EP1857680B1 - Pump rotor - Google Patents

Description

The invention relates to a rotor assembly for a pump, in particular for a rotary piston pump.

Rotary pumps usually have two parallel-lying rotor shafts, which are coupled in their rotational movement with each other and each carry a rotatable piston or a gear at one axial end. The pistons or gears mesh with each other and form a positive displacement pump. It is important for these pumps that the pistons run synchronously. In this respect, both the piston and the transmission elements, which couple the two shafts rotatably connected to the rotor shafts rotatably connect. At the same time an accurate adjustment of the elements on the shafts is required to ensure the synchronous running of the two pistons so that they rotate into each other.

In known shaft-hub connections, precise alignment is difficult due to the given tolerances.

Out US 4,490,102 a screw compressor is known, which has two intermeshing screw shafts which are interconnected by a gear pair. One of these gears is fixed via a conical connection to the associated rotor shaft. With such a tapered connection, the rotationally accurate alignment of the drive gear on the shaft is difficult because the gear, when in contact with the shaft, due to the conical surfaces blocked relatively quickly and can no longer be aligned in the rotation angle.

It is therefore an object of the invention to provide an improved rotor assembly for a pump, which allows a simpler angle of rotation accurate adjustment of transmission elements on the rotor shaft.

This object is achieved by a rotor assembly having the features specified in claim 1. Preferred embodiments will be apparent from the dependent claims.

In the case of the rotor assembly according to the invention, at least one rotor shaft and a drive or output pinion rotatably connected thereto are provided. This rotor assembly is intended in particular for use in a rotary piston pump in which a plurality of rotor shafts must be coupled together in their rotational movement. For this purpose, a first pinion is preferably arranged non-rotatably on a driven rotor shaft and arranged on a second, parallel rotor shaft, a second, meshing with the first pinion pinion, so that one rotor shaft is driven by the other.

According to the invention, the drive pinion has a central recess with a conical inner peripheral surface. This inner circumferential surface extends conically around the longitudinal or rotational axis of the rotor shaft and the drive pinion. The drive shaft has a corresponding conical outer peripheral surface, wherein the conical inner peripheral surface and the conical outer peripheral surface for fixing the drive pinion on the rotor shaft engage or abut each other. In this way, the drive pinion is rotatably held on the rotor shaft.

Preferably, a cylindrical contact surface adjoining the smaller diameter end of the conical inner peripheral surface is formed in the recess of the rotor, and the rotor shaft has a corresponding cylindrical contact surface which adjoins the smaller diameter end of the conical outer peripheral surface. This embodiment facilitates the placement of the drive pinion on the rotor shaft, since first the cylindrical contact surfaces can be brought into engagement with each other. The pinion is already aligned centrally on the rotor shaft, but initially still remains rotatable about it, so that the drive pinion can then be aligned in its angular position with respect to the rotor shaft. Subsequently, the drive pinion is further axially displaced relative to the rotor shaft, so that the conical inner peripheral surface runs onto the corresponding conical outer circumferential surface and thus the drive pinion is fixed firmly, in particular rotationally fixed on the rotor shaft.

In addition, it is possible that the drive pinion and the rotor shaft are glued together to realize an even firmer connection.

The rotor assembly according to the invention for a pump, in particular for a rotary piston pump, preferably has at least one rotor mounted on the rotor shaft. The rotor forms the piston in the rotary piston pump, which preferably engages with the piston of a second rotor shaft. The rotor has a recess into which the rotor shaft engages.

