Rotary expansible chamber devices – Working chamber surface expressed mathematically
Reexamination Certificate
2000-05-16
2001-05-08
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Working chamber surface expressed mathematically
C418S092000
Reexamination Certificate
active
06227832
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention pertains to a rotary piston machine in which a rotor rotates in an enclosure and radially movable slides in the rotor form chambers of varying volume between the enclosure and the rotor, wherein an even number of slides are provided and mutually opposing slides are joined together into a rigid unit.
Such a rotary piston machine is known from GB 430 715 B. Here the enclosure has the form of a Reuleaux triangle and the rotor is arranged centrally in the triangle. The advantage of such an arrangement over and above the use of one-sided spring-loaded slides is that in the rotation of the rotor, the enclosure wall need overcome only the inertial mass of the slide to move it back and forth while the centrifugal acceleration is at least essentially cancelled by the joining of the diametrically opposing slides, and spring forces that must always be provided for individual slides in order to press them against the wall in the first place can be completely eliminated.
Thus, a rotary piston machine of the type mentioned initially is subjected to considerably reduced wear in comparison to rotary piston machines with individually movable slides.
As more distant prior art pertaining to these other rotary piston machines that one can refer to, for instance, to DD-33 914 A in which the enclosure has a circular cross section, and the rotor arranged eccentrically in the enclosure likewise has an essentially circular cross section but with recesses bounded in cross section by a circular arc being cut out of the rotor in order to increase the size of the chambers formed. The (four) slides are each pressed outward from the rotor by springs against the enclosure wall, which, together with the centrifugal acceleration, leads to large contact pressures and high wear.
Despite its advantages over and above DD-A, it is disadvantageous in the rotary piston machine known from GB-B in that, because of the compulsorily prescribed shape of a Reuleaux triangle, the formation of three enclosure pockets is inevitable during rotation, each pocket forming by a slide an initially expanding and then again shrinking chamber between the slides. In internal combustion engines, for instance, this necessarily leads to the formation of 6-stroke systems with intervening cooling sections. Another disadvantage caused by this is that each slide is pushed radially back and forth three times during a rotation which in turn in the course of a rotation leads to relatively high acceleration peaks.
SUMMARY OF THE INVENTION
The invention intends to create a remedy for this, and to specify a rotary piston machine of the type defined initially in which each slide is pushed back and forth only once in a [single] rotation of the rotor.
This is achieved, according to the invention, in that the rotor is arranged eccentrically in the enclosure, in that the enclosure is symmetrical with respect to the connection line between the shaft of the rotor and the point of the enclosure closest to this axis, the south pole and in that, based on an XY coordinate system placed through the axis of rotation of the rotor and running orthogonally to and in the direction of the axis of symmetry, and with polar coordinates (r, j) with their center in the rotor shaft and the angle j=0 lying in the direction of the positive X-axis, the inside wall of the enclosure satisfies the following equation:
r
(j)
={a>>b>>/[a>>
cos >>(1(
j+D/
2))+
b
>> sin >>(1(
j+D/
2))]}
½
where:
b is the shortest distance between the rotor shaft and the enclosure wall at the south pole,
a is given by the formula
a
(d,b)
={[3(
d
/2)
4
−2
b
>>(
d
/2)>>]/[2(
d
/2)>>−
b
>>]}
½
where:
d is the length of the chords of the inside enclosure wall through the axis of rotation of the rotor, thus, the radial extension of the slides, and 1 is given by the formula
1=2
/D
arccos ({[
a
>>−(
a
4
+b
4
−a>>b>>
)
½
]/(
a>>−b>>
)}
½
)
Thus, the shape of the inside enclosure wall is completely determined by the choice of b and d; that is, the shortest distance between rotor shaft and inside enclosure wall, on the one hand, and the radial extension of the slides, on the other, since due to the requirement of symmetry with respect to the Y-axis, the curve need only be fixed in one quadrant and it will be fixed in the other quadrant; the others [sic; other parameters] result immediately.
Added to the above are the boundary conditions: the horizontal profile (parallel to the X-axis) at the south pole (that at the north pole will result automatically), the position of the inside enclosure wall at the intersection with the X axis in a spacing d, the requirement for continuous differentiation two times in order to design the rotation-displacement motion of the slides without any jumps, monotonic increase of r
(j)
in the fourth quadrant and always non-negative curvature, whereby the curve is fixed.
Configurations of the invention pertain to the formation of the slides and their guidance in the rotor or along the enclosure.
REFERENCES:
patent: 2985110 (1961-06-01), Burt et al.
patent: 3785758 (1974-01-01), Adams et al.
patent: 3873246 (1975-03-01), Hansen
patent: 4616984 (1986-10-01), Inagaki et al.
patent: 165176 (1958-10-01), None
patent: 3824882 (1990-01-01), None
patent: 57-097094 (1982-06-01), None
patent: 62-271985 (1987-11-01), None
patent: 1-125588 (1989-05-01), None
patent: 1321919 (1987-07-01), None
Denion Thomas
Stockton Kilpatrick
Trieu Theresa
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