GB2255595A

GB2255595A - Spiral bladed compressor.

Info

Publication number: GB2255595A
Application number: GB9209371A
Authority: GB
Inventors: Klaus-Dieter Emmenthal; Otto Schafer; Claus Muller; Klaus Schubert
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 1991-05-06
Filing date: 1992-04-30
Publication date: 1992-11-11
Also published as: GB9209371D0; DE4214613A1; FR2676254A1; JPH05231347A

Description

1 2 2 -3 5 5 5 c

DESCRIPTION SPIRAL DISPLACING MACHINE

The invention relates to a spiral displacing machine for compressible media having a rotor which can be eccentrically rotated in a housing, the rotor having blades designed in the shape of a spiral on a rotor disc which interact with corresponding blades in the housing to form spiralshaped working chambers.

A machine of this type, also known as a spiral compressor or G-compressor, can be used to pressurize internal combustion engines and among other things is described in the motoring magazine MTZ 46 (1985) Pages 323-327. A disc-shaped rotor having blades axially arranged and designed in the shape of a spiral rotate eccentrically in a housing which is also fitted with spiral-shaped blades. As a result of the eccentric movement, a large rotating inertia force occurs in the region of a main bearing of the rotor. The highest permissible rotational speed and at the same time also the flow capacity of the machine are limited in this way.

An object of the present invention is to reduce by means of structural measures the inertia force which is generated during operation of the rotor.

In accordance with the present invention the rotor blades have a crosssection with a hollow c -2chambered profile. The inertia force which occurs can thus be reduced considerably. At the same time it is possible to produce the rotor blades economically from continuously cast sections. In this case the rotor blades are firmly connected to the rotor disc by suitable types of connections.

The rotor disc advantageously also has a crosssection with a hollow chambered profile to reduce the weight.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which:

Fig.1 is a cross-section through a rotor in accordance with the invention having rotor blades; Fig.2 is an illustration of the attachment between the rotor blade and the rotor disc in a view according to Fig.1; Fig.3 is a further type of attachment between the rotor blade and rotor disc in a view according to Fig.l; Fig.4 is a further design of the rotor blades in a view according to Fig. 1; Fig.5 is a design in accordance with the invention of a rotor disc in a view according to Fig.1; Fig.6 is a top view of a part of a rotor disc j v 1 -3according to Fig.5; and Fig.7 is a top view of a rotor blade for use in connection with the design of the rotor disc according to Fig.6.

Reference is made to the construction and the method of functioning of a spiral displacing machine as described in the motoring magazine mentioned initially. A rotor, also called a displacer, rotates eccentrically in a housing. in order to form spiralshaped rotating working chambers, the rotor and the housing each have spiral-shaped blades. The rotor is driven by two shafts, a drive shaft and a somewhat smaller guide shaft. The present Fig.1 shows a rotor 10 having a rotor disc 11 and blades 12,13 in the cross-section from a hub 14 for a drive shaft, not illustrated, up to an auxiliary hub 15 for a guide shaft which is also not illustrated. The rotor disc 11 is designed solidly in one piece and has orifices 16,17 to accommodate the blades 12,13. These are inserted into the orifices 16,17 and firmly attached to the rotor disc 11 by solder, adhesive or by formlocking. The orifices 16,17 extend around the hub 14 in a spiralshape corresponding to the shape of the blade. Reference is also directed to Fig.6; an orifice for a blade is designated here with the reference No. 18. The spiral shape of the blades 12,13 c corresponds to one of the blades 19 shown in Fig.7.

The blades 12,13 in Fig.1 have a cross-section with a hollow chambered profile. Partitions 20 extend along the blades, both in a peripheral direction and in a radial direction, and form individual chambers 21 within the blade profile. The blades 12,13 have a small mass with sufficient stability and are advantageously produced from a continuously cast section, in particular from aluminium.

The blades 12,13 have recesses 24 extending both in an axial direction and at the same time in the direction of the centre lines 22.23. the recesses 24 being formed by an appropriate arrangement of the outer partitions 25, respectively. The recesses 24 are used to accommodate a sealing strip. not illustrated, to axially seal the rotor 10 in the housing of the spiral displacing machine.

