DK1857680T3

DK1857680T3 - rotor module

Info

Publication number: DK1857680T3
Application number: DK06010218.3T
Authority: DK
Inventors: Antony Mark Brown
Original assignee: Hilge Gmbh & Co Kg
Priority date: 2006-05-18
Filing date: 2006-05-18
Publication date: 2017-05-08
Also published as: EP1857680B1; ES2622876T3; EP1857680A3; EP1857680A2; PL1857680T3

Description

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

Rotary piston pumps usually have two parallel rotor shafts which are coupled together in respect of their rotary movement and which at an axial end each carry a respective rotatable piston or a gear. The pistons or gears engage into each other and thus form a positive displacement pump. It is important with those pumps that the pistons rotate synchronously. In that respect both the pistons and also the transmission elements which rotatably moveably couple the two shafts are to be connected to the rotor shafts in non-rotatable relationship. In that respect at the same time precise adjustment of the elements on the shafts is required in order to ensure synchronous operation of the two pistons so that they rotatingly engage into each other.

In known shaft-hub connections precise alignment is difficult because of the tolerances occurring. US 4 490 102 discloses a screw compressor having two interengaging screw shafts connected together by a pair of gears. One of those gears is fixed to the associated rotor shaft by a taper connection. In such a taper connection aligning the drive gear on the shaft in accurate rotational angle relationship is difficult as, when the gear comes into contact with the shaft, it blocks relatively quickly by virtue of the taper surfaces and can no longer be aligned in respect of its rotational angle.

Therefore the problem of the invention is to provide an improved rotor assembly for a pump, that permits easier adjustment which is accurate in respect of the rotational angle of transmission elements on the rotor shaft.

That problem is solved by a rotor assembly having the features recited in claim 1. Preferred embodiments are set forth in the appendant claims.

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

According to the invention the drive pinion has a central recess having a conical inner peripheral surface. That inner peripheral surface in that case extends conically around the longitudinal axis or the axis of rotation 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 are in engagement or contact with each other for fixing the drive pinion on the rotor shaft. In that way the drive pinion is held non-rotatably on the rotor shaft.

Preferably provided in the recess of the rotor is a cylindrical contact surface adjoining the end, which is smaller in diameter, of the conical inner peripheral surface, and the rotor shaft has a corresponding cylindrical contact surface which adjoins the end, which is smaller in diameter, of the conical outer peripheral surface. That configuration facilitates fitment of the drive pinion on to the rotor shaft as to begin with the cylindrical contact surfaces can be brought into engagement with each other. In that case the pinion is already centrally aligned on the rotor shaft, but initially still remains rotatable about same so that the drive pinion can then be aligned in its angular position with respect to the rotor shaft. The drive pinion is then displaced further axially relative to the rotor shaft so that the conical inner peripheral surface moves on to the corresponding conical outer peripheral surface and thus the drive pinion is secured fixedly, in particular non-rotatably, on the rotor shaft.

In addition it is possible for the drive pinion and the rotor shaft to be glued together to implement an even stronger connection.

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

For non-rotatably mounting the rotor to the rotor shaft the rotor shaft preferably has at the outer periphery at least one pocket which is in the form of a segment of a circle in cross-section. The pocket in the form of a segment of a circle in its cross-section has a recess in the form of a segment of a cylinder and whose diameter or centre line preferably extends parallel to the longitudinal axis or axis of rotation of the rotor shaft. Provided in oppositely disposed relationship on the inner periphery of the recess in the rotor is a corresponding pocket which is in the form of a segment of a circle in cross-section. In other words that pocket also forms a recess in the form of a segment of a cylinder, whose longitudinal axis or centre line preferably extends parallel to the longitudinal axis or the axis of rotation of the rotor. In that respect the longitudinal axis or the axis of rotation of the rotor is identical to the longitudinal axis or axis of rotation of the rotor shaft. The two oppositely disposed pockets in the form of a segment of a circle preferably jointly form a circular-cylindrical recess or hole which extends parallel to the longitudinal axis of the rotor shaft between the inner periphery of the recess and the outer periphery of the rotor shaft. A connecting element which is of corresponding cross-section and which is preferably of a circular shape, that is to say of a circular-cylindrical shape, is fitted into those mutually opposite pockets. That connecting element forms the positively locking non-rotatable connection between the rotor and the rotor shaft.

