DE102011054607A1 - vacuum pump - Google Patents

Abstract

The invention relates to a vacuum pump (1), in particular a screw pump, with two displacer shafts (2, 3) that drive displacement bodies (13, 14) and a motor with a motor rotor (19), a motor shaft (2) and a motor stator ( 20), furthermore a pump housing is provided, which is divided into a working space (5) in which the displacement bodies (13, 14) are arranged, and a motor / gear compartment (7), which spaces are further divided by one of the displacement body shafts (2, 3) penetrated partition wall (9) are separate. In order to specify a vacuum pump, in particular a screw pump, which enables advantageous storage conditions with a space-saving and inexpensive design, it is proposed that the motor shaft (2), which is also designed as one of the displacement body shafts (2, 3) and on which the motor rotor (19) is attached , is mounted in the partition (9), and that with respect to the partition (9) opposite to the motor rotor (19), the displacement body (13) driven by this displacement body shaft is arranged, the displacement body shafts (2, 3) each also being in a an outer wall forming work space wall are mounted.

Description

The invention relates to a vacuum pump, in particular a screw pump, with two drivingly coupled, displacer driving Verdrängerkörperwellen, and a motor with a motor rotor, a motor shaft and a motor stator, wherein a pump housing is further provided in a working space in which the displacer are arranged and a motor / gear compartment is divided, which spaces are further separated by a partition wall penetrated by the Verdrängerkörperwellen.

Such vacuum pumps have already become known in many embodiments. The state of the art, for example, on the WO 94/29596 A1 ( US 5 767 635 A ) and the WO 01/79701 A1 ( US 2003/0152468 A1 ).

From the last-mentioned document, it is known in terms of the arrangement to perform the motor shaft as a hollow shaft and one of the Verdrängerkörperwellen, the first Verdrängerkörperwelle to pass through the motor shaft, wherein the drive of the first Verdrängerkörperwelle is derived from the second Verdrängerkörperwelle, via a transmission with Transmission shaft between the engine body shaft and the second displacement body shaft is driven and in turn drives the first Verdrängerkörperrwelle, which passes through the motor shaft. The structure is not only expensive, but also associated with system-related cost disadvantages, since it can be used in terms of the engine is not on standard components. The former document relates to a vacuum pump of other construction. The displacement body shafts are arranged one behind the other, without overlapping transverse to the shaft longitudinal axis, and driven at their opposite ends. For this purpose, each a separate electric motor is provided, wherein an electronic control is provided for the synchronization of the corresponding comparatively far apart drives.

Based on the first-mentioned prior art, the invention deals with the technical problem of a vacuum pump, in particular a screw pump to specify that allows for space-saving and cost-effective structure advantageous storage conditions.

A possible solution of the problem is given according to a first inventive idea in an object in which at the same time as a (first) of the positive displacement shaft formed motor shaft on which the motor rotor is mounted, is mounted in the partition and at which further with respect to the partition opposite to the motor rotor of the displacer body driven by this displacement shaft body is arranged, wherein in addition the Verdrängerkörperwellen are stored in addition to a storage in the partition wall in an outer wall forming working space wall.

One, and preferably only one, the displacement shaft thus also forms the motor shaft at the same time. Nevertheless, this displacement shaft forming the motor shaft is also mounted on both sides of the motor, and outside the motor, namely on the one hand in the partition and on the other hand in the working space wall. These are conventional positive-displacement shaft bearings, which can therefore be elaborate in comparison to a motor shaft bearing of an electric motor as such. In particular, they can, as explained below in detail, be designed as oil-lubricated bearings. The fact that the engine is formed as it were integrated with one of the positive displacement body shafts, the space required in the engine / gear compartment is comparatively low. It only requires one drive, which can be achieved in a simple manner by means of a gear engagement, and thus simultaneous synchronization of the second displacement body shaft through the first displacement body shaft. Both displacer shafts can be mounted assigned to the same space, the engine / gear room with the same bearings, such as oil-lubricated bearings stored. There are no other types of bearings in the engine / gear compartment necessary. In this case, the bearings received in the dividing wall are preferably designed to accommodate both operationally occurring axial and radial forces. The bearings received in the outer engine compartment wall, on the other hand, are preferably essentially (only) designed to absorb radial forces. The one (first) displacement body is arranged in alignment with and on the same shaft as the motor rotor. The first displacement shaft has on both sides of the partition on comparable large masses. Both preferred side by side and mutually parallel displacement body waves may be the same, especially the same length, be formed. With respect to the drive, the electric motor, standard components can be used, since the installation dimensions can be chosen so that they correspond to standard dimensions with regard to the rotor to be applied on the shaft as well as the rotor adapted to the stator.

