NZ704805B2 - Centrifugal de-clutch - Google Patents
Centrifugal de-clutch Download PDFInfo
- Publication number
- NZ704805B2 NZ704805B2 NZ704805A NZ70480512A NZ704805B2 NZ 704805 B2 NZ704805 B2 NZ 704805B2 NZ 704805 A NZ704805 A NZ 704805A NZ 70480512 A NZ70480512 A NZ 70480512A NZ 704805 B2 NZ704805 B2 NZ 704805B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- centrifugal
- clutch
- flexures
- flexure
- motor
- Prior art date
Links
- 230000036316 preload Effects 0.000 claims abstract description 11
- 239000002131 composite material Substances 0.000 claims description 6
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 5
- 239000004917 carbon fiber Substances 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 229910000831 Steel Inorganic materials 0.000 claims description 2
- 238000005452 bending Methods 0.000 claims description 2
- 239000010959 steel Substances 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 150000002739 metals Chemical class 0.000 claims 1
- 230000000712 assembly Effects 0.000 description 4
- 230000015654 memory Effects 0.000 description 3
- 238000004590 computer program Methods 0.000 description 2
- 239000000789 fastener Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000003287 optical Effects 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 230000001070 adhesive Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000004761 kevlar Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
- B64C11/02—Hub construction
- B64C11/04—Blade mountings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C27/00—Rotorcraft; Rotors peculiar thereto
- B64C27/32—Rotors
- B64C27/46—Blades
- B64C27/473—Constructional features
- B64C27/48—Root attachment to rotor head
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C29/00—Aircraft capable of landing or taking-off vertically, e.g. vertical take-off and landing [VTOL] aircraft
- B64C29/0008—Aircraft capable of landing or taking-off vertically, e.g. vertical take-off and landing [VTOL] aircraft having its flight directional axis horizontal when grounded
- B64C29/0016—Aircraft capable of landing or taking-off vertically, e.g. vertical take-off and landing [VTOL] aircraft having its flight directional axis horizontal when grounded the lift during taking-off being created by free or ducted propellers or by blowers
- B64C29/0025—Aircraft capable of landing or taking-off vertically, e.g. vertical take-off and landing [VTOL] aircraft having its flight directional axis horizontal when grounded the lift during taking-off being created by free or ducted propellers or by blowers the propellers being fixed relative to the fuselage
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D43/00—Automatic clutches
- F16D43/02—Automatic clutches actuated entirely mechanically
- F16D43/04—Automatic clutches actuated entirely mechanically controlled by angular speed
- F16D43/14—Automatic clutches actuated entirely mechanically controlled by angular speed with centrifugal masses actuating the clutching members directly in a direction which has at least a radial component; with centrifugal masses themselves being the clutching members
- F16D2043/145—Automatic clutches actuated entirely mechanically controlled by angular speed with centrifugal masses actuating the clutching members directly in a direction which has at least a radial component; with centrifugal masses themselves being the clutching members the centrifugal masses being pivoting
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D43/00—Automatic clutches
- F16D43/02—Automatic clutches actuated entirely mechanically
- F16D43/04—Automatic clutches actuated entirely mechanically controlled by angular speed
- F16D43/14—Automatic clutches actuated entirely mechanically controlled by angular speed with centrifugal masses actuating the clutching members directly in a direction which has at least a radial component; with centrifugal masses themselves being the clutching members
- F16D43/18—Automatic clutches actuated entirely mechanically controlled by angular speed with centrifugal masses actuating the clutching members directly in a direction which has at least a radial component; with centrifugal masses themselves being the clutching members with friction clutching members
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D59/00—Self-acting brakes, e.g. coming into operation at a predetermined speed
- F16D59/02—Self-acting brakes, e.g. coming into operation at a predetermined speed spring-loaded and adapted to be released by mechanical, fluid, or electromagnetic means
-
- Y10T477/816—
-
- Y10T477/847—
-
- Y10T477/86—
Abstract
