Note: Descriptions are shown in the official language in which they were submitted.
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Background and Summary
The present invention relates to a rotary drive appara-
tus, and in particular, to one having a pair of rotary elements
which rotate about a common axis in start-and-stop cycles which
are out of phase with each other.
In my U.S. Pa~tent No. 4,127,3~7 issued November 28,
1978, there is disclosed a rotary fluid motor having a pair of
start-and-stop rotary elements which are driven alternately in a
forward direction under the influence of an external source of
pressurized gas. The rotary elements are coupled to a rotary
drive shaft in the motor by means of a spring drive connection
which operates to "cushion" the torque which is applied to the
drive shaft from the two start-and-stop elementæ, thus providing
a substantially smooth drive connection between the elements and
the drive shaft. ~he springs are subject to rapid metal fatigue
and ultimately may lose some or most of their elasticity. ~7hen
this occurs~ the rotational movement of the drive shaft acquires
more of the start-and-stop character of the driving rotary ele-
ments.
In the rotary fluid apparatus of the present invention,
the rotary elements are coupled to the drive shaft by a fluid
gradient which is formed in response to rotational advancement of
the rotary elements with respect to the shaft. In the embodiment
of the in~ention described herein, the drive shaft in the appara-
tus has, adjacent opposed shaft ends, angularly spaced vanes
; which are interspersed with angularly spaced vanes on associated
rotary elements to form substantially sealed fluid chambers. Gas
compression and expansion in alternate fluid chambers produced by
relative rotational movement of the rotary elements with respect
to the shaft acts to drive the shaft at a relatively constant
velocity.
A general object of the invention is to provide a
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rotary fluid apparatus which overcomes performance and maintenance
problems inherent in a rotary fluid motor having spring-like
connections between its drive shaft and a pair of start-and-stop
driving elements.
Another specific object of the present invention is to
provide in a rotary fluid motor having a pair of start-and-stop
rotary elements a compressible fluid drive connection between the
rotary elements and a drive shaft in the motor.
Another object of the present invention is to provide a
rotary fluid apparatus having a substantially constant velocity
drive output.
Another object is to provide a rotary drive apparatus
comprising a casing having a hollow interior, an elongate power-
output shaft journaled in said casing and extending through the
interior thereof between its ends, a first rotary element coaxial
with said shaft within the casing interior and adjacent one end of
the casing rotatable relative to said shaft and said casing and
including a disc surrounding and extending radially of said shaft
with inner and outer perimeters of the disc fluidly sealed relative
to the shaft and casing, respectively, a first series of power-
transmitting vanes distributed circumferentially about and secured
to one side of said disc and extending axially toward one end of
the casing and a first series of motor vanes distributed
circumferentially about and secured to the other side of said disc
and extending axially toward the casing's opposite end, a second
rotary element coaxial with said shaft within the casing interior
and adjacent the opposite end of the casing rotatable relative to
said shaft and casing and including another disc spaced axially
toward the opposite end of the casing from the first-mentioned disc
and extending radially of said shaft with inner and outer
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perimeters of the disc fluidly sealed relative to the shaft casing,
respectively, another series of power-transmitting vanes
distributed circumferentially about and secured to one side of said
other disc and extending axially toward the casing's opposite end
and another series of motor vanes distributed circumferentially
about and secured to the other side of said disc and extending
axially toward the casing's said one end, said first series of
motor vanes and said other series of motor vanes being interspersed
with each other and forming a plurality of angularly spaced fluid
lo motor chambers located between said first-mentioned and other disc
within said casing, means on the casing to admit gas under pressure
into alternate ones of said fluid chambers and to exhaust gas from
alternate ones of said fluid motor chambers, a first series of
shaft vanes secured to and circumferentially distributed about the
shaft with.in the casing interior adjacent one end of the casing
interspersed with the fir~t series of power-transmitting vanes of
the first rotary element and a second series of shaft vanes secured
to and distributed circumferentially about the shaft within the
casing interior adjacent the opposite end of the casing
interspersed with said other series of power-transmitting vanes of
the second rotary element, each series of shaft vanes together with
`. the power-transmitting vanes of a rotary element interspersed
therewith forming plural, substantially air-tight fluid end
chambers and rotational advancement of the rotary element in one
direction with respect to said shaft producing between adjacent
fluid end chambers fluid pressure gradients which act to rotate the
shaft in the direction of such advancement, and relative means on
the casing associated with each of the rotary elements operable to
prevent rotation of the rotary element in a direction opposite to
said one direction, whereby gas alternately admitted under pressure
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into alternate ones of said fluid motor chambers and exhausted from
alternate adjacent fluid motor chambers drives s~id rotary elements
alternately in said one direction.
These and other objects and features o~ the present
invention will become more fully apparent when the following
detailed description of a preferred embodiment ~f the invention is
read in connection with the accompanying drawings.