Such a vacuum pump is characterized by cost-effective production by comparatively small dimensions and a comparatively low weight of the pump unit, this also achieved with a comparatively very small number of components.

Although above and below a first and a second displacement shaft is described, but is the concept of the vacuum pump not limited thereto. It is also possible to provide one or more further displacement body shafts with correspondingly applied displacement bodies. Optionally, even a further displacement shaft with simultaneously applied rotor and displacer, and of course then also further assigned stator. However, an embodiment with only two displacement body shafts, as also described here, is preferred.

Further features of the invention are described below, also in the figure description and the drawing, often in their preferred assignment to the concepts already explained above, but they can also be assigned to only one or more individual features described herein or are represented graphically, or independently or in another overall concept of importance.

Thus, it is preferred that all bearings, in any case the bearing of the vacuum pump assigned to the engine / gear compartment, ie both the bearings in the partition wall and also bearings in the (outer) engine compartment wall, are oil-lubricated. The usual in an electric motor and when the engine in the engine / gear compartment, as basically provided here, then located in the engine / gear compartment grease-lubricated bearings can be omitted here in the engine / gear compartment. This allows a uniform, high-quality bearing training in any case based on the engine / gear compartment. The thus formed bearings can also be supplied uniformly (via an oil pump) and maintained.

With respect to the displacement body is preferred that they are interchangeable with the displacement body shaft - respectively - are connected. On the other hand, different materials can be selected for the displacer shaft on the one hand and the displacer on the other hand. For example, a displacement body made of aluminum or other good heat-conducting material may be formed. In view of the associated good heat conduction, such a design can achieve a highly uniform heat distribution in the displacers, which at the same time ensures a nearly equal thermal expansion of the displacer. In turn, a high accuracy of fit with a high degree of independence from the operating temperature is possible.

The material of a displacement shaft may be chosen in particular based on a non-magnetizable material, such as a high-alloy steel.

More preferably, the motor rotor is also interchangeably connected to the motor shaft or the first displacement body shaft. In this way, you can easily realize different engine performance. The connection can be realized via a shaft-hub connection of conventional type, for example via driver elements such as a feather key. Also with the help of a clamping set, d. H. Ring parts cooperating with each other via conical surfaces.

The motor stator may be shrunk into the gearbox / motor housing. It can also be used already shrunk into a socket motor stator by means of the socket in the engine / gear compartment.

With regard to a displacer shaft, in particular the displacer shaft, which is also designed as a motor shaft, it is preferred for it to be hollow. In this case, it is further preferred that coolant is guided in the cavity, for cooling both the motor rotor and the displacement body. The hollow configuration can be realized by means of a through bore. It is preferred that only the same time designed as a motor shaft Verdrängerkörperwelle is cooled in this way. But it is also possible to additionally form the further, second displacement shaft as a hollow shaft and to cool accordingly in the same way.

In a further preferred embodiment, it is provided that the motor shaft designed as the first Verdrängerkörperwelle is supported at its working space end by a third bearing. More preferably, both displacement body shafts are supported at their working space end by a third bearing. This third bearing is further preferably designed such that it can absorb axial movements of the displacement body shaft, in particular caused by thermal change in length, readily. For this purpose, a resilient support in the axial direction of the shaft end may be provided in the third bearing. More preferably, said third bearing is designed for a limited uptake of radial forces. For this purpose, an outer ring of the third bearing can be provided radially damped. This third bearing may be further preferably designed as a grease-lubricated bearing, moreover preferably as provided with a cap, so-called capped bearing.

