WO2012055734A2

WO2012055734A2 - Vacuum pump

Info

Publication number: WO2012055734A2
Application number: PCT/EP2011/068248
Authority: WO
Inventors: Rudolf Bahnen; Uwe Drewes; Klaus Rofall; Markus LÖBEL
Original assignee: Gebr. Becker Gmbh
Priority date: 2010-10-27
Filing date: 2011-10-19
Publication date: 2012-05-03
Also published as: WO2012055734A3; JP2013541669A; DE102011054607A1

Abstract

The invention relates to a vacuum pump (1), in particular a screw pump, comprising two displacement body shafts (2, 3) which are drivingly coupled and drive displacement bodies (13, 14), and a motor having a motor rotor (19), a motor shaft (2), and a motor stator (20), wherein a pump housing is further provided, which is partitioned into a working chamber (5) in which the displacement bodies (13, 14) are arranged, and a motor/transmission chamber (7), said chambers being further separated by a partition wall (9) through which one of the displacement body shafts (2, 3) penetrates. In order to disclose a vacuum pump, in particular a screw pump, allowing space-saving and cost-saving assembly and advantageous storage conditions, the motor shaft (2) simultaneously designed as one of the displacement body shafts (2, 3) and to which the motor rotor (19) is fastened, is mounted in the partition wall (9), and the displacement body (13) driven by said displacement body shaft is arranged opposite the motor rotor (19) with respect to the partition wall (9), wherein the displacement body shafts (2, 3) are each also mounted in a working chamber wall forming an outer wall.

Description

vacuum pump

The invention relates to a vacuum pump, in particular screw pump, with two drive-coupled, displacer driving Verdrän- gerkörperwellen, 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 arranged the displacement are divided, and a motor / gear compartment, which spaces are further separated by a penetrated by the Verdrängerkörperwellen partition.

Such vacuum pumps have already become known in many embodiments. The prior art, for example, to refer to WO 94/29596 AI (US 5,767,635 A) and WO 01/79701 AI (US 2003/0152468 AI). 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 Drive shaft between the engine body shaft and the second displacement body shaft is driven and in turn drives the first displacement body shaft, 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, a separate electric motor is provided in each case, with the synchronizing tion of the corresponding comparatively far apart drives an electronic control is provided.

On the basis of the first-mentioned prior art, the invention deals with the technical problem of specifying a vacuum pump, in particular a screw pump, which makes possible advantageous storage conditions with space-saving and cost-effective construction.

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 body is arranged, wherein also 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 takes one step, which can be achieved in a simple way by means of gear meshing. Ren drive and thus simultaneous synchronization of the second displacer body shaft through the first displacement body shaft. Both displacer shaft can be assigned to the same space, the engine / gear room with the same bearings, for example, oil-lubricated bearings are 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 designed essentially (only) for receiving 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 displacer body waves may be the same, especially the same length, be formed. With regard to the drive, the electric motor, standard components can be used, since the installation dimensions can be selected to correspond to standard dimensions with regard to the rotor to be applied on the shaft as well as the stator adapted in relation to the rotor. 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 a first and a second displacement shaft is described above and below, the concept of the vacuum pump is not limited thereto. It is also possible to provide one or more further displacement body shafts with correspondingly mounted displacement bodies be. 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.

It is thus preferred that all bearings, in any case the bearings of the vacuum pump assigned to the engine / gearbox compartment, ie both the bearings in the partition wall and 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 enables a uniform, high-quality bearing training, at least with reference to 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 displacement shaft on the one hand and the displacement on the other hand. For example, a displacement of aluminum or other good heat conducting material 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 embodied at the same time 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 formation can by means of a through hole be realized. 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 displacer body shafts are supported at their working-side 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. With regard to the first displacer shaft, it is possible to achieve not only cooling of the motor rotor but also of the displacer arranged on the first displacer shaft. chen. Although the coolant also flows out of the engine / gear compartment into the area of the working chamber due to the hollow formation of the displacer bodies, it is hermetically sealed from the space outside the displacer body shafts since it only flows inside the displacer body shafts separated. Specifically, it is preferable that the

Lubricant pump is driven by a portion of a Verdrängerkörperwelle that projects beyond an - outer - Arbeitsraumwandung. 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. In particular, the lubricant pump is 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 preferred directly through the second displacement body shaft This also results in a regulation of the lubricant pump which is adapted to the rotational speed.

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 body.

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 engine. 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 comprising 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 tooth Wheels can also be reproduced in the given during balancing positioning in the course of assembly in a simple manner 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:

Fig. 1 is a schematic cross-sectional view of a Vakuumpum PE, in horizontal section;

FIG. 2 shows the article according to FIG. 1 in a vertical section; FIG.

3 shows the representation of a first assembly;

4 shows the illustration of a second assembly;

Fig. 5, the engine / transmission housing before inserting 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 displacement body shaft 3.

Preferably, it is a dry-running pump.

The vacuum pump 1 further comprises a pump housing, which in a housing part 4 concerning a working space 5 and a housing part 6, the one Engine gear chamber 7 forms, is divided. The housing parts 4, 6 are, in particular with regard to the housing part 6, housing parts which are closed radially relative to the displacer body shafts 2, 3 and are preferably integrally formed in this respect. For example, they can be castings. In the axial direction of the displacement body shafts 2, 3 closure plates are provided, wherein the engine / transmission chamber 7 associated closure plate forms a working space wall 8.