Centrifugal de-clutch (100) to prevent a rotor from rotating below a threshold speed. The de-clutch is coupled to a motor including a rotating part and stationary part, and comprises: a ring including an inner circumference and an outer circumference, the ring including a plurality of flexures (103) extending circumferentially in a same direction along the inner circumference of the ring. Each of the plurality of flexures (103) includes a first end (107) and a second end (109), the first end (107) of each flexure extending from the inner circumference of the ring and each flexure extending circumferentially along the inner circumference of the ring from the first end (107) of the flexure to the second end of the flexure; and a plurality of friction pads (101), each friction pad (101) coupled to one of the plurality of flexures; wherein each of the plurality of flexures (103) is configured to preload the friction pad (101) coupled to the flexure against the stationary part of the motor to engage the centrifugal de-clutch; and wherein each of the plurality of flexures (103) is configured to bend outward to disengage the friction pad (101) coupled to the flexure from the stationary part of the motor to allow the rotating part to freely rotate above the speed threshold extending circumferentially in a same direction along the inner circumference of the ring. Each of the plurality of flexures (103) includes a first end (107) and a second end (109), the first end (107) of each flexure extending from the inner circumference of the ring and each flexure extending circumferentially along the inner circumference of the ring from the first end (107) of the flexure to the second end of the flexure; and a plurality of friction pads (101), each friction pad (101) coupled to one of the plurality of flexures; wherein each of the plurality of flexures (103) is configured to preload the friction pad (101) coupled to the flexure against the stationary part of the motor to engage the centrifugal de-clutch; and wherein each of the plurality of flexures (103) is configured to bend outward to disengage the friction pad (101) coupled to the flexure from the stationary part of the motor to allow the rotating part to freely rotate above the speed threshold
Description
CENTRIFUGAL DE-CLUTCH
Inventor:
Geoffrey A. Long
BACKGROUND
Field of the Invention
This disclosure describes mechanical mechanisms that mechanically prevent a rotor
from rotating below a threshold speed, but allow the rotor to rotate freely above the
threshold speed.
Description of Related Art
The rotary wing aircraft, or helicopter, is one common type of vertical takeoff and
landing (VTOL) aircraft. VTOL aircraft have large rotors that provide either or both both
vertical and horizontal thrust. Often, when a rotor is not being used, the rotor is kept
stationary.
Conventional systems typically use a motor that is coupled to the rotor and
adapted to prevent the rotor from rotating when it is not in use. The motor applies a torque
to keep the rotor stationary. Thus, conventional systems require the supply of energy to the
motor in order to reject disturbance torques that would cause the rotor to rotate. Supplying
the energy required to keep the rotor stationary drains energy from a battery that provides
the energy to the motor and also causes the motor to generate unwanted heat.
SUMMARY
Aspects of the present invention are described herein and in New Zealand
specification 619855, from which the present specification is divided. Reference may be
made in the description to subject matter which is not in the scope of the appended claims
but relates to subject matter claimed in the parent specification. That subject matter should
be readily identifiable by a person skilled in the art and may assist putting into practice the
invention as defined in the appended claims.
In accordance with an aspect of the present invention, there is provided a
centrifugal de-clutch coupled to a motor including a rotating part and stationary part, the
centrifugal de-clutch comprising: a ring including an inner circumference and an outer
circumference, the ring including a plurality of flexures extending circumferentially from the
inner circumference of the ring in a same direction along the inner circumference of the ring,
each of the plurality of flexures including a first end and a second end, the first end of each
flexure extending from the inner circumference of the ring and each flexure extending
circumferentially along the inner circumference of the ring from the first end of the flexure
to the second end of the flexure; and a plurality of friction pads, each friction pad coupled to
one of the plurality of flexures; wherein each of the plurality of flexures is configured to
preload the friction pad coupled to the flexure against the stationary part of the motor to
resist rotation of the rotating part below a speed threshold of the rotating part to engage the
centrifugal de-clutch; and wherein each of the plurality of flexures is configured to bend
outward to disengage the friction pad coupled to the flexure from the stationary part of the
motor to allow the rotating part to freely rotate above the speed threshold to disengage the
centrifugal de-clutch.
