EP0066255A1 - External-axis rotary-piston blower - Google Patents

Abstract

Rotary piston blower with two overlapping parallel-axis cylindrical spaces (2,3), each of which is penetrated radially by a shaft. On the shaft of one space forming a hollow cylinder (9), a working rotor (10) having a ratchet tooth (15) rotates contact-free and a cut-off rotor (23) for the passage of the locking tooth (23) has a recess (28) for the passage of the locking tooth . The working gas is sucked in through the hollow shaft and through the shut-off tooth of the working rotor and pushed out through an outlet channel (43) provided in the housing jacket. A fixed sleeve (12), which has a control opening (21), is arranged in the hollow shaft and is steered through the recess of the shut-off rotor during the passage of the shut-off tooth. In order to improve the flow conditions and the efficiency, a connecting channel that is open to the working space between the recess of the shut-off rotor and the outlet channel can be provided in the housing jacket. In order to meet the requirements at high speeds, the hollow cylinder (9) can run on an inner bearing on its suction side, additional flow paths leading around this inner bearing being provided. Furthermore, axially directed slots can be provided in the shut-off part of the sleeve and in the corresponding shut-off part of a further sleeve arranged in the first sleeve, which slots can be made to coincide when the inner sleeve is rotated at higher speeds.

Description

The invention relates to an external-axis rotary piston blower with a housing formed from at least two overlapping parallel-axis cylindrical inner spaces, each of which is penetrated by a shaft, with on one shaft a cylindrical working space providing a ring-shaped working space with a shut-off tooth and forming a ring with the surrounding housing wall the other shaft rotating in the opposite direction has a cylindrical shut-off rotor running against the housing wall and rolling on the working rotor with a recess for the contact-free passage of the shut-off tooth and the body of the working rotor is a hollow cylinder, which temporarily comes into cover with a control opening provided in the shut-off teeth or with a further control opening in a fixed sleeve arranged in the hollow cylinder during its circulation.

Such machines have the advantage over other small blowers, among which the root blowers and the screw compressors developed from them are the most commonly used types, that no rotor contours formed from cycloids are necessary. In addition, cheap compression diagrams can be achieved with them. Such a blower is described in US Pat. No. 2,130,054, in which the working rotor has two or three shut-off teeth and accordingly two or three shut-off rotors are arranged. The fixed sleeve, around which the hollow cylinder representing the body of the working rotor rotates, forms an annular space penetrated by the drive shaft. The working rotor and the shut-off rotor run against each other with a toothing which is interrupted by the toothed teeth which cooperate with the recesses of the shut-off rotor and which otherwise occupy their entire axial surface, so that a synchronous gear is not required.

Another such machine is described in DE-OS 22 22 500, in which only one shut-off tooth and one shut-off rotor are provided, which are driven in opposite directions by a 1: 1 gearbox.

This makes it possible to avoid the direct interlocking of the rotors, which is difficult, expensive and considerable in terms of production, and results in power losses due to squeezing currents between the teeth.

Both constructions have a disadvantageously complicated flow path of the working gas, particularly when it is being expelled. Above all, it is sucked in via circumferential inlets in both cases and guided inward through the working runner and deflected axially. It was assumed that there was an obvious prejudice that smaller flow cross sections were required for the compressed gas. However, it has been shown that pressure fluctuations in the annular work space caused by traffic jams occur in such gas ducts, which cause a considerable additional outlay in terms of performance, which in most cases precludes practical use of such machines. In addition, the two aforementioned solutions are not suitable for cheap, small, and mass-produced blowers, such as are needed above all in the vehicle engine industry as loaders. There is another disadvantage. After the passage of the shut-off tooth through the recess of the shut-off slide, a leakage path is possible via the gap spaces between the shut-off rotor and the housing side walls on their part engaging in the annular working space, which leakage path can be particularly effective because of its brevity. according to which the axial play of the gate valve must be kept very small. It therefore requires a greater design effort to keep this leakage path as small as possible and, on the other hand, to prevent the shut-off rotor from starting on the housing side walls.

The object of the invention is to avoid the described flow obstructions due to accumulation and pressure vibrations and the power losses caused thereby, and also to avoid the leakage paths between the housing side walls and the shut-off rotor while allowing a greater axial play of this rotor, but at the same time a very simple and accordingly inexpensive overall construction to find.

According to the invention, this object is achieved in that the hollow cylinder is mounted in a first part of the housing and is fixedly and coaxially connected to the drive shaft mounted in the other side part of the housing, and that the sleeve, which is sealed by the hollow cylinder and is fixed in the first side part, is also provided their entire interior is an inlet channel for the intake air and that in this in the direction of rotation of the back side of the hollow shut-off tooth there is an inlet opening for the working gas into the suction space and in the housing jacket an outlet channel for the delivered working gas, which is essentially tangential to the movement of the working area Direction runs.