Brief Description of the Drawinas
Fig. 1 is a sectional view of the apparatus of the
present inven~ion, taken substantially along a plane containing the
drive shaft in the apparatus; and
Fig. 2 is a sectional, partially cutaway view of the
apparatus in Fig. 1 taken aiong line 2-2 therein.
Detailed Descri~tion of a Preferred Embodiment of the Invention
A fluid drive motor, or apparatus, constructed according
to the present invention is shown at 10 in Figs. 1 and 2. The
motor includes a casing 12 in which the moving parts of the engine
are housed. The casing is formed of a pair of mirror-image end
sections 14, 16 and an annular center section 18 bolted
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between the end sections, as seen in ~ig. 1. Section 14 includes
a cylindrical wall 20 and an annular flange 22 adjacent the
left end edge of wall 20 in Fig. 1. The flange and end region
of wall 20 define an upright annular channel, as seen in the
figure. The section is capped at its right end in Fig. 1 by an
end plate 26.
Center section 18 defines, at its opposite ends, a
pair of upright annular channels (Fig. 1) which form with the
confronting annular channels in end sections 14, 16, a pair of
annular spaces, such as space 27 between sections 18, 14. The
end of the wall in each end section, such as section 14, and the
confronting wall edge in section 18 define therebetween, a disc-
shaped gap, such as gap 24. Section 18 has a hollow annular
interior region 32. Sections 14, 16, 18 are formed conventionally
by metal casting.
A drive shaft 36 is journaled to casing 12 by bearings,
such as bearing 38, for rotation about axis 34. A pair of discs
40, 42 are concentrically mounted adjacent the shaft's right and
left ends, respectively, in Fig. 1, and secured thereto for
rotation with the shaft about axis 34. Conventional labyrinth
seals placed between the peripheral edges of the discs and con-
fronting wall portions in the casing provide substantially fluid-
tight rotary seals therebetween.
A cylindrical sleeve 44 extends between the inwardly
facing (confronting) sides of discs 40, 42 and may be rigidly
secured at its opposed ends to the the two discs for rotation
with shaft 36 as shown in Fig. 1, or may be mounted on the discs
by bearings for independent rotation with respect to the shaft.
A central, radially-enlarged step 46 on sleeve 44 forms a pair of
annular shoulders at its left and right ends in ~ig. 1 which are
axially aligned with the two gaps, such as gap 24, formed in
casing 12.
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A pair of rotary elements 52, 54 are mounted in casing
12 for independent rotation about axis 34 Element 52, which is
representative, includes a disc-like plate 56 dimensioned to
extend radially from sleeve 44 through gap 24 into space 27, as
shown in Fig. 1. Plate 56 is mounted on element 22 for rotation
with respect thereto by a pair o~ bearings 58. Conventional
labyrinth seals placed between plate 56 and the annular casing
wall edges forming gap 24, and between the inner edge of the
plate and sleeve 44 provide substantially fluid-tight rotary
seals therebetween. A plate 60 in element 54 is similarly mounted
for rotation in the casing. The confronting sides of plates 56,
60 and the annular wall portions of step 46 and casing 12 which
the two plates bound define an annular central cavity -62 which
has the rectangular cross sectional shape seen in Fig. 1.
Located within cavi~y 62 i8 a plurality o equally
angularly spaced vanes, such as vanes 63 (Figs 1 and 2) and 64
(Fig. 2), which are rigidly secured to plate 56 to extend axially
into cavity 62. The vanes, which have the cross sectional curv-
ature seen in Fig. 2, are dimensioned to span the cross sectional
area of cavity 62. The spacing between the free edges of the
vanes and associated wall portions defining cavity 62 is such as
to provide substantially fluid tight seals therebetween as the
vanesiare moved within the cavity.
Interspersed between the vanes in element 52 are an
equal number of vanes, such as vane 66 (Figs. 1 and 2) and 68
(Fig. 2), carried on plate 60 at equal angularly spaced intervals.
These vanes, like the vanes in element 52, are constructed for
substantially fluid-sealed movement within cavity 62. Thus, with
reference to Fig. 2, the pairs of interspersed vanes in the two
rotary elements define in cavity 62 a plurality of fluid chambers,
such as chamber 70 defined between vanes 64, 68, and chamber 72
defined ~etween vanes 63, 68.
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A plurality of angularly spaced inlet ports, such as
ports 73, 74, 75 seen in one or both of the figures, extend
through the inner wall in center section 18 and are angularly
spaced thereon to communicate with individual fluid chambers in
cavity 62. Plural outlet ports, such as ports 76, 77, 78 seen in
one or both of the figures, are similarly disposed on section 18
to communicate with the fluid chambers in the caYity. The inlet
and outlet ports are connected to suitable manifold devices (not
shown) which function to convey compressed gas to alternate inlet
ports while exhausting gas from the adjacent alternate outlet
ports. The inlet and outlet ports thus form means for admitting
and exhausting gas, respectively, in the fluid chambers in cavity
62.