The cross-sectional surfaces which are in the form of a segment of a circle of the pockets at the outer periphery of the rotor shaft and at the inner periphery of the recess in the rotor are preferably so dimensioned that they jointly form a circular cross-section. Particularly preferably the two pockets are of a semicircular configuration in cross-section so that the pockets at the outer periphery of the rotor shaft and at the inner periphery of the recess in the rotor are respectively of a semicylindrical shape which jointly define a cylindrical recess into which a cylindrical connecting element can be fitted.

The pockets in the rotor and in the outer periphery of the rotor shaft are preferably milled into same there so that they can be produced with a high level of accuracy at the desired angular position. The cylindrical connecting element can then be appropriately inserted only when the pockets at the inner periphery of the rotor and at the outer periphery of the rotor shaft are in precisely mutually opposite relationship, that is to say the rotor is in a predetermined angular position with respect to the rotor shaft. A play-free positively locking connection can be achieved between the rotor and the rotor shaft by a suitable tight fit.

Preferably both the centre lines or longitudinal axes of the pockets on the rotor shaft and the rotor and also the longitudinal axis of the connecting element which is of circular cross-section extend parallel to the axis of rotation of the rotor shaft and therewith the rotor.

Preferably a plurality of pockets which are semicircular in cross-section are provided at the outer periphery of the rotor shaft and a corresponding plurality of respective oppositely disposed pockets of semicircular cross-section are provided at the inner periphery of the recess of the rotor, wherein a connecting element of circular cross-section is respectively fitted into the mutually opposite pockets. In other words, the pockets at the outer periphery of the rotor shaft are arranged in corresponding relationship with the pockets at the inner periphery of the recess in the rotor at identical angular positions so that a respective pocket on the outer periphery of the rotor shaft is always disposed in accurate opposite relationship with a pocket at the inner periphery of the recess so that those two pockets together form a receiving opening for the connecting element, which opening is of circular cross-section, that is to say overall being circular-cylindrical. A respective connecting element is fitted into each of those pairs of pockets. That provides a positively locking connection between the rotor and the rotor shaft, which can carry a heavier loading and by way of which higher torque levels can also be transmitted.

The plurality of pockets on the rotor shaft and the corresponding oppositely disposed pockets on the rotor are preferably distributed irregularly over the periphery. That configuration provides that the rotor can be fixed to the rotor shaft only in a predetermined angular position with respect to the axis of rotation so that incorrect assembly can be excluded. That is important as in the case of use in a rotary piston pump in which the rotor cooperates with a second rotor the rotor must move in defined fashion with respect to the second rotor. An irregular arrangement of the pockets can be effected for example in such a way that actually all pockets are arranged at regular angular positions relative to each other, but at an angular position at which actually a pocket would have to be provided by virtue of that regular distribution, no pocket is provided.

Further preferably the connecting elements are glued in the pockets on the rotor and/or in the pockets on the rotor shaft. In that way the connecting elements are secured in the pockets so that they cannot slip out or come loose. A durable connection between the rotor and the rotor shaft can thus be provided.

Alternatively or additionally the connecting elements can be adapted to be spreadable in the direction of their diameter. That makes it possible for the connecting elements to be easily fitted into the mutually opposite pockets and then spread so that they are braced in the pockets. A firm connection is then produced between the rotor and the rotor shaft. At the same time this permits automatic accurate alignment or adjustment of the mutually opposite pockets upon spreading of the connecting element. In that way the rotor is then automatically oriented and fixed in the defined predetermined angular position with respect to the rotor shaft. Precise centering can also be effected by virtue of spreading of the connecting elements. In addition the connecting elements can be of such a structure that their spreading is reversible so that they can be released again so that for example the rotor can be removed from the rotor shaft for maintenance operations or for replacing worn parts.

For that purpose the connecting elements preferably comprise two cylinder bodies which are arranged axially relative to each other and at least one spreading element which is disposed axially between the cylinder bodies, wherein the two cylinder bodies are connected to each other axially displaceably relative to each other. That can be effected for example by a screw connecting the two cylinder bodies together. When the two cylinder bodies are moved towards each other by adjustment of the adjusting element, for example a screw, the spreading element disposed therebetween can be spread. That can be effected for example by conical surfaces being provided between the spreading element and the cylinder bodies, the conical surfaces upon pressing of the cylinder bodies in the axial direction against the spreading element producing a force which acts on the spreading element in the radial direction and which urges the spreading element apart in the radial direction so that it is pressed against the inside walls of the pockets into which the connecting element is fitted.

