US 2112890 A
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Description (OCR text may contain errors)
April 5, 1938'. T. M. GUNN 2,112,890
ROTARY POWER DEVICE Filed Oct. 22, 1936 2 Sheets-Sheet 1 Gnu/um;
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ROTA Y POWER DEVICE Filed Oct. 22', 1936 2 Sheets-Sheet 2 [him 511% 610m Patented. Apr. 5, 1938 ROTARY POWER DEVICE Thomas M. Gunn, Woodbury, N. 1., assignor Socony-Vacuum Oil- Company, Incorporated, New York, N. Y., a corporation of New York Application October 22, 1936, Serial No. 107,001
This invention relates to rotary power devices, such as pumps, compressors and engines of the type in which two coacting rotary members are eccentrically mounted one within another in driving and driven relationship in such a manner that during their rotation a closed pocket of constantly changing area is formed by cooperating faces of the members for receiving a fluid and for subsequently expelling the same through suitably located ports which are periodically placed in communication with the pockets during rotation of the members. Such general type of mechanism is disclosed in the patent of Gollings, No.
448,335, dated March 17, 1891.
It is an important object of my invention to provide a mechanism of theabove character in which the internal rotary member is providedwith radially-extending vanes so shaped as to travel with a combined rolling and sliding action about the contours of correspondingly shaped recesses formed upon the inner circumference of the external rotary member, thus maintaining throughout a portion of their cycle of rotation two points of fluid-tight contact with the latter and defining pockets for confining the fluid. In those cases in which the mechanism is embodied in a compressor or pump, the external rotary member advantageously is directly driven from a suitable source of power to discharge the fluid under pressure; while in those cases in which the mechanism is utilized as a motor, the fiuid may comprise an expansible gas, such as steam, which furnishes the energy for driving the rotary members.
In the preferred form of my invention a discharge port is provided for affording expulsion of the fluid from the pockets through a'relatively short stub shaft which supports the internal rotary member. Thus, when the mechanism is embodied in a compressor or pump, it may be efliciently and economically operated at relatively high speeds without building up excessively high back pressures in the exhaust line.
Other objects and advantages will be apparent from the following detailed description ofa preferred embodiment of my invention, reference being had to the annexed drawings in which:
Figure 1 is a vertical cross-sectional View Of Claims. (Cl. 103-421) an air compressor incorporating the principles of the invention;
Figure 2 is a transverse cross-sectional view of the compressor of Fig. 1 taken on the line 2-2 of that figure;
Figure 3 is a detail view of one of the vanes of the internal rotary member; and
Figure 4 is a vertical cross-sectional view of pressor.
The' air compressor shown in Figs. 1 and 2 comprises a circular housing l closed at one side by a removable cover plate 2 and having its other side" closed by an integral wall portion 2a. Air is admitted to the interior of thehousing through a large aperture 9 opening to the atmosphere.- The wall 2a is provided with a central opening through which extends a rotatable shaft 3, this shaft being supported by a sleeve 4 surrounding the opening and having one of its ends united .with the wall to. Surrounding shaft 3 and enclosed by the sleeve are bushings 5, of a soft metal, providing bearings for the shaft, and the gland Ii.
The portion of the shaft 3 disposed beyond the end of sleeve 6 is adapted to be suitably connected by means, not shown, to a source of power for imparting rotation thereto, while the opposite end of the shaft which lies within the housing l terminates in a flat disk I. To the outer face of this disk is aflixed a ring 8 of substantial transverse thickness having its outer circumference 8a disposed coincident with the periphery of the disk, and having an inner circumference 8b which defines a connected series of six identically-shaped, equidistantly-spaced recesses III, as later will be more particularly described. A side plate II is associated with the ring 8 opposite the disk I, and the ring and plate are fastened to the disk by means of bolts l2 having their headed ends countersunk within the plate and their opposite ends threaded into tapped openings in the disk. The disk 1 and plate H are provided with laterally-disposed circumferential lips la and Na which snugly fit within correspondingly shaped rabbets formed in' the circumference of the ring. The ring 8 together with disk I and side plate ll thus forms a virtually closed pumping chamber constituting the external rotary member.
