EP0557598B1 - Scroll type fluid machinery - Google Patents

Description

Field of the Invention

The invention relates to a positive displacement machine for compressible media with a spiral housing arranged in a fixed housing, and with a displacement body assigned to the conveying body, consisting essentially of a disc with spiral strips arranged vertically on both sides, one opposite for guiding the displacement body relative to the housing a first eccentric arrangement with a second eccentric arrangement is provided, the guide shaft mounted in the housing is positively connected to the main shaft of the first eccentric arrangement, and wherein the main shaft is driven by a pulley.

State of the art

Displacement machines of the spiral type are known for example from DE-C-26 03 462. A compressor constructed according to this principle is characterized by an almost pulsation-free conveyance of the gaseous working medium, which consists, for example, of air or an air-fuel mixture, and could therefore also be used with advantage for charging purposes of internal combustion engines, among other things. During the operation of such a compressor, several, approximately sickle-shaped working spaces are enclosed between the spiral-shaped displacement body and the two peripheral walls of the displacement chamber, which move from the inlet through the displacement chamber to the outlet, their volume constantly decreasing and the pressure of the work equipment is increased accordingly.

A machine of the type mentioned at the outset is known from DE-A-3 313 000. The fact that two eccentric arrangements are arranged at a distance from one another, one of which can be driven via a drive shaft, results in a statically determined mounting, which also extends to the upper and lower dead centers of the runner position ensure that the runner is guided. In order to achieve clear guidance of the rotor even in the dead center positions of the rotor, a guide shaft of the second eccentric arrangement mounted in the housing is positively connected to the drive shaft via a toothed belt drive.

In these known machines, which are used as loaders, the main eccentric shaft is usually driven directly by a belt from the crankshaft of the internal combustion engine, usually an internal combustion engine. A disadvantage of this type of drive, which is permanently engaged, is the frictional power and friction in the partial load area, in which charging of the internal combustion engine is not required Pumping losses. This also applies in the event that excess air is blown at partial load.

This could be remedied by using a magnetic coupling, such as is used in automotive construction for air conditioning compressors and sometimes also for cooling air fans. However, such couplings are designed in accordance with the relatively low number of switching operations of these elements to be driven and as such are not directly suitable for switching a mechanical charger on and off; in the latter, the number of operations is 10 to 100 times higher than, for example, in cooling air fans. The frequent switching on and off of the clutch is accompanied by a corresponding temperature development in the clutch. This must be limited by appropriate means.

Presentation of the invention

The invention has for its object to make a displacement machine of the type mentioned above can be switched off during engine operation.

• dass zwischen der Hauptwelle und einer mit der Riemenscheibe versehenen Eingangswelle eine Magnetkupplung angeordnet ist, wozu eine Magnetspule ortsfest in einem Gehäusedeckel angeordnet ist, ein Ankerring über eine Mitnehmerscheibe drehfest mit der Hauptwelle verbunden ist und eine Ankerscheibe drehfest mit der Eingangswelle verbunden ist,
• und dass auf der Eingangswelle ein Lüfter befestigt ist, dessen aktiver Teil sich zwischen einem die Magnetspule aufnehmendem Eisenkern und der Lagerung der Eingangswelle befindet.

The task is solved

• that a magnetic coupling is arranged between the main shaft and an input shaft provided with the pulley, for which purpose a magnetic coil is arranged in a stationary manner in a housing cover, an armature ring is connected to the main shaft in a rotationally fixed manner via a driving plate, and an armature plate is connected in a rotationally fixed manner to the input shaft,
• and that a fan is attached to the input shaft, the active part of which is located between an iron core receiving the magnetic coil and the bearing of the input shaft.

The advantage of the invention can be seen in the fact that this connection concept is particularly suitable for orbiting machines because of the low moment of inertia of the rotating rotor. Acceleration shocks can also be handled with magnetic couplings of small dimensions. The permanently rotating fan ensures ventilation and thus cooling of the encapsulated magnetic coupling insofar as, due to the special arrangement of the active fan part, the cooling air flows around the iron core in the greatest possible way and thus with the longest exposure time.