For rotationally fixed attachment of the rotor to the rotor shaft, the rotor shaft preferably has at least one cross-sectionally circular pocket on the outer circumference. The cross-sectionally circular-shaped pocket forms a cylinder-segment-shaped recess whose Diameter or central axis preferably extends parallel to the longitudinal or rotational axis of the rotor shaft. Opposite is formed on the inner circumference of the recess of the rotor a corresponding, circular cross-section shaped pocket. That is, this pocket also forms a cylinder-segment-shaped recess whose longitudinal or central axis preferably extends parallel to the longitudinal or rotational axis of the rotor. The longitudinal or rotational axis of the rotor is identical to the longitudinal or rotational axis of the rotor shaft. The two opposite, circular segment-shaped pockets preferably together form a circular-cylindrical recess or a circular-cylindrical hole which extends parallel to the longitudinal axis of the rotor shaft between the inner circumference of the recess and the outer circumference of the rotor shaft. In this so opposite pockets a corresponding cross-section, preferably circular, ie circular cylindrical connecting element is used. This connecting element produces the positive, rotationally fixed connection between rotor and rotor shaft.

The circular segment-shaped cross-sectional areas of the pockets on the outer circumference of the rotor shaft and on the inner circumference of the recess of the rotor are preferably dimensioned such that together they form a circular cross-section. Particularly preferably, the two pockets are semicircular in cross section, so that the pockets on the outer circumference of the rotor shaft and on the inner circumference of the recess of the rotor each have a semi-cylindrical shape, which together define a cylindrical recess into which a cylindrical connecting element can be used.

The pockets in the rotor or in the outer circumference of the rotor shaft are preferably milled there, so that they can be formed there with high accuracy at the desired angular position. The cylindrical connecting element can then only be used appropriately be when the pockets on the inner circumference of the rotor and on the outer circumference of the rotor shaft exactly opposite each other, that is, the rotor is with respect to the rotor shaft in a predetermined angular position. By correspondingly close fit, a backlash-free, positive connection between rotor and rotor shaft can be achieved here.

Preferably, both the central and longitudinal axes of the pockets on the rotor shaft and on the rotor and the longitudinal axis of the circular cross-section connecting element extend parallel to the axis of rotation of the rotor shaft and thus of the rotor.

Preferably, on the outer circumference of the rotor shaft, a plurality of semicircular in cross-section pockets and formed on the inner circumference of the recess of the rotor, a corresponding plurality of respectively opposite and semi-circular in cross-section pockets, each in the opposite pockets a circular cross-section connecting element is inserted. That is, the pockets on the outer circumference of the rotor shaft are arranged corresponding to the pockets on the inner circumference of the recess of the rotor in the same angular positions, so that always one pocket on the outer circumference of the rotor shaft of a pocket on the inner circumference of the recess exactly opposite, so that these two pockets together a cross-sectionally circular, d. H. form a total circular cylindrical receiving opening for a connecting element. In each of these bag pairings, a connecting element is used in each case. In this way, a more resilient, positive connection between the rotor and the rotor shaft is provided, via which larger torques can be transmitted.

The plurality of pockets on the rotor shaft and the corresponding opposite pockets on the rotor are preferably irregular arranged distributed over the circumference. By this configuration it is achieved that the rotor can be attached to the rotor shaft only in a predetermined angular position with respect to the axis of rotation, so that incorrect assembly can be excluded. This is important because when used in a rotary lobe pump in which the rotor co-operates with a second rotor, the rotor must move in a defined manner with respect to the second rotor. An irregular arrangement of the pockets can for example be done in such a way that actually all pockets are arranged at regular angular positions to each other, but at an angular position at which due to this regular division actually a bag should be formed, no pocket is formed.

More preferably, the connecting elements are glued in the pockets on the rotor and / or in the pockets on the rotor shaft. In this way, the fasteners are secured in the pockets so that they can not slip out or come loose. So a durable connection between rotor and rotor shaft can be created.

Alternatively or additionally, the connecting elements may be designed to be spreadable in their diameter direction. This makes it possible to easily insert the connecting elements in the opposite pockets and then to spread so that they tense in the pockets. So then a firm connection between rotor and rotor shaft is created. At the same time this allows an automatic accurate alignment or adjustment of the opposite pockets during spreading of the connecting element. Thus, the rotor is then automatically aligned and fixed in the defined, predetermined angular position with respect to the rotor shaft. Also, the exact centering can be done by spreading the fasteners. Furthermore, the connecting elements can be formed be that their spread is reversible, they can be solved again, so that, for example, for maintenance or replacement of wearing parts to be able to remove the rotor from the rotor shaft.

