DE102013020535A1 - compressor - Google Patents

Abstract

A screw compressor (10) for compressing refrigerant comprising an electric motor (14) having a rotor (16) and a stator (18) and a drive shaft (20) and a compression device (22) having a compressor screw (24), wherein the compressor screw (24) and the rotor (16) of the electric motor (14) on or on the drive shaft (20) are arranged, wherein the drive shaft (20) by means of a first, a second and a third radial bearing (27, 28, 30 ), wherein the first radial bearing (27) between the rotor (16) of the electric motor (14) and the compressor screw (24) is arranged, wherein the second radial bearing (28) on a first radial bearing (27) opposite side of Compressor screw (24) is arranged, and wherein the third radial bearing (30) on a first radial bearing (27) opposite side of the rotor (16) of the electric motor (14) is arranged, wherein the first radial bearing and the second radial bearing jewei Is designed as a rolling bearing, and the third radial bearing (30) is designed as a sliding bearing.

Description

The present invention relates to a screw compressor according to the preamble of patent claim 1.

Such screw compressors are used in many applications because their construction is robust and the achievable efficiency is high. As a drive device for the actual compression device, which has, for example, two intermeshing compressor screws or screw rotor, an electric motor is usually provided.

The motors of the above-described compactors, which may be designed, for example, as semi-hermetic compact screw compressors, are usually cantilevered. In the compressors of this type are the compressor rotor, d. H. a first compressor screw, and the motor rotor, d. H. the rotor of the electric motor, arranged on a common shaft (drive shaft) having two radial bearing points. In this case, a first radial bearing point is arranged on the compressor-side end of the shaft and a second radial bearing point is located on the shaft section between the compressor rotor and the motor rotor. That is, a bearing of the drive shaft or the rotor of the motor is present only on one side of the engine. A disadvantage is that resonances can occur with the increasing compressor size and with the increasing engine speed, which can lead to the motor rotor to start the motor stator.

In order to avoid resulting damage is in the EP 1 348 077 A1 discloses a compressor having a third radial bearing in the form of a rolling bearing at the motor end of the shaft. Thus, the motor of the compressor is mounted on both sides by means of rolling bearings. Due to the three bearings, however, there is an overdetermination of the position of the drive shaft, which can be compensated only by the fact that the occurring between the first radial bearing and the third radial bearing portion of the drive shaft between the radial bearings misalignment is formed compensating. This is realized by a flexurally elastic portion of the drive shaft.

The construction described above requires a high design and manufacturing effort.

Based on this, it is the object of the present invention to provide a compressor, which prevents a collision of the rotor and the stator of the motor and at the same time can be realized in a simple and cost-effective manner.

This object is achieved by a compressor having the features of patent claim 1.

Accordingly, the object is achieved by a screw compressor for compressing refrigerant, comprising an electric motor with a rotor and a stator, and a drive shaft and a compression device with (at least) a compressor screw or (at least) a screw rotor, wherein the compressor screw and the rotor of the electric motor are arranged on or on the drive shaft. The drive shaft is rotatably supported by means of a first, a second and a third radial bearing and the first radial bearing is arranged between the rotor of the electric motor and the compressor screw. The second radial bearing is arranged on a side of the compressor screw opposite the first radial bearing, and the third radial bearing is arranged on a side of the rotor of the electric motor opposite the first radial bearing. The first radial bearing and the second radial bearing is each formed as a rolling bearing, and the third radial bearing is designed as a sliding bearing.

The formation of the third bearing as a sliding bearing ensures a corresponding clearance at the bearing itself, so that the position overdetermination of the drive shaft, which is due to the storage of the same in three points, can be compensated without additional bending elasticity of the drive shaft or other compensating measures , while the two bearings provide a positionally accurate mounting of the drive shaft.

Further optional features of the invention are specified in the dependent claims, as well as the following description of the figures. The described respective features can be realized individually or in any combination. The invention will therefore be described below with reference to the accompanying drawings by means of exemplary embodiments. In the drawings show:

1 a sectional view of an exemplary embodiment of a compressor according to the invention; and

2 an enlarged view of a portion of the compressor according to 1 ,

In 1 is a possible embodiment of a compressor according to the invention, more precisely a screw compressor according to the invention 10 , hereinafter also briefly as a compressor 10 is designated, shown. The compressor 10 has a housing 12 and one in the housing 12 arranged electric motor 14 on. The electric motor 14 has a rotor 16 and a stator 18 on. Further points the screw compressor 10 a drive shaft 20 and a compacting device 22 with a first and a second intermeshing compressor screw and a first and a second intermeshing screw rotor 24 and 26 on, with the first compressor screw 24 as well as the rotor 16 of the electric motor 14 on or on the drive shaft 20 are arranged. The drive shaft 20 is therefore by the electric motor 14 rotationally driven and simultaneously drives the compacting device 22 at. In alternative embodiments, the compressor according to the invention can only have one compressor screw 24 or also have three or more than three compressor screws.

