U.S. patent application number 14/272839 was filed with the patent office on 2015-11-12 for coaxial counter-rotating unmanned helicopter.
This patent application is currently assigned to Hirobo Co., Ltd.. The applicant listed for this patent is Hirobo Co., Ltd.. Invention is credited to Shunichi Suzuki, Takakazu Uebori.
Application Number | 20150321754 14/272839 |
Document ID | / |
Family ID | 54367142 |
Filed Date | 2015-11-12 |
United States Patent
Application |
20150321754 |
Kind Code |
A1 |
Uebori; Takakazu ; et
al. |
November 12, 2015 |
Coaxial Counter-Rotating Unmanned Helicopter
Abstract
To configure the yaw axis control mechanism of a coaxial
counter-rotating unmanned helicopter to be able to accurately
control the pitch angle of the upper rotor blade by a simple
configuration even if the precise adjustment is not performed. A
rudder control rod is inserted into a main mast of a coaxial
counter-rotating helicopter, a lower end portion thereof is
connected to an output lever of the rudder servo, and a mixing rod
head is fixed to an upper end portion. A link mechanism connected
to the upper swash plate is attached to a side surface portion of
the mixing rod head, the vertical displacement of the mixing rod
head moving up and down together with the rudder control rod is
converted into a displacement for tilting an upper blade holder
around the spindle via the link mechanism, thereby changing the
pitch angle of the upper rotor blades.
Inventors: |
Uebori; Takakazu;
(Fuchu-shi, JP) ; Suzuki; Shunichi; (Fuchu-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hirobo Co., Ltd. |
Fuchu-shi |
|
JP |
|
|
Assignee: |
Hirobo Co., Ltd.
Fuchu-shi
JP
|
Family ID: |
54367142 |
Appl. No.: |
14/272839 |
Filed: |
May 8, 2014 |
Current U.S.
Class: |
244/17.23 |
Current CPC
Class: |
B64C 2201/042 20130101;
B64C 2201/146 20130101; B64C 27/10 20130101; B64C 39/024 20130101;
B64C 27/605 20130101; B64C 2201/141 20130101; B64C 2201/024
20130101; G05D 1/0011 20130101 |
International
Class: |
B64C 27/10 20060101
B64C027/10; G05D 1/00 20060101 G05D001/00; B64C 39/02 20060101
B64C039/02 |
Claims
1. A coaxial counter-rotating unmanned helicopter comprising upper
and lower main rotors attached to a rotary shaft rotating in
opposite directions to each other on a same axis provided on a main
mast to fly by changing a pitch angle of rotor blades of the upper
and lower main rotors by tilting upper and lower swash plates,
wherein the helicopter has a configuration in which a rudder
control rod is inserted into the main mast, a rudder servo is
connected to a lower end portion of the rudder control rod
protruding from a lower end portion of the main mast via a link
mechanism, and the rudder control rod moves up and down by an
operation of the rudder servo, a mixing rod head is fixed to an
upper end portion of the rudder control rod protruding from an
upper end portion of the main mast, the link mechanism configured
to connect an upper blade holder rotatably mounted to a yoke of the
upper main rotor and the upper swash plate is mounted to both right
and left side portions of the mixing rod head, and the other end
portion of an adjusting rod having one end portion connected to a
rudder stopper plate attached to the yoke of the upper main rotor
is connected to both front and rear sides of the mixing rod head,
the mixing rod head moving up and down along with the rudder
control rod by the operation of the rudder servo is supported by
the rudder stopper plate and the adjusting rod, and the vertical
displacement of the mixing rod head is converted into a
displacement of tilting the upper blade holder around a spindle via
the link mechanism to change a pitch angle of the upper rotor
blade, thereby providing a difference in the pitch angles of the
rotor blades of the upper and lower main rotors.
2. The coaxial counter-rotating unmanned helicopter according to
claim 1, wherein the helicopter has a configuration in which the
upper and lower main rotors are provided so that gyro precession of
each of the main rotors as an output with respect to an operation
input from the upper and lower swash plates appears within a range
smaller than 90.degree., mounting positions of the upper and lower
main rotors are provided at an angle smaller than 90.degree. around
the main mast with respect to input positions of each of cyclic
controls to the upper and lower main rotors using the upper and
lower swash plates, and the upper and lower main rotors and the
upper and lower swash plates are connected to one another via the
link mechanism.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a coaxial counter-rotating
unmanned helicopter in which upper and lower main rotors rotating
in opposite directions to each other are provided on a main mast
and which flies by a remote control or an autonomous control.