Extending through cover plate 2 of the housing and side plate H of the pumping chamber is a stub shaft l3 having its exteriorly projecting end circumferentially screw-threaded to receive a a modified form of electrically-driven air comouter end of the sleeve is closed by a packing nut II which clamps against the side plate and having its inner end enlarged to form an eccentric l axially offset with respect to the shaft 3. The stub shaft and eccentric are suitably recessed to provide an exhaust passage i6 extending from the circumference of the eccentric to the outer end of the stub shaft.
Journaled upon and rotatable about the eccentric I5 is a spurwheel I8 constituting the internal rotary member designed to be driven by the ring 8. This spur wheel comprises a hub portion l8a and six curved radially disposed vanes, or spurs, l9 which project into the recesses ill of the ring. The vanes I8, as best shown in Fig. 3, are each of approximately uniform width throughout their length and are formed with rounded outer ends l8a, while each vane at its root, i. e., at the locality where it joins the hub, is curved as indicated at |9b .in such a manner as to smoothly merge with the contours of two adjacent vanes. From the root of a vane to its rounded-outer end the vane is curved outwardly and forwardly, that is, in the direction of its rotation, upon an are representing a quadrant of a circle. The outline of the spur wheel thus presents a connected series of smooth unbroken curves defining the working faces of the vanes.
Each recess III of ring 8 is of an outline corresponding to that of a vane, as best illustrated in- Fig. 2 so that the smoothly curved working faces of the recesses thus defined correspond to the working faces of the vanes. However, the recesses are made sumciently oversize so as to afford a substantial area of clearance between the companion faces of the recesses and the vanes. This construction permits a change of position of the vanes within the recesses so that at any moment during a cycle of rotation of the external and internal rotary members, due to the eccentric mounting of the latter, certain of the vanes will be in rubbing contact with the working faces of their recesses while otherof the vanes will be disposed out of contact therewith.
The spur wheel is of a width, or transverse thickness, so as to make a snug sliding fit between the'disk I and side plate II and thus close the pumping chamber. Each recess is in communication with the interior of housing by means of a pair of aligned transverse ports 2| formed in the disk I and side plate These ports are equidistantly spaced apart about the axis of the external rotary member and are located in the same relative position with respect to each recess, that is, at approximately midheight but offset to a position adjacent the forward working face of a recess. I prefer to drill these ports in the disk and side plate prior to assembly of these parts so that when they are associated with the ring 8 they partially cover the ports in the manner shown in the drawings. Additionally there are provided a series of equidistantly-spaced discharge ports 22 extending radially through the hub Ho and opening to each of the recesses l0 through the rear working face of a vane adjacent its root or base.
From the foregoing description it will be apparent that when shaft 3 is driven so as to rotate the ring 8 in the direction indicated by the arrow in Fig. 2, that is, in a direction corresponding to the direction of outward curvature of the vanes, this ring will impart rotation in the same direction to the spur wheel l8. This rotation of the ring and spur wheel, due to the eccentric mounting of the latter, will cause the faces of the vanes to bear against and move along the faces of the recesses with a combined rolling and sliding moshaft 8 each vane will have successively passed through the positions, with respect to its particular recess, shown by each of the six yanes. depicted in this figure.-
Because of the complementary curvature of the vanes and recesses, during a portion of a revolution of the internal and external rotary members the rear and forward working faces of two adjacent vanes will make sealing contact with the faces of their respective recesses and together define a closed pocket which progressively decreases in size (as indicated by the shaded areas in Fig. 2) during continued rotation of the members. It is to be noted that the inlet ports 2| are uniformly spaced about the axis of rotation of ring 8, while the discharge ports 22 are uniformly spaced with respect to the axis of rotation of the spur wheel l8. Consequently as the external rotary member is rotated by shaft 3 to drive the internal rotary member, the vanes due to the movement imparted by the eccentric to the latter member, will cover and uncover the inlet ports 2| while each of the discharge ports 22 will move periodically into alignment with the exhaust passage i6 opening through the circumference of the eccentric.