This reversal of the flow direction compared to known blowers of this type and the additional measures mentioned to improve the flow guidance result in a considerably lower power consumption of the blower with the same working gas throughput or the same compression. The pressure fluctuations in the ring-shaped working space which obstruct the flow and the energy-consuming turbulences generated by the deflection of the outlet flow are avoided in the construction according to the invention. A particular advantage is the arrangement of the outlet in the circumference of the housing shell, whereby the centrifugal forces acting on the working gas can be used, against which it had to be pushed out in known constructions. The energy saving achieved is just as important for the use of such fans as the cheap manufacture which the construction according to the invention enables. Further embodiments result from the claims.

A better degree of filling, in particular at high speeds, namely of about 20 to 30% and a corresponding improvement in efficiency can be achieved in that in the wall of the cylindrical space facing the outlet duct, in which the shut-off rotor rotates, a connecting duct from this cylindrical space is provided for the outlet channel with an axial length of about 80 to 90% of the length of the shut-off rotor, which widens after the outlet channel and which is too open after the cylindrical space in which the working rotor rotates.

At higher speeds, at which the hollow cylinder of the working rotor can no longer be stored in an external bearing, which in itself lends itself to having the entire cross section of the hollow cylinder available as an inlet opening, if an inner bearing is arranged in the hollow cylinder, an equally large inflow cross section for the working gas can be obtained by the fact that the hollow cylinder is mounted in the inner flange in the outer flange in the first side part, that a central passage opening for the sucked-in working gas and a plurality of lateral passage openings for the working gas surrounding this central passage opening have bearing through the inner bearing and the sleeve Webs are separated, and that an annular space surrounding the inner bearing is formed in the side part, via which the lateral passage openings are connected to openings in the wall of the hollow cylinder.

Furthermore, the sealing of the working chambers among themselves and the sealing of the pressurized ejection chambers can be improved in that the right side wall has a recess which is coaxial with the shaft and into which a cylindrical extension of the hollow cylinder which is coaxial with this recess engages without contact, the fit in the recess is narrower in the radial direction than in the axial direction.

In order to be able to improve the delivery pressure or delivery quantity of the working gas, it is proposed to design the sleeve so that it has a plurality of axially directed slots in its part which blocks the control opening of the hollow cylinder, and that the sleeve has a further one which can be rotated arbitrarily from the outside about its longitudinal axis Sleeve encloses, which has a control opening corresponding to the control opening of the first sleeve as well as axial shut-offs in its shut-off part corresponding to the shut-off part of the first sleeve, which, when this additional sleeve is rotated, come into congruence with the slots of the first sleeve or can shut them off.

It has turned out to be the best embodiment that three slots of equal width are arranged in the fixed sleeve with equally large distances between the slots and that the center line of the slots are at a distance of 34 ° from one another.

In order to achieve the most favorable flow conditions, it is expedient that the closed side of the shut-off tooth facing the working space has an angle of 20 to 30 ° with respect to the radial central axis of the shut-off tooth both on its inner wall and on its outer wall in radial section.

• Fig. 1 einen Radialschnitt durch ein erfindungsgemäßes Rotationskolbengebläse in Ebene I-I in Fig. 2;
• Fig. 2 einen Axialschnitt durch das gleiche Gebläse in Ebene II-II in Fig. 1;
• Fig. 3 acht schematische Radialschnitte des gleichen Gebläses in verschiedenen aufeinanderfolgenden Bewegungsphasen;
• Fig. 4 einen gleichen Radialschnitt wie in Fig. 1, jedoch mit Darstellung eines Verbindungskanales zwischen Auslaßkanal und der Ausnehmung im Absperrläufer;
• Fig. 5a bis b vier schematische Radialschnitte des gleichen Gebläses wie in Fig. 4 in verschiedenen aufeinanderfolgenden Bewegungsphasen;
• Fig. 6 eine andere Ausführungsform des erfindungsgemäßen Rotationskolbengebläses im Axialschnitt;
• Fig. 7 eine weitere Ausführungsform des erfindungsgemäßen Gebläses im Axialschnitt in.Ebene VIII-VIII in Fig. 8;
• Fig.^-8 einen Radialschnitt durch das in Fig. 7 dargestellte Gebläse in Ebene VII-VII

An embodiment of the invention is described with reference to the drawings. Show it