[0003] 2. Description of Related Art
[0004] A coaxial counter-rotating helicopter is configured to
simultaneously achieve a generation of lift and an offset of torque
by rotating upper and lower main rotors disposed coaxially along
the main mast in opposite directions to each other, and a direction
control (a control of a yaw axis) of a nose of an aircraft changed
to a tail rotor is achieved by providing a difference in pitch
angles of the rotor blades in the upper main rotor and the lower
main rotor in a variable pitch type.
[0005] In this case, in a configuration in which the tilting of the
upper and lower main rotors are individually controlled by a
method, such as attaching a servo to the main mast, to provide a
difference in the pitch angles of the upper and lower rotor blades,
mechanisms around the main mast become significantly complicated
(for example, see Patent Document 1).
[0006] Therefore, a configuration has been known in which an inner
shaft is provided inside a main mast in a vertically movable
manner, a relay link device connected via an upper swash plate, a
rod, and a link arm is disposed in a portion between an upper main
rotor of the main mast and the upper swash plate, a connecting rod
provided vertically downward through a yoke of the upper main rotor
from a leading end of the inner shaft is connected to the relay
link device, the inner shaft is vertically moved to vertically
displace the relay link device, as a result, a fixed arm of the
upper main rotor connected to the upper swash plate via the rod is
rotationally moved to change a pitch angle of a rotor blade, and
thus, a control of a yaw axis of an aircraft is performed (for
example, see Patent Document 2).
RELATED ART
Patent Document
[0007] [Patent Document 1] JP 62-12500 A
[0008] [Patent Document 2] JP 2002-316699 A
SUMMARY OF THE INVENTION
[0009] In the above-described related art, since the relay link
device is disposed between the upper main rotor and the upper swash
plate, there has been a problem in that a distance between the
upper and lower main rotors becomes necessarily longer, which makes
it difficult to form a compact aircraft, and a degree of freedom of
an aircraft design is also limited. Furthermore, since the
connecting rod is caused to pass through the interior of the yoke
for fixing the upper main rotor to the main mast, strength of the
yoke is low, and there has been a structural problem in that the
connection portion between the upper main rotor and the main mast
to which great force is applied during flight is likely to be
damaged.
[0010] Furthermore, since the link arm is attached to a peripheral
surface of the relay link device and the rod connected to the upper
swash plate disposed immediately below is connected to the link
arm, a vertical operation region along the main mast of the relay
link device is very small, and even when the relay link device is
slightly moved up and down, the pitch angle of the rotor blade
controlled by the upper swash plate greatly changes.
[0011] In other words, since an amount of change in the pitch angle
of the rotor blade with respect to an amount of displacement of the
relay link device moved up and down by the inner shaft is very
great, it is difficult to adjust an amount of operation range of
the link mechanism so that the pitch angle of the rotor blade is
precisely and accurately set, and since it is difficult to perform
the yaw axis control of the aircraft by slightly adjusting the
pitch angle, it is difficult to achieve satisfactory operability
and flight stability in the remote control type.
[0012] Furthermore, in various forms of remote control helicopters
(hereinafter, collectively referred to as an R/C helicopter),
including a coaxial counter-rotating R/C helicopter, as a result of
verifying a position where the gyro precession of the main rotor
with respect to the operation input of the swash plate appears, the
present applicant has found that the gyroscopic precession appears
within a range smaller than 90.degree. with respect to the
operation input from the swash plate, regardless of the weight of
the main rotor blade.
[0013] It is reasonable that the main rotor is disposed at a
position where the gyro precession actually appears, and thus, it
is believed that operability and flight stability of the coaxial
counter-rotating R/C helicopter may be improved.
[0014] In view of such problems of the related art, an object of
the present invention is to make an accurate control of the pitch
angle of the upper rotor blade possible even when a precise
adjustment is not performed, by providing a simple yoke axis
control mechanism of a coaxial counter-rotating unmanned helicopter
in which members such as a rod and a relay link for a yaw axis
control are not disposed around the main rotor, and to stabilize
the flight operation of the coaxial counter-rotating unmanned
helicopter including the yaw axis control, thereby improving the
operability.
