Note: Descriptions are shown in the official language in which they were submitted.
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~ P F C ~ F I C A T I O N
VARIABLE C~PACIT~7 ~ HEEL '~IECHANISM
This invention relates to a variable capacity flywheel
mechallism which is coupled to the rotary shaf, of the engine of
2 motorcycle or an automobile. More particularly, the invention
relates to a main flywheel and an auxiliary flywheel together
with novel mechainism for connecting them in driving relationship.
It is known to provide flywheel mechanisn in which the
inertial moment is not constant, but is diffe-:ent for high and
15w engine speeds. F`or example, a ~7ariahle capacity flywheel
mechanism i5 known which has its inertial moment automatically
varied in proportion to engine r.p.m.
In another variable capacity flywheel mechanism
~nown in the prior art, a mair. flywheel and an auxiliar~7 fly-
wheel are engaged and disengaged in accordarlce with the low and
high speed ranges, respectively, of ,he engine, and this is
1.5 accomplished by the action of a centrifugal clutch, so -tha~
the inertial moment mav be changed.
In the variable capacity flywheel }~echanism usillg
such a centrifugal clutch, however, the clutch repeats the
enaagemen.t and disengagement when the r.p.n~. G th_ engille
~0 shaft is near the ,hreshold value of the o~era-tion of- the
cent-iugal clutch. The clutch exerts as a ~riction damper its
action upon the rotary shaft, i.e., the crankshaft sustains a
power loss, thereby inviting deterioration in the fuel economy
of the engine. In case abrupt deceleration is efEected from
that threshold value, moreover, the centrifugal clutch is
insufficien-tly responsive, so that i~ cannot pro~ptly follow
the abrupt deceleration of the rotary shaft and thereby fails
to couple the auxiliary flywheel to the main flywheel. It may
therefore be possible for the engine to fail to maintain
rotations in the idling speed range, so that the engine stops.
The present invention provides a variable capacity
flywheel mechanism which avoids the problems outlined above and
which uses an electromagnetic clutch to provide reliable opera-
tion and quick response.
In particular the present invention provides a vari-
able capacity flywheel mechanism for an engine having a rotary
shaft comprising: a main flywheel coupled to the rotary shaft,
an auxiliary flywheel, means for supplying a magnetizing signal,
and an electromagnetically actuable clutch for selectively
coupling said main flywheel and said auxiliary flywheel in
response to the magnetizing signal, said electromagnetically
actuable clutch including material therein which partially
couples said main flywheel and said auxiliary flywheel.
The present invention still further provides in a
variable capacity flywheel mechanism for an engine having a
rotary shaft, the combination of: a main flywheel adapted for
connection to the rotary shaft, an auxiliary flywheel, an
electromagnetic clutch for connecting said flywheels for con-
joint operation, said electromagnetic clutch being of the
friction-disk type, means for generating a magne-tizing signal
to operate said electromagnetic clutch, and oil supply means
for supplying oil into clearance spaces between the friction
disks of the electromagnetic clutch.
The present invention still further pro~ides in a
variable capacity flywheel mechanism for an engine having a
rotary shaft, the combination comprising: a main flywheel
mounted on a rotary shaft, an auxiliary flywheel supported for
rotation with said main flywheel, and a friction clutch
assembly coupling said auxiliary flywheel in driven rela-tion-
ship by said main flywheel, said friction clu~ch assembly
including a friction clutch plate assembly for transferring a
portion of the torque of said main flywheel to said auxiliary
flyw~eel to rotate said auxiliary flywheel at a controlled
rotational speed different from said rotational speed of said
main flywheel.
The presen-t inven-tion still further provides in a
variable capacity flywheel mechanism the combination of: a
main flywheel having a first group of projections, said main
flywheel adapted to be coupled to the rotary shaft of an
engine, an auxi]iary flywheel haviny a second group of projec-
tions, a friction disk type electromagnetically actuated clutch
for selectively coupling said flywheels in response to a
magnetizing signal, and oil supply means for supplying oil to
the gaps between the friction disks of said clutch and said
first and second groups of projections on each of said fly-
wheels in the vicinity of the friction disks and adjacent to
each other for frictionally coupling said first and second
groups of projections.
The auxiliary flywheel can be easily maintained at a
predetermined r.p.m. so that the shocks when the clutch is
applied or released can be minimized, because the flywheel
mechanism has its continued operation insured by the use of the
electromagnetic clutch.
