EP0899423B1 - Scroll compressible fluid displacement machine - Google Patents

Abstract

A spiral vane air compressor has a rotating disc (2), on an eccentric mounting and on which are fitted sets of spiral vanes (3,3') each with inner (31,31') and outer (30.30') sealing flanges to produce sickle shaped chambers whose volume is reduced during the rotation of the disc and which move air from outer inlet ducts to inner outlet ducts. The leading edges ( 32,33) of the sealing flanges are offset by a set angle to even out pressure pulses generated by the spiral vanes.

Description

The present invention relates to a displacement machine for compressible media according to the preamble of the claim 1.

A generic displacement machine based on the spiral principle is known for example from DE-A-42 03 346. Machines of this type are characterized by pulsations of relatively low amplitude promotion of for example from air or an air-fuel mixture existing gaseous working medium and can therefore also for charging internal combustion engines Advantage. During the operation of one such as a positive displacement machine along spiral conveying spaces between also spirally formed, acting as a displacer Strips and the two cylinder walls of the delivery rooms, due to different curvature of the spiral shape, about crescent-shaped work chambers included, which themselves from an inlet for the work equipment through the Move delivery rooms through to an outlet, whereby their volume is constantly decreasing and the pressure of the Working medium is increased accordingly. The two each on one side of an eccentrically driven one Discs arranged strips are relative to each other offset by approximately 180 ° and extend over approximately 360 °. Each ledge has outer faces when viewed in the radial direction and inner sealing surfaces, which at the beginning on the inlet side of the strips start and at the outlet end the last end. Each of the strips thus forms together with the corresponding cylinder wall of the assigned delivery chamber a working chamber every 180 ° angle of rotation of the drive.

CH Patent Specification No. 673 679 also shows in detail the way, as in displacement machines after the Spiral principle the working chambers by a circular movement the one attached to the disc of the displacer Last in cooperation with the spiral conveyor rooms arise in the housing. Such work chambers will be both through the inside of the bar and through the Outside limited. Typical of this arrangement is that from a spiral ledge as it progresses Rotary movement of the eccentric drive and guide shafts a new working chamber every 180 ° is formed, or the filling process of a working chamber is completed.

In those from DE-A-42 03 346 and the CH patent No. 673 679 known displacement machines with four conveying rooms, with two on each side of the disc around 180 ° offset from each other, spiraling from the one in question Mirror-symmetrically arranged inlet to outlet Delivery rooms are available, closes in machine operation about every 180 ° of the eccentric Drive and guide shafts fill the working chambers from. Analogous to the filling process of the working chambers behaves the order of opening the working chambers towards the central outlet. In the four funding areas, such as they are described by the progressive movement of the spiral bars on the disc of the Are held per full revolution of the shafts A total of eight work rooms were created, four of which were synchronized work together. This leads to a low frequency pulsating promotion of the working medium. The remaining one Irregularity of both the intake volume flow as well as the outgoing volume flow of the working medium generates a noise with the fundamental frequency of the double speed of the drive.

Furthermore, in the known displacement machines, a bar inside and outside Working chambers of different volumes. This inequality the working chambers can cause unwanted pulsations in the lines that lead the working medium to the displacement machine or lead away from it.

When displacement machines of this type for charging Internal combustion engines are used, this can be low-frequency Noise is disruptive during machine operation. The damping of this noise is an additional effort both on the suction side and on the delivery side connected.

DE-A-41 33 429 discloses a possibility of symmetrical Disrupt sequence of suction and delivery cycles. The The solution shown therein assumes that the funding areas in the Housing and the spiral strips on the disc of the To shift the rotor polarly so that the Sequence of suction and delivery cycles no longer uniform is. Furthermore, the strips are on the pane the runner no longer mirror-symmetrical on both sides arranged the disc, but again angular with respect the axis of rotation of the eccentric drive shaft against each other postponed. This creates the desired irregularity the suction and delivery cycles of the machine elevated.

This solution for smoothing the intake and delivery volume flow However, the disadvantage of the working medium is liable Asymmetry of the reaction forces acting on the groin of the working medium. In the symmetrical version of the displacement machines according to DE-A-42 03 346 and CH patent No. 673 679 the reaction forces act from Pumped medium during machine operation on the Last act symmetrically and the resulting reaction force lies in the plane of the disc of the runner. This does not create any forces caused by special precautions would have to be supported. With asymmetrical Arrangement, however, as disclosed in DE-A-41 33 429 is, tilting forces very well arise, both through the uneven loading caused by the reaction forces the working medium, as well as by the the asymmetrical arrangement of the strips and therefore uneven Mass distribution caused on the disc become. The second cause, that of the asymmetrical Mass distribution, especially at high speeds harmful because the inertial or mass forces in such Operating conditions are particularly high.