[0015] According to an aspect of the invention for solving the
above-described problems, there is provided a coaxial
counter-rotating unmanned helicopter in which upper and lower main
rotors are attached to a rotary shaft rotating in opposite
directions to each other on the same axis provided on a main mast,
and which flies by changing a pitch angle of rotor blades of the
upper and lower main rotors by tilting upper and lower swash
plates, in which the helicopter has a configuration in which a
rudder control rod is inserted into the main mast, a rudder servo
is connected to a lower end portion of the rudder control rod
protruding from a lower end portion of the main mast via a link
mechanism, and the rudder control rod moves up and down by an
operation of the rudder servo, a mixing rod head is fixed to an
upper end portion of the rudder control rod protruding from an
upper end portion of the main mast, the link mechanism configured
to connect an upper blade holder rotatably mounted to a yoke of the
upper main rotor and the upper swash plate is mounted to both right
and left side portions of the mixing rod head, and the other end
portion of an adjusting rod having one end portion connected to a
rudder stopper plate attached to the yoke of the upper main rotor
is connected to both front and rear side portions of the mixing rod
head, the mixing rod head moving up and down along with the rudder
control rod by the operation of the rudder servo is supported by
the rudder stopper plate and the adjusting rod, and a vertical
displacement of the mixing rod head is converted into a
displacement of tilting the upper blade holder around a spindle via
the link mechanism to change a pitch angle of the upper rotor
blade, thereby providing a difference in the pitch angles of the
rotor blades of the upper and lower main rotors.
[0016] Furthermore, according to the invention, the coaxial
counter-rotating unmanned helicopter of the above-described
configuration has a configuration in which the upper and lower main
rotors are provided so that gyro precession of each of the main
rotors as an output with respect to an operation input from the
upper and lower swash plates appears within a range smaller range
than 90.degree., mounting positions of the upper and lower main
rotors are provided at an angle smaller than 90.degree. around the
main mast with respect to input positions of each of cyclic
controls to the upper and lower main rotors using the upper and
lower swash plates, and the upper and lower main rotors and the
upper and lower swash plates are connected to one another via the
link mechanism.
[0017] According to the present invention, the helicopter is
configured so that the mixing rod head is fixed to an upper end
portion of the rudder control rod projecting from the upper end
portion of the main mast through the rudder control rod which
operates up and down within the main mast, and the link mechanism
connected to the upper swash plate is attached to a side surface
portion of the mixing rod head, that is, the upper part of the
upper main rotor, the input from the upper swash plate and the
vertical displacement of the mixing rod head accompanied by the
vertical movement of the rudder control rod are mixed with each
other by the link mechanism and are transmitted to the upper blade
holder, the pitch angle of the upper rotor blade changes by tilting
of the upper blade holder, and a difference is generated in the
pitch angles of the lower main rotor and the rotor blade.
[0018] Since the member for controlling the yaw axis is installed
above the upper main rotor, there is no need to set a distance
between the upper and lower main rotors longer than necessary, a
degree of freedom of the aircraft design increases compared to the
related art, and the compact aircraft can be formed.
[0019] Further, the mixing rod head as a vertically displacing
member is installed on the upper end of the rudder mixing rod, a
large arrangement interval is set between the mixing rod head and
the upper swash plate, and both members are connected by the link
mechanism. Thus, by providing a certain degree of large vertical
operating range of the mixing rod head and setting an amount of
changing the pitch angle of the upper rotor blade in response to
the operating range, even when the amount of operation range of the
link mechanism is not subtly adjusted, it is possible to precisely
and accurately control the pitch angle of the upper rotor blade to
a predetermined angle. Since it is possible to perform the yaw axis
control of the aircraft by precisely controlling the pitch angle of
the upper rotor blade, it is possible to obtain the satisfactory
operability and flight stability in the remote control type.
[0020] Furthermore, according to the present invention, in response
to the appearance of the gyro precession of the main rotor as the
output with respect to the operation input from the swash plate
within a range smaller than 90.degree., by adjusting the phase
angle of the upper and lower main rotors with respect to the
operation input from the swash plate to a range of an acute angle
rather than 90.degree. and attaching the main motors to the main
mast, respectively, even when various setting positions of the
aircraft and the transmitter are not precisely adjusted, it is
possible to stabilize the flight operation of the unmanned
helicopter, thereby dramatically improving the operability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a front view and a side view of an R/C helicopter
equipped with a rotor head of an embodiment of the present
invention.
[0022] FIG. 2 is an enlarged external perspective view as a front
perspective view and a rear perspective view of the aircraft of a
state in which a cowl of the R/C helicopter of FIG. 1 is
removed.
[0023] FIG. 3 is an external perspective view of the rotor head
illustrating an enlarged lower main rotor side of the aircraft of
FIG. 2.