It is expedient if the fan is provided with a closed cover plate on the bearing side. As a result, the bearings of the input shaft, which are generally permanently lubricated roller bearings, are sealed off from the negative pressure generated by the fan. This prevents the bearings from drying out.

It makes sense if the magnetic coil is housed in a bell on the housing cover. The outer diameter of the iron core ring receiving the coil can then take over the mutual centering of the housing cover with the mounting of the input shaft and the drive-side housing with the mounting of the main shaft. This measure ensures the coaxiality of the input shaft and the skin shaft and the belt tension can be easily transferred to the housing via the centering points.

Brief description of the drawing

Fig. 1

eine Vorderansicht eines Gehäuseteils der Verdrängermaschine;

Fig. 2

eine Vorderansicht eines Läufers;

Fig. 3

einen Längsschnitt durch die Verdrängermaschine;

In den Fig. 1 und 3 sind die Strömungsrichtungen des Arbeitsmediums und des Kühlmediums mit Pfeilen bezeichnet.In the drawing, an embodiment of the invention is shown schematically.
It shows:

Fig. 1

a front view of a housing part of the displacement machine;

Fig. 2

a front view of a runner;

Fig. 3

a longitudinal section through the displacement machine;

1 and 3, the directions of flow of the working medium and the cooling medium are indicated by arrows.

Way of carrying out the invention

In order to explain the operation of the compressor, which is not the subject of the invention, reference is made to the already mentioned DE-C3-2 603 462. In the following, only the machine structure and process flow necessary for understanding are briefly described.

For the sake of clarity, the machine is shown in FIGS. 1 and 2 in the disassembled state.

The rotor of the machine is designated as a whole by 1. On both sides of the disc 2, two spiral-shaped displacers are arranged, which are offset by 180 ° to one another. These are strips 3, 3 'which are held vertically on the pane 2. In the example shown, the spirals themselves are formed from a plurality of circular arcs adjoining one another. 4 with the hub is designated with which the disc 2 is mounted on a roller bearing 22. This bearing sits on an eccentric disk 23, which in turn is part of the main shaft 24. 5 with a radially outside of the strips 3, 3 'is designated for receiving a guide bearing 25 which is mounted on an eccentric bolt 26. This is in turn part of a guide shaft 27. At the spiral end, two openings 6 are provided in the disk so that the medium can get from one disk side to the other, for example in order to be drawn off in a central outlet 13 (FIG. 3) which is only arranged on one side.

In Fig. 1, the housing half 7b shown on the left in Fig. 3 is composed of two halves 7a, 7b, via fastening eyes 8 shown for receiving screw connections interconnected machine housing. 9 symbolizes the holder for the drive shaft, 10 the holder for the guide shaft. 11 and 11 'denote the two delivery spaces, each offset by 180 °, which are worked into the two housing halves in the manner of a spiral slot. They each run from an inlet 12, 12 'arranged on the outer circumference of the spiral in the housing to an outlet 13 provided in the interior of the housing and common to both delivery spaces. They have essentially parallel cylinder walls 14, 14', 15, 15 arranged at a constant distance from one another ', which in the present case, like the displacement body of the disk 2, comprise a spiral of approximately 360 °. The displacer bodies 3, 3 ′ engage between these cylinder walls, the curvature of which is dimensioned such that the strips almost touch the inner and outer cylinder walls of the housing at several, for example at two points each.

The drive and the guide of the rotor 1 are provided by the two spaced-apart eccentric arrangements 23, 24 and. 26, 27. The main shaft 24 is mounted in the roller bearing 17 and in the slide bearing 18. Counterweights 20 are arranged on it to compensate for the inertial forces arising when the rotor is eccentrically driven. The guide shaft 27 is inserted in a sliding bearing 28 within the housing half 7b.