- 2a
In a vehicle such as a motorcycle equipped with a
low-load rotary device such as a pump (referred to hereinafter
as "auxiliary devices") for supplying the engine with cooling
water, oil, air, and so on, necessary for the operation of the
engine, drive mechanisms are required for driving these auxi-
liary devices. The auxiliary flywheel of the variable capacity
flywheel mechanism can provide the power for driving such
auxiliary devices.
The variable capacity clutch according to the present
invention is constructed such that the selective coupling and
the coupling of the main flywheel and the auxiliary flywheel is
effected by the electromagnetic clutch, such that the control
of the electromagnetic clutch can be accomplished by an
external circuit including an r.p.m. detecting circuit applied
to the rotary shaft, and such that power from the auxiliary
flywheel is used to drive a rotary mechanism of relatively low
load.
Lubricating oil under suitable pre~sure is supplied
to the gaps or spaces between the friction disks of the
electromagnetic clutch so that when the clutch is released a
portion of the torque of the main flywheel is transmitted to
the auxiliary flywheel so that it may be rotated at a predeter
mined r.p.m. and thereby restrain shocks when the electromag-
netic clutch is closed.
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In the drawings:
Figure 1 is a sectional elevation showing a preferred
embodiment of this invention.
Figure 2 is a circuit diagram showing the clutch
control circuit for the mechanism shown in Figure 1.
Figures 3 and 4 are diagrams showing the construction
of other embodiments of the present invention.
Figure 5 is a sectional elevation showing another
modification.
Figure 6 is a detail showing an enlargement of a
portion of Figure 5.
Figure 7 is a sectional elevation showing another
modification.
Figure 8 is a sectional elevation partly broken away,
showing another modification of this invention.
Figures 9 and 10 are circuit diagrams showing the
control circuits of the oil pressure regulator valves.
Figure 11 is a diagram showing another control circuit.
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Referring to the drawings, the variable capacity
flywheel mechanism shown in Figure 1 and embodying the present
invention includes a crankshaft 1 rotatably supported in a
crankcase 2 by bearings 3. The crankshaft has a projecting
end portion la formed into a taper shape and having an internal
threaded opening lb. A sprocket 4 is fixed on the crankshaft 1
and drives a chain, nct shown, for operating a cam shaft, not
shown.
The main flywheel 5 is seated on the tapered end
portion la of the crankshaft 1 and is secured thereto by means
of the bolt 6. A friction clutch 7 comprising a pile of
clutch plates 7a is clamped between the clutch pressure plate 8
and a side face 5a of the main flywheel 5. The main flywheel 5
is formed with an oil passage 5b which communicates between
the region adjacent the head of the bolt 6 and the sliding
portions of the clutch plates 7a.
A stationary core member 9 is fixed to the crankcase 2
by a bracket 10 and threaded fasteners 11. The core member 9
is generally C-shaped in cross section so that its recess
portion is filled with a stationary annular magnetizing coil 12.
An opening in an end portion of the crankcase 2 is
closed by a flywheel cover 13 to form a casing enclosing both
the main flywheel 5 and an auxiliary flywheel 14. This
auxiliary flywheel 14 is annular in shape and is generally
C-shaped in cross section. It is supported on bearings 15
encircling a central hollow support member 13a provided on
the stationary flywheel cover 13. Accordingly, the auxiliary
flywheel 14 is supported for rotation coaxially of the main
flywheel 5 and adapted for connection thereto through the
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friction clutch assembly 7. When the magnetizing coil 12 is
supplied with a magnetizing current through its paired input
terminals 12a and 12b, the core member 9 attracts the clutch
pressure plate 8 to close the clutch assembly 7 and thereby
couple the main flywheel 5 and the auxiliary flywheel 14 in
driving relationship.
The stationary flywheel cover 13 has its central
support member 13a provided with an axial opening 18 which is
connected to an oil supply pipe 17. This pipe 17 connects to
an oil pump, not shown, through an oil pressure regulator valve
~7a. The inner open end of the axial opening 18 is so positioned
with respect to the auxiliary flywheel 14 as to face the head
of the bolt 6. A generally cylindrical oil guide member 19 is
formed with a flanged portionwhich is fitted in the auxilia~y fl~heel 14.
The oil guide member 19 is formed in its inner side with such
an annular oil seal member 20 as contacts with the inner open
end of the opening 18.