• 1 shows a radial section through a rotary piston fan according to the invention in plane II in Fig. 2.
• Figure 2 is an axial section through the same fan in plane II-II in Fig. 1.
• 3 shows eight schematic radial sections of the same fan in different successive movement phases;
• 4 shows the same radial section as in FIG. 1, but with a connection channel between the outlet channel and the recess in the shut-off valve;
• 5a to b show four schematic radial sections of the same fan as in FIG. 4 in different successive movement phases;
• 6 shows another embodiment of the rotary piston fan according to the invention in axial section;
• 7 shows a further embodiment of the blower according to the invention in axial section in plane VIII-VIII in FIG. 8;
• Fig. ^- 8 is a radial section through the fan shown in Fig. 7 in plane VII-VII

The blower shown in Fig. 1,2 and 3 has a housing 1 that consists of two overlapping parallel-axis cylindrical spaces 2 and 3, which are formed by a housing shell 4 and side parts 5 and 6, the latter side part integral with the shell part connected is. In the larger space 3 protrudes axially and concentrically in the right side part 6 in the ball bearing 7 drive shaft 8, to which a coaxial hollow cylinder 9 is welded in the interior of the space 3, which forms the body of the working runner 10. This hollow cylinder 9 is supported from the outside at its left end on a further ball bearing 11 arranged in the side part 5. In the same side part 5, a sleeve 12 is screwed to an outer flange 13, which projects coaxially into the cylinder 9 almost to its end. On the inside of the hollow cylinder 9 is a coating 14 made of slidable material, for. B. from tetrafluoroethylene provided on the Sleeve 12 starts slidingly and sealingly and completely fills the gap between hollow cylinder 9 and sleeve 12. On the hollow cylinder 9, a shut-off tooth 15, which together forms the working runner 10, is screwed together, which runs along the jacket raceway 16 of the housing jacket 4 with its edges 17 without contact, but forming a very small gap.

The working tooth 15 is fastened to the hollow cylinder 9 with screws. On its rear side in the direction of rotation, the shut-off tooth has an inlet opening 19 for the entry of the working gas into the space 3, which takes up the entire available axial width and radial height of the working tooth 15. In the hollow cylinder 9, a control opening 20 is provided which takes up the entire base of the interior of the shut-off tooth 15. This control opening 20 is in register with a further control opening 21 in the sleeve 12 in the intake stroke. The control opening 21 has the same axial width as the control opening 20 in the hollow cylinder 9 and an extent in the circumferential direction of 40 ° to 325 ° after the TDC position of the workman, that is to say the position shown in FIG. 1. The open side of the sleeve 12 in FIG. 2 is the inlet 22 for the working gas, at which a suction nozzle can be arranged.

In the smaller cylindrical working space 2, a shut-off rotor 23 which starts at its jacket raceway with a very small clearance is arranged coaxially, which has the same radial diameter as the hollow cylinder 9 and rolls on it. the shut-off rotor 23 is mounted on shaft ends 24, 25 in ball bearings 26, 27 in side parts 5, 6. In radial cross section, it has a circular arc-shaped recess 28 for the passage of the shut-off tooth 15. The axial extent of the space 2 is wider than that of the space 3. The side parts 5 and 6 accordingly have recesses 29, 30 into which the shut-off rotor projects laterally. The purpose of this is to achieve a better seal. The cylinder wall of the stopper 23 and the recesses 29 and 30 can be fitted much more closely to a narrow gap than the necessary clearance between the side walls 31 and 32 of the stopper 23 and the counter surfaces 33, 34 of the recesses 29, 30 allow. This axial play can therefore be that of the commercially available ball bearing, i.e. about 0.5 mm.

For its balancing, the shut-off rotor 23 has cavities 35 on its side opposite the recess 28 and recesses 36, 37 on its side walls 31, 32. Tie rods are provided at 38 and 39. The shut-off tooth 15, which is made of cast aluminum, does not need to be balanced, since its weight corresponds to the material of the hollow cylinder 9 removed to produce the control opening 20, which is made of steel.

The drive shaft 8 of the working rotor 10 and the stub shaft 25 of the shut-off rotor 23 are non-positively connected by a gear 42 consisting of two gear wheels 40, 41 in a ratio of 1: 1.

The outlet channel 43 for the working gas is arranged in the housing jacket 4 directly in front of the line of intersection of the cylindrical spaces 2 and 3 and has its axis in a tangential direction to the direction of rotation of the working rotor 10 in order to allow an unobstructed discharge of the working gas without a significant change in direction. For this purpose, the transition from the jacket raceway 16 to the outlet duct 43 is rounded off at 44 in order to avoid a vortex-forming edge.