[0024] FIG. 4 is an external perspective view of the rotor head
illustrating an enlarged upper main rotor side of the aircraft of
FIG. 2.
[0025] FIG. 5 is an external view of the upper main rotor portion
of a state of removing the rotor blades of the aircraft of FIG.
2.
[0026] FIG. 6 is a schematic transverse cross-sectional view of the
aircraft of FIG. 2 (break line is omitted for clarity).
[0027] FIG. 7 is a diagram illustrating an arrangement relation
between an input position of a cyclic control of a swash plate
around the main mast and the main rotors, FIG. 7(A) illustrates a
conventional rotor head, and FIG. 7(B) illustrates a rotor head of
the present invention.
[0028] FIG. 8 is a side view of a gear box unit of an aircraft of
FIG. 2.
[0029] FIG. 9 is a side view of the gear box unit when raising the
mixing rod head from the state of FIG. 8.
[0030] FIG. 10 is a side view of the gearbox unit when lowering the
mixing rod head from the state of FIG. 8.
DESCRIPTION OF THE INVENTION
[0031] A preferred embodiment of the invention will be described
with reference to the drawings.
[0032] FIG. 1 illustrates an external form of an R/C helicopter
equipped with a rotor head of an embodiment of the invention. As
illustrated, the present embodiment is an application of the
invention to a coaxial counter-rotating R/C helicopter having upper
and lower main rotors that coaxially counter-rotate to each other.
In FIG. 1, reference numeral 1 is an R/C helicopter, 2 is a cowl,
and 3 is a battery that drives an electric motor to be described
later.
[0033] FIG. 2 illustrates an external form of a front side and a
rear side of an aircraft of the R/C helicopter 1 in a state of
removing the cowl 2. As illustrated in FIG. 2, an aircraft 4 is
configured so that respective unitized members, such as a gearbox
unit 6 formed by assembling an electric motor 8 to a rotor head 7
to which the upper and lower main rotors are attached, a motor
control box 9 in which a control circuit of the electric motor 8 is
housed, a servo control box 10 in which control circuits of each
servo are housed, skids 11, and a receiver of a steering signal
(not illustrated) are integrally attached to an aircraft frame 5
configured by assembling pipes made of aluminum in a frame shape.
Reference numeral 12 is a ducted motor cover which accommodates a
motor fan for cooling the electric motor 8 therein.
[0034] As illustrated in FIGS. 3 to 6, the rotor head 7 is
configured to include members such as a main mast 13, upper and
lower main rotors 14 and 15, swash plates 16 and 17, an elevator
servo ES, an aileron servo AS, a pitch servo PS, and a rudder RS,
and rods that connect actuating units of these members to one
another to constitute a link mechanism.
[0035] Specifically, the main mast 13 is configured so that an
upper main mast 13b longer than a hollow lower main mast 13a is
mounted on the interior of the hollow lower main mast 13a and is
coaxially disposed, as illustrated in FIG. 6, bevel gears 18a and
18b fixed to each of lower end portions of both masts are engaged
and connected to a bevel gear 18c fixed to an output shaft of the
electric motor 8 installed below the main mast 13, and both masts
rotate in opposite directions to each other by driving the electric
motor 8.
[0036] A rudder mixing rod 13c is slidably inserted into the upper
mainmast 13b along an inner circumferential surface of the upper
main mast 13b, the upper end portion of the rudder mixing rod 13c
projects above the main mast 13, a mixing rod head 26 to be
described later is integrally f fixed thereto, and an end portion
of a rudder push-pull arm 19 is connected to a lower end portion
thereof via a bearing.
[0037] The mixing rod head 26 is attached to the upper main rotor
15 via a rudder stopper plate 31 and an adjusting rod 28 that will
be described later, and rotates integrally with the upper main
rotor 15 within the main mast 13.
[0038] The other end portion of the rudder push-pull arm 19 is
pivotally supported at one end portion of a rudder mixing arm 20
attached below the main mast 13 in a state in which a center
thereof is rotatably pivotally supported, the other end portion of
the rudder mixing arm 20 is connected to the other end portion of
the rudder push-pull arm 19, one end of which is connected a
downward output lever 34 connected to the servo horn of the rudder
servo RS (see FIG. 6).
