EP1019633B1 - Screw-type compressor - Google Patents

Abstract

A screw-type compressor comprises a housing (12) in which a primary rotor (14) and a secondary rotor (16) are arranged each of which is provided with a shaft (18,24) and a screw rotor (20,26). The secondary rotor (16) is axially supported by the primary rotor (14). Only the primary rotor (14) comprises an axial bearing part (22) which is supported in an axial bearing part (66) of the housing (12). The omission of an axial bearing between the secondary rotor and the housing simplifies the support of the secondary rotor.

Description

The invention relates to a screw compressor a housing in which a main rotor and a secondary rotor are arranged, each a shaft and have a screw rotor.

Screw compressors are used to make a gaseous Compress substance, such as air, and to be made available as compressed gas. From DE-A-42 27 332 a screw compressor is known in which a main rotor driven by a motor, a secondary rotor drives. The waves of the main and secondary rotor are at both ends by roller bearings stored radially. Furthermore, the waves are both Runner at one end by several ball bearings axially supported. These thrust bearings carry the through the Gas compression occurring between the screw rotors Forces in the axial direction of the main and secondary rotor. The roller bearings develop heat during operation an inhomogeneous heat distribution and thus tension lead in the wave. From DD-PS 84 891 and US-A-38 11 805 compressors are known in which the main and Each have a thrust bearing, which as Plain bearings are formed and therefore less heat produce. In US 32 75 226 is a screw compressor shown in the main and secondary rotor axially Rolling bearings are supported, with the main rotor additionally is axially supported by a disc. Through the many bearings for the main and secondary runner are Constructions of the known screw compressors are complex and therefore expensive to manufacture.

The object of the invention is the storage of the main and Simplify the secondary rotor in a screw compressor and improve.

This object is achieved with the features of claim 1 solved.

In the screw compressor according to the invention Secondary rotor axially supported on the main rotor. Just the main rotor has a thrust bearing part that an axial bearing part of the housing is supported. The The secondary runner is only direct through radial bearings supported on the housing. The runner is however no longer with its own axial bearing directly on the Supported housing. The axial forces of the secondary rotor through its screw rotor onto the screw rotor of the main runner. The thrust bearing of the Main rotor, formed by the thrust bearing parts of the Main rotor and housing, so it takes all axial Forces of the main rotor and the secondary rotor.

By eliminating the thrust bearing between the secondary runner and housing is the total effort for storing the Main and secondary rotor around at least one (axial) bearing reduced.

There is only one thrust bearing supported on the housing intended for the main runner, on the anyway most of the gas compression Axial forces act. The secondary runner on the considerably lower axial forces due to gas compression, is over the tooth flanks of his screw rotor supported on the screw rotor of the main rotor.

The main rotor expediently has the only thrust bearing on, since larger axial on the main rotor Forces act as on the secondary runner. With this configuration only have the relatively low axial forces of the secondary rotor over the screw rotor teeth on the Main runners are transferred. Basically, however also the secondary rotor with an axial bearing be supported on the housing while the main rotor axially supported on the secondary rotor via the screw rotors and is not a separate thrust bearing with the housing having.

In a preferred embodiment, this is of the Thrust bearing parts formed thrust bearings a plain bearing. The radial bearings can also be designed as plain bearings his. The axial plain bearing is structurally simpler as a roller bearing and thereby facilitates a cheaper one Manufacture of the screw compressor. Have plain bearings also the advantage of not generating any significant heat, so that the rotor shafts even at high speeds stay tension-free. The plain bearing can with the be lubricated with the same medium as Lubricant and sealant in the compressor room of the Screw compressor is used. As a sliding, Lubricating and sealing fluids can serve oil or water. However, air can also be used as the sliding bearing fluid become.

With a belt drive of the main rotor, the Drive side preferably a roller bearing as a radial bearing used because the slide bearing is extremely flexible high radial loads are not suitable.

In a preferred embodiment, the secondary runner exclusively via the meshing teeth of the screw rotors axially supported on the main rotor. The teeth the screw rotors can be designed such that there is very little or none at all on the secondary runner axial forces occur so that these small axial Forces of the secondary rotor can be easily applied via the screw rotor teeth can be transferred to the main runner. Another device for transmitting the axial forces from the secondary runner to the main runner.

The secondary rotor preferably has an axial clamping device that axially preloads the secondary runner. The axial clamping device has no stop, to which the secondary runner could be supported, but acts on the secondary runner, preferably the Secondary rotor shaft, with a constant preload force, the approximate expected axial load of the secondary runner due to the gas compression. The tensioning device compensates approximately the axial forces occurring on the secondary rotor, so that only very little or no axial forces from that Secondary runner must be transferred to the main runner. In a preferred embodiment, the axial Clamping device a hydraulic clamping device, on the shaft or the screw rotor of the secondary rotor acts. The clamping device can also be used Be fed by air.