This will be clear from a consideration of Fig. 2. Air entering the chamber through inlet ports 2| fills apocket defined by two adjacent vanes in bearing contact with the working faces of their recesses and the discharge ports 22 of the recesses being at this time out of alignment with the exhaust passage l6. Continued rotation causes the vanesto slide past the inlet ports of their respective recesses and, due to the contours of the vanes and recesses, divide each recess into two pockets, indicated A and B in the figure. Forward,
pocket A is open to the interior of housing I through the inlet ports 2|, while rear pocket B is cut off from these ports and completely closed by the vanes of two adjacent recesses which make sealing contact with the .working faces of their respective recesses. The air entrapped within pocket B is subjected to compression as the size of this pocket diminishes until the discharge port associated with this pocket rides into alignment with exhaust passage It. At this time the air is expelled under pressure, expulsion being completed by the time communication between the discharge port and the exhaust passage is broken. Further movement of the internal and external rotary members causes the leading vane to break its contact with the rear working face of its recess and to move over toward the opposite or forward working face of the recess. This allows the air filling pocket A to be displaced into pocket B before the vane closes the inlet ports 2|. The vane then moves past the inlet ports 2| and again compresses the air in pocket B as before described. This cycle of op eration is repeated for every revolution of the internal and external rotary members.
An important feature of the mechanism just described is the provision of continuously curved coacting working faces of the vanes and recesses which results in a. combination of rolling and sliding contact therebetween and which reduces wear to a minimum.
As will be apparent from the above description, by virtue of the inclination of the vanes toward their direction of rotation and owing to the complemental curvature of the working faces of these vanes and recesses, fiuid-tight contact is constantly maintained between these members from cover plate 2 closingone side of the housing i issecured in place by bolts 23 which pass through elongated slots 24 in the cover plate. These slots. preferably extend in a direction parallel to a line connecting the axes of rotation of the ring 8 and spur wheel l8. Since the eccentric is carried by the cover plate 2, the former may be adJusted by simply loosening the bolts 23, shifting the cover plate to reduce the excess clearance between the working faces of the vanes and recesses, and then electric motor.
leads (not shown) to a source-of electric current. v concentrically located within and in inductive retightening the bolts.
For lubricating the apparatus, there is provided an oil passage 25 which extends from the circumference of shaft 3 axially to the eccentric i5 from which it branches to spaced points upon the circumference of the latter. The packing gland 6 is interrupted intermediate its length so as to define a pocket 26 surrounding the shaft 3 which is adapted to supply lubricant to this passage. A thrust spring 26a is interposed between the two divided sections of the packing to maintain their spacing.
In Fig. 4 is shown a modified form of air compressor providing a small and compact unit especially well suited for operation at high speed and with relatively light loads.
This form of compressor includes a housing 30 composed of a cylindrical shell 31, a base plate 33 and a cover 34. Supported upon the interior of the shell is an iron core 35 suitably connected by windings 35a. constituting the I stator of an The windings are connected by relation thereto is a rotor 36 fixed upon anupright hollow armature shaft 31 surrounding a normally stationary shaft 38. Between these shafts is positioned a bushing 39 having a circumferential spirally extending lubricating groove 39a and terminating at its lower end in a radial flange 48' upon which rests the lower.-
end of the armature shaft. The lower end of the bushing below the flange 48 seats within a socket formed in the base plate 33 and the bushing is held from turning by a key 40a passing through the flange into the base plate. The lower end of the stationary 'shaft138 terminates a short distance above the corresponding end of the bushing 39 so as to leave a pocket 32 for the reception of oil and communicating with the spiral lubricating groove 39a surrounding the bushing and, through a slot 32a, with the interior of the shell 31. v a
The upper end of the stationary shaft passes through an opening in the cover 34 and is sealed by a packing gland 4| telescoping within a countersink in the bottom of a hollow boss 42 and retained in place by screws 41a passing through a. circumferential flange upon the packing gland into the cover.
cap 43 removably bolted thereto.
with its periphery is a ring 46. This ring is in all substantial respects identical with the ring 8 of the form of apparatus illustrated in Figs. 1
The hollow boss is closed by a and 2 and is provided with recesses 10:: corresponding to the recesses 10 of that apparatus.
