WO2015086158A1

WO2015086158A1 - Compressor

Info

Publication number: WO2015086158A1
Application number: PCT/EP2014/003342
Authority: WO
Inventors: Wolfgang SANDKÖTTER; Bernd KWIATKOWSKI; Dmytro Zaytsev
Original assignee: Gea Refrigeration Germany Gmbh
Priority date: 2013-12-12
Filing date: 2014-12-12
Publication date: 2015-06-18
Also published as: EP3080455A1; US20160327040A1; DE102013020535A1; EP3080455B1; CN105874205A

Abstract

The invention relates to a screw-type compressor (10) for compressing refrigerant, which comprises: an electric motor (14), which has a rotor (16) and a stator (18); a drive shaft (20); and a compressing device (22) having a compressor screw (24); wherein the compressor screw (24) and the rotor (16) of the electric motor (14) are arranged against or on the drive shaft (20), wherein the drive shaft (20) is rotatably supported by means of a first, a second, and a third radial bearing (27, 28, 30), wherein the first radial bearing (27) is arranged between the rotor (16) of the electric motor (14) and the compressor screw (24), wherein the second radial bearing (28) is arranged on a side of the compressor screw (24) opposite the first radial bearing (27), and wherein the third radial bearing (30) is arranged on a side of the rotor (16) of the electric motor (14) opposite the first radial bearing (27), wherein the first radial bearing and the second radial bearing are both designed as rolling-element bearings, and the third radial bearing (30) is designed as a plain bearing.

Description

compressor

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, for example, two intermeshing

Compressor screws or screw rotor has, is usually an electric motor

intended.

The engines of the above-described compactors, for example as

Semi-hermetic compact screw compressor can be formed, are usually stored on the fly. In the compressors of this type, the compressor rotor, i. a first compressor screw, and the motor rotor, i. 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 on the compressor-side end of the shaft

arranged and a second radial bearing point is located at the shaft portion between the compressor rotor and the motor rotor. That is, a storage of

Drive shaft or the rotor of the motor is present only on one side of the motor. The disadvantage here is that with the increasing compressor size and with the rising

1

CONFIRMATION COPY Motor speed resonances may occur that can cause the motor rotor to start up to the motor stator.

In order to avoid damage resulting therefrom, EP 1 348 077 A1 discloses a compressor which has a third radial bearing point in the form of a roller bearing at the end of the shaft on the motor side. 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 only be compensated by the fact that located between the first radial bearing and the third radial bearing portion of the drive shaft between the radial bearings occurring

Alignment error is compensated. 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 compacting

Solved refrigerant comprising an electric motor with a rotor and a stator, and a drive shaft and a compression device with (at least) one

Compressor screw or (at least) has 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 on a side of the compressor screw opposite the first radial bearing

arranged, and the third radial bearing is on a first radial bearing

arranged opposite side of the rotor of the electric motor. 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 plain 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 is a sectional view of an exemplary embodiment of a compressor according to the invention; and

2 is an enlarged view of a portion of the compressor of FIG .. 1

In Fig. 1, a possible embodiment of a compressor according to the invention, more specifically a screw compressor 10 according to the invention, which is also referred to below as a compressor 10, shown. The compressor 10 has a housing 12 and an electric motor 14 arranged in the housing 12. The electric motor 14 has a rotor 16 and a stator 18. Furthermore, the screw compressor 10 has a drive shaft 20 and a compression device 22 with a first and a second intermeshing compressor screw and a first and a second intermeshing screw rotor 24 and 26, wherein the first compressor screw 24 and the rotor 16 of the electric motor 14 at or on the Drive shaft 20 are arranged. The drive shaft 20 is thus rotationally driven by the electric motor 14 and simultaneously drives the compacting device 22. In alternative embodiments, the compressor according to the invention can only one

Have compressor screw 24 or even three or more than three compressor screws. The drive shaft 20 is rotatably supported by a first, a second and a third radial bearing 27, 28 and 30 in the compressor 10, wherein the first radial bearing 27 is disposed between the rotor 16 of the electric motor 12 and the first compressor screw 24. The second radial bearing 28 is arranged on a side of the first compressor screw 24 opposite the first radial bearing 27, and the third radial bearing 30 is arranged on a side of the rotor 16 of the electric motor 12 opposite the first radial bearing 27. While the first and the second radial bearing 27, 28 are formed as rolling bearings, the third radial bearing 30 is formed as a 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). At this point it should be noted that a hydrodynamic plain bearing for damping of

Wave movements and thus also and in particular for damping vibrations is suitable.

The third radial bearing 30, which is also referred to below as sliding bearing 30, communicates 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 chamber, 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 discharge 34 is further connected to a second volume (not shown in the figures), which is at a second pressure, in the possible embodiment described here about a suction pressure of the compressor 10 is acted upon in combination. In the described embodiment, the second volume is a closed compression work space of the

Compressor 10, i. the working space of the compressor 10, where the suction has already ended and the compression process has just begun. In this working space, the pressure is almost equal to the suction pressure.