[0039] As illustrated in FIG. 3, the lower main rotor 14 is
constituted by a lower yoke 14a integrally fixed to an outer
periphery of the lower main mast 13a, a pair of lower blade holders
14b and 14b rotatably attached to both right and left sides of the
lower yoke 14a about an axial direction perpendicular to the main
mast 13, and lower rotor blades 14c and 14c that are integrally
attached to the lower blade holders 14b and 14b at a predetermined
pitch angle by interposing between the base end portions of the
lower blade holders 14b and 14b from both upper and lower surfaces
and allowing a bolt to pass therethrough.
[0040] The lower yoke 14a is integrally fixed with a lower radius
block 21 on a circumferential surface portion of the lower yoke 14a
integrally fixed to an outer circumferential surface of the lower
main mast 13a, and a lower radius arm 22 connected to the lower
radius block 21 is integrally connected to a lower rotary swash 16b
of a lower swash plate 16 to be described later.
[0041] Furthermore, end portions of mixing arm lowers 23 and 23
rotatably attached to the lower yoke 14a about the axial direction
perpendicular to the mast 13 as a fulcrum are rotatably connected
to the lower blade holders 14b and the 14b respectively, via the
lower pitch arm 24.
[0042] The other end portions of the mixing arm lowers 23 and 23
are connected to the upper end portions of the adjusting rods 25
and 25 vertically disposed parallel to the mast 13, and the lower
end portions of the adjusting rods 25 and 25 are connected to the
lower rotary swash 16b of the lower swash plate 16.
[0043] The lower main rotor 14 is configured so that the tilting
motion of the lower swash plate 16 to be described later is
transmitted to the lower blade holders 14b and 14b via the
adjusting rod 25, the mixing arm lower 23, and the lower pitch arm
24, while rotating integrally with the lower main mast 13a, and the
entire lower main rotor 14 is appropriately tilted in accordance
with titling of the lower blade holders 14b and 14b about the axis
direction perpendicular to the main mast 13, thereby changing the
pitch angle of the lower rotor blades 14c and 14c.
[0044] As illustrated in FIG. 4, the upper main rotor 15 is
configured in the same manner as the lower main rotor 14, by an
upper yoke 15a integrally fixed to the outer periphery of the upper
main mast 13b, a pair of upper blade holders 15b and 15b attached
to both right and left sides of the upper yoke 15a so as to be
freely rotatable around the axial direction perpendicular to the
main mast 13, and upper rotor blades 15c and 15c integrally
attached to the upper blade holders 15b and 15b at a predetermined
pitch angle by interposing the base end portions of the upper blade
holders 15b and 15b from both upper and lower surfaces and allowing
a bolt to pass therethrough.
[0045] Above the upper main rotor 15, the mixing rod head 26 is
attached to the end portion of the rudder mixing rod 13c protruding
from the upper end of the main mast 13. Upper mixing arms 27 and 27
are attached to both right and left sides of the mixing rod head 26
positioned above the upper yoke 15a so as to be freely rotatable
about the axis direction, as a fulcrum, perpendicular to the mast
13. Furthermore, the adjusting rods 28 and 28, which are freely
rotatable about the axial direction, as a fulcrum, perpendicular to
the mast 13 and disposed along the axial direction of the upper
main rotor 15, are attached to both front and rear sides of the
mixing rod head 26.
[0046] Upper pitch arms 29 and 29 are attached to one side of the
upper blade holders 15b and 15b, and the end portion of the upper
pitch arm 29 is connected to a shaft unit provided in an
intermediate portion of the mixing arm upper 27 via an adjusting
rod 30. Furthermore, as illustrated in FIG. 5, a rudder stopper
plate 31 is attached to the upper yokes 15a and 15a, and the other
end portion of the adjusting rod 28 connected to the mixing rod
head 26 at one end is connected to the end portion of the rudder
stopper plate 31. The rudder stopper plate 31 and the adjusting rod
28 have also a function that supports the mixing rod head 26 so
that the mixing rod head 26 moving up and down along the main mast
13 is not twisted by force exerted with the rotation of the main
mast 13 during flight.
[0047] Furthermore, the end portions of the mixing arm uppers 27
and 27 are connected to the mixing arm upper 32 pivotally supported
on the outer circumferential surface of the upper yoke 15a via the
adjusting rod 40, and the mixing arm upper 32 is connected to an
upper top rotary swash 17b of an upper swash plate 17 to be
described later via an adjusting rod 33 that is pivotally supported
to the end portion.