The axial bearing part of the main rotor is preferably on the screw rotor of the main rotor. Not the shaft of the main rotor, but the screw rotor the main rotor is supported on the housing. The Screw rotor on which the axial forces by the Pressure generation as well as those transmitted by the secondary runner axial forces occur, so is directly on the Housing mounted so that the axial forces without one Transmission can be supported by another component. This eliminates the axial load on the shaft by the axial load forces of the main rotor, so that the shaft less by corresponding torques and thrust is used.

In a preferred embodiment, the thrust bearing part of the main rotor an axial end wall of the screw rotor. The thrust bearing part of the housing is one washer-like tread, both axial bearing parts together form the plain bearing. The front wall of the The main rotor screw rotor therefore forms a bearing surface, the on the ring-like tread of the housing outsourced. With this construction, no warehouse-specific Parts are provided on the main runner. The manufacture of the main rotor is in this configuration so little effort.

In an alternative embodiment, the main runner on an axial end face of the screw rotor as Axial bearing part on a plain bearing disc, which with a Thrust bearing tread of the housing the plain bearing forms. On one end of the main rotor an annular slide bearing washer is provided, which forms a closed radial tread.

The screw rotor end wall or the plain bearing disc is essentially radial Grooves for a sliding fluid. Through this Grooves can be the sliding fluid that is close to the shaft or on the base of the screw rotor is introduced by the centripetal forces continue to reach the outside. On this way, over the entire radius and perimeter of the screw rotor creates a sliding film.

In a preferred embodiment, the grooves an arcuate course, the radially outer End of each groove opposite to the direction of rotation of the rotor is bent. This results in very even results Sliding fluid distributions over the entire radius and Scope of the screw rotor.

The grooves preferably have a T-shaped course, the vertical part being radial and the horizontal part Part arranged tangentially in the circumferential direction are. The T-shaped grooves allow a good one Plain bearing lubrication in both directions of the Main rotor.

In a preferred embodiment there is an end face axially supporting the secondary rotor screw rotor on the plain bearing disc of the main rotor. The Beat the face of the rotor teeth of the secondary rotor So on the rotor side of the plain bearing disc on. This is an axial bearing with simple means of the secondary runner, through which also larger ones Axial forces can be transmitted.

In a preferred embodiment, the screw rotor, the shaft and the plain bearing washer of the main rotor integrally formed with each other. The main runner can be cast from a composite material, Syringes etc. be made in a negative form.

Alternatively, the plain bearing disc can be formed separately and with the shaft and / or the screw rotor of the Main rotor cast, screwed or on others Be attached way. In this separate production the plain bearing disc and the main rotor can be different Materials for shaft, rotor and plain bearing disc can be chosen that correspond to the respective physical Requirements of the respective component better adapted can be. The screw rotor can for example in a conventional manner, for example Composite, be milled and the metal plain bearing washer then screwed to the screw rotor become.

According to a preferred embodiment, the shaft a special radial bearing running layer of the main and the secondary rotor applied. The main runner can for example, be made in one piece, and on the Shaft then a super sliding material for the Radial bearings are applied.

The following are with reference to the figures Embodiments of the invention explained in more detail.

Fig. 1

einen Schraubenverdichter mit einem Hauptläufer mit einem axialen Gleitlager und einem Nebenläufer, der an dem Hauptläufer axial abgestützt ist,

Fig. 2

eine erste Ausführungsform des Axiallagerteils des Hauptläufers,

Fig. 3

eine zweite Ausführungsform eines Axiallagerteils des Hauptläufers,

Fig. 4

eine dritte Ausführungsform eines Axiallagerteils des Hauptläufers,

Fig. 5

eine erste Ausführungsform eines Hauptläufers mit einer separaten Gleitlagerscheibe,

Fig. 6

der Hauptläufer und die montierte Gleitlagerscheibe der Fig. 5,

Fig. 7

eine zweite Ausführungsform des Hauptläufers, der einstückig ausgebildet ist, und

Fig. 8

eine dritte Ausführungsform eines Hauptläufers, auf dessen Welle eine Radiallager-Laufschicht aufgebracht ist.

Show it:

Fig. 1

a screw compressor with a main rotor with an axial slide bearing and a secondary rotor which is axially supported on the main rotor,

Fig. 2

a first embodiment of the axial bearing part of the main rotor,

Fig. 3

a second embodiment of an axial bearing part of the main rotor,

Fig. 4

A third embodiment of an axial bearing part of the main rotor,

Fig. 5

a first embodiment of a main rotor with a separate plain bearing disc,

Fig. 6

the main rotor and the mounted plain bearing disc of Fig. 5,

Fig. 7

a second embodiment of the main rotor, which is integrally formed, and

Fig. 8

a third embodiment of a main rotor, on the shaft of a radial bearing running layer is applied.