In addition, it is preferred that a lubricant pump is provided. This serves in any case to supply said oil-lubricated bearings, but preferably also for cooling, for example with regard to the already described possible hollow design of one or both displacement body shafts. The cooling is preferably carried out with the aid of the lubricant, which is more preferably a lubricating oil. It can be with respect to the first displacement shaft not only a cooling of the Motor rotor, but at the same time also reach the arranged on the first displacement shaft displacement body. Although the coolant also flows out of the engine / gear chamber into the region of the working chamber due to the hollow design of the displacer body, it is at the same time hermetically separated from the space outside the displacer body shafts since it only flows within the displacer body shafts. In this case, it is particularly preferred that the lubricant pump is driven by a section of a displacement body shaft which projects beyond an outer working space wall. The lubricant pump is accordingly preferably arranged outside the housing. It is thus directly accessible. It is so cool synonymous cool. More preferably, said portion of the displacement body shaft also forms the shaft of the lubricant pump. It is in the lubricant pump in particular an oil pump. More preferably, the lubricant pump is driven by a second displacement body shaft, which is not at the same time motor shaft.

The motor stator can be cooled by externally formed on the transmission / motor housing cooling fins. Optionally also actively supported by a separate fan, which acts on these cooling fins with an air flow. Alternatively or additionally, a liquid cooling can be provided by means guided by cooling channels formed in the housing cooling liquid. Further additionally or alternatively, cooling of winding heads with oil or (altogether) oil mist cooling can be provided for cooling.

The drive, the electric motor, is preferably speed-controlled via a frequency converter. It is such a speed well above the speeds of standard motors possible. The motor is preferably designed for a super-synchronous speed (in relation to the mains frequency). Since the lubricant pump is preferably driven directly by the second displacement body shaft, this results in a directly adapted to the speed regulation of the lubricant pump.

Due to the arrangement of the rotor on the first Verdrängerkörperwelle and the speed control, no reduction gear and a further drive shaft usually provided therein is required. It only requires a Direktkoppung or Sychron coupling between the displacement lobe.

The two displacement body shafts work together via a synchronous toothing. In this way, on the one hand, the drive power is transmitted from the first, at the same time designed as a motor shaft Verdrängerkörperwelle on the second displacement body shaft and on the other hand ensures the synchronism of the Verdrängerkörperwellen. In particular, it is preferred that the synchronous toothing is arranged between the working space wall and the motor. This arrangement is particularly advantageous with regard to a mounting of the vacuum pump. In addition, also what is always associated with the assembly in such aggregates, with a view to balancing the unit.

The overall arrangement described is advantageous in terms of balancing in that a preassembled assembly consisting of a Verdrängerkörperwelle together with the bearings and bushings, in the case of the first Verdrängerkörperwelle with already mounted motor rotor, each with a seated synchronizing gears, can be balanced , Only the synchronizing gears are to be removed for installation again, otherwise the pre-assembled kit described here can be introduced into the pump housing and fastened there without a disassembly would be required again. By marking the position of the synchronizing gears and their given in the balancing positioning in the course of assembly can be easily reproduced again. A repeated balancing in the installed state in the pump housing can be omitted.

The invention will be explained below with reference to the accompanying drawing, which also shows only one embodiment. Hereby shows:

1 A schematic cross-sectional view of a vacuum pump, in horizontal section;

2 the object according to 1 in a vertical section;

3 the representation of a first assembly;

4 the representation of a second assembly;

5 the engine / transmission housing prior to insertion of the first - or second assembly.

Shown and described is a vacuum pump 1 , which is formed in the embodiment as a screw pump. The vacuum pump 1 has a first displacement body shaft 2 and a second displacer shaft 3 on.

Preferably, it is a dry-running pump.