[0048] The upper main rotor 15 is configured so that the tilting
motion of the upper swash plate 17 to be described later is
transmitted to the upper blade holders 15b and 15b via the
adjusting rod 33, the mixing arm upper 32, the upper mixing arm 27,
and the upper pitch arm 29, while rotating integrally with the
upper main mast 13b, and the entire upper main rotor 15 is
appropriately tilted in accordance with titling of the upper blade
holders 15b and 15b about the axis direction perpendicular to the
main mast 13, thereby changing the pitch angle of the upper rotor
blades 15c and 15c.
[0049] Furthermore, in the upper main rotor 15, as will be
described below, when vertically moving the rudder mixing rod 13c
along the mast 13 by actuating the rudder RS, the rudder mixing rod
13c and the mixing rod head 26 fixed to the upper end thereof are
vertically displaced, the upper mixing arms 27 and 27 vertically
rotate in response to the displacement, thereby mixing and
transmitting the input from an upper top rotary swash 17b to be
described later to the upper blade holders 15b and 15b, the pitch
angle of the upper rotor blades 15c and 15c changes to provide a
difference between the pitch angle of the upper main rotor 15 and
the pitch angle of the lower main rotor 14 so that the yaw axis
control of the R/C helicopter 1 is performed.
[0050] As illustrated in FIG. 3, the lower swash plate 16 is
configured so that the lower rotary swash 16b is rotatably
supported on the upper side of the lower fixing swash 16a via a
bearing (not illustrated). The main mast 13 passes through an
opening formed in the center thereof and is tiltably mounted about
the axis of the direction perpendicular to the mast around the
mast.
[0051] Each servo of the an elevator servo ES, the aileron servo
AS, and the pitch servo PS is installed below the lower swash plate
16, thereby connecting an upward output lever 34 connected to each
of the servo horns to the outer circumferential three sides of the
lower fixing swash 16a, respectively.
[0052] The lower rotary swash 16b is attached to the lower yoke 14a
via the lower radius arm 22 and the upper radius block 21 to rotate
integrally with the lower main mast 13a. Furthermore, the lower end
portions of the adjusting rods 25 connected to the mixing arm lower
23 at the upper end portion are connected to the opposed positions
of the outer circumferential surface of the lower rotary swash 16b,
the lower end portions of the four adjusting rods 35 are connected
to the outer circumferential four sides, and the upper end portions
of the adjusting rods 35 are connected to the outer circumferential
four sides of the upper bottom rotary swash 17a of the upper swash
plate 17 to be described below.
[0053] As illustrated in FIG. 4, the upper swash plate 17 is
configured so that the upper top rotary swash 17b is rotatably
supported on the upper side of the upper bottom rotary swash 17a
via a bearing (not illustrated). The main mast 13 passes through an
opening formed at the center thereof and is tiltably attached about
the axis of the direction perpendicular to the mast around the
mast.
[0054] Furthermore, the outer circumferential four sides of the
upper bottom rotary swash 17a are connected to the outer
circumferential four sides of the lower rotary swash 16b via the
adjusting rod 35, are fixed to the lower yoke 14a via the upper
radius block 36 and the upper radius arm 37, and are attached so as
to rotate integrally with the lower main rotor 14.
[0055] Furthermore, the upper top rotary swash 17b is fixed to the
upper radius block 39 fixed to the outer circumferential surface of
the upper main mast 13b via the upper radius arm 38 to rotate
integrally with the upper main mast 13b along with the upper main
rotor 15.
[0056] Furthermore, the lower end portions of the adjusting rod 33
connected to the mixing arm upper 32 at the upper end portion are
connected to the opposed positions of the outer circumferential
surface of the upper top rotary swash 17b, respectively.
[0057] In the lower swash plate 16 and the upper swash plate 17,
when driving the elevator servo ES, the aileron servo AS, or the
pitch servo PS to move up and down the upward output lever 34
connected to each servo horn, the lower fixing swash 16a and the
lower rotary swash 16b of the lower swash plate 16 are tilted
around the main mast 13 in response to the position of the output
lever 34 moving up and down, and along with the tilting of the
lower rotary swash 16b, the upper and lower rotary swashes 17a and
17b of the upper swash plate 17 are attached to tilt around the
main mast 13 in parallel to the lower swash plate 16.
[0058] Furthermore, in the conventional R/C helicopter, as
illustrated in FIG. 7(A), on the basis of the finding that the gyro
precession appears to be delayed by 90.degree. with respect to the
input, the rudder is input at a position delayed by 90.degree. with
respect to the rotary direction R of the main rotor MR using this,
that is, the swash plate is tilted at a position delayed by
90.degree. with respect to the rotary direction of the main rotor
MR, and the operation input SI is input to the main rotor MR via
the adjusting rod to change the pitch angle of the main rotor
MR.
