EP0545189B1 - Scroll type fluid displacement machine - Google Patents

Description

Field of the Invention

The invention relates to a displacer for compressible media with at least one spiral-like conveying chamber arranged in a fixed housing and with a spiral-like displacer associated with this conveying chamber, which is held on a disk-shaped rotor which can be driven eccentrically with respect to the housing in such a way that during operation each of its points is one of performs limited circular movement of the peripheral walls of the delivery chamber, and its curvature relative to that of the delivery chamber is dimensioned such that it almost touches the inner and outer peripheral walls of the delivery chamber on at least one sealing line that progresses continuously during operation, one opposite to guide the rotor relative to the housing a first eccentric arrangement at a distance from the second eccentric arrangement is provided, the guide shaft of which is mounted in the housing with the main shaft of the first eccentric arrangement is positively connected, 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 loss of frictional power remaining in the partial load region, in which charging of the internal combustion engine is not required. This also applies in the event that excess air is blown at partial load.

Furthermore, displacement machines with a magnetic coupling between the pulley and the main shaft are already known (for example from EP-A-0 123 407), in which the air gap cannot be adjusted.

Presentation of the invention

The invention is therefore based on the object of designing a displacement machine of the type mentioned at the outset to be switched off during engine operation.

The object is achieved in that an adjustable magnetic coupling is arranged between the main shaft and an input shaft provided with the drive pulley, a magnetic coil being arranged in a stationary manner in a housing cover and an anchor ring being connected in a rotationally fixed manner to the main shaft, and for the purpose of adjusting the air gap between the armature ring and a washer arranged on the input shaft, the input shaft is mounted axially displaceably in the housing cover.

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. Commercially available magnetic clutches are usually offered as a structural unit in which the air gap cannot be adjusted. Since, however, the size of the air gap is decisive for the correct functioning of the connection, it is advantageous to make the input shaft, which is in operative connection with the anchor ring via the holding disk, movable and thus adjustable.

It is particularly expedient if the input shaft is mounted in the housing cover by means of a roller bearing, the inner ring of the roller bearing having a sliding seat on the input shaft, and if the input shaft is arranged by means of spring elements which are arranged between the inner ring of the roller bearing and a shoulder of the input shaft. is tense. This ensures the adjustability and adjustability of the air gap. This concept can avoid the otherwise required large number of narrow axial tolerances which the components determining the air gap would have to have.

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 chewing shaft and that 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;

Fig. 4

einen Teillängsschnitt durch den Antrieb der Verdrängermaschine.

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;

Fig. 4

a partial longitudinal section through the drive of the displacement machine.

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.

1 shows the housing half 7b shown on the left in FIG. 3 of the machine housing which is composed of two halves 7a, 7b and is connected to one another via fastening eyes 8 for receiving screw connections. 9 symbolizes the holder for the drive shaft, 10 the holder for the guide shaft. 11 and 11 'denote the two in each case by 180 ° against each other staggered delivery spaces, which are incorporated in the manner of a spiral slot in the two housing halves. 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, crescent-shaped work spaces enclosing the working medium result on both sides of the strips, which are displaced by the delivery chambers during the drive of the rotor disk in the direction of the outlet . The volumes of these working spaces decrease and the pressure of the working fluid is increased accordingly.

As can be seen in FIGS. 3 and 4, 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 consists of 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. With its outer diameter, the iron core ring sits at one end in a recess 38 in the bell 7d. At its other end, the iron core ring 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 shoulder 45 is provided on the axially displaceable input shaft 21, by means of which the shaft is braced with the housing cover. The bracing is carried out via spring elements 34, here two disc springs, and via the inner rings 36 of the roller bearings 29.

Arranged on the input shaft 21 in the area of the magnetic coupling is a holding disk 33, the outer diameter of which is limited by the iron core ring. This in Fig. 4 in Disc shown in section forms on its free face together with the free face of an anchor ring 32, the air gap 44. This air gap is not visible in Fig. 4, since the clutch is shown in the engaged state. The anchor ring 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.

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 holding 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 magnet coil is switched off, whereupon the leaf spring 46 pulls the armature ring back 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.

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 bearings

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

Holding disc

34

Spring element

35

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

Shoulder on 21st

46

Leaf spring

47

Drive plate

48

Screw connection of 32 + 46 + 47

Claims (3)

1. Displacement machine for compressible media, having at least one spiral-shaped delivery chamber (11, 11') disposed in a fixed housing (7a, 7b) and having a spiral-shaped displacement body (1-4) assigned to the delivery chamber, which displacement body is held in such a way on a disc-shaped rotor (1), which can be driven eccentrically relative to the housing, that, during running, each of its points performs a circular motion limited by the peripheral walls of the delivery chamber, and the curvature of which displacement body is dimensioned relative to that of the delivery chamber such that it virtually touches the inner and outer peripheral walls of the delivery chamber at, respectively, at least one sealing line which constantly advances during running, there being provided, for the guidance of the rotor relative to the housing, a second eccentric arrangement (26, 27), which is spaced apart from a first eccentric arrangement (23, 24) and the guide shaft (27) of which, which is mounted in the housing, is connected in forcible closure to the main shaft (24) of the first eccentric arrangement, and the main shaft (24) being driven by means of a belt pulley (19), characterized in that between the main shaft (24) and a primary shaft (21) provided with the belt pulley (19) there is disposed an adjustable magnetic coupling (30), a magnet coil (31) being fixedly disposed in a housing cover (7c) and an anchoring ring (32) being connected in rotational securement to the main shaft (24), and, for the purpose of adjusting the air gap between the anchoring ring (32) and a holding disc (33) disposed on the primary shaft (21), the primary shaft (21) being mounted such that it is axially displaceable in the housing cover (7c).
2. Displacement machine according to Claim 1, characterized in that the primary shaft (21) is mounted in the housing cover (7c) by means of a roller bearing (29), the inner race (36) of the roller bearing being seated with a sliding fit upon the primary shaft (21), and in that the primary shaft (21) is braced by means of spring elements (34) disposed between the inner race (36) of the roller bearing and a shoulder (45) of the primary shaft (21).
3. Displacement machine according to Claim 1, characterized in that the magnet coil (31) is housed in a bell (7d) of the housing cover (7c), the iron-core ring (35) which receives the coil serving with its outside diameter to centre, one against the other, the housing cover (7c) with the mounting of the primary shaft (21) and the drive-side housing (7b) with the mounting of the main shaft (24).

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