Closing the upper side of the ring is a plate 41 which is centrally recessed and secured in tight association with the ring by bolts 48 extending through the plate and ring and threaded into openings in the flange. Flange 45, ring 46 and plate 41 thus together form a pumping chamber constituting the external rotary member- Stationary shaft 38 passes upwardly through the central recess in plate 41 and this shaft is intermediately provided with an eccentric 58 located between the flange 45 and plate 41. Adapted to rotate upon this eccentric is a spur wheel 18$ constituting the internal rotary member and corresponding in all substantial respects to the spur wheel 18 of the compressor of Figs. 1 and 2. This spur wheel is provided with radial vanes I91: identically shaped with those of that compressor, these vanes being designed to project -into the recesses of the ring 46 and to define pockets therewith in a manner which has already been described in connection with the embodiment of Figs. 1 and 2.
Below the eccentric 50 the flange 45 is centrally provided with a countersink in which is press-fitted a collar 49 snugly encircling stationary shaft 38 and disposed flush with the upper surface of the flange.
Flange 45 and plate 41 are recessed'to provide pairs of axially aligned inlet ports 53 extending between the interior of housing 30 and the punip ing chamber of the external rotary member.
has already been described, are adapted, during rotation of the spur wheel under the urge of the ring, to be periodically brought into alignment -with an exhaust passage 55 leading from the circiunference of the eccentric to the upper end of stationary shaft 38. The upper end of shaft 38 opens to a compartment 56 recessed within the lower face of the cap 43 and this compartment communicates with-an air discharge line 51.
As wear between the working faces of the vanes and recesses occurs, this may be compensated for from time to time. For accomplishing this object, the bore in the bushing 39 through which the stationary shaft 38 extends is disposed slightly eccentrically to the axis of the cylindrical bushing. To the upper end of the stationary shaft 38 v is attached a disk 58 having notches 59 formed in its circumference. This disk is nested within the hollow boss 42 which has notches 68 formed upon its inner circumference. the arrangement being such that by removing the cap 43 the disk 58 may be rotated and a pin 6| then inserted in any selected one of the aligned notches 59 and 6'8 to retain the stationary shaft in its position of adjustment. By turning disk 58, the stationary shaft is rotated within its offcenter mounting in the bushing causing eccentric 50 to shift spur wheel 18a closer to or farther from the inner circumference of the ring 46.
For lubricating purposes the bottom of the housing will contain a supply of lubricating oil to the approximate level indicated by dotted lines. and this oil will pass through slot 32a into and filling the pocket 32 within the bushing below the stationary shaft 38. ,Rotation of armature shaft 31 will move the oil from the .pocket up through the lubricating groove 39a to the top of the bushing and maintain a film of oil between the bushing and the armature shaft. The stationary shaft ll is provided with a'straight diagonal pas- ,sageway 39b opening at its lower end through a slot 390 to the spiral groove 33a and opening at its upper end to the circumference of the cam III, for lubricatingthe surface of the cam about which the spur wheel II rotates.
The cycle operation of this form of compressor is substantially the same as the one previously described in connection with Figs. 1 and 2. Instead of the external rotary member being driven by power transmitted to the driving shaft 3 exteriorly of the housing, this rotary member in the present instance is fastened upon the armature shaft of an electric motor concealed within the housing;
It is obvious that the principle of the mechanisms described above may be embodied in an expansion engine in which an expansible gas such as steam is usedas the source of energy, the mechanism in such a case serving as a power transmission device. Other changes in the forms of the mechanisms described above may be made without departing from the spirit of my invention.
'1. In a rotary power device of the class described, an external rotary member and an internal rotary member independently and eccentrically mounted within the external rotary member, said external rotary member comprising a closed chamber having a series of correspondingly shaped communicating recesses formed upon its inner circumference and said internal rotary member comprising a spur wheel provided with a series of radial vanes receivable within the recesses, and ports for admitting afluid into the recesses and for exhausting the fluid therefrom, the vanes corresponding in number and shape to the recesses but being of smaller size than said recesses so as to afford a clearance space within each recess and the varies and recesses being of corresponding extended arcuate form for the major portion of their lengths whereby the perimetral working faces of the vanes make combined rolling and sliding contact with the perimetral working faces of the recesses when said rotary members are rotated in driving and driven relationship, the inner and outer perimetral faces of the vanes defining smooth curves extending in the same direction and merging with the perimetral faces of adjacent vanes by smooth curves.