The drive shaft 20 is by means of a first, a second and a third radial bearing 27 . 28 and 30 in the compressor 10 rotatably mounted, wherein the first Rediallager 27 between the rotor 16 of the electric motor 12 and the first compressor screw 24 is arranged. The second radial bearing 28 is on a first radial bearing 27 opposite side of the first compressor screw 24 arranged, and the third radial bearing 30 is on a first radial bearing 27 opposite side of the rotor 16 of the electric motor 12 arranged. While the first and second radial bearings 27 . 28 are designed as rolling bearings, the third radial bearing 30 as sliding bearing (here as a sliding bearing with fluid friction or hydrodynamic sliding bearing, in alternative embodiments but also as a dry-running sliding bearing) is formed. At this point it should be noted that a hydrodynamic sliding bearing is also suitable for damping wave movements and thus also and in particular for damping vibrations.

The third radial bearing 30 , the below also as plain bearings 30 is designated, stands with a lubricant supply 32 in the form of an oil supply channel and a lubricant discharge 34 in the form of an oil return channel. The lubricant supply 32 is further connected to a first volume (oil distribution space, not shown in the figures), which is acted upon by a first pressure, in the possible embodiment described here with a compression end pressure of the compressor in combination. The lubricant removal 34 is further provided with a second volume (not shown in the figures) which, at a second pressure, in the possible embodiment described herein, is approximately a suction pressure of the compressor 10 can be acted upon, in conjunction. In the described embodiment, the second volume is a closed compression work space of the compressor 10 ie the working space of the compressor 10 where the suction process has already ended and the compression process has just begun. In this working space, the pressure is almost equal to the suction pressure.

This construction provides for a supply of lubricant under relatively high pressure, so that the storage as well as possible and friction-free, ie with a closed lubricant film between the plain bearing 30 and the drive shaft 20 , can be done. The application of lubricant removal 34 With a relatively low pressure provides for a reliable discharge of the lubricant, which in the presently described embodiment by the oil, which is also the compressor 10 used as a lubricant is formed

The plain bearing 30 is in a bearing socket 36 arranged, which at least partially in the housing 12 is arranged. The bearing socket 36 is parallel and concentric with the drive shaft 20 arranged. The bearing socket 36 has a first end 38 through which the drive shaft 20 passed through, and a second end 40 on, the first end 38 opposite.

The bearing socket 36 is at both its first and second ends 38 . 40 against the environment, ie the interior of the housing 12 , sealed off, with the seal at the first end 38 through which the drive shaft 20 extending therethrough, by means of a first lid 42 which is a drive shaft feedthrough 44 and a radial shaft seal 46 has occurred. At the second end 40 is for sealing a second lid 48 arranged, which optionally using suitable sealing materials at the second end 40 is appropriate.

Alternatively, however, the second end may also be formed closed, for example, ie, the bearing receiving socket 36 may alternatively be formed, for example in the form of a blind hole or a cylinder closed on one side. This is the plain bearing 30 arranged sealed against the environment, which means that no lubricant can escape to the environment.

The compressor 10 has for collecting and targeted discharge of the sliding bearing lubricant in the presently described embodiment within the bearing receiving socket 36 arranged lubricant collection room 50 on top of that with the lubricant drainage 34 communicates. The lubricant collecting chamber is connected to the sliding bearing 30 in fluid communication or is against the sliding bearing 30 open to unhindered lubricants of the plain bearing 30 while he is analogous to the sliding bearing 30 sealed against the environment.

The seal against the environment takes place, as well as for the plain bearing 30 , by the first cover 42 including radial shaft seal 46 and the second lid 48 , The lubricant collection room 50 is therefore of an inner wall 52 the bearing socket 36 , as well as the first and second lids 42 . 48 limited, which at the radial ends of the bearing receiving socket 36 are arranged. The lubricant deflation chamber 50 may also be outside of the bearing socket in alternative embodiments 36 be arranged and with the plain bearing 30 For example, be connected via a channel.

