Parallel-and external-axial rotary piston blower operating in meshing engagement

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BRIEF DESCRIPTION OF THE DRAWINGS

This object, and other objects and advantages of the present invention, will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 is a radial cross sectional view through a blower or supercharger machine in accordance with the present invention as taken along line I--I in FIG. 2;

FIG. 2 is an axial cross sectional view through the same blower or supercharger machine as taken along II--II in FIG. 1;

FIG. 3 is an illustration of the angle measurements decisive or crucial for the present invention;

FIGS. 4, 5, 6, 7, 8 and 9 schematically show position illustrations for the blower or supercharger machine having features according to FIGS. 1 and 2;

FIG. 10 illustrates a further constructive development of the blower or supercharger machine for FIGS. 1 and 2;

FIG. 11 illustrates a blower or supercharger machine for FIGS. 1 and 2 with an improved construction of the inlet and outer connections;

FIG. 12 is an axial cross sectional view through a further structural embodiment of a rotary piston for the blower or supercharger machine of FIGS. 1 and 2;

FIG. 13 is a partial radial cross sectional view for the structural embodiment of FIG. 12; and

FIGS. 14A and 14B are two comparatively illustrated radial cross sections through a Roots blower or supercharger machine.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings in detail, the blower or supercharger machine illustrated in FIGS. 1 and 2 has a machine casing or enclosed housing 1, which consists of a casing part 2, a left side part 3 and a right side part 4, which parts are connected with each other by screws 5 and 6. The casing part 2 has parallel and equally large cylindrical internal curved surfaces or inner cylindrical surfaces 7 and 8 intersecting relative to each other. The side plates or housing plate elements 3 and 4 are vertical and two shafts 9 and 10 pass or extend therethrough coaxially of the cylindrical internal curved surfaces or inner cylindrical surfaces 7 and 8. The upper shaft 9 in FIG. 1 has a driver or drive journal 11. The two shafts 9 and 10 are connected frictionally by a synchronous transmission 14 consisting of two identical gears 12 and 13 located in the right side plate or housing plate element 4, so that the gears rotate oppositely during propulsion via the driver or drive journal 11. The two shafts 9 and 10 are mounted or journaled in ball bearings 15 and 16 in the side plates or housing plate elements 3 and 4. Two rotary pistons, indicated generally by arrows 17 and 18, are rigidly rotated with these shafts and revolve on the shafts 9 and 10; the rotary pistons 17 and 18, as represented generally, include a semicylinder 19 with a large radius coaxial to the respective shaft 9 or 10 and a semicylinder 20 with a small radius coaxial to the same shaft. The large radius is smaller by a nominal gap measurement than the radius of the semicylindrical internal curved surfaces 7 and 8. The small radius is smaller by 2.5 times than the large radius.

The cylindrical peripheral area of the semicylinder 19 with the large radius discontinues at 15.degree. to 25.degree., preferably 20.degree. angle of rotation to the base plane of the semicylinder thereof in flanks or transition surfaces 21 with an edge angle of 30.degree. to the plane of symmetry of the rotary piston 17, 18 (FIG. 3). The peripheral area of the semicylinder 19, accordingly with the exemplified embodiment illustrated in FIGS. 1 and 2, extends only over 140.degree. angle of rotation.

These flanks or transition surfaces 21 and the base surfaces 22 of the semicylinder 19 with the large radius between the cutting edges with the flank 21 and the onset or beginning edge of the semicylinder 20 with the small radius form the mating surfaces of the rotary pistons 17 and 18 during the rotation thereof between the phases of mutual rolling-off respectively of the semicylinder 19 with the large radius and of the semicylinder 20 with the small radius of the other rotary piston 17 or 18. The radii of the semicylinders are so measured or apportioned, that these radii permit the outer corners or edges 23 and the rounded-off portions, inner corners or edges 24 of the flanks or transition surfaces 21 cooperate with only a narrow or close gap therebetween and these corners or edges themselves pass along the base surfaces 22 of the other rotary piston without engagement. The corners 24 are curved or rounded-off arcuately for forming a circular arch in order to avoid a direct engagement therewith.