The described embodiments provide a centrifugal de-clutch. The centrifugal de-
clutch is a mechanical mechanism that mechanically prevents a rotor of an aircraft from
rotating. The centrifugal de-clutch comprises a plurality of high friction pads, a plurality of
flexures, and a plurality of stop tabs according to one embodiment.
In one embodiment, a rotor assembly of an aircraft comprises a rotor, a motor
comprising a stationary part and a rotating part, and the centrifugal de-clutch. In particular,
the centrifugal de-clutch is coupled to the rotating part of the motor such that the flexures of
the de-clutch preload the high friction pads against the stationary part of the motor. The
high friction pads prevent the rotor from rotating until the motor generates enough torque
to overcome the friction force generated by the friction pads. As the rotational speed of the
rotor increases, a proof mass that is mounted to or that is a part of each flexure applies a
centrifugal force on the friction pads that counteracts the flexure preload. Above a certain
speed threshold, the friction pads are completely disengaged from the stationary part of the
motor, thereby allowing the rotor to rotate freely.
The features and advantages described in this summary and the following
detailed description are not intended to be limiting. Many additional features and
advantages will be apparent to one of ordinary skill in the art in view of the drawings,
specification and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 illustrates a centrifugal de-clutch in accordance with one embodiment.
Figs. 2 illustrates a rotor assembly including the centrifugal de-clutch in
accordance with one embodiment.
Figs. 3A and 3B respectively illustrate the centrifugal de-clutch when engaged
and disengaged in accordance with one embodiment.
Fig. 4 illustrates a view of a personal aircraft vehicle that incorporates the
centrifugal de-clutch in accordance with one embodiment.
The figures depict, and the detail description describes, various non-limiting
embodiments for purposes of illustration only. One skilled in the art will readily recognize
from the following discussion that alternative embodiments of the structures and methods
illustrated herein may be employed without departing from the principles described herein.
DETAILED DESCRIPTION
Fig. 1 illustrates a centrifugal de-clutch 100 in accordance with one embodiment.
The centrifugal de-clutch 100 is a mechanical mechanism that mechanically prevents a rotor
of an aircraft from rotating. In one embodiment, the centrifugal de-clutch is constructed out
of metal (e.g., steel, titanium, or aluminum) or composite material (e.g., carbon fiber or
Kevlar). Note that in other embodiments other materials may be used to construct the
centrifugal de-clutch.
In one embodiment, the centrifugal de-clutch is a circular ring comprising a
plurality of friction pads 101, a plurality of flexures 103, and a plurality of stop tabs 105. The
friction pads 101 are composed of brake pad material (asbestos, organic, or semi-metallic
formulations) that provide a high coefficient of friction such as .1 to 5. Note that other
coefficients of friction may be used. The flexures 103 are curved arms each comprising a
first end 107 and a second end 109 according to one embodiment. In one embodiment, the
flexures 103 are “L” shaped. The first end 107 of a flexure 103 is connected to the centrifugal
de-clutch 100. The second end 109 of each flexure 103 is not connected to the centrifugal de-
clutch and is coupled to a friction pad 101. A friction pad 101 may be coupled to the second
end of a flexure 103 using adhesive or other mechanisms such as fasteners (e.g., screws or
rivets).
The stop tabs 105 prevent the flexures 103 from moving outside of a predefined
range of movement. The stop tabs 105 thus prevent the flexures 103 from being damaged
(i.e., breaking). As shown in Fig. 1, the stop tabs 105 protrude toward the center of the
centrifugal de-clutch 100. In one embodiment, the stop tabs 105 are positioned on the
centrifugal de-clutch 100 at a location proximate to the second end 109 of the flexures 103.