Fig.2 shows a part of the rotor disc 11 having a blade 26 of a different design. A central region 27 of the blade is designed here with a stronger crosssection'. Fig.3 shows, in contrast to this, a solidly designed central region 28 having a cross-section which is Slightly less reinforced.

The blade 26 is attached in Fig.2 by wedging the material in the radially arranged region of the blade approximately at the location of the arrow 29.

F 1 c Fig.4 shows another design of blade, designated here by the figure 30. The partitions within the blade profile are designed to be inclined with respect to the radial direction and are designated by the figure 31. The inclined arrangement illustrated facilitates the precise production and profiling of the blades when manufacturing from initially elongate profile pieces, in particular with the continuously cast sections mentioned above. In each case the outer partitions 32 are also arranged to form the recesses 33.

Fig.5 shows the rotor disc 11 also having a cross-section in the shape oi a hollow chambered profile. This is achieved by forming the disc from two disc parts 34,35. A blade 36 is form-lockingly inserted into the rotor disc 11 and held in this by means of a thickening 37. The figure 38 designates a bolt or a pin which establishes a desired distance between the disc parts 34,35 and moreover connects the two firmly to each other. Correspondingly, the hub designated here by the figure 39 is inserted into the rotor disc 11 or rather is held by this in the region of a circular collar 40. Fig.6 shows the top view of one of the two disc parts 34,35 having separating ribs 41 attached instead of the bolts 38 shown in Fig.S. In Fig.6 the two disc parts are connected by solder, c adhesive or additional bolts or pins. In the disc part 34 there are, furthermore, orifices 42,43 for the hub 39 and the auxiliary hub. The recesses to accommodate the blade 36 are designated by the figure 18 in the Fig.6 (Fig.5).

Fig.7 shows a special design of blade 19. This has a hollow chambered profile with axially arranged chambers 44 and partitions 45 correspondingly arranged axially and radially between the chambers. When being produced as a continuously cast profile, for example from aluminium, the cast profile already has the necessary curved blade shape. The thickness of the blade - arrow 46 - can also be adjusted simply to the desired size. In order to accommodate axially operating sealing strips, the axial end surfaces of the blade 19 can by machining, possibly by milling, be provided with a contour corresponding to the recess 24.

The designs described are light and still resistant to distortion particularly when produced from aluminium. In comparison to a solid design of a die cast metal rotor. the rotor in accordance with the invention only requires a small amount of machining.

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Claims

1. A spiral displacing machine for compressible media, having a rotor which can be rotated eccentrically in a housing, the rotor having blades which are designed in the shape of a spiral and located on at least one (axial) side of a rotor disc and which interact with corresponding blades in the housing to form spiral-shaped working chambers, the rotor blades having a cross-section with a hollow chambered profile.

2. A spiral displacing machine as claimed in claim 1, wherein partitions or cross-pieces, which extend substantially in a radial direction and in the peripheral direction of the blades, are arranged to form individual chambers or hollow spaces in the profile.

3. A spiral displacing machine as claimed in claim 1, wherein partitions or cross-pieces, which extend substantially in a radial or axial direction, are arranged to form individual chambers or hollow spaces in the profile.

4. A spiral displacing machine as claimed in claim 2 or 3, wherein the partitions or cross-pieces run at an angle to the radial direction.

5. A spiral displacing machine as claimed in claim 1, 2 or 4, wherein the partitions or cross- c -8pieces are arranged to form axially open recesses in the region of and at a distance from the axial end surfaces of the rotor blades.

6. A spiral displacing machine as claimed in claim 1, 2, 4 or 5, wherein the blades have a stronger cross-section in the region of a connection to the disc rotor or to disc parts and/or are solidly constructed in this region.

7. A spiral displacing machine as claimed in any of claims 1 to 6, wherein the rotor disc has a crosssection with a hollow chambered profile.

8. A spiral displacing machine as claimed in claim 7, wherein the rotor disc is formed with an intermediate space which is created by two disc parts disposed at a distance from one another.

9. A spiral displacing machine as claimed in claim 8. wherein one or more spacers are fitted between the disc parts for spacing and/or connecting the disc parts.

10. claim 9', or ribs.

11. A spiral displacing machine substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

A spiral displacing machine as claimed in wherein said spacers are in the form of bolts 2