It is an object of the present invention, a generic To create displacement machine in its operation the pulsations are almost completely smoothed out.

This task is solved with a displacement machine, having the features of claim 1.

The displacement machine according to the invention has given Speed of the drive an increased periodicity of Suction and delivery cycles. Show any pulsations therefore only very small amplitudes.

Furthermore, the present invention leaves a completely symmetrical one Arrangement of the strips on the pane too what helps the pulsations as well as tilting moments on the Prevent or reduce displacers.

Are those from DE-A-42 03 346 and the CH patent No. 673 679 known displacement machines according to the invention trained, no longer work two groups of four working chambers synchronized with each other, but four groups too two working chambers. All close about 90 ° angle of rotation of the drive each two working chambers their suction process from. The same applies to the push-out processes.

Fig. 1

im Längsschnitt entlang der Linie I-I der Fig. 2 eine Verdrängermaschine;

Fig. 2

ein Gehäuseteil des entlang der Linie II-II der Fig. 1 aufgetrennten Gehäuses mit darin inliegendem Verdränger bekannter Bauart;

Fig. 3

in Ansicht einen Verdränger bekannter Bauart mit spiralförmigen Leisten;

Fig. 4

in Ansicht einen erfindungsgemässen Verdränger;

Fig. 5a

in Ansicht ein geöffnetes Gehäuse mit darin angeordnetem Verdränger einer erfindungsgemässen Verdrängermaschine zu einem ersten Zeitpunkt eines Arbeitszyklus, in welchem der Antrieb eine Nullgrad-Ausgangsstellung einnimmt;

Fig. 5b

in gleicher Darstellung wie Fig. 5a die dort gezeigte Verdrängermaschine zu einem zweiten Zeitpunkt des Arbeitszyklus, zu welchem der Antrieb um 90° im Uhrzeigersinn rotiert hat;

Fig. 5c

in gleicher Darstellung wie Fig. 5a die dort gezeigte Verdrängermaschine zu einem dritten Zeitpunkt des Arbeitszyklus, zu welchem der Antrieb um 180° im Uhrzeigersinn rotiert hat; und

Fig. 5d

in gleicher Darstellung wie Fig. 5a die dort gezeigte Verdrängermaschine zu einem vierten Zeitpunkt des Arbeitszyklus, zu welchem der Antrieb um 270° im Uhrzeigersinn rotiert hat.

The drawing shows a displacement machine with a displacer of a known type and an embodiment of a displacement machine according to the invention. It shows purely schematically:

Fig. 1

in longitudinal section along the line II of Figure 2, a positive displacement machine.

Fig. 2

a housing part of the housing cut along the line II-II of Figure 1 with a known type of displacer therein;

Fig. 3

in view a displacer of known design with spiral strips;

Fig. 4

in view a displacer according to the invention;

Fig. 5a

in view an open housing with a displacer arranged therein of a displacement machine according to the invention at a first point in time of a work cycle in which the drive assumes a zero degree starting position;

Fig. 5b

in the same representation as FIG. 5a, the displacement machine shown there at a second point in time of the working cycle, at which the drive has rotated 90 ° clockwise;

Fig. 5c

in the same representation as FIG. 5a, the displacement machine shown there at a third point in the working cycle, at which the drive has rotated clockwise by 180 °; and

Fig. 5d

in the same representation as FIG. 5a, the displacement machine shown there at a fourth point in time of the working cycle, at which the drive has rotated clockwise by 270 °.

1 denotes a displacer of a displacement machine, which is arranged as a rotor in a housing 7 " both sides of a disc 2 of the displacer 1 are each two offset by at least approximately 180 ° to one another, spiral-shaped displacer arranged; it are strips 3, 3 'which are perpendicular to the Disk 2 are held. The spirals themselves are shown in the Example of several, adjoining Arcs formed. As a result of that apparent from FIG. 1 large ratio between axial length and wall thickness, is the inlet-side end of the strips 3, 3 'in each case reinforced. 4 denotes a hub, with which the disc 2 is mounted on a bearing 22 is. The bearing 22 itself sits on an eccentric disk 23, which in turn is part of a drive shaft 24 is. With 5 a radially outside of the strips 3, 3 'is arranged Eye of the disc 2, which is a guide bearing 25 picks up, which on an eccentric bolt 26 is raised. This, in turn, is part of one on the housing 7 '' mounted guide shaft 27. The eccentricity e (Fig. 2) of the eccentric 23 on the drive shaft 24 corresponds to that of the eccentric bolt 26 the guide shaft 27. Are the outlet side of the strips 3, 3 ' 2 openings 6 are present in the disk, so that the working medium get from one side of the disc to the other can, for example, through a central outlet 13 to be led away, the one on the right in Fig. 1 shown housing part 7 'of the housing 7 "is formed. With 19 a pulley is designated, which is rotatably with the drive shaft 24 is connected.