1 shows a screw compressor 10, the generation of an oil-free compressed gas, for example Air serves. The screw compressor 10 from a housing 12 in which axially parallel to each other a main rotor 14 and a secondary rotor 16 are arranged are. The main rotor 14 consists essentially of a shaft 18, a screw rotor 20 and one Plain bearing washer 22, which acts as a thrust bearing part of the main rotor 14 serves. The secondary runner 16 is in turn essentially from a shaft 24 and the Screw rotor 26. Both the shaft 24 and the Screw rotor 26 of the secondary rotor are in diameter each smaller than the shaft 18 and the screw rotor 20 of the main runner 14. Both the main runner 14 and the secondary rotor 16 are also made in one piece from a composite material manufactured.

The main rotor 14 is a shaft extension 28, the is led out of the housing 12, driven. This drive is preferably carried out directly via a axially aligned with the main rotor longitudinal axis Electric motor.

To absorb the radial forces acting on the main rotor 14 act, the main rotor shaft 18 with two Radial bearings 30,32 stored in the housing 12. Also the Secondary rotor 16 is in the with two radial bearings 34,36 Housing 12 stored. All radial bearings are 30,32,34,36 designed as a plain bearing. The one enclosed by the housing 12 Space in which the main rotor screw rotor 20 and the secondary rotor screw rotor 26 are arranged are, the compression space 27 of the screw compressor 10, in which the gas is compressed. The housing 12 does not have one on the side of the shaft extension 28 shown gas opening into which to be compressed Gas can flow into the compression chamber 27. In through the teeth 21, 25 of the screw rotors 20, 26 formed spaces, the gas in the compression space 27 compressed and at the opposite axial end of the compression space 27 by a not shown Casing opening compressed omitted. This outlet side the screw compressor or the main and secondary rotor 14, 16 is referred to as the print page.

The radial bearings 30, 32 and 36 are in principle all built up the same. Via a sliding fluid inlet 38, 39, 41 a sliding fluid, namely water, runs into an annular groove 44. Sits on the shaft 18, 24, each from the annular groove 44 surround a bearing bush 46, each three radial Has holes 48 through which the sliding fluid reach the outer circumference of the respective shaft 18, 24 can.

With the two pressure-side radial bearings 32,36 the sliding fluid is axially distributed along the shaft 18, 24, the flowing in the direction of compression space 27 Lubricating fluid via an annular groove 50 and collecting channels 52, 54 enters a sliding fluid collecting space 57. About two Bores 56, 58 will slide the lubricating fluid into the compression chamber 27 injected.

In the drive-side radial bearing 30 of the main rotor 14 the sliding fluid flows along the bearing bush 46 in both axial directions, namely in the direction a sliding fluid drain 60 and in the direction of the plain bearing disc 22nd

In the radial bearing 34 facing away from the pressure side Secondary rotor 16 runs the sliding fluid through an axial Shaft bore 62 and three arranged at 120 ° to each other radial bores 64 of the shaft 24 to the shaft circumference or to the bearing bush 47. From there it runs Sliding fluid on the shaft circumference in the direction of the compression space 27th

The main rotor 14 has a thrust bearing 15, which as Plain bearing is formed. The one axial bearing part of the Axial bearing 15 is formed by the plain bearing disc 22, which are arranged on the end face of the screw rotor 20 and axially closes it. The other Axial bearing part is from an annular disk-like tread 66 of the housing 12 is formed. The washer-like Running surfaces 66,68 of the plain bearing disc 22 and the housing 12 together form a plain bearing, which Screw rotor 20 of the main rotor 18 directly on the housing 12 supports.

The sliding fluid for the thrust bearing 15 is a Inlet 70 fed to an annular groove 72 of the main rotor shaft 18, which extends axially up to the slide bearing washer 22 extends. The sliding fluid is at a pressure of approximately 10 bar supplied, which is approximately the gas pressure of the compressed gas corresponds.

As shown in Fig. 2, the plain bearing disc 22 a plurality of radially and arched outwards, tapered grooves 23, due to the the centripetal forces occurring when the main rotor 14 rotates the sliding fluid comes out.

The sliding fluid emerges from the grooves 23 of the plain bearing disc 22 out and forms between the treads 66,68 of the thrust bearing 15, a fluid film for the sliding storage ensures. The lubricating fluid continues to flow to the outside and finally gets into the compression space 27th

The secondary rotor 16 is with the teeth 25 of its screw rotor 26 with the teeth 21 of the screw rotor 20 of the main rotor 14 meshing. Over the tooth flanks the teeth 21 and 25 are axial forces of the Secondary rotor 16 on the teeth 21 of the main rotor 14 transfer.