Each base surface 22 is a portion of the piston of greater radius and has a distance greater than twice the small radius and smaller than twice the large radius that extends from an axis of a shaft toward an inner cylindrical surface of the casing, and the transition surfaces 21 on each of the pistons are formed between the base surface 22 and the arc of greater radius; the transition surfaces begin at the outer location of the base surfaces 22 that extend and are disposed to cooperate with corresponding transition surfaces of the other piston in a seal close gap relationship, for example, illustrated progressively by FIGS. 4-8 inclusive.

The position of the two rotary pistons 17 and 18 is always such that, in each of the phases of movement thereof, symmetrical relationship exists with respect to each other and relative to the housing.

The semicylinders 20 with the small radius are made unitary or in one piece with the shafts 9 and 10 thereof so that these semicylinders 20, in the region of the axial length of the rotary pistons 17 and 18, have a semicircular shaped cross section, in the planar surface of which there lies the shaft middle or central axis. The semicylinders 19 with the large radius contrary to the semicylinders 20 with the smaller radius consisting of massive or solid steel are made of hollow-drawn or extruded aluminum for the purpose of balancing and are rigidly connected with the shaft 9 or 10 by screws.

The shafts 9 and 10 axially adjacent to the rotary pistons 17 and 18 have disks 27 and 28 running in the recesses 25 and 26 located or provided in the housing side walls, plates or plate elements; the disks 27 and 28, in the sides thereof away or remote from the rotary pistons 17 and 18, have recesses 29 and 30, which serve for further balancing of the rotary pistons. These disks 27 and 28 with the peripheral areas or surfaces 31 and 32 thereof pass along relative to the recesses 25 and 26 with most narrow gap relationship remaining therebetween, while after the end faces of these disks there is permissible a greater play or clearance with respect to the end faces of the recesses 25 and 26. The sealing of the end faces of the rotary pistons is problematical because of the bearing play or clearance; however, via this feature, the sealing of the end faces of the rotary pistons is shifted or relocated in the gap between the peripheral surfaces or areas 31 and 32 and the recesses 25 and 26; this gap can be produced with the required accuracy without difficulty. The rotary pistons movable in the casing operate along the walls of the side plate and conform to complement each other continuously having the close gap relationship therewith.

Rotational balancing means encompass such an annular disk (27,28 respectively 64,65) attached for rotation with each of said pistons, an annular recess 25,26 is formed in the casing 1,3,4 and attached to receive the annular disks 27,28; the annular disk provides rotational balance attained by removal of recessed or hollow portions 29,30 at appropriate locations thereon; the gaps between the adjacent peripheral 31,32 and side surfaces of the disks 27,28 and the recess 25,26 at the same time provide an additional function of tortuous gap seals for the fluid.

As to the meaning of "tortuous gap seals", there is meant the sealing gap relationship between the parts 27 respectively 28 (left and right disks) and the adjoining side parts 3 and 4 in FIG. 2. These disks run in the recesses 25 and 26 in the side parts 3 and 4 with narrow play; while the gap between the base of these recesses 25 and 26 and the end of the faces of the disks 27 and 28 can have a greater play, being held wider, the base of the recesses 25 and 26 being located in a vertical or upright plane in the drawing. The purpose of this arrangement is that the last-mentioned wider gap between the recess base and the face side of the disk cannot be permitted to be too narrow because of the axial oscillations or vibrations of the rotating rotary piston. The seal consequently is displaced from occurrence in the adjacent axial direction into occurrence in the radial location, accordingly into the ring gap near the reference numeral 25 in FIG. 2. This can be very narrow with the exact or accurately journaled shaft and most of all can be produced by simple or straightforward turning-out and turning-off with corresponding tolerances in a satisfactory fabrication thereof.

"Tortuous" gap refers to the gap in narrowest possible space relationship existing for example, between the end face of the disk and the recess base included in the sealing path and considered to be in a sense a "labyrinth seal". Thus, the "narrowest gap" must be taken literally as to the meaning thereof to represent the tightest or closest relationship of the parts relative to each other ("tortuous" means "full of twists and turns" literally per dictionary).

There has been shown and proven in practice that a completely sufficient or adequate sealing-off can be attained herewith. Most of all, the suctioning of oil from the space or chamber of the synchronous transmission 14 into the operating or working spaces or chambers can be precluded as a consequence of the pressure pulsations arising therein. The housing in itself running dry, thus, can deliver pressure medium completely free of oil.