[0059] In contrast, in the arrangement of the lower main rotor 14
and the lower swash plate 16 around the lower main mast 13a in this
embodiment, on the basis of the finding that the gyro precession
appears within a range smaller than 90.degree., in response
thereto, as illustrated in FIG. 7(B), the mounting position of the
lower main rotor 14 is provided to become an angle smaller than
90.degree. around the lower main mast 13a with respect to the input
position of the cyclic control to the lower main rotor 14 using the
lower swash plate 16, that is, at the position where an angle of
intersection in a plan view between line segments in the
longitudinal axis direction of the lower main rotor 14 and the
position of the operation input of the lower rotary swash 16b that
is input to the lower main rotor 14 via the adjusting rod 25
becomes an acute phase angle .alpha..
[0060] Moreover, the lower main rotor 14 and the lower rotary swash
16b are connected by the adjusting rod 25, and the operation input
of the lower rotary swash 16b is input to the lower main rotor 14
at a position advanced by the acute phase angle .alpha., thereby
changing the pitch angle.
[0061] In addition, in the arrangement of the upper main rotor 15
and the upper swash plate 17 around the upper main mast 13b, in the
same manner as described above, the mounting position of the upper
main rotor 15 is provided to become an angle smaller than
90.degree. around the upper main mast 13b with respect to the input
position of the cyclic control using the upper swash plate 17, and
an angle of intersection in a plane view between the line segments
in the longitudinal axis direction of the upper main rotor 15 and
the position of the operation input of the upper top rotary swash
17b that is input to the upper main rotor 15 via the adjusting rod
33 becomes the acute phase angle .alpha..
[0062] Moreover, the upper main rotor 15 and the upper top rotary
swash 17b are connected by the adjusting rod 33, and the operation
input of the upper top rotary swash 17b is input to the upper main
rotor 15 at a position advanced by the acute phase angle .alpha.,
thereby changing the pitch angle.
[0063] In addition, the operation input positions of each of the
upper and lower swash plates 16 and 17, and the mounting positions
of the upper and lower main rotors 13 and 14 may be set to be
advanced or delayed by a relatively suitable acute angle around the
upper and lower main masts 16a and 16b so as to become the acute
phase angle .alpha..
[0064] The yaw axis control of the R/C helicopter 1 of the present
embodiment configured as described above is performed as
follows.
[0065] First, as illustrated in FIG. 8, in a state in which there
is no difference in the pitch angles of the rotor blades 14c and
15c of the upper and lower main rotors 14 and 15, the output lever
34 of the rudder servo RS is held at an intermediate position of
the operating range thereof.
[0066] From this state, when lowering the output lever 34 by
operating the rudder RS, as illustrated in FIG. 9, the rudder
mixing rod 13c which is loaded in the main mast 13 and rotates
integrally with the upper main mast 13b rises, and the upper mixing
rod head 26 fixed to the upper end portion is displaced upward.
[0067] The upper mixing arms 27 and 27 rotatably attached to the
upper mixing rod head 26 rotate around the mounting part in
response to the displacement, the end portion is displaced
downward, the displacement and the input from the upper top rotary
swash 17b connected to the upper mixing arms 27 and 27 via the
adjusting rod 33, the mixing arm upper 32, and the adjusting rod 40
are mixed with each other, and are converted into a displacement
that tilts the upper blade holders 15b and 15b around the spindles
of the upper yokes 15a and 15a. Moreover, the converted
displacement is transmitted to the upper blade holders 15b and 15b
via the upper pitch arms 29 and 29, the upper blade holders 15b and
15b and the upper rotor blades 15c and 15c are tilted to change the
pitch angle, as a result, a difference is generated in the pitch
angles of the lower main rotor 14, and the yaw axis control of the
aircraft is performed.
[0068] In contrast, when raising the output lever 34 of the rudder
servo RS, as illustrated in FIG. 10, the rudder mixing rod 13c and
the upper mixing rod head 26 are displaced downward, and in
response to this displacement, the end portions of the upper mixing
arms 27 and 27 are displaced upward. Moreover, the displacement and
the input from the upper top rotary swash 17b are mixed with each
other, converted into a displacement for tilting the upper blade
holders 15b and 15b, and transmitted to the upper blade holders 15b
and 15b via the upper pitch arms 29 and 29, the upper blade holders
15b and 15b and the upper rotor blades 15c and 15c are tilted in
the direction opposite to the above-described direction to change
the pitch angle, a difference is generated between the pitch angle
of the upper main rotor 15 and the pitch angle of the lower main
rotor 14, and thus, the yaw axis control of the aircraft is
performed.