For each rotary element in apparatus 10, such as element
52, there i5 provided one or more reverse-motion brakes, such as
the brake 7~ shown in Fig. 2, which functions to prevent reverse-
direction rotation of the associated rotary element. Brake 79,
which is representative, includes a ball 80 which may move angu-
larly within a tapered cavity 81 against the biasing of a spring
83. It can be appreciated in Fig. 2 that movement of element 52
in a counterclockwise direction in this figure moves ball 80
upwardly, in the direction of spring biasing, to a wedged posi-
tion where the ball acts to brake further counterclockwise
movement of the element. Movement of eleme~nt 52 in a clockwise
direction, acts to m~ve the ball away from its wedged, braking
position, and thus allows free clockwise movement of the rotary
element. Brakes, such as brake 79, are also referred to herein as
reactive means for preventing reverse rotation of the rotary
elements. This reactive means, and the just-mentioned means for
admitting and exhausting gas in the fluid chambers in cavity 62
are also referred to herebelow collectively as fluid drive means.
The reader is referred to my U.S. Patent No. 4,127,367 for addi-
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tional details of fluid drive means such as that employed herein.
According to the important feature of the present
inve!ntion, rotary elements 52, 54 are connected to shaft 36 -- to
drive the same at a substantially constant velocity about axis 34
-- by fluid compression means associated with each of the rotary
elements. Describing the fluid compression means associated with
element 52, and with reference first to Fig. 1, it is seen that
plate 56 and disc 40 on shaft 36 define therebetween an annular
end cavity 82 havin~ the rectangular cross section shown. It is
noted here that cavity 82 is substantially sealed during engine
operation by virtue of the above-mentioned labyrinth seals.
Carried on the right face of plate 56 in Fig. 1, at
equal angularly spaced intervals thereon, is a plurality of outer
vane~, such as vanes 84 (Figs. 1 and 2) and 86 (Fig. 2). These
vanes, which have the cross sectional shape seen in Fig. 2, are
dimensioned to form a substantially fluid tight seal with wall
portions of the cavity against which relative movement occurs.
Interspersed with the outer vanes on element 52 are an equal
number of vanes, such as vanes 88, 90 (Fig. 2). These vanes are
carried on the left face of disc 40 in Fig. 1 and are dimensioned
to form a substantially fluid tight seal with relatively moving
wall portions defining cavity 82. The interspersed vanes in
cavity 82 form plural, substantially sealed fluid chambers, such
as chambers 92, 94 between vanes 84, 90, and vanes 90, 86, re-
spectively. The fluid compression means associated with element
54 is substantially identical to that just-described.
In operation, compressed gas is supplied to alternate
inlet ports communicating with alternate fluid chambers in cavity
62, and simultaneously exhausted from alternate adjacent chambers
by means of manifold devices mentioned above~ The two elements
then rotate relatively to allow volume expansion in the gas-
supplied fluid chambers. That is, one of the elements rotates
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slightly to a braked position and the other element rotates in a
clockwise direction in Fig. 2. After the m~ving element has
advanced a defined distance in relation to the inlet and outlet
ports, the supply and exhaust of gas to the chambers, through the
above-mentioned manifolds, is switched so that previously evacuated
chambers are supplied compressed gas and chambers previously
supplied co~pressed gas are evacuated. The element which was
previously stationary now advances rotationally, in a clockwise
direction, while the other element is held in a braked condition.
With continued alternate supply of compressed gas to alternate
chambers in cavity 62, rotary elements 52, 5~ advance rotationally
about axis 34 in start-and-stop cycles which are 180 out of
phase with one another.
Looking at Fig. 2, it ~s appreciated that a~ element 52
rotates in a clockwise d~rection, relative to shaft 36, vanes 84,
86 on the element move to~ard and away from vane 9~, respectively.
This relative movement increases the gas pressure on the left
side of vane 90 in Fig. 2 and similarly decreases the gas pressure
on the right side thereof, producing a gas pressure gradient
which acts to rotate shaft 36 in a clockwise direction. After
the rotational phase of element 52 ends, the shaft continues to
rotate by inertia into the rotational phase of element 54, which
then acts to drive the shaft in the same direction. Accordingly,
as the two rotary elements alternately and recurrently advance
rotationally, the shaft experiences alternate torque "pulses"
which act to keep the shaft rotating at a relatively constant
velocity, (equal to the combined average velocity of the two
stop-and-start elements).
Fro~ the above, it is seen how the objects of the
present invention are met. The fluid drive means described
herein effectively replaces spring-like elements formerly used in
the drive connection of a rotary fluid motor driven by a pair of
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stop-and-start elements. Unlike spring elements, which lose
their resilience over time, the instant fluid drive means
provides smooth torque coupling between start-and-stop elements
and a drive shaft over long time periods. This is particularly
advantageous in minimizing motor wear due to uneven shaft rotation.
Maintenance is also reduced by eliminating the need for periodic
spring replacement.
While a preferred embodiment of the invention has be~n
disclosed herein, it is obvious that various changes and modifi-
cations can be made without departing from the spirit of theinvention.