The mode of operation of the blower is shown in the position diagrams of FIG. 3: In FIG. 3 a, the preceding expulsion of the working gas is completed and in FIG. 3 b the intake stroke begins with the opening of the control opening 21 in the sleeve 12 through the control opening rotating about it 20 in the shut-off tooth 15, while the shut-off rotor 23 divides the annular working space into a suction chamber 45 and an ejection or compression chamber 46. Figures 3 h, a, b. show the passage of the shut-off tooth 15 through the shut-off rotor 23, whereby no squeezing currents can occur in the working gas due to the acute-angled tooth shape and the narrow radial contact surface of the shut-off tooth.

With this arrangement and in this direction of rotation of the fan, there is a smooth flow course, in which congestion effects and pressure vibrations are avoided, and in which the centrifugal forces acting on the gas pushed out are exploited by the tangential direction of the outlet duct 43. The size of the inlet openings 22, 21, 20, 19 avoids inlet throttling.

If higher densities are desired, the circumferential expansion of the control opening 21 in the sleeve 12 can be shortened accordingly, but the best results are achieved with the indicated values of 40 to 320 °.

The described embodiment is very simple and extremely cheap to manufacture in mass production. All parts that come into contact with one another have the shape of circular arcs, which enables simple manufacture by drilling and round milling, and which also allows very precise adjustment. The shut-off tooth is a simple casting. The axial clearances do not require any special tolerance and, finally, the ratio between drive power and throughput is much more favorable than with other known solutions.

Strength in _F. 4 at 47 the connecting channel between the outlet channel and the space 2 or the recess 28 is shown in the shut-off valve 22. Its mode of operation results from FIGS. 5a to d. There, the arrows 47 show the direction of the flow of the working gas in the individual movement phases. The arrangement of this connecting channel at a higher speed causes the pressure of the working gas reaching the recess 28 in the position in FIG. 5a in the following positions according to FIGS. 5b to 5d to be conveyed into the outlet channel until complete relaxation and not into the subsequent suction chamber passes.

6 shows a left side part 105, in which the hollow cylinder runs in an inner bearing 111 against the sleeve 112. On the side part 105, an outer flange 113 is arranged, which has a central passage opening 114 for the working gas, and lateral passage openings 115, between which webs 116 are provided which support the inner bearing 111. The sleeve 112 is also fastened to the fixed part of this bearing and the hollow cylinder 109 to its movable part.

In the side part 105, the annular space 117 is also provided, through which the working gas entering the side inlet openings 115 passes through the openings 118 gets into the hollow cylinder 109. This arrangement is necessary at high speeds, since an outer bearing with the diameter as shown in FIG. 2 would be overloaded. The reduction in the cross section of the inlet opening in the hollow cylinder 109 through the inner bearing 111 is compensated for by the measures described.

Figs. 7 and 8 show the arrangement of an internal controller. The sleeve 212, which has three axially directed slots 214 in its shut-off part 213, encloses a further sleeve 215 which can be rotated arbitrarily from the outside about its longitudinal axis and which in turn has axially directed slots 216 in its shut-off part 217. Both sleeves have corresponding control openings 218 and 219.

By rotating the sleeve 215, the slots 214 of the sleeve 212 are partially or completely covered, and when the slots 214 are opened, the control opening 220 of the hollow cylinder 221 is not completely covered by the shut-off part 213 of the sleeve 212. ^* )

FIG. 8 shows a preferred embodiment with three slots 214 and 216 each, the axial center lines of the slots 214 being 34 ° apart.

7 also shows a floating mounting of the hollow cylinder 221 in a double bearing 222 which ( ^* The sleeve 215 is rotated with a pin arranged at 225, which engages through a slot in the outer flange 226.

Shaft 223 in the right-hand side part 224. However, such a mounting is only possible with short fans in which the length of the hollow cylinder 221 does not significantly exceed its diameter. However, such an arrangement does not leave the scope of the invention.

The angle which the closed outer wall of the shut-off tooth facing the working space has on its inside as well as on its outside in radial section with respect to the radial central axis of the shut-off tooth is most suitably approximately 20 °. This avoids squeezing flows and tests have shown that the best flow conditions and efficiencies can be achieved with the angular dimensions mentioned.