In order to achieve clear guidance of the rotor in the dead center positions, the two eccentric arrangements are synchronized with precise angles. This is done via a toothed belt drive 16. On the occasion of operation, the double eccentric drive ensures that all points of the rotor disk and thus also all points of the two strips 3, 3 'perform a circular displacement movement. As a result of the multiple, alternating approaches of the strips 3, 3 'to the inner and outer cylinder walls of the associated delivery chambers, the working medium results in crescent-shaped working medium on both sides enclosing workspaces that are moved through the delivery chambers towards the outlet while the rotor is being driven. The volumes of these working spaces decrease and the pressure of the working fluid is increased accordingly.

As can be seen in FIG. 3, an adjustable magnetic coupling 30 is now installed between the input shaft 21 and the main shaft 24 according to the invention. For this purpose, the housing cover 7c, which is connected to the drive-side housing part 7b via the screw connection 39, is provided with a bell 7d. The two roller bearings 29 for supporting the input shaft 21 with their outer rings are pressed into the central bore of this bell. The bearings 29 are located in the plane of the drive pulley 19. This pulley is connected to the input shaft 21 in a rotationally fixed manner via its hub 40 and a thread. An additional anti-rotation device is provided in the form of a weld 41 between the hub and the shaft. The input shaft is guided with a sliding fit in the inner rings 36 of the roller bearings and is therefore axially movable.

The magnetic coupling has a magnetic coil 31 which is arranged in a stationary manner in the housing cover 7c. For this purpose, the magnetic coil is embedded in an iron core ring 35 which surrounds it on all sides. At its outer diameter, the iron core ring is seated with an axial part 35a at its left end in a recess 38 in the bell 7d. At its right end, the iron core ring part 35a sits with its outer diameter in a recess 42, which is incorporated in a support element 43 connected to the housing part 7b. The iron core ring 35 thus fulfills a centering function for the housing cover 7c and the drive-side housing part 7b. A radially extending ring web 35b forms the bearing-side boundary of the iron core ring.

The remaining parts of the iron core ring 35 are arranged in a rotationally fixed manner on the input shaft 21. These parts are the axially extending part 35c, which represents the radially inner boundary of the iron core ring, and the radially extending armature disk 33, which is limited in its outer diameter by the axial part 35a. The two interconnected parts 35c and 33 are fastened to the input shaft 21 via spokes 34.

The armature disk 33 forms with its free end face, together with the free end face of an anchor ring 32, the actual clutch disks, including an air gap 44. This air gap is not recognizable, since the clutch is shown in the engaged state.

The armature ring 32 is in turn connected to the main shaft 24 in a rotationally fixed manner. This is done via a leaf spring 46, which is connected on the one hand to the anchor ring 32 and on the other hand to a drive plate 47 with fastening means, in the present case screws 48. The connection is designed such that the armature ring 32 can move axially away from the drive plate 47 against the return force of the spring 46. The drive plate 47 is rigidly attached to the main shaft 24 by conventional means. It is provided with continuous recesses 49, the outermost diameter of which corresponds to the inner diameter of the anchor ring 32.

During machine operation, the device works as follows: if, for example, the vehicle is driven from part load to full load, the magnet coil 31 is energized. The armature ring 32 is attracted by the magnet against the return force of the spring 46, bridges the air gap 44 and comes into contact with the armature disk 33. The coupling process is thus completed and the rotary movement of the input shaft is transmitted to the main shaft. When the main shaft is taken out of operation, the solenoid is de-energized, whereupon the leaf spring 46 retracts the anchor ring against the drive plate 47 and thereby restores the air gap 44. The activation and deactivation can take place automatically as a function of any suitable or process size.

A shoulder is provided on the input shaft 21, which is axially displaceable to form the gap 44, against which the hub of a radial fan 45 abuts. On the opposite side, the hub bears against the inner ring 36 of the inner roller bearing 29. The active part of this fan 45, i.e. the fan blades are located in a suction space 50 between the radial ring web 35b of the iron core ring and the radial part of the bell housing 7d. A continuous cover plate 51 extends on the bearing side from the hub to the ends of the fan blades. By means of this cover plate 51, the storage space under atmospheric pressure is shielded from the suction space under vacuum.

