reporting systems can be used to ensure independent
propulsion systems are used and are constructed using modular
distributed components. A range of thrust levels can be obtained
through selection of the number and type of motors. Further the
modular design offers greater reliability as each part of the
system is separate allowing for individual parts to be replaced or
upgraded at any time without having to remove the entire system.
Also the use of modular compartments allows for accurate spacing of
the jet pumps and equipment to maintain existing centre of gravity
for all individual board designs so the ride and handling is not
significantly affected. Further multiple independent propulsion
systems provides redundancy so that if one propulsion system (or
part thereof) fails, other independent systems can continue to
operate and ensure the rider can safely return to shore.
[0092] More generally the modular compartment design allows all the
parts to be located into any board exactly where they are needed to
be to ensure the board's original centre of gravity can be
maintained. This ensures the ride remains as natural as possible
with power ON or OFF. Also different motor power options can be
selected to achieve different power options, thrust levels and run
times. This allows customisation of the power system to an
individual, the board and the intended surf conditions. Further
individual parts can be selected as required based on the board and
replaced as required. Finally all this can be provided in such a
way that the ride and handling characteristics are preserved so
that unskilled or impaired riders can more fully enjoy the surfing
experience.
[0093] Those of skill in the art would understand that information
and signals may be represented using any of a variety of
technologies and techniques. For example, data, instructions,
commands, information, signals, bits, symbols, and chips may be
referenced throughout the above description may be represented by
voltages, currents, electromagnetic waves, magnetic fields or
particles, optical fields or particles, or any combination
thereof.
[0094] Those of skill in the art would further appreciate that the
various illustrative logical blocks, modules, circuits, and
algorithm steps described in connection with the embodiments
disclosed herein may be implemented as electronic hardware,
computer software, or combinations of both. To clearly illustrate
this interchangeability of hardware and software, various
illustrative components, blocks, modules, circuits, and steps have
been described above generally in terms of their functionality.
Whether such functionality is implemented as hardware or software
depends upon the particular application and design constraints
imposed on the overall system. Skilled artisans may implement the
described functionality in varying ways for each particular
application, but such implementation decisions should not be
interpreted as causing a departure from the scope of the present
invention.
[0095] Throughout the specification and the claims that follow,
unless the context requires otherwise, the words "comprise" and
"include" and variations such as "comprising" and "including" will
be understood to imply the inclusion of a stated integer or group
of integers, but not the exclusion of any other integer or group of
integers.
[0096] The reference to any prior art in this specification is not,
and should not be taken as, an acknowledgement of any form of
suggestion that such prior art forms part of the common general
knowledge.
[0097] It will be appreciated by those skilled in the art that the
invention is not restricted in its use to the particular
application described. Neither is the present invention restricted
in its preferred embodiment with regard to the particular elements
and/or features described or depicted herein. It will be
appreciated that the invention is not limited to the embodiment or
embodiments disclosed, but is capable of numerous rearrangements,
modifications and substitutions without departing from the scope of
the invention as set forth and defined by the following claims.
* * * * *
References