This design provides for a supply of lubricant under relatively high pressure, so that the storage as well as possible and friction, ie with a closed lubricant film between the sliding bearing 30 and the drive shaft 20, can be done. Applying the lubricant discharge 34 at a relatively low pressure provides for a reliable discharge of the lubricant, which in the presently described embodiment is formed by the oil which also uses the compressor 10 as a lubricant The sliding bearing 30 is arranged in a bearing receiving bush 36, which is arranged at least partially in the housing 12. The bearing receiving socket 36 is arranged parallel and concentric with the drive shaft 20. The bearing receiving socket 36 has a first end 38, through which the drive shaft 20 extends therethrough, and a second end 40, which is opposite to the first end 38.

The bearing receptacle 36 is at its first as well as at its second end 38, 40 against the environment, i. the interior of the housing 12, sealed off, the

Sealing at the first end 38, through which the drive shaft 20 extends, by means of a first cover 42, which a drive shaft passage 44 and a

Radial shaft seal 46, takes place. At the second end 40, a second cover 48 is arranged for sealing, which is optionally attached to the second end 40 using suitable sealing materials.

Alternatively, however, the second end may be formed closed, e.g. 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. As a result, the sliding bearing 30 is 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 on the lubricant collecting chamber 50 which communicates with the lubricant discharge 34 in

Connection stands. The lubricant collecting space is in fluid communication with the sliding bearing 30 or is open against the sliding bearing 30 in order to be able to absorb lubricant of the sliding bearing 30 unhindered, while it is sealed against the environment analogously to the sliding bearing 30.

The sealing against the environment takes place, as well as for the sliding bearing 30, through the first cover 42 together with the radial shaft seal 46 and the second cover 48. The lubricant collecting chamber 50 is accordingly formed by an inner wall 52 of the bearing receiving socket 36 and the first and second covers 42, 48 limited, which are arranged at the radial ends of the bearing receiving socket 36. In alternative embodiments, the lubricant deflation chamber 50 can also be arranged outside the bearing receiving bush 36 and, for example, with the sliding bearing 30 be connected via a channel.

By using the sliding bearing 30 with fluid friction is provided for the lowest possible heat generation in the field of storage. By additionally forming a lubricant collection chamber 50, which is in communication with the sliding bearing (fluid connection, fluid communication), the lubricant can additionally be collected in a targeted manner. The fact that the sliding bearing 30, and the Schmierstoffammeiraum 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 flow 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 compressors

12 housing

14 electric motor

16 rotor

18 stator

0 drive shaft

2 compacting device

4 first compressor screw

6 second compressor screw

7 first radial bearing

8 second radial bearing

0 third radial bearing

2 lubricant supply lubricant delivery

Bearing receiving bush

first end of the bearing retainer socket 36 second end of the bearing retainer socket 36 first cover

Drive shaft bushing

Radial shaft seal

second lid

Lubricant collection space

Inner wall of the bearing receptacle 36

Claims

claims

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) are arranged on or on the drive shaft (20), 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) is arranged, wherein the second radial bearing (28) on a first radial bearing (27) opposite side of the 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, characterized in that

the first radial bearing and the second radial bearing is each formed 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 sliding bearing (30) is in communication with a lubricant supply (32) and a lubricant outlet (34), 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) can be acted upon, is in communication and / or the

Lubricant removal (34) having a second volume, which is acted upon by a second pressure, in particular approximately a suction pressure of the compressor (10), in

Connection stands. Compressor (10) according to one of the preceding claims

characterized in that

the lubricant discharge with a closed compression work space in

Connection stands.

Compressor (10) according to one of the preceding claims

characterized in that

the compressor (10) has a lubricant collecting space (50) for plain bearing lubricants.

Compressor (10) according to claim 4

characterized in that

the lubricant collecting space (50) is in communication with a lubricant outlet (32).

Compressor (10) according to one of the preceding claims,

characterized in that

the sliding bearing (30) and the lubricant collecting space (50) are arranged sealed against the environment.

Compressor (10) according to one of the preceding claims,

characterized in that

the slide bearing (30) is disposed in a bearing retainer (36) having a first end (38) through which the drive shaft (20) extends and a second end (40), the bearing retainer (36) being secured to both of its seats is sealed against the environment at first as well as at its second end (38, 40), wherein the

Sealing at the first end (38), through which the drive shaft (20)

extends therethrough, by means of a first lid (42), which a

Drive shaft passage (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) of an inner wall (52) of the / Bearing receptacle (36) and one / the first and second covers (42, 44) are arranged, which are arranged at radial ends of the bearing receiving bush (36).

9. Compressor according to one of the preceding claims,

characterized in that

the plain bearing, in particular for damping vibrations, is designed as a hydrodynamic sliding bearing.