Referring now to Fig. 2, a rotor assembly 200 is illustrated in accordance with one
embodiment. The rotor assembly 200 includes a rotor 201 that in one embodiment has a 16
inch radius, and is made from carbon fiber composite material, and in an alternative
embodiment from carbon fiber composite blades attached to an aluminum hub. In other
embodiments, rotor 201 is made from wood blades attached to an aluminum hub, or wood
blades attached to a carbon fiber composite hub. The rotor may be a single piece that bolts
onto the motor assembly. The rotor 201 may comprise blades attached to a hub, or may be
manufactured as a single piece with an integral hub. The hub provides a central structure to
which the blades of the rotor 201 connect, and in some embodiments is made in a shape that
envelops the motor.
In one embodiment, the rotor assembly 200 also includes a motor. The motor
includes a rotating part 203 (portion) and a stationary part 205. In one embodiment the
rotating part 203 is concentric to the stationary part 205, known as a radial flux motor. In
this embodiment, the stationary part 205 may form the inner ring of the motor, known as an
outrunner motor. In some embodiments the motor parts are low-profile so that the entire
motor fits within the hub of the rotor, presenting lower resistance to the air flow when flying
forward. The rotor 201 is attached to the rotating part 203 of the motor. Thus, when the
rotating part 203 of the motor rotates, the rotor 201 also rotates. The stationary part 205 of
the motor is attached to the propulsion boom of the aircraft. In some embodiments, the
motor is a permanent magnet motor and is controlled by an electronic motor controller. The
electronic motor controller sends electrical currents to the motor in a precise sequence to
allow the rotor 201 to turn at a desired speed or with a desired torque.
As shown in Fig. 2, the centrifugal de-clutch 100 is included in the rotor assembly
200. In one embodiment, the centrifugal de-clutch 100 is coupled to the rotating part 203 of
the motor via fasteners such as screws or rivets. The centrifugal de-clutch is mounted to the
rotating part 203 of the motor such that the flexures 103 preload the high friction pads 101
against the stationary part 205 of the motor included in the rotor assembly 200. When the
rotating part 203 of the motor is stationary, the high friction pads 101 press against the
stationary part 203 of the motor preventing the rotor 201 from rotating. That is, the friction
provided by the friction pads 101 resists motion. Fig. 3A illustrates the centrifugal de-clutch
100 when engaged. Particularly, Fig. 3A shows a flexure 103 preloading a friction pad 101
against the stationary part 205 of the motor when the rotating part 203 of the motor is not
rotating or is rotating below a speed threshold.
If the motor provides a torque that overcomes the friction torque provided by the
flexures 103 preloading the friction pads 101 on the stationary part 205 of the motor, the
rotating part 203 of the motor rotates thereby causing the rotor 201 to also rotate. When the
rotating part 203 is rotating, a proof mass that is mounted to or is a part of each flexure 103
applies a centrifugal force on the high friction pad 101 mounted on each flexure 103. The
centrifugal force counteracts the preload on the stationary part 205 provided by the flexures
103.
As the speed of the rotating part 203 of the motor increases, the centrifugal force
increases resulting in reduced friction torque because the flexures 103 begin to bend away
from the stationary part 205 of the motor thereby disengaging the friction pads 101. At a
threshold speed, the friction pads 101 are completely disengaged from the stationary part
205 of the motor allowing the rotating part 203 and rotor 201 to rotate freely without any
friction torque from the friction pads 101. In particular, the centrifugal force at the threshold
rotational speed causes the flexures 103 to bend outward thereby resulting in the friction
pads 101 no longer being in contact with the stationary part 205 of the motor. The stop tabs
105 prevent the flexures 103 from bending too far outward and causing damage to the
flexures 103. Fig. 3B illustrates the friction pad 101 completely disengaged from the
stationary part 205 of the motor. As shown in Fig. 3B, the friction pad 101 is no longer in
contact with the stationary part 205 of the motor and the second end 109 of the flexure 103 is
in contact with the stop tab 105. As the speed of the rotating part 203 of the motor decreases
below the threshold speed, the flexures 103 begin to preload the friction pads 101 against the
stationary part 205 of the motor as shown in Fig. 3A.