For this purpose, the connecting elements are preferably made of two axially arranged cylindrical bodies and at least one expansion element located axially between the cylinder bodies, wherein the two cylinder bodies are mutually axially adjustably connected to each other. This can be done for example by a screw which connects the two cylinder body together. If the two cylinder body to be moved toward each other by adjusting the adjusting element, such as a screw, the spreading element located between them can be spread. This can be done, for example, in that conical surfaces are formed between the expansion element and the cylinder bodies which, upon pressing the cylinder body in the axial direction on the expansion element generate a force acting on it in the radial direction, which forces the expansion element apart in the radial direction, so that this is pressed against the inner walls of the pockets into which the connecting element is inserted.

At least one of the two cylinder body of a connecting element is preferably fixedly connected to the rotor and / or the rotor shaft, preferably non-rotatably connected to the rotor and / or the rotor shaft. In this way, for example, in the case that the two cylinder body are connected to a screw, be prevented that rotates when turning the screw, the cylinder body. The rotationally fixed connection can be made for example by a positive engagement or by clamping or gluing.

As described, the rotor assembly as described above is preferably part of a rotary piston pump, which preferably has two rotor assemblies as described above.

Fig. 1

eine Schnittansicht einer Drehkolbenpumpe mit einer Rotorbaugruppe gemäß der vorliegenden Erfindung,

Fig. 2

eine Explosionsansicht einer ersten Ausführungsform der Erfindung,

Fig. 3

eine Detailansicht des Rotors gemäß Fig. 2,

Fig. 4

eine Schnittansicht der montierten Rotorbaugruppe gemäß Figuren 1 bis 3,

Fig. 5

eine zweite Ausführungsform der erfindungsgemäßen Rotorbaugruppe,

Fig. 6

eine Detailansicht des Rotors gemäß Fig. 5,

Fig. 7

eine Schnittansicht eines Verbindungselementes, wie es bei der Rotorbaugruppe gemäß Figuren 5 und 6 eingesetzt ist,

Fig. 8

eine Explosionsansicht des Verbindungselementes gemäß Fig. 7,

Fig. 9

eine perspektivische Ansicht der Befestigung eines Antriebsritzels bei einer erfindungsgemäßen Rotorbaugruppe und

Fig. 10

eine Schnittansicht der Rotorbaugruppe gemäß Fig. 9 mit montiertem Antriebsritzel.

The invention will now be described by way of example with reference to the accompanying drawings. In these shows:

Fig. 1

a sectional view of a rotary piston pump with a rotor assembly according to the present invention,

Fig. 2

an exploded view of a first embodiment of the invention,

Fig. 3

a detailed view of the rotor according to Fig. 2 .

Fig. 4

a sectional view of the assembled rotor assembly according to FIGS. 1 to 3 .

Fig. 5

A second embodiment of the rotor assembly according to the invention,

Fig. 6

a detailed view of the rotor according to Fig. 5 .

Fig. 7

a sectional view of a connecting element, as in the rotor assembly according to FIGS. 5 and 6 is used,

Fig. 8

an exploded view of the connecting element according to Fig. 7 .

Fig. 9

a perspective view of the attachment of a drive pinion in a rotor assembly according to the invention and

Fig. 10

a sectional view of the rotor assembly according to Fig. 9 with mounted drive pinion.

The rotor assembly according to the invention is particularly suitable for use in a rotary piston or rotary piston pump, as for example in the sectional view in Fig. 1 is shown. Such rotary piston pumps have in their interior two mutually parallel rotor assemblies 2 and 4, which via pinion 6 and 8 are engaged with each other. The rotor assembly 2 is driven via its shaft end 10 by a motor, not shown. At the opposite end, the shafts of the rotor assemblies 2 and 4 are each connected to a rotor or rotary pistons 12, 14, which mesh with each other and thus form a positive displacement pump.