By using the plain bearing 30 with fluid friction ensures the lowest possible heat generation in the area of the bearing. By an additional formation of a lubricant collecting space 50 , which is in communication with the sliding bearing (fluid connection, fluid communication), the lubricant can additionally be selectively collected. Because of the plain bearing 30 , as well as the lubricant collection room 50 are arranged sealed against the environment and by the targeted removal of the lubricant there is no storage-related lubricant entry into the suction gas stream of the compressor 10 , The pressurized lubricant supply leads to the best possible lubricating effect and thus to a further reduced heat development.

However, while the invention will be described in terms of embodiments having fixed feature combinations, it also encompasses any conceivable further advantageous combination as particularly, but not exhaustively, given by the subclaims. All disclosed in the application documents features are claimed as essential to the invention, as far as they are new individually or in combination over the prior art.

LIST OF REFERENCE NUMBERS

10

compressor

12

casing

14

electric motor

16

rotor

18

stator

20

drive shaft

22

compacting device

24

first compressor screw

26

second compressor screw

27

first radial bearing

28

second radial bearing

30

third radial bearing

32

lubricant feed

34

lubricant delivery

36

Bearing receiving bush

38

first end of the bearing socket 36

40

second end of the bearing socket 36

42

first lid

44

Drive shaft bushing

46

Radial shaft seal

48

second lid

50

Lubricant collection space

52

Inner wall of the bearing socket 36

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

• EP 1348077 A1 [0004]

Claims (9)

Screw compressor ( 10 ) for compressing refrigerant, comprising an electric motor ( 14 ), which has a rotor ( 16 ) and a stator ( 18 ), and a drive shaft ( 20 ) and a compacting device ( 22 ) with a compressor screw ( 24 ), wherein the compressor screw ( 24 ) as well as the rotor ( 16 ) of the electric motor ( 14 ) on or on the drive shaft ( 20 ) are arranged, wherein the drive shaft ( 20 ) by means of a first, a second and a third radial bearing ( 27 . 28 . 30 ) is rotatably mounted, wherein the first radial bearing ( 27 ) between the rotor ( 16 ) of the electric motor ( 14 ) and the compressor screw ( 24 ), wherein the second radial bearing ( 28 ) on a first radial bearing ( 27 ) opposite side of the compressor screw ( 24 ), and wherein the third radial bearing ( 30 ) on a first radial bearing ( 27 ) opposite side of the rotor ( 16 ) of the electric motor ( 14 ) is arranged, characterized in that the first radial bearing and the second radial bearing is in each case designed as a rolling bearing, and the third radial bearing ( 30 ) is designed as a sliding bearing. Compressor ( 10 ) according to one of the preceding claims, characterized in that the plain bearing ( 30 ) with a lubricant supply ( 32 ) and a lubricant discharge ( 34 ), wherein the lubricant supply ( 32 ) having a first volume which is at a first pressure, in particular approximately a compression end pressure of the compressor ( 10 ), is in communication and / or the lubricant removal ( 34 ) having a second volume which is at a second pressure, in particular approximately a suction pressure of the compressor ( 10 ) can be acted upon, is in communication. Compressor ( 10 ) according to one of the preceding claims, characterized in that the lubricant discharge is in communication with a closed compression work space. Compressor ( 10 ) according to one of the preceding claims, characterized in that the compressor ( 10 ) a lubricant collecting space ( 50 ) has for sliding bearing lubricant. Compressor ( 10 ) according to claim 4, characterized in that the lubricant collecting space ( 50 ) with a lubricant removal ( 32 ). Compressor ( 10 ) according to one of the preceding claims, characterized in that the plain bearing ( 30 ) and the lubricant collection room ( 50 ) are arranged sealed against the environment. Compressor ( 10 ) according to one of the preceding claims, characterized in that the plain bearing ( 30 ) in a bearing receptacle ( 36 ) which has a first end ( 38 ), through which the drive shaft ( 20 ), and a second end ( 40 ), wherein the bearing receiving bush ( 36 ) at both its first and second ends ( 38 . 40 ) is sealed against the environment, wherein the seal at the first end ( 38 ), through which the drive shaft ( 20 ), by means of a first lid ( 42 ), which drives a drive shaft ( 44 ) and a radial shaft seal ( 46 ), is realized. Compressor according to one of claims 4 to 7, characterized in that the lubricant collecting space ( 50 ) from an inner wall ( 52 ) of a bearing receptacle ( 36 ), and one / the first and second lid ( 42 . 44 ), which at radial ends of the bearing receptacle ( 36 ) are arranged. Compressor according to one of the preceding claims, characterized in that the sliding bearing, in particular for damping vibrations, is designed as a hydrodynamic sliding bearing.

Images