Proof Mass Calculation
As mentioned previously, a proof mass that is mounted to or is a part of each
flexure 103 applies a centrifugal force on high friction pad 101 mounted on each flexure 103.
In one embodiment, the proof mass is calculated according to the following variables:
• τ = torque applied by the centrifugal de-clutch;
• = speed at which there is no torque applied by the centrifugal de-clutch;
• = force of the friction pad 101 on the stationary part 205 of the motor;
• = = friction force;
• = radius of the stationary part 205 of the motor;
• = mass of the proof mass; and
• = coefficient of friction of the friction pad 101.
Assume that the flexures 103 provides a preload torque such that 0 =
= . The preload at 0 rpm represents the desired brake torque provided by the de-
clutch 100. In one embodiment, the centrifugal force is represented as a function of the
above variables as shown below:
= −
= − (1)
=
= −
= − (2)
As described in equation (1), the force of the friction pad 101 on the stationary
part 205 of the motor at speed is equal to the force of the friction pad on the motor at zero
RPM ( minus the magnitude of the centripetal force of the proof mass ( . The
torque ( at speed is derived by substituting equation (1) into the equation for torque
( .
If is specified, equation (2) can be simplified to determine the mass of the
proof mass as represented by equation (3) shown below:
0 = −
= (3)
Based on equation (3), if is 10 Nm, R is 2.75 inches, is 500 revolutions per
minute (rpm), and is 0.5, then the mass of the proof mass is 3.3 pounds for example. If
is changed to 1,500 rpm, then the proof mass is 0.4 pounds for example.
Aircraft
Referring now to Fig. 4, an aircraft 400 is illustrated that incorporates the rotor
assembly 200 shown in Fig. 2. The aircraft 400 uses the rotor assemblies 200 for vertical lift.
Specifically, the rotor assemblies 200 provide enough thrust to lift the aircraft 400 off the
ground and maintain control. When at an appropriate altitude, in one embodiment the rotor
assemblies 200 are turned off since they are used for vertical lift. Forward flight propellers
401 are used for forward propulsion. The centrifugal de-clutch 100 described above keeps
the rotor assemblies 200 stationary when not in use according to the description above.
Although this description has been provided in the context of specific
embodiments, those of skill in the art will appreciate that many alternative embodiments
may be inferred from the teaching provided. Furthermore, within this written description,
the particular naming of the components, capitalization of terms, the attributes, data
structures, or any other structural or programming aspect is not mandatory or significant
unless otherwise noted, and the mechanisms that implement the described invention or its
features may have different names, formats, or protocols. Further, some aspects of the
system including components of the flight computer 500 may be implemented via a
combination of hardware and software or entirely in hardware elements. Also, the particular
division of functionality between the various system components described here is not
mandatory; functions performed by a single module or system component may instead be
performed by multiple components, and functions performed by multiple components may
instead be performed by a single component. Likewise, the order in which method steps are
performed is not mandatory unless otherwise noted or logically required.
Unless otherwise indicated, discussions utilizing terms such as “selecting” or
“computing” or “determining” or the like refer to the action and processes of a computer
system, or similar electronic computing device, that manipulates and transforms data
represented as physical (electronic) quantities within the computer system memories or
registers or other such information storage, transmission or display devices.
Electronic components of the described embodiments may be specially
constructed for the required purposes, or may comprise one or more general-purpose
computers selectively activated or reconfigured by a computer program stored in the
computer. Such a computer program may be stored in a computer readable storage
medium, such as, but is not limited to, any type of disk including floppy disks, optical disks,
DVDs, CD-ROMs, magnetic-optical disks, read-only memories (ROMs), random access
memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, application specific
integrated circuits (ASICs), or any type of media suitable for storing electronic instructions,
and each coupled to a computer system bus.