Around the central support member 13a of the flywheel
cover 13 there are equidistantly arranged a plurality of magnetic
poles 21 which are wound with electromotive coils 22. An
annular magnet 23 is fixed to the inner wall of the auxiliary
flywheel 14 so as to face the magnetic poles 21, and thereby
to constitute a dynamo so that the electric power generated
in the electromotive coils 22 is delivered through the terminals
22a and 22b.
In order to measure the r.p.m. of the crankshaft 1
and the main flywheel 5 coupled thereto, one or more magnetic
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projections 24 are positioned near the circumferential edge
portion of the crankshaft 1, and a stationary magnetic sensor 25
is fixed to tHe crankcase 2 The magnetic sensor 25 includes
a magnet and a coil and its output is carried to its output
terminals 25a and 25b. Similarly, in order to measure the
r.p.m. of the auxiliary flywheel 14, one or more magnetic
projections 26 are positioned on the outer circumference of
the auxiliary flywheel 14. A stationary magnetic sensor 27,
similar to the magnetic sensor 25, is fixed on the inner wall
of the flywheel cover 13 in a mannex to face the magnetic
projection or projections 26 so that its output is carried to
the output terminals 27a and 27b. It will be understood that
magnetic sensors for r.p.m. could be replaced by various other
sensors such as optical sensors.
Lubricating oil supplied under pressure through the
pipe 17 passes through the opening 18, the oil guide member 19,
the oil passage 5b and into the restricted clearances between
the clutch plates 7a. The torque transmitting characteristics
of the electromagnetic clutch 7 provide the torque necessary
for rotating the auxiliary flywheen 14 at a predetermined r.p.m.,
even though the electromagnetic clutch may be in its released
state.
The auxiliary flywheel 14 is equipped with the annular
magnet 23 by which a dynamic brakin~ operation is effected,
so that a predetermined braking force can be applied to the
auxiliary flywheel 14. Moreover, the torque to be transmitted
can be controlled to a suitable value by regulating the flow
rate of the oil supplied by way of the pipe 17, by the action
of the oil pressure regulator valve 17a.
163/lll
The magnetizing drive circuit of the electromagnetic
clutch of the variable capacity flywheel mechanism shown in
Figure 1 is illustrated by way of example in Figure 2. As
shown, a pulsing signal having a frequency corresponding to
the r.p.m. of the crankshaft 1 is provided by the magnetic
sensor 25, and it has its waveform shaped through the terminals
25a and 25b by a waveform shaper 30. It is then fed into an
fV converter 31. This fV converter 31 generates a voltage
corresponding to the frequency of the input signal, and that
voltage is fed to a comparator 32 which is composed of an
operational amplifier OP and resistors Rl and R2. The
comparator 32 generates a "0" signal when the input voltage
exceeds a reference voltage Vrl (which corresponds to 3000
r.p.m., for example). The comparator 32 is presented with
such hysteresis by the existence of the resistors Rl and R2
as to prevent the output voltage from the undesirable so-called
"hunting" or repeating between "1" and "0" even if the input
voltage fluctuates in the vicinity of the reference voltage
Vrl. The output of the comparator 32 is fed to the base of
a transistor Ql which acts as a drive switch 33 of the
magnetizing coil 12.
By using the magnetizing drive circuit of Figure 2
as the control circuit of the variable capacity flywheel
mechanism of Figure 1, the inertial moment of the variable
capacity flywheel mechanism can be reliably varied in accordance
with the r.p.m. of the crankshaft 1.
Figure 3 is a diagram showing a modification of the
variable capacity flywheel mechanism embodying the present
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invention. In this modification the main flywheel 5 for the
crankshaft 1 is connected to a primary shaft ~0 through a
gear 41, and the primary shaft 40 is coupled through an
electromagnetic clutch 42 to the auxiliary flywheel. The
clutch 43 transmits the torque to a transmission 44. The degree
of freedom, such as the selection of the inertial moment of
the auxiliary flywheel 14, can be increased by suitably
selecting the gear ratio of the gears 41.
Figure ~ is a diagram showing another modification
of this invention, wherein the crankshaft has its one end
coupled to the main flywheel 5 and its other end coupled
through the electromagnetic clutch 42 to the auxiliary flywheel.
This construction has an advantage that transverse weight
balance can be achieved with respect to the engine's cylinders.