[0069] Furthermore, according to the R/C helicopter of this
embodiment, when driving the elevator servo ES, the aileron servo
AS or the pitch servo PS to move up and down the output lever 34
connected to each servo horn, in response to the position of the
output lever 34 moving up and down, the lower swash plate 16 and
the upper swash plate 17 are appropriately tilted around the main
mast 13, and according to this, the tilting of the lower rotary
swash 16b is transmitted to the lower main rotor 14 via the
adjusting rod 25 to tilt the lower main rotor 14 and change the
pitch angle of the lower rotor blades 14c and 14c, and the tilting
of the upper top rotary swash 17b is transmitted to the upper main
rotor 15 via the adjusting rod 33 to tilt the upper main rotor 15
and change the pitch angle of the upper rotor blades 15c and
15c.
[0070] Along with tilting of the upper and lower main rotors 14 and
15 and the change in the pitch angles of the rotor blades 14c and
15c, the gyro precession is applied to each of the upper and lower
main rotors 14 and 15, but the gyro precession appears to be
delayed within a range smaller than 90.degree. with respect to the
rotary direction of each of the upper and lower main rotors 14 and
15.
[0071] In this embodiment, as illustrated in FIG. 7(B), in response
to the appearance of the gyro precession within the range smaller
than 90.degree., the mounting positions of the upper and lower main
rotors 14 and 15 are set so as to form a phase angle .alpha.
smaller than 90.degree. around the main mast 13 with respect to the
input position of the cyclic control to the upper and lower main
rotors 14 and 15 using the upper and lower swash plates 16 and 17,
and are connected to the upper and lower main rotors 14 and 15 via
a link mechanism at the input positions of each of the upper and
lower swash plates 16 and 17, and the operation inputs of the upper
and lower swash plates 16 and 17 are input to each of the upper and
lower main rotors 14 and 15 at the position of the acute phase
angle .alpha., thereby changing the pitch angle of each of the
rotor blades 14c and 15c.
[0072] Accordingly, along with the change of the pitch angles of
the rotor blades 14c and 15c of each of the upper and lower main
rotors 14 and 15, the direction of force of the gyro precession
acting on the aircraft matches the direction for controlling the
aircraft, thereby making it possible to stabilize the flight
operation of the R/C helicopter.
EXAMPLES
[0073] An industrial coaxial counter-rotating R/C helicopter
equipped with the rotor head of this embodiment was constituted.
The rotor blade was made of FRP, and a weight of a piece was 2 kg.
The total weight of the aircraft including electrical equipment
such as a motor, a receiving device, and a battery was 92 kg.
[0074] The phase angle .alpha. (a phase difference of the
arrangement with respect to the operation input) illustrated in
FIG. 7(B) between the operation input position of the upper and
lower swash plates with respect to the upper and lower main rotors
and the upper and lower main rotors was set to approximately
35.degree..
COMPARATIVE EXAMPLE
[0075] The upper and lower main rotors was disposed similar to the
conventional R/C helicopter illustrated in FIG. 7(A) using the same
aircraft and rotor blades as the above-described embodiment, that
is, disposed so that the mounting positions of the upper and lower
main rotors with respect to the operation input of the swash plate
become a phase angle of 90.degree., thereby constituting the
coaxial counter-rotating R/C helicopter.
[0076] When allowing the R/C helicopter of a comparative example to
fly by the remote control, the operation of causing the aircraft to
go straight was difficult, and behavior bent in a direction of
either left or right occurred. When operating the operation stick
of the transmitter to correct this, the flight attitude was lost,
which makes it difficult to smoothly control the flight direction
of the aircraft.
[0077] In contrast, even when the R/C helicopter of the embodiment
was operated to fly in any direction of front, rear, left or right,
it smoothly flew in the operation direction, and it was possible to
stably control the flight direction without losing the flight
attitude.
[0078] In addition, the illustrated embodiment is an example, the
present invention is also applicable to a coaxial counter-rotating
R/C helicopter of other suitable forms or a coaxial
counter-rotating unmanned helicopter that flies by the autonomous
control. The invention is also applicable to a relatively large
industrial R/C helicopter, an unmanned R/C helicopter, a hobby R/C
helicopter flying outdoors, or an indoor compact lightweight R/C
helicopter.
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