Between the motor / gear chamber 7, and the working space 5, a partition wall 9 is formed, which is formed here in one piece with the motor / gear housing forming housing part 6. In the partition wall 9, the displacement body shafts 2, 3 are mounted by means of first bearings 10,11. Associated with the working space 5 are associated with the bearings 10, 11 upstream, received in sealing bushings seals 12. It may be touching and / or non-contact shaft seals. The seals and sealing bushes are preferably arranged only on one side of the partition wall 9 accordingly.

On the working space side, the displacement body shafts 2, 3 are provided with displacement bodies 13, 14. These act helically in the usual manner in the embodiment, but without touching.

At the end remote from the working space 5, the displacement body shafts 2, 3 are mounted in second bearings 15, 16. These bearings 15, 16 are received in the outer wall 8. Specifically, they are accommodated in the outer wall 8 in turn inserted bearing receivers 17, 18. On the first displacement body shaft 2, a motor rotor 19 is arranged with regard to a drive in the motor / gear compartment 6. The first displacement body shaft 2 thereby forms at the same time the motor shaft. Further, in the engine / gear room 7, the associated motor stator 20 provided surrounding the arrangement area of the motor rotor 19 is arranged. It can, according to a standard procedure in standard motors, be shrunk into the housing part 6 or be installed in the housing part 6 by means of a bush in which it is shrunk.

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

The displacement body shafts 2, 3 are supported not only by the first bearings 10, 11 and the second bearings 15, 16, but also by a respective third bearing 21, 22. The third bearing 21, 22 is in each case by means of its own receiving part 23, 24 attached to the suction side of the housing part 4 final housing cover 25. The housing cover 25 also simultaneously forms an inlet 26 of the vacuum pump 1.

The first and second bearings 10, 11 and 15, 16 are oil-lubricated. By contrast, the third bearings 21, 22 are preferably grease-lubricated. As can be seen from the illustration according to FIG. 2, an outlet 28 of the vacuum pump 1 equipped with the silencer 27 is provided below the inlet 26. The displacement body 13, 14 are attached to the displacement body shafts 2, 3 interchangeable. Specifically, in each case a clamping plate 29, 30 is provided, by means of which the displacement bodies 13, 14 are clamped by means of displacer body shafts continued in the region of the displacement bodies 13, 14 in the form of tubular parts 31, 32.

Also, the motor rotor 19 is interchangeably mounted on the first displacement body shaft 2, in the embodiment by means of key 33.

From FIG. 2 it can be seen that a motor cable 34 of the motor stator 20 opens into a power connection 36 on the outside of the housing part 6 by means of an oil-tight cable feedthrough 35. The cable feedthrough 35 is sealed to a machined surface of the housing part 5 by means of a flat gasket 37. An oil leakage to the outside is thereby effectively prevented. Between the motor rotor 19 and the motor stator 20 and the outer wall 7 are provided on the Verdrängerkörperwellen 2, 3 provided for driving and synchronization gears 38, 39. These are also releasably secured to the displacement body shafts 2, 3. Preferably by means of a transition fit.

An outer diameter of the motor rotor 19 is selected to be smaller than the diameter of a through opening 40 formed in the housing partition wall 9 into which the first bearing 10 is inserted. This makes it possible that the assembly shown in FIG. 4, with the exception of the gear 38, in the axial direction of the Verdrängerkörper- shaft 2 in the housing part 6 can be used. The same can be understood with respect to the assembly of the displacement body shaft 3 shown in FIG. 3. Thereafter, the essentially cylinder-like housing part 4 can also be pushed over the displacement body for connection to the housing part 6 in the region of the partition wall to form the working space 5. Alternatively, an embodiment may be provided in which the housing parts 4, 6 are already connected to each other when said assemblies are used.

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

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

On the outside of the outer wall 8 a here only schematically indicated lubricant pump 41 is arranged. This lubricant pump 41 has a pump shaft, which is also formed here by the displacement body shaft 3. The described design 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 displacement body shafts 2, 3, other (longer or shorter building) displacement body 13, 14 are mounted. This can be borne by a corresponding excess length and related axial clearance in the working space 5, based on a smallest version within the kit. 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.

Claims

Vacuum pump (1), in particular screw pump, with two drive-coupled, displacement bodies (13, 14) driving positive displacement body shafts (2, 3), and a motor with a motor rotor (19), a motor shaft (2) and a motor stator (20) wherein a pump housing is further 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 further through one of the displacer body shafts (2, 3) separated partition wall (9) are separated, characterized in that at the same time as one of the Verdrängerkör- waves (2, 3) formed motor shaft (2) on which the motor rotor (19) is fixed, in the partition wall ( 9) is mounted, and that with respect to the partition (9) opposite to the motor rotor (19) driven by this displacement body shaft displacer (13) is arranged, wherein further the Verdrängerkörperwellen (2, 3) in each case in an A outer wall forming working space wall are stored.

2. Vacuum pump according to claim 1 or in particular according thereto, characterized in that all the engine / gear chamber (7) associated bearing (10, 11, 15, 16) are oil lubricated.

3. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the

Displacer (13, 14) are interchangeably connected to the Verdrängerkörperwellen (2, 3).

4. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the motor rotor (19) is exchangeably connected to the displacement body shaft (2).

5. 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.

6. 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.

7. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the third bearing absorbs changes in length of the displacement body shaft (2, 3).

8. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that a lubricant pump is provided.

9. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the lubricant pump is driven by a Verdrängerkörperwelle (2, 3).

10. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the lubricant pump (4) cooperates with a via a wall (8) of the motor / gear housing outwardly projecting part of the displacement body shaft (3).

11. Vacuum pump according to one or more of the preceding claims or in particular according thereto, characterized in that the Verdrängerkörperwellen (2, 3) cooperate via a synchronous toothing.

12. 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 (8) and the

Engine is arranged.