The vacuum pump 1 further comprises a pump housing, which in a housing part 4 concerning a workroom 5 and a housing part 6 that has a motor gearbox 7 forms, is divided. In the case parts 4 . 6 It is, in particular with regard to the housing part 6 radially to the displacement shaft 2 . 3 closed and preferably in this respect integrally formed housing parts. For example, they can be castings. In the axial direction of the displacer shaft 2 . 3 are closure plates provided, wherein the engine / gear compartment 7 associated closure plate a working space wall 8th formed.

Between the engine / gear compartment 7 , and the workroom 5 is a partition 9 formed here in one piece with the motor / Getieberaum forming housing part 6 is trained. In the partition 9 are the displacer shafts 2 . 3 by means of first bearings 10 . 11 stored. The workroom 5 are assigned to the camps 10 . 11 upstream seals received in sealing bushes 12 assigned. It may be touching and / or non-contact shaft seals. The seals and sealing bushes are preferred according to only one side of the partition 9 arranged.

Working space side are the displacement body shafts 2 . 3 with displacers 13 . 14 Mistake. These act helically in the usual manner in the embodiment, but without touching.

At the of the workroom 5 opposite end are the displacer shaft 2 . 3 in second camps 15 . 16 stored. These bearings 15 . 16 are in the outer wall 8th added. Specifically, they are in the outer wall 8th again used stock photographs 17 . 18 added.

On the first displacement shaft 2 is with regard to a drive in the engine / gear compartment 6 a motor rotor 19 arranged. The first displacement shaft 2 thereby forms at the same time the motor shaft.

Next is in the engine / gear compartment 7 the associated, in the arrangement area of the motor rotor 19 surrounding provided motor stator 20 arranged. It can, according to a standard procedure in standard motors, in the housing part 6 shrunk or by means of a socket, in which he shrunk, in the housing part 6 be installed.

With respect to the first displacer shaft 2 is the displacer 13 with regard to the partition wall 9 opposite to the motor rotor 19 arranged. On one side of the partition 9 is on the same shaft, the displacer shaft 2 , the displacer 13 and on the other side the motor rotor 19 arranged.

The displacer shaft 2 . 3 are not just through the first camp 10 . 11 and the second camps 15 . 16 stored, but also still by a third camp 21 . 22 , The third camp 21 . 22 is each by means of its own recording part 23 . 24 on the suction side, the housing part 4 final housing cover 25 attached. The housing cover 25 also forms an entrance at the same time 26 the vacuum pump 1 out.

The first and second bearings 10 . 11 respectively. 15 . 16 are oil lubricated. In contrast, the third camp 21 . 22 preferably grease-lubricated.

As shown in the illustration 2 it can be seen below the inlet 26 one with the muffler 27 equipped outlet 28 the vacuum pump 1 intended.

The displacer 13 . 14 are at the displacer shaft 2 . 3 attached exchangeably. In detail, each is a clamping plate 29 . 30 provided, by means of which the displacer 13 . 14 by means of in the region of the displacement body 13 . 14 in the form of pipe parts 31 . 32 Continued positive displacement shaft are braced.

Also the motor rotor 19 is interchangeable on the first displacement shaft 2 , in the embodiment by means of feather key 33 , appropriate.

Out 2 is apparent that a motor cable 34 of the motor stator 20 by means of an oil-tight cable bushing 35 outside of the housing part 6 in a power connection 36 empties. The cable entry 35 is on a machined surface of the housing part 5 by means of a flat gasket 37 sealed. An oil leakage to the outside is thereby effectively prevented.

Between the motor rotor 19 or the motor stator 20 and the outer wall 7 are on the displacer shafts 2 . 3 provided for drive and synchronization gears 38 . 39 arranged. These are also solvable me the displacement shaft 2 . 3 befefestigt. Preferably by means of a transition fit.

An outer diameter of the motor rotor 19 is chosen smaller than the diameter of one in the housing bulkhead 9 trained passage opening 40 into which the first camp 10 is used.