At least one of the two cylinder bodies of a connecting element is preferably fixedly connected to the rotor and/or the rotor shaft, preferably non-rotatably to the rotor and/or the rotor shaft. In that way for example in the situation where the two cylinder bodies are connected with a screw it is possible to prevent the cylinder body also rotating when the screw is turned. The non-rotatable connection can be implemented for example by a positively locking engagement or also by clamping or gluing.

As described the rotor assembly as was described hereinbefore is preferably part of a circular piston or rotary piston pump which preferably has two rotor assemblies according to the foregoing description.

The invention is described by way of example hereinafter with reference to the accompanying Figures in which:

Figure 1 shows a sectional view of a rotary piston pump having a rotor assembly according to the present invention,

Figure 2 shows an exploded view of a first embodiment of the invention,

Figure 3 shows a detail view of the rotor of Figure 2,

Figure 4 shows a sectional view of the assembled rotor assembly of Figures 1 to 3,

Figure 5 shows a second embodiment of the rotor assembly according to the invention,

Figure 6 shows a detail view of the rotor of Figure 5,

Figure 7 shows a sectional view of a connecting element as is used in the rotor assembly shown in Figures 5 and 6,

Figure 8 shows an exploded view of the connecting element of Figure 7,

Figure 9 shows a perspective view of the fixing of a drive pinion in a rotor assembly according to the invention, and

Figure 10 shows a sectional view of the rotor assembly of Figure 9 with fitted drive pinion.

The rotor assembly according to the invention is particularly suitable for use in a circular piston or rotary piston pump as is shown for example in the sectional view in Figure 1. In their interior such rotary piston pumps have two rotor assemblies 2 and 4 arranged in mutually parallel relationship, which are in engagement with each other by way of pinions 6 and 8. The rotor assembly 2 is driven by way of its shaft end 10 by a motor (not shown). At the opposite end the shafts of the rotor assemblies 2 and 4 are respectively connected to a rotor or rotary piston 12, 14 which mesh with each other and thus form a positive displacement pump.

The invention concerns the rotor assemblies 2 and 4 and there the fixing of the rotors 12 and 14 on the rotor shafts 16, 18. The invention further concerns the fixing of the pinions 6 and 8 to the rotor shafts 16, 18. When hereinafter the further configurations of those fixings are described only by reference to one of the two rotor assemblies 2 and 4 however it is to be understood that the configuration is selected in corresponding fashion with the respective other rotor assembly.

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

The rotor 12 is connected at a shaft end to the rotor shaft 16 in such a way that it is fitted on to the rotor shaft in the direction of the axis of rotation. For that purpose in its interior the rotor 12 has in central relationship with the longitudinal axis or axis of rotation X a recess 20 into which the rotor shaft 16 engages with its shaft end 22. Provided at the outer periphery of the shaft end 22 are semicircular or semicylindrical pockets 24 whose longitudinal axes and peripheral surfaces extend parallel to the axis of rotation X.

Provided in the interior of the recess 20 at the inner periphery are corresponding pockets 26 which are also of a semicircular cross-section or are semicylindrical in shape and whose centre lines extend parallel to the axis of rotation X. The pockets 26 are arranged at the inner periphery of the recess 20 in such a way that they are disposed around the longitudinal axis X at the same angular positions as the pockets 24 so that, with the desired angular position of the rotor 12 with respect to the rotor shaft 16, there is always a respective pocket 24 in precisely opposite relationship with a pocket 26. In that way a pocket 24 jointly with a pocket 26 always forms a cylindrical recess which is disposed in the plane of contact between the inner periphery of the recess 20 and the outer periphery of the shaft end 22, and into which a cylindrical or roller-shaped connecting element 28 is fitted. In that way the connecting elements 28 produce a positively locking connection between the rotor shaft 16 and the rotor 12, that permits 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 implemented by the connecting elements 28 as they are arranged distributed over the entire periphery of the rotor shaft 16 or the shaft end 22 respectively and with a suitable fit fix the rotor 12 in play-free manner in the radial direction on the shaft end 22. Alternatively it is possible to already produce a corresponding fit between the inner periphery of the recess 20 and the outer periphery of the shaft end 22 so that play-free fitment of the rotor 12 to the shaft end 22 is possible.