Inlet 33 has a width in radial section compared with the outlet 34 such that the width of the inlet 33 is larger by approximately 1.35 times for improvement of the flow conditions or relationships. In the exemplified embodiment illustrated in FIG. 10, there is a trough or depression 35 continuously over the entire length of the rotary piston 17 or 18 arranged in the base plane or surface 22 for improvement of the flow guidance or conveyance during passage of the outer corner 23 of the flank 21.

In a further specific embodiment according to FIG. 11, an inlet 36 and an outlet 37 are shown before which bodies 38 and 39 are arranged for the flow guidance or conveying. These bodies 38 and 39 extend with identical cross section over the entire axial length of the inlet 36 and outlet 37. These bodies 38 and 39 together with the curved or bent walls 40 and 41 of the inlet connection 44 or the curved or bent walls 42 and 43 of the outlet connection 45 form the two inlet passages or channels 46 and 47 for the two outlet passages or channels 48 and 49, which reroute or divert the flow in a more tangential direction to the casing inner cylindrical surfaces or internal curved surfaces respectively released or cleared by the rotary piston.

FIG. 12 represents a single rotary piston (the second rotary piston is entirely the same), as corresponding to the rotary piston 17 respectively 18 in FIG. 2 and the rotary piston of FIG. 12 is shown in the same axial section or position.

In FIG. 12 there is illustrated a specific embodiment of the rotary pistons 17 and 18 intended for a simple fabrication, production or manufacture. The shaft 52 is produced unitary or in one piece together with the semicylinder 53 with a small radius, whereby the semicylinder 53, first together with the shaft 52 together with the shoulders 54 and 55 provided on both sides of the semicylinder, is turned-out fully round or machined into the shape of a recess 59 as far as to the plane of the center axis of the shafts which recess 59 extends as far as into the shoulders. The recess 59 of the semicylinder with large radius is formed of one hollow body of aluminum which has semi-round extension, on opposite sides therein with radius like that of the shoulders being formed therein. For the insertion of the semicylinder 56 with large radius of aluminum illustrated in a radial section in FIG. 13, there is milled-out or reamed the semicylinder 53 with a small radius as far as to a plane 57, in which the shaft axis 58 lies, in a recess 59, which recess 59 extends or mates at 60 and 61 into he shoulders 54 and 55. That part forming the semicylinder 56 with the large radius on the one hand has semicircular or half-round extensions 62 and 63 with the same radius as that forming the shoulders 54 and 55, which extend as far as to the ends of the recesses at 60 and 61 in FIG. 12. After insertion of the part forming the semicylinder 56 with the large radius, then the disks 64 and 65 with a fitting bore are pushed over the shoulders 54 and 55 and the extensions 62 and 63, which thereby are held together securely, without requiring any screws or union. The disks 64 and 65 for example can be shrunk-on and friction-welded. The disks 64 and 65 correspond to the disks 27 and 28 and have the recesses 29 and 30.

The following can be noted as to how disks 64 and 65 are accommodated over shoulders 54 and 55 and extensions 62 and 63 as well as what is meant when referring to a fitting bore. The disks 64 and 65, correspond to the aforementioned disks 27 and 28 in FIG. 2 and have the aforementioned function of sealing-off and simultaneously the function of balancing as counterweights, such disks 64 and 65 having a central bore therewith. The disks 64 and 65 are moved over the "shoulder" 54 respectively 55 of the shaft which supports the semi-cylinder 53 with small radius, whereby the fit is so narrow or close that further fixation for accuracy is not required (for example, via shrinking or pressure-welding). The disks 64 and 65 touch over the extensions 62 and 63 of the semi-cylinder 65 with a large radius, which is installed in a recess 59 of the semi-cylinder 53 with a small radius. Accordingly, in FIG. 12 there is illustrated a simplified construction of the blower according to FIG. 1 which does not require any screw or bolt connection.

Referring now to the illustrations of FIGS. 4 through 9 inclusive, the upper rotary piston 17 in FIG. 4 carries out an induction or intake stroke by opening and expanding of the upper working or operating chamber 49, while the lower rotary piston 18 exhausts the gas suctioned thereby in the lower working or operating chamber 50. The inlet 36 is separated from the outlet 37 by the two rotary pistons 17 and 18, whereby split or divided chambers or spaces located and formed collectively between the internal curved surfaces or inner cylindrical surfaces 7 and 8 and the peripheral beginning areas or surfaces of the semicylinder 19 with a large radius are very long and thus practicall