Finally, it should be noted that the language used in the specification has been
principally selected for readability and instructional purposes, and may not have been
selected to delineate or circumscribe the inventive subject matter. Accordingly, the
disclosure is intended to be illustrative, but not limiting, of the scope of the invention.
The term “comprising” as used in this specification and claims means “consisting
at least in part of”. When interpreting statements in this specification and claims which
include the term “comprising”, other features besides the features prefaced by this term in
each statement can also be present. Related terms such as “comprise” and “comprised” are
to be interpreted in a similar manner.
Claims (12)
1. A centrifugal de-clutch coupled to a motor including a rotating part and stationary part, the centrifugal de-clutch comprising: a ring including an inner circumference and an outer circumference, the ring including a plurality of flexures extending circumferentially from the inner circumference of the ring in a same direction along the inner circumference of the ring, each of the plurality of flexures including a first end and a second end, the first end of each flexure extending from the inner circumference of the ring and each flexure extending circumferentially along the inner circumference of the ring from the first end of the flexure to the second end of the flexure; and a plurality of friction pads, each friction pad coupled to one of the plurality of flexures; wherein each of the plurality of flexures is configured to preload the friction pad coupled to the flexure against the stationary part of the motor to resist rotation of the rotating part below a speed threshold of the rotating part to engage the centrifugal de-clutch; and wherein each of the plurality of flexures is configured to bend outward to disengage the friction pad coupled to the flexure from the stationary part of the motor to allow the rotating part to freely rotate above the speed threshold to disengage the centrifugal de-clutch.
2. The centrifugal de-clutch of claim 1, wherein the ring further includes a plurality of stop tabs protruding from the inner circumference towards the center of the ring, each stop tab configured to prevent at least one of the plurality of flexures from bending beyond a position of the stop tab.
3. The centrifugal de-clutch of claim 1, wherein the centrifugal de-clutch is made from a metal selected from a group of metals consisting of aluminum, steel, and titanium.
4. The centrifugal de-clutch of claim 1, wherein the centrifugal de-clutch is made from a composite material.
5. The centrifugal de-clutch of claim 4, wherein the composite material comprises carbon fiber.
6. The centrifugal de-clutch of claim 1, wherein each flexure curves from the first end to the second end.
7. The centrifugal de-clutch of claim 1, wherein each of the plurality of friction pads is coupled to a second end of one of the plurality of flexures.
8. The centrifugal de-clutch of claim 1, wherein the plurality of friction pads is made of brake pad material.
9. The centrifugal de-clutch of claim 1, wherein the plurality of flexures are configured to reengage the plurality of friction pads to the stationary part of the motor when a speed of the rotor decreases below the speed threshold.
10. The centrifugal de-clutch of claim 1, wherein the plurality of flexures are configured to disengage the plurality of friction pads from the stationary part of the motor due to centrifugal force applied by a mass of each of the plurality of flexures.
11. The centrifugal de-clutch of claim 1, further comprising a plurality of proof masses, each proof mass coupled to a flexure.
12. The centrifugal de-clutch of claim 11, wherein the plurality of flexures are configured to disengage the plurality of friction pads from the stationary portion of the motor due to centrifugal force applied by the plurality of proof masses.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/298,154 US8602942B2 (en) | 2011-11-16 | 2011-11-16 | Centrifugal de-clutch |
US13/298,154 | 2011-11-16 | ||
NZ619855A NZ619855B2 (en) | 2011-11-16 | 2012-11-14 | A rotor assembly with a centrifugal de-clutch |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ704805A NZ704805A (en) | 2016-01-29 |
NZ704805B2 true NZ704805B2 (en) | 2016-05-03 |
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