The rotor 12 is fixed in the axial direction by a fixing screw 30 which is screwed into an end threaded bore 32 in the direction of the longitudinal axis X into the shaft end 22 and thus secures the rotor 12 to the rotor shaft 16 in the axial direction. In that arrangement the head of the fixing screw 30 engages over the peripheral edge of the recess 20.

The connecting elements 28 in accordance with the embodiment shown in Figures 2 to 4 involve solid roller bodies for example of steel. They can be glued in the pockets 24 and 26 for additional securing thereof. It is also possible to additionally apply an adhesive between the outer periphery of the shaft end 22 and the inner periphery of the recess 20.

An alternative connection between the rotor 14 and the rotor shaft 18 is described with reference to Figures 5 to 8. In this embodiment the shaft end 22 with the pockets 24 is of the configuration as described hereinbefore by means of the first embodiment. The recess 20 with the pockets 26 is also identical to the first embodiment according to the foregoing description. That second embodiment only differs in the configuration of the connecting elements 28 which are here in the form of clamping or bracing elements and are described in greater detail with reference to Figures 7 and 8. Those connecting elements 28 can be braced after insertion into the pockets 24 and 26 so that they expand in the radial direction and thus produce a clamping force between the rotor 12, 14 and the associated rotor shaft 16, 18. In that case it is possible to achieve complete fixing of the rotor 12, 14 to the rotor shaft 16, 18 and it is possible to dispense with the fixing screw 30 which however can also be additionally provided.

The connecting elements 28 of the second embodiment are in cross-section also circular, that is to say overall of a circular-cylindrical or barrelshaped configuration. They are formed by two axially spaced cylinder bodies 34 which are connected together by a screw 36. In that arrangement the screw 36 passes through the one cylinder body 34 through a hole 38 without a thread and engages into a thread 40 in the other cylinder body 34. The cylinder bodies 34 can thus be moved towards and away from each other in the axial direction by rotation of the screw 36.

Arranged between the two cylinder bodies 34 is a ring 42 which at the axial ends does not come into contact with the adjoining cylinder bodies 34. The ring 42 has centrally at the outer periphery a projection 44 which is beveled or inclined at the sides facing towards the cylinder bodies 34. The ends of the cylinder bodies 34 which are towards the projection 44 are correspondingly inclined in such a way that outwardly expanding annular grooves are formed between the cylinder bodies 34 and the projection 44. Clamping rings 46 are arranged in those grooves.

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, because of the inclined contact surfaces at the cylinder bodies 34 and the projection 44, the clamping rings 46 are urged radially outwardly and thus a clamping action can be produced in the pockets 24 and 26.

In the arrangements of the pockets 24 and 26 as are shown in Figures 2 to 6 they are distributed regularly over the periphery of the shaft end 22 or the inner periphery of the recess 20, in which respect however it will be noted that a pocket 24 and an oppositely disposed pocket 26 have been omitted in that regular distribution so that a greater spacing 48 is produced between two adjacent pockets 26 at a location at the outer periphery of the shaft end 22 and at a location in correspondingly opposite relationship there is a region with a greater spacing between two adjacent pockets 26. That asymmetrical arrangement makes it possible for the rotor 12, 14 to be fitted on to the rotor shaft 16, 18 only in a predetermined angular position.

Reference is now made to Figures 9 and 10 to describe fixing according to the invention of the pinions 6, 8 to one of the rotor shafts 16, 18. The pinion or drive pinion 6 has a conical central recess 48 with which the pinion 6 is fitted on to a corresponding conical contact surface 50, that is to say which is inclined at the same angle, on the rotor shaft 16. Adjoining the tapered end of the conical outer peripheral surface or contact surface 50 is a cylindrical contact surface 52, the conical contact surface 50 being separated from the contact surface 52 by a groove 54. Corresponding to the cylindrical contact surface 52, provided at the inner periphery of the recess 48 at the tapered end of the conical inner peripheral surface is a cylindrical contact surface 56 which is of substantially the same diameter as the cylindrical contact surface 52.

That configuration of the connection between the pinion 6 and the rotor shaft 16 facilitates alignment of the pinion 6 in a given angular position with respect to the longitudinal axis X upon assembly. That alignment is required as the rotors 12 and 14 must be arranged relative to each other and rotate relative to each other at a given angle.