The invention relates to the rotor assemblies 2 and 4 and there the attachment of the rotors 12 and 14 to the rotor shafts 16, 18. Further, the invention relates to the attachment of the pinion 6 and 8 on the rotor shafts 16, 18. If below the further embodiments of these fasteners only will be described with reference to one of the two rotor assemblies 2 and 4, it is understood, however, that the configuration is selected according to the respective other rotor assembly.

Fig. 2 to 4 show a first embodiment according to the invention of the attachment of the rotor 12 to the rotor shaft 16.

The rotor 12 is connected to the rotor shaft 16 at a shaft end, in such a way that it is plugged onto the rotor shaft in the direction of the axis of rotation or rotation. For this purpose, the rotor 12 has in its interior, concentric with the longitudinal or rotational axis X, a recess 20, into which the rotor shaft 16 engages with its shaft end 22. On the outer circumference of the shaft end 22 semicircular or semi-cylindrical pockets 24 are formed, the longitudinal axes and circumferential surfaces extending parallel to the axis of rotation X.

Inside the recess 20 corresponding pockets 26 are formed on the inner circumference, which also have a semi-circular cross-section or a semi-cylindrical shape and their central axes extend parallel to the axis of rotation X. The pockets 26 are arranged on the inner periphery of the recess 20 so that they are arranged around the longitudinal axis X at the same angular positions as the pockets 24 so that at the desired angular position of the rotor 12 with respect to the rotor shaft 16 is always a pocket 24 a pocket 26th exactly opposite. In this way, a cylindrical recess formed in the plane of contact between the inner circumference of the recess 20 and the outer circumference of the shaft end 22 is always formed by a pocket 24 together with a pocket 26, into which a cylindrical or roller-shaped connecting element 28 is inserted. In this way, the connecting elements 28 produce a positive connection between the rotor shaft 16 and the rotor 12, which enables a torque transmission from the rotor shaft 16 to the rotor 12.

The defined orientation of the rotor 12 in the radial direction of the rotor shaft 16 can also be done by the connecting elements 28, since they are distributed over the entire circumference of the rotor shaft 16 and the shaft end 22 and with appropriate fit the rotor 12 without play in the radial direction of the Fix shaft end 22. Alternatively, it is also possible to already produce a corresponding fit between the inner circumference of the recess 20 and the outer circumference of the shaft end 22, so that a play-free attachment of the rotor 12 to the shaft end 22 is possible.

In the axial direction of the rotor 12 is fixed by a fixing screw 30 which is screwed into a front-side threaded bore 32 in the direction of the longitudinal axis X in the shaft end 22 and thus secures the rotor 12 in the axial direction of the rotor shaft 16. In this case, the head of the fixing screw 30 engages over the peripheral edge of the recess 20.

In the connecting elements 28 according to the embodiment, which in the FIGS. 2 to 4 is shown, it is massive reel body, for example made of steel. For additional security, these can be glued in the pockets 24 and 26. Furthermore, it is also possible to additionally apply an adhesive between the outer circumference of the shaft end 22 and the inner circumference of the recess 20.

Based on FIGS. 5 to 8 An alternative connection between rotor 14 and rotor shaft 18 will be described. In this embodiment, the shaft end 22 is formed with the pockets 24 as described above with reference to the first embodiment. Also, the recess 20 with the pockets 26 is formed identical to the first embodiment according to the foregoing description. This second embodiment differs only in the configuration of the connecting elements 28, which are designed here as clamping or clamping elements and in more detail with reference to FIG FIGS. 7 and 8 to be discribed. These connecting elements 28 can be tensioned after insertion into the pockets 24 and 26, so that they expand in the radial direction and thus generate a clamping force between the rotor 12, 14 and the associated rotor shaft 16, 18. In this respect, a complete fixation of the rotor 12, 14 on the rotor shaft 16, 18 can be achieved, and it can be dispensed with the fixing screw 30, which can also be arranged in addition.