Figure 5 shows a further modification of the variable
capacity flywheel mechanism embodying the present invention.
This modification differs from that shown in Figure 1 mainly
in that a single plate clutch is used as the electromagnetic
clutch, and in that the auxiliary flywheel is not equipped with
an electrical generating mechanism. More specifically, the
crankshaft 1 is carried in the crankcase 2 by means of bearings 3
and has its taper-free end lc externally threaded. A drive
disk acting as the main flywheel 5 is fitted on and fastened
to the taper portion la by means of a nut 51. The drive disk 50
is formed on its circumferential edge portion with a plurality
of drive holes 50a which are arranged in an equi-angular
position, and an annular armature 53 is carried on drive pins 52
which are fitted in the drive holes 50a. The annular armature 53
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is made of a highly permeable magnetic material. Moreover, the
annular armature 53 has its surface formed with an annular groove 53a
and with a clutch facing 54. Stop rings 55 are attached to the lead-
ing ends of the respective drive pins 52, and return springs 56 are
press-fitted between the stop rings 55 and the drive disk 50, thereby
to thrust the armature 53 onto the drive disk 50. Opposite faces of
the drive disk 50 and the rotor 1~ are provided with first and second
aroups of projections 59 and 60 which extend axially in opposite
directions and toward each other. The projections are arranged
~0 equidistantly ln the circumferential direction, as in an impeller,
thereby to impart a suitable drag to the oil.
Figure 6 shows an enlargement of the portion of Figure 5
which is encircled by a dashed line. A hole 71 is plugged by a
valve element 72 thrust from the outside by means of a leaf spring
73, thus providing a relief valve. A governor weight 74 is mounted
on the outer side of the valve member 72. This embodiment is
similar to that of Figure 4 except that the oil pressure regulator
valve 17a can be eliminated because of the provision of the relief
valve 72, as described.
Figure 7 shows another of the variable capacity
flywheel mechanism embodying the present invention. This
modification is different from the mechanism of Figure 1 mainly
in that an electromagnetic powder-type clutch is used as the
electromagnetic clutch. More specifically, as shown in Figure 7,
a drive member 60 fixed to the crankshaft 1 and a rotor 62
carried on a shaft 61 are arranged to hold maanetic powder
therebetween. The shaft 61 is supported in the crankcase 2.
The field core 9 having a generally C-shaped section, which
is loosely fitted into the drive member 60, is fixed to the
inl)er wall of the cran~case 2 and accommodates the rnagnetizing
coil 12 therein. The rernaining parts, other than the afore
mentioned electromagnetic clutch, are substantially similar
to those of the mechanism of Figure 1. The variable capacity
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flywheel mechanism shown in Figure 7 utilized the electromagnetic
powder-type clutch so that the torque to be transmitted by
the clutch is proportional to the magnetizing current. By
controlling this magnetizing current, therefore, the control
of the torque transmission to the auxiliary flywheel 14 can
be readily accomplished. As a result, by replacing the
comparator 32 of the control circuit of Figure 2 by a r~ere
amplifier, for example, the magnetizing coil 12 can be
magnetized by an analog signal corresponding to the r.p.m.
of the crankshaft 1.
The modification of the variable capacity flywheel
mechanism shown in Figure 8 includes a crankshaft 1 rotatably
supported in a crankcase 2 by means of bearings 3. The project-
ing end portion la of the crankshaft 1 is tapered and it is
provided with an interna~ly threaded opening lb. A sprocket 4
is fixed on the projecting portion of the crankshaft 1 to be
engaged by a chain, not shown, for driving a cam shaft, not shown.
The main flywheel is secured to the free end portion la of the
crankshaft 1 and is fastened thereto by means of a bolt 6. A
friction clutch 7 employing a pile of clutch plates 7a operates
the
- to connect the main flywheel 5 to/auxiliary flywheel 14. The
pressure plate 8 is provided on one side of the clutch plates 7a
and the flanged portion 5a of the main flywheel 5 is positioned
on the other side. The main flywheel 5 is formed with an oil
passage 5b which provides communication between the internal
space near the vicinity of the head of the bolt 6 and the
sliding portions of the clutch plates 7a. The stationary core
member 9 is fixed to the crankcase 2 by means of bracket 10 and
threaded fastenings 11. The core member 9 has a generally
C-shaped cross section which contains a magnetized coil 12.