Upon assembly the pinion 6 can firstly be pushed on to the rotor shaft so that firstly only the cylindrical contact surfaces 52 and 56 come into contact. In that position the pinion 6 is aligned in the radial direction on the rotor shaft 16, but can still be displaced in the axial direction along the longitudinal axis X and in the peripheral direction. When the desired angular alignment is reached the pinion 6 is further displaced in the axial direction towards the shaft end 22 so that the conical inside surface of the recess 48 comes to bear against the conical contact surface 50 of the rotor shaft 16. In that case a force-locking or frictionally locking connection is made between the conical contact surface 50 and the conical inside surface of the recess 48, which results in a non-rotatable connection of the pinion 6 on the rotor shaft 16. In the operation of pushing it on to the conical contact surface 50 that also involves accurate centering of the pinion on the shaft.

List of references 2, 4 rotor assemblies 6, 8 pinion 10 shaft end 12, 14 rotors 16,18 rotor shafts 20 recess 22 shaft end 24, 26 pockets 28 connecting elements 30 fixing screw 32 threaded bore 34 cylinder body 36 screw 38 hole 40 thread 42 ring 44 projection 46 clamping rings 48 recess 50 contact surface 52 contact surface 54 groove 56 contact surface X longitudinal axis or axis of rotation

Claims

A rotor module for a pump comprising at least one rotor shaft (16; 18) and one drive sprocket (6; 8) connected pivotally to the rotor shaft (16; 18), the drive sprocket (6; 8) comprising a central recess ( 48) having an inner conical circumferential surface, and the drive shaft (16; 18) comprises a corresponding outer conical circumferential surface (50) which abut each other for attaching the drive sprocket (6; 8) to the rotor shaft (16; 18), characterized in that: that in the recess (48) of the drive sprocket (6; 8) is formed a cylindrical contact surface (56) which joins the end with a smaller diameter of the inner conical circumferential surface and the rotor shaft (16; 18) comprises a corresponding cylindrical contact surface ( 52) having the same diameter joining the smaller diameter end of the outer conical circumferential surface (50).

Rotor module according to claim 1, characterized in that the drive sprocket (6; 8) and the rotor shaft (16; 18) are adhered to each other.

Rotor module according to any of the preceding claims, characterized in that the rotor module (2; 4) is part of a rotary piston pump, which preferably comprises two rotor modules (2; 4) according to any one of the preceding claims.

Rotor module (2; 4) according to any one of the preceding claims, characterized by a rotor (12; 14) comprising a recess (20) into which the rotor shaft (12; 14) engages, wherein at least one pocket (24) having a circular segmental cross section, preferably semi-circular, is formed at the outer circumference of the rotor shaft (16; 18) and opposite to it on the inner circumference of the recess (20) of the rotor (12, 14) is formed. a pocket (26) having a corresponding circular segmental cross-section, preferably semi-circular, wherein a preferably circular connecting element (28) having a cross-sectional fit to the circular segmental shape of the pockets is arranged in each of the opposite pockets (24, 26) .

Rotor module according to claim 4, characterized in that the longitudinal axis of the pockets (24, 26) and the longitudinal axis of the connecting element (28) lie parallel to the axis of rotation (X) of the rotor shaft (16; 18).

Rotor module according to claim 4 or 5, characterized in that a plurality of cross-sectional semi-circular pockets (24) are formed on the outer circumference of the rotor shaft (16; 18) and a corresponding plurality of respective pockets (26), having a corresponding semicircular cross-section is formed on the inner circumference of the recess (20) of the rotor (12; 14), wherein a connecting element (28) having a circular cross-section is inserted into each of the opposite pockets (24, 26) ).

Rotor module 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 arranged irregularly distributed along the circumference.

Rotor module according to any of claims 4 to 7, characterized in, Awa # 160367 that the connecting element (28) in the pocket (24) of the rotor (12; 14) and / or in the pocket (26) of the rotor shaft (16; 18) is stuck.

Rotor module according to any of claims 4 to 8, characterized in that the connecting elements (28) are designed expandable in their diameter directions.

Rotor module according to any of claims 4 to 9, characterized in that the connecting elements (28) are formed by at least two cylinder bodies (34) which are axially arranged with one another and are formed with at least one expansion element (46), located axially between the cylinder bodies (34), where both cylinder bodies (34) are connected to each other so that they are axially adjustable.

Rotor module according to claim 10, characterized in that at least one of the two cylinder bodies (34) of a connecting element (28) is fixedly connected to the rotor (12; 14) and / or the rotor shaft (16; 18), preferably pivotally. Awa # 160367