Claims (12)

1. External-axis rotary piston blower with one formed from at least two overlapping parallel-axis cylindrical interior spaces
Housings, each of which is penetrated by a shaft, with on one shaft a cylindrical working space provided with a shut-off tooth forming a ring-shaped working space with the housing wall surrounding it, and on the other shaft running in the opposite direction, a cylindrical shut-off rotor running against the housing wall and rolling off the working rotor are arranged with a recess for the contact-free passage of the shut-off tooth and the body of the worker is a hollow cylinder which, with a control opening provided in the shut-off tooth, temporarily comes into cover with a further control opening in a fixed sleeve arranged in the hollow cylinder during its circulation,
characterized in that the hollow cylinder (9) is mounted in a first side part (5) of the housing (1) and is fixedly and coaxially connected to the drive shaft (8) mounted in the other side part (6), that further the sleeve (12), which is sealed by the hollow cylinder (9) and is fixed in the first side part (5) and has a control opening (.21), with its entire interior is an inlet duct for the working gas that is sucked in and that in the direction of rotation of the working rotor (10) is rearward On the side of the hollow shut-off tooth (15) there is an inlet opening (19) for the working gas into the suction space (45), and in the housing jacket (4) there is an outlet channel (43) for the pumped working gas, which is essentially in the movement of the working rotor (10 ) tangential direction. 2. Rotary piston blower according to claim 1, characterized in that the shut-off rotor (23) extends in its axial extent in recesses (29, 30) in the side parts (5, 6) which are non-contact with the cylindrical surface of the shut-off rotor (23) are missed in the narrowest gap. 3. Rotary piston blower according to claim 1, characterized in that the transition from the jacket raceway (16) in the outlet channel (43) is rounded. 4. Rotary piston blower according to claim 1, characterized in that between the hollow cylinder (9) and the sleeve (12) an intermediate layer made of a material with high: lubricity is arranged, which fills the gap between the hollow cylinder and sleeve sealing. 5. Rotary piston blower according to claim 1, characterized in that the shut-off tooth (15) made of aluminum and the hollow cylinder (9) made of steel - and that the shut-off tooth (15) by removing material to form the control opening (20) from the hollow cylinder ( 9) is balanced. 6. Rotary piston blower according to claim 1, characterized in that the housing shell (4) and a side part (6) are in one piece and that the cylindrical interior spaces (2, 3) in the housing shell (4) and the recesses (29, 30) for the shut-off rotor are produced by round milling. 7. Rotary piston blower according to claim 1, 2, 3, 4, 5, 6, characterized in that in the wall of the cylindrical space (2), in which the shut-off rotor (23) rotates, to the suction duct (43), a connecting duct (47 ) from this cylindrical space (2) to the outlet channel (43) with an axial length of approximately 80 to 90% of the length of the gate valve (23) is provided, which widens after the outlet channel (4 ₃ ) and which is open towards the cylindrical space (3) in which the shut-off rotor (23) rotates. 8. Rotary piston blower according to claim 1,2,3,4,5,6,7, characterized in that the hollow cylinder (109) in the first side part (105) in an inner bearing (111) in the outer flange (113) is mounted that a has central passage opening (114) for the sucked-in working gas and a plurality of lateral passage openings (115) for working gas surrounding this central passage opening (114), which are separated by webs (116) carrying the inner bearing (111) and the sleeve (112), and that an annular space (117) surrounding the inner bearing (111) is formed in the side part (105), via which the lateral passage openings (115) are connected to openings (118) in the wall of the hollow cylinder (109). 9. Rotary piston fan according to claim 1, 2, 3, 4, 5, 6, 7, 8, characterized in that the side wall (105) has a recess (119) which is coaxial with the shaft (108) and into which a recess (119) 119) coaxial cylindrical extension (120) of the hollow cylinder (109) engages without contact, the fit in the recess (119) being narrower in the radial direction than in the axial direction. 10. Rotary piston blower according to claim 1,2,3,4,5,6,7,8,9, characterized in that the sleeve (212) in its the control opening (220) of the hollow cylinder (221) shutting off part (213) Has a plurality of axially directed slots (214) and that the sleeve (212) encloses a further sleeve (215) which can be rotated arbitrarily from the outside about its longitudinal axis and which has a control opening (217) corresponding to the control opening (218) of the fixed sleeve (212) and has in its shut-off part (213) corresponding shut-off part (217) axial slots (216) which, when this further sleeve (215) is rotated, come into congruence with the slots (214) of the fixed sleeve (212) or can shut them off . 11. Rotary piston blower according to claim 10, characterized in that in the sleeve (212) three slots of equal width are arranged with equal distances between these slots and that the center lines of the slots from each other; have a distance of 34 °. 12. Rotary piston blower according to claim 1,2,3,4,5,6,7,8, 9,10,11,
characterized in that the closed side of the shut-off tooth (15) facing the working space (45, 46) has an angle of 20 to 30 ° both on its inner wall and on its outer wall in radial section with respect to the radial central axis of the shut-off tooth.

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