The drive shaft 24 is in one by means of a bearing 58 1 on the left in FIG. 1 and by means of of a bearing 62 in the housing part 7 '. Through the pulley 19 becomes the displacer 1 via the drive shaft 24 driven. On the also mounted on the housing part 7 " Guide shaft 27 is also fixed against rotation Toothed belt pulley 10 which by means of a toothed belt 16 for angularly accurate synchronous drive of the guide shaft 27 with the drive shaft 24 coupled to the toothed belt pulley 9 is. Through the drive designed in this way leads the displacer 1 a rotating, rotation-free in machine operation Sliding movement off. 40, 40 'are centrifugal weights, which are attached to the drive shaft 24. They serve to compensate for the displacer 1 during Machine operation acting on the eccentric 23 Centrifugal force.

In Fig. 2 is the housing part shown on the left in Fig. 1 7 'of the two axially abutting housing parts 7, 7 'assembled, via mounting eyes 8 for receiving of screw connections 8 'interconnected housing 7 '' shown. 11 and 11 'respectively denote two Conveyor spaces offset by 180 °, which according to Art a spiral slot in each of the two housing parts 7, 7 'are incorporated. They always run one on the radially outer circumference of the spiral in the housing 7 " arranged inlet 12, 12 'to the centrally arranged, two delivery rooms 11, 11 'common outlet 13. Sie have essentially parallel, at a constant distance mutually arranged cylinder walls 14, 14 ', 15, 15 ', which in the present case, like the strips 3, 3' on the disc 2, include a spiral of approximately 360 °. Grip between the cylinder walls 14, 14 'and 15, 15' strips 3, 3 ', the curvature of which is dimensioned that they have the radially outer and radially inner cylinder walls 14, 14 'or 15, 15' of the housing 7 "in operation several, for example almost in two places touch. As a result of those caused by the drive alternating approach of the strips 3, 3 'to the inner Cylinder walls 15, 15 'and outer cylinder walls 14, 14' of the assigned delivery rooms 11, 11 'result from both sides of the strips 3, 3 'sickle-shaped, the working medium enclosing working chambers, which during the drive of the displacer 1 through the conveying spaces 11, 11 'in the direction of the outlet 13. The volumes of these working chambers are reduced and the pressure of the working medium is increased accordingly.

With regard to the basic mode of operation of such displacement machines reference is also made to DE-C-26 03 462.

From Fig. 2 it can also be seen that in the area of the inlet 12 'a web 17' with the outer cylinder wall 14 ' in a web 18 'with the inner cylinder wall 15 continues. The measure also applies in the area of Inlet 12 too. The transition here is from a footbridge 17 to a web 18. On the free end faces of the strips 3, 3 'and the webs 17, 17', 18, 18 'are seals 21 in appropriate grooves inserted. With them, the work rooms against the side walls 28, 28 'of the housing, respectively sealed against the displacement disk 2.

To further illustrate the mode of operation of the displacement machine 3 the displacer 1 is better known Design shown separately. In this figure they are radial outer and radially inner sealing surfaces 30, 30 'or 31, 31 'forming sections of the strips 3, 3', which on the outer cylinder walls 14, 14 'and inner Cylinder walls 15, 15 'of the machined into the housing parts 7, 7' Funding rooms 11, 11 'for formation and displacement approach the working chambers, entered in bold.

In this embodiment of the displacer 1, the inlet side Beginning 32, 33 and the outlet end 34, 35 of the inner sealing surfaces 31, 31 'and outer sealing surfaces 30, 30 ', in the direction of movement of the medium and thus viewed in the circumferential direction, for example opposite.

4 now shows a displacer designed according to the invention 1, in which the - also bold - Sealing surfaces 30, 31 and 30 ', 31' on the strips 3, 3 'in Are arranged offset staggered. The beginning 32 the respective outer sealing surface 30, 30 'is opposite Start 33 of the respective inner sealing surface 31, 31 'to the outlet 13 significantly shifted. The same applies for the ends 34, 35 of the outer and inner sealing surfaces 30, 30 'or 31, 31'.