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A stationary flywheel cover 13 encloses the main
flywheel 5 and the auxiliary flywheel 14. This auxiliary
flywheel 14 has an annular shape generally C-shaped in cross
section and is carried by bearing 15 mounted on the central hollow
support member 13a. Accordingly, the auxiliary flywyeel 14 is
supported for rotation coaxially of the main flywheel 5 and
is adapted for connection thereto through the frictio~ clutch
assembly 7. When the magnetizing coil 12 is supplied with a
magnetizing current through its paired input terminals 12a and
1~ 12b, the core member 9 attracts the clutch pressure plate 8 to
close the clutch assembly 7 and thereby couple the main flywheel 5
and the auxiliary flywheel 14 in driving relationship.
The hollow support member 13a ofthe flywheel cover 13
is provided with a with a through opening 18 which extends axially
thereof and which has its outer end connected to the oil supply
pipe 17 through an oil pressure regulator valve 17a. The inner
open end of the through opening 18 is so positioned in the
central recess of the auxiliary flywheel 14 to face the head
of the bolt 6. A generally cylindrical oil guide member 19
has a flanged portion which is fitted into a central recess
in the auxiliary flywheel 14. This oil guide member has an
annular oil seal member provided on its inner side 20 which
contacts with the inner open end of the through hole 18.
In order to detect the r.p.m. of the crankshaft 1
and the main flywheel 5, one or more magnetlc projections are
arranged in the vicinity of the circumferential edge portion
of the crankshaft 1, and a magnetic sensor 25 comprising a
magnet and a coil is fixed to the crankcase 2 so that its
output is derived through its output terminals 25a and 25_.
In order to detect the r.p.m. of the auxiliary flywheel 14,
-12-
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one or more magnetic projections 26 are placed on the outer
circumference of the auxiliary flywheel 14, and a magnetic
sensor 27 similar to the magnetic sensor 25 is mounted on the
inner wall of the flywheel cover 13 in a manner to face the
magnetic projections 26. The output is carried through the
output terminals 27a and 27_. Other type sensors such as an
optical sensor can be used in place of the magnetic sensors
25 and 27.
Lubricating oil supplied through the oil supply pipe 17
is pumped by way of the through o~ening 18, the oil guide member
19, the oil passage 5b into the restricted clearance spaces
between the clutch plates 7_, to vary the degree of coupling,
i.e., the torque transmitting characteristics of the electromagnetic
clutch 7 and thereby to effect the so-called "accompanying
rotations" of the auxiliary flywheel 14 even in the released
state of the electromagnetic clutch 7.
The mechanism of Figure 8 employs an auxiliary device
such as an oil pump, an air supply pump or a water pump driven
from the constant-speed rotating torque of the auxiliary
flywheel 14. As shown, the torque transmitting means comprises
a gear 90 ~ixed to the auxiliary 'lywheel 14 and a gear 91
which meshes with the gear 90. The gear 91 is fixed on the
rotary shaft 94 of a water pump 93. The shaft 94 is carried
in bearings 95 and 96, and an impeller 97 having a plurality
of vanes is fitted on the free end portion of the rotary shaft 94.
The impeller 97 has a recess 97a at one end and another recess
97b at its other end, and the impeller 97 is clamped in position
on the shaft 94 by means of a ring 98 and a bolt 99. A housing
100 encloses the impeller 97 and is provided with a water
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inlet lOl and a water outlet 102. In the space between the
impeller 97 and the bearing 95, there is disposed coaxially
with the rotary shaft 94 an annular member 103 having a generally
C-shaped cross section. A spring 105 thrusts a ring 104 into
the recess 97b and an axially extending rubber member 106 is
positioned inwardly of the spring 105. The construction and
operction of the water pump are well known in the art and need
not be detailed here.
The variable capacity flywheel mechanism having the
construction shown in Pigure ~ and described above employs a
gear driven water pump instead of a magneto. The flywheel
cover 13 is formed with an opening large enough for insertion
of the gear 9l to mesh with the gear 90. Thus, the auxiliary
flywheel 14 rnay be rotated at a desired constan-t speed. As a
result, the water pump 93 is driven at a desired r.p.m.
The rnagnetizing drive circuit of the electromagnetic
clutch 7 is similar to that pr~viously described.
Having fully described our invention, it is to be
understood that we are not to be limited to the details herein
set forth but that our invention is of the full scope of the
appended claims.