The connecting elements 28 according to the second embodiment are also circular in cross-section, that is, they are generally circular-cylindrical or barrel-shaped. They are formed by two axially spaced cylinder bodies 34, which are interconnected by a screw 36. In this case, the screw 36 penetrates the one cylinder body 34 through a hole 38 without thread and engages in the other cylinder body 34 in a thread 40 a. By turning the Screw 36 can thus be the cylinder body 34 in the axial direction towards each other and moved apart.

Between the two cylinder bodies 34, a ring 42 is arranged, which does not come into contact with the adjacent cylinder bodies 34 at the axial end faces. The ring 42 has centrally on the outer circumference a projection 44 which is bevelled or gripped on the cylinder bodies 34 facing sides. Accordingly, the end faces of the cylinder body 34, which face the projection 44, are chamfered such that between the cylinder bodies 34 and the projection 44 annular grooves are formed, which widen outwardly. In these grooves clamping rings 46 are arranged.

When the screw 36 is tightened and the cylinder bodies 34 are moved towards each other, the grooves in which the clamping rings 46 are arranged become narrower, so that the clamping rings 46 are pressed radially outward due to the inclined abutment surfaces against the cylinder body 34 and the projection 44 be and can develop a clamping effect in the pockets 24 and 26.

At the in FIGS. 2 to 6 shown arrangements of the pockets 24 and 26, these are evenly distributed over the circumference of the shaft end 22 and the inner circumference of the recess 20, although in this uniform division a pocket 24 and an opposite pocket 26 has been omitted, so that on the outer circumference of the shaft end 22 at a location a greater distance 48 between two adjacent pockets 24 and correspondingly opposite at one point an area with a greater distance between two adjacent pockets 26 is provided. This asymmetrical arrangement makes it possible for the rotor 12, 14 to be placed on the rotor shaft 16, 18 only in a predetermined angular position.

Based on FIGS. 9 and 10 An attachment according to the invention of the pinions 6, 8 on one of the rotor shafts 16, 18 will be described. The pinion or drive pinion 6 has a conical, central recess 48, with which the pinion 6 is placed on a corresponding, ie inclined at the same angle, conical contact surface 50 on the rotor shaft 16. At the tapered end of the conical outer peripheral surface or contact surface 50, a cylindrical contact surface 52 connects, wherein the conical contact surface 50 is separated from the contact surface 52 by a recess 54. Corresponding to the cylindrical contact surface 52, a cylindrical contact surface 56 is formed on the inner periphery of the recess 48 at the tapered end of the conical inner peripheral surface, which has substantially the same diameter as the cylindrical contact surface 52.

This embodiment of the connection between the pinion 6 and the rotor shaft 16 facilitates the alignment of the pinion 6 in a certain angular position with respect to the longitudinal axis X during assembly. This alignment is required because the rotors 12 and 14 must be arranged at a certain angle to each other and rotate each other.

During assembly, the pinion 6 can first be pushed onto the rotor shaft such that initially only the cylindrical contact surfaces 52 and 56 come to rest. In this position, the pinion 6 is aligned in the radial direction on the rotor shaft 16, but can still be moved in the axial direction along the longitudinal axis X and in the circumferential direction. When the desired angular orientation is achieved, the pinion 6 is further displaced in the axial direction toward the shaft end 22, so that the conical inner surface of the recess 48 comes to rest on the conical bearing surface 50 of the rotor shaft 16. In this case, a frictional or frictional connection between the conical contact surface 50 and the conical inner surface of the recess 48 realized, which leads to a rotationally fixed connection of the pinion 6 on the rotor shaft 16. When pushed onto the conical bearing surface 50, it also comes to a precise centering of the pinion on the shaft.