This makes it possible that the in 4 shown assembly, with the exception of the gear 38 , in total in the axial direction of Verdrängerkörperwelle 2 in the housing part 6 can be used. The same goes for the in 3 shown assembly of the displacement body shaft 3 , After that can be used to form the working space 5 this also essentially cylinder-like housing part 4 via the displacer for connection to the housing part 6 be pushed over in the area of the partition. Alternatively, an embodiment may be provided in which the housing parts 4 . 6 already connected to each other when said assemblies are used.

The relevant housing part 6 without the end wall 8th and the housing part 4 is in 5 shown in cross section.

Due to this structure of the pump housing and the assemblies, it is possible in the 3 respectively. 4 shown assemblies in total ready to be balanced. Only the gears 38 . 39 must be removed for installation and then in the installed state of the displacement body shafts 2 . 3 through the end through the outer wall 8th closed opening to be placed.

Outside on the outside wall 8th is a lubricant pump indicated here only schematically 41 arranged. This lubricant pump 41 has a pump shaft, here at the same time by the displacement shaft 3 is formed.

The described construction of the vacuum pump 1 also allows the formation of a pump kit on the manufacturer side in a simple manner. This with regard to different pumping speeds and / or different drive power. With otherwise unchanged Verdrängerkörperwellen 2 . 3 can other (longer or shorter building) displacer 13 . 14 to be assembled. The can by a corresponding excess length and related axial clearance in the workspace 5 , based on a smallest version within the kit, be taken into account. The different drive power can initially be achieved via different operating speeds. However, it can also be achieved in addition or alternatively by modifying the stator / rotor diameter and / or the stator / rotor length. All other components can be unchanged despite the different pump parts mentioned.

All disclosed features are essential to the invention. The disclosure of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in full in the disclosure of the application, also for the purpose of including features of these documents in claims of the present application. The subclaims characterize in their optional sibling version independent inventive development of the prior art, in particular to make on the basis of these claims divisional applications.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 94/29596 A1 [0002]
• US 5767635 A [0002]
• WO 01/79701 A1 [0002]
• US 2003/0152468 A1 [0002]

Claims (12)

Vacuum pump ( 1 ), in particular screw pump, with two antriesbmäßig coupled, displacement body ( 13 . 14 ) driving displacement shaft ( 2 . 3 ), and a motor with a motor rotor ( 19 ), a motor shaft ( 2 ) and a motor stator ( 20 ), wherein further a pump housing is provided, which in a working space ( 5 ), in which the displacer ( 13 . 14 ) are arranged, and a motor / gear room ( 7 ), which spaces are further divided by one of the displacer body shafts ( 2 . 3 ) penetrated partition ( 9 ) are separate, characterized in that at the same time as one of the displacement body waves ( 2 . 3 ) formed motor shaft ( 2 ) on which the motor rotor ( 19 ), in the partition wall ( 9 ) and that with respect to the partition wall ( 9 ) opposite to the motor rotor ( 19 ) of the displacer body driven by this displacement body ( 13 ), wherein further the displacement body waves ( 2 . 3 ) are each also stored in an outer wall forming a working space wall. Vacuum pump according to claim 1 or in particular according thereto, characterized in that all the engine / gear compartment ( 7 ) associated bearing ( 10 . 11 . 15 . 16 ) are oil lubricated. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the displacement bodies ( 13 . 14 ) interchangeable with the displacer shafts ( 2 . 3 ) are connected. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the motor rotor ( 19 ) exchangeable with the displacement shaft ( 2 ) connected is. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the hollow motor shaft ( 2 ) is cooled by means guided in the cavity coolant. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the motor shaft ( 2 ) is supported at its working space end by a third bearing. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the third bearing changes in length of the displacement body shaft ( 2 . 3 ). Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that a lubricant pump is provided. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the lubricant pump by a Verdrängerkörperwelle ( 2 . 3 ) is driven. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the lubricant pump ( 4 ) with one over a wall ( 8th ) of the engine / gear space outwardly projecting part of the displacement body shaft ( 3 ) cooperates. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the Verdängerkörperwellen ( 2 . 3 ) interact via a synchronous toothing. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the synchronous toothing between the working space wall ( 8th ) and the motor is arranged.

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