As can be seen in FIGS. 5a to 5d, the Crosspieces 17, 17 'towards beads protruding inwards 36, which are intended to begin with 32 of the concerned to cooperate with the outer sealing surface 30 or 30 '. The webs 18, 18 'are on their outer side a recess 37 which is intended to the beginning 33 of the respective inner sealing surface 31, 31 'to cooperate. The webs 18, 18 'further point in the direction against inside protruding thickenings 38, which for Cooperation with the ends 34 of the outer sealing surfaces 30, 30 'are determined. Accordingly, the strips 3, 3 'at the end 35 of the inner sealing surfaces 31, 31' against the inside protruding thickening 39, which is intended for this with the end of the webs 18, 18 'on this side co.

The mode of operation of the inventive method is shown in FIGS. 5a to 5d Shift of beginnings 32, 33 and ends 34, 35 of the sealing surfaces 30, 30 ', 31, 31' on the strips 3, 3 '. For the sake of clarity, it is displacer 1 analogous to Fig. 2 inside the housing part 7 ' shown.

5a shows the displacer 1 in a first position, in the outer spiral sealing surface 30 of the strip 3 a first working chamber 41, which is indicated by hatching is included. The angle of rotation of the drive is next to the housing 7 '' based on the position of the center of rotation 59 of the drive shaft 24 and the center axis 61 of the eccentric disk 23 shown.

5b shows the displacer 1 in a second position which is the drive with respect to that shown in Fig. 5a Position rotated clockwise by approximately 90 ° Has. The working chamber 41 is in this position open on the outlet side and the inner spiral sealing surface 31 the bar 3 closes a second working chamber 42, the also hatched is a. This Working chamber 42 has at least approximately the same Size as the working chamber 41.

Correspondingly, FIGS. 5c and 5d show the outside Sealing surface 30 'or inner sealing surface 31' included Working chamber 43 and 44, the further rotation of the drive by about 90 ° angle of rotation be formed.

From FIGS. 5a to 5d it can thus be seen that according to the invention on each side of the disc 2 of the rotor 1 at intervals of approximately 90 ° angle of rotation of the drive in each case a working chamber 41, 42, 43, 44 included becomes. The strips 3, 3 'are opposite the disc 2 of the Displacer 1 arranged symmetrically and the beginnings 32, 33 and ends 34, 35 of the sealing surfaces 30, 30 ', 31, 31' so that the machine operation per revolution of the The resulting working chambers are about the same size are.

Claims (6)

1. A displacement machine for compressible media, having at least two delivery spaces (11, 11') which are arranged in a housing (7") and lead spirally from a radially outer inlet (12, 12') to a radially inner outlet (13), and having a displacer (1) which, when operating, executes a circulating but non-rotating movement, has a disk (2) and spiral bars (3, 3') arranged on a side of the disk (2), the bars, as viewed in the radial direction, having outer and inner sealing faces (30, 30', 31, 31') which cooperate with outer and inner cylindrical walls (14, 14', 15, 15') of the delivery spaces (11, 11') in order, when operating, to form working chambers (41, 42, 43, 44) that move from the inlet (12, 12') to the outlet (13), wherein the outer and inner sealing faces (30, 30', 31, 31') of the bars (3, 3') are offset, as viewed in the circumferential direction, in order to form a working chamber (41, 42, 43, 44) each in a uniform rotational angle interval of the movement of the displacer (1).
2. The displacement machine as claimed in claim 1, wherein the outer and inner sealing faces (30, 30', 31, 31') have beginnings (32, 33) on the inlet side which are arranged on the bars (3, 3') in such a way that, at least approximately in the rotational angle interval of 90°, a working chamber (41, 42, 43, 44) is in each case closed.
3. The displacement machine as claimed in claim 1 or 2, wherein the outer and inner sealing faces (30, 30', 31, 31') have ends (34, 35) on the outlet side which are arranged on the bars (3, 3') in such a way that, at least approximately in the rotational angle interval of 90°, a working chamber (41, 42, 43, 44) is in each case opened.
4. The displacement machine as claimed in one of claims 1 to 3, wherein on one side of the disk (2) two bars (3, 3') are arranged so that they are offset by 180°, and on each bar (3, 3') the outer sealing face (30, 30') is arranged so that it is offset in relation to the inner sealing face (31, 31') by at least approximately a rotational angle interval of 90°.
5. The displacement machine as claimed in one of claims 1 to 4, wherein the beginnings (32, 33) on the inlet side and the ends (34, 35) on the outlet side of the outer and inner sealing faces (30, 30', 31, 31') are arranged on the bars (3, 3') in such a way that the working chambers (41, 42, 43, 44) are at least approximately equally large when closed and at least approximately equally large when opened.
6. The displacement machine as claimed in one of claims 1 to 5, wherein bars (3, 3') are arranged on both sides of the disk (2), with mirror symmetry to the latter, and cooperate with associated delivery spaces (11, 11').

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