LIST OF REFERENCE NUMBERS

2, 4

- Rotor assemblies

6, 8

- pinion

10

- shaft end

12, 14

- rotors

16, 18

- Rotor shafts

20

- recess

22

- shaft end

24.26

- bags

28

- fasteners

30

- Fixing screw

32

- threaded hole

34

- Cylinder body

36

- screw

38

- hole

40

- Thread

42

- Ring

44

- Head Start

46

- Clamping rings

48

- recess

50

- contact surface

52

- Contact surface

54

- puncture

56

- Contact surface

X

- longitudinal or rotational axis

Claims (11)

1. Rotor assembly for a pump, which comprises at least one rotor shaft (16, 18) and a drive pinion (6, 8) non-rotatably connected therewith, wherein the drive pinion (6, 8) comprises a central recess (48) having a conical inner peripheral surface and the rotor shaft (16, 18) comprises a corresponding conical outer peripheral surface (50), which are attached to each other on the rotor shaft (16, 18) in order to fix the drive pinion (6, 8), characterized in that attached to the end of the conical inner peripheral surface, which is smaller in diameter, a cylindrical contact surface (56) is provided in the recess (48) of the drive pinion (6, 8) and the rotor shaft (16, 18) comprises a corresponding cylindrical contact surface (52) with the same diameter, which is attached to the end of the conical outer peripheral surface (50), which is smaller in diameter.
2. Rotor assembly according to claim 1, characterized in that the drive pinion (6, 8) and the rotor shaft (16, 18) are glued together.
3. Rotor assembly according to one of the preceding claims, characterized in that the rotor assembly (2, 4) is part of a rotary piston pump, which preferably comprises two rotor assemblies (2, 4) according to one of the preceding claims.
4. Rotor assembly (2, 4) according to one of the preceding claims, characterized by a rotor (12, 14), which comprises a recess (20), in which the rotor shaft (12, 14) engages, wherein
   a pocket (24) which is circular-segmented in its cross section, preferably semicircular, is formed on the outer periphery of the rotor shaft (16, 18) and opposite to said pocket, a corresponding pocket (26) which is circular-segmented in its cross section, preferably semicircular, is formed, wherein a preferably circular connecting element (28) is arranged in the pockets (24, 26) facing each other, which is adapted to the circular segment form of the pockets.
5. Rotor assembly according to claim 4, characterized in that the longitudinal axes of the pockets (24, 26) and the longitudinal axis of the connecting element (28) are located parallel to the axis of rotation (X) of the rotor shaft (16, 18).
6. Rotor assembly according to claim 4 or claim 5, characterized in that on the outer periphery of the rotor shaft (16, 18) a plurality of pockets (24), which are semicircular in their cross section, and a corresponding plurality of each opposite and in cross section semicircular pockets (26) are formed, wherein in each of the oppositely arranged pockets (24, 26) a connecting element (28) being circular in cross section is inserted.
7. Rotor assembly according to claim 6, characterized in that the plurality of pockets (24) on the rotor shaft (16, 18) and the corresponding opposite pockets (26) on the rotor (12, 14) are unevenly distributed on the circumference.
8. Rotor assembly according to one of claims 4 to 7, characterized in that the connecting elements (28) in the pockets (24) on the rotor (12, 14) and/or in the pockets (26) on the rotor shaft (16, 18) are glued.
9. Rotor assembly according to one of claims 4 to 8, characterized in that the connecting elements (28) are formed expandable in their direction of diameter.
10. Rotor assembly according to one of claims 4 to 9, characterized in that the connecting elements (28) are formed by at least two axially arranged cylinder bodies (34) and at least one expansion element (46) being axially arranged between the cylinder bodies (34), wherein the two cylinder bodies (34) are axially adjustably connected to each other.
11. Rotor assembly according to claim 10, characterized in that at least one of the two cylinder bodies (34) of a connecting element (28) is firmly attached to the rotor (12, 14) and/or the rotor shaft (16, 18), preferably in a torque-proof manner.

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