' ber, said external rotary member comprising a closed chamber having a series of correspondingly shaped communicating recesses formed upon its inner circumference and said internal rotary member comprising a spur wheel provided with a series of radial vanes receivable within the recesses, said vanes corresponding in number to the number of recesses, and ports for admitting fluid into the recesses and for exhausting the fluid therefrom, each of said vanes being arcuately curved and of substantially uniform width from adjacent its inner end to adjacent its free outer end and each of said recesses being of a shape corresponding to the outline of a vane but appreciably larger in size, and the axes of the external member and internal member being so related as to cause the vanes in two adjacent recesses to form a closed pocket therebetween when the rotary members are rotated in driving and driven relationship.
3. In a rotary power device of the class described, an external rotary member and an influid therefrom, each of said vanes being arcuately curved and of substantially uniform width from adjacent its inner end to adjacent its free outer end and each of said recesses being of a shape corresponding to the outline of a vane but appreciably larger in size, the ports for admitting fluid into the recesses passing transversely through a wall of the chamber, and the axes of the external member and the internal member being so related as to cause the varies in two adjacent recesses to form a closed pocket of progressively diminishing area therebetween when the members are rotated in driving and driven relationship.
4. In a rotary power device of the class described, an external rotary member and an in: ternal rotary member independently and eccentrically mounted within the external rotary member, said external rotary member comprising a closed chamber having a series of correspondingly shaped communicating recesses formed upon its inner circumference and said internal rotary member comprising a spur wheel having a hub rotatably mounted upon a stationary eccentric and provided with a series of radial vanes receivable within the recesses, said vanes corre-.
sponding in number to the number of recesses, and ports for admitting fluid into the recesses and for exhausting the fluid therefrom, each of said vanes being arcuately curved and of substantially uniform width from adjacent its inner end to adjacent its free outer end and each of said recesses being of a shape corresponding to the outline of a vane but appreciably larger in size, the ports for admitting fluid into the recesses passing transversely through awall of the chamber, and the ports for exhausting thefiuid therefrom comprising an exhaust passage extending from the circumference of the eccentric out wardly through its axis, and a plurality of discharge ports extending through the hub from the recesses to the circumference of the eccentric, said external and internal rotary members having their axes of rotation so related as to cause thevanes in two adjacent recesses to form a closed pocket therebetween of progressively diminishing area when the members are rotated in driving and driven relationship, and to cause the discharge ports in the hub to successively ride into and out of engagementwith the exhaust passage in the eccentric.
5. In a rotary power device of the class described, an external rotary member and an internal rotary member independently and eccentrically mounted within the external rotarymember, said external rotary member compris- 7 arcuately curved vanes receivable within the recesses, and ports for admitting a fluid into the recesses and for exhausting the fluid therefrom, the vanes corresponding in number and shape to the recesses but being of smaller size than said recesses so as to afford a, clearance space within each recess, the perimetral working faces of the vanes and recesses being so formed as to make line-bearing contact when the external and in-- ternal rotary members are rotated, an electric motor for rotating said rotary members in-driv-. ing and driven relationship, said motor comprising a rotor and a stator in inductive relation, a hollow armature shaft supporting said rotor, means fixedly connecting said rotor to one of said rotary members, a, housing enclosing the external rotary member, internal rotary member andmotor, and meansfor varying the position of the eccentric mounting of one of said rotary members relative to the other, said last-mentioned means comprising a bushing slidably receivable within the bore of the hollow armature shaft and having an opening therethrough disposed in axially offset relation with respect to the bore of the hollow armature shaft, a stationary shaft rigidly connected to the eccentric and slidably fitting within the opening in the bushing, the end of said stationary shaft extending beyond the housing, and a settable disk upon an end of the extended end of the stationary shaft for rotating the stationary shaft, and means for locking the disk in any one of a plurality of positions of angular adjustment.
- THOMAS M. 'GUNN.