During operation, the permanently rotating fan now draws in the cooling air from the interior of the housing cover 7c. The coolant enters the suction space 50 through the recesses 49 of the driving disk 47, the free inner ring surface of the anchor ring 32 and through the spokes 34. The rotating parts of the iron core ring are flowed around and cooled accordingly. The armature disk 33, thanks to its large radial expansion, rotates at a relatively high peripheral speed in the well-ventilated interior of the housing cover 7c and is thus adequately cooled.

The cooling air flows radially outward from the suction space 50 and in the process sweeps past the radially extending annular web 35b of the iron core ring. The coolant flowing out of the fan also acts on the outer surface of the housing bell 7d provided with cooling ribs 52. As a result, the heat of the axial iron core ring part 35a lying against this bell part can also be dissipated.

LIST OF DESIGNATIONS

1

runner

2nd

disc

3, 3 '

strip

4th

hub

5

eye

6

breakthrough

7a, 7b

Half of the housing

7c

Housing cover

7d

Bell jar

8th

Mounting eye

9

Recording for 24

10th

Recording for 27

11, 11 '

Funding area

12, 12 '

inlet

13

Outlet

14, 14 '

Cylinder wall

15, 15 '

Cylinder wall

16

timing belt drive

17th

Rolling bearings for 24

18th

Slide bearing for 24

19th

V-belt pulley

20th

Counterweight on 24

21

Input shaft

22

Plain bearing for 23

23

Eccentric disc

24th

Main shaft

25th

Guide warehouse

26

Eccentric bolt

27

Guide shaft

28

Slide bearing for 27

29

Rolling bearings for 21

30th

Magnetic coupling

31

Solenoid

32

Anchor ring

33

Armature plate

34

spoke

35, 35a, b, c

Iron core ring

36

Inner ring of 29

38

Notch in 7c

39

Screw connection of 7c and 7b

40

Hub from 19

41

Welding

42

Recess in 43

43

Support element

44

Air gap

45

Fan

46

Leaf spring

47

Drive plate

48

Screw connection of 32 + 46 + 47

49

Recess in 47

50

Intake space

51

Cover plate

52

Cooling fin

Claims (5)

1. Displacement machine for compressible media, having spiral-shaped delivery spaces arranged in a stationary casing, and having a displacement body, associated with the delivery spaces, consisting essentially of a disc with spiral-shaped strips vertically arranged on both sides, a second eccentric arrangement arranged at a distance relative to a first eccentric arrangement being provided to guide the displacement body relative to the casing, the guide shaft of which second eccentric arrangement being supported in the casing and positively connected to the main shaft of the first eccentric arrangement and the main shaft being driven by means of a belt pulley, characterized in that

   - a magnetic clutch is arranged between the main shaft and an input shaft provided with the belt pulley, for which purpose a magnet coil is arranged at a fixed location in a casing cover, an armature ring is connected to the main shaft in a rotationally fixed manner by means of a drive disc, and an armature disc is connected to the input shaft in a rotationally fixed manner, and

   - a fan, whose active part is located between an iron core ring, accommodating the magnet coil, and the mounting of the input shaft, is fastened to the input shaft.
2. Displacement machine according to Claim 1, characterized in that the fan is provided with a closed cover plate at the bearing end.
3. Displacement machine according to Claim 1, characterized in that the armature disc is connected by means of spokes to the input shaft.
4. Displacement machine according to Claim 3, characterized in that the armature disc is fastened to the spokes by means of the radially inner, axially extending part of the iron core ring.
5. Displacement machine according to Claim 1, characterized in that the magnet coil is accommodated in a bell of the casing cover and the outer diameter of the iron core ring, which accommodates the coil, centres the casing cover relative to the input shaft mounting and the drive-end casing relative to the main shaft mounting.

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