In the area of the end face 74 of the shaft 24 of the secondary rotor 16, a fluid space 76 is covered by a cover 78 of the Enclosed housing 12 in which the sliding fluid for Radial bearing 34 is introduced through the inlet 40. The Lubricant works with its fluid pressure of approximately 10 bar on the end face 74 of the shaft 24 and generated therefore a force on the secondary rotor in the axial direction 16, which on the secondary runner 16 through the Counteracts gas pressure acting axial force. This arrangement thus acts as a pneumatic clamping device, which axially cushions the secondary rotor 16, however no stop for fixing the secondary rotor 16 in a certain axial position.

In addition to the axial clamping device 80 and the axial Support of the secondary rotor via the screw rotors 20.26 will also be the runner from the back 82 of the plain bearing washer 22 supported End faces 83 of the teeth 25 of the secondary rotor screw rotor 26 support.

In Fig. 3 is a second embodiment of a plain bearing disc 22 'shown in the sliding fluid grooves 84 are arranged in a T-shape. It is the vertical groove 85 radial and the horizontal groove arranged tangentially. With this configuration the Grooves 84 can be the main rotor 14 'in both directions of rotation are operated, in both directions adequate lubrication is guaranteed.

4 is another embodiment of the main rotor 14 "shown, but with no plain bearing washer is provided, but the end face 88 the teeth 25 serves as a sliding bearing surface. For better Distribution of the sliding fluid are also in the face 88 arcuate grooves 89 are provided.

5, a main rotor 90 is shown, the consists essentially of two parts: the shaft 92, which are made in one piece with the screw rotor 94 is, for example made of a composite material or Metal, and the slide bearing disc 22 ', which consists of a Material with good sliding properties is made. The plain bearing disc 22 has four axial driver pins 95 on the corresponding holes in the Screw rotor 94 fit.

As shown in Fig. 6, the plain bearing washer 22 'pushed onto the shaft 92 and the driving pins 95 in the corresponding openings of the screw rotor 94 inserted. The plain bearing disc 22 ' is then screwed to the screw rotor 94.

Alternatively, the plain bearing disc can be separated first manufactured and then when casting the main rotor 90 can be cast in.

FIG. 7 shows the main rotor 14 of FIG. 1.

In Fig. 8, a main rotor is shown in the the shaft 18 on both sides of the screw rotor 26 one radial bearing running layer 102 is applied in each case is, the better sliding properties than the shaft material has, and consist of so-called super sliding materials can.

Claims (15)

1. A screw-type compressor with a housing (12) in which a primary rotor assembly (14) and a secondary rotor assembly (16) are arranged, each having a shaft (18, 24) and a screw-type rotor (20, 26),
   characterized in that the secondary rotor assembly (16) is supported axially at the primary rotor assembly (14), and
   that only the primary rotor assembly (14) has an axial bearing member (22) supported at a stationary axial bearing member (66) of the housing (12).
2. The screw-type compressor of claim 1, characterized in that the axial bearing (15) formed by the axial bearing members (22, 66) is a plain bearing.
3. The screw-type compressor of claim 1 or 2, characterized in that the secondary rotor assembly (16) is axially supported at the primary rotor assembly (14) exclusively by the meshing teeth (21, 25) of the screw-type rotors (20, 26).
4. The screw-type compressor of claims 1-3, characterized in that an axial tensioning device (80) is provided that prestresses the secondary rotor assembly (16) axially toward the outlet side.
5. The screw-type compressor of claim 4, characterized in that the axial tensioning device (80) is a hydraulic tensioning device acting on the shaft (24) or the screw-type rotor (26) of the secondary rotor assembly (16).
6. The screw-type compressor of claims 1-5, characterized in that the axial bearing member (22) of the primary rotor assembly (14) is provided at the screw-type rotor (20).
7. The screw-type compressor of claim 6, characterized in that the axial bearing member of the primary rotor assembly (14") is an axial front end wall (88) of the screw-type rotor (20') and that the axial bearing member of the housing (12) is an annular running surface (66), wherein both axial bearing members together form the plain bearing (88, 66).
8. The screw-type compressor of claim 6, characterized in that the primary rotor assembly (14) has a plain bearing disc (22) as the axial bearing member provided on an axial front face of the screw-type rotor (20), the disc forming the plain bearing together with a running surface (66) of the axial bearing member in the housing (12).
9. The screw-type compressor of claims 7 or 8, characterized in that the front end wall (88) of the screw-type rotor orthe plain bearing disc (22) has substantially radially extending grooves (23, 89) for an antiseize fluid.
10. The screw-type compressor of claim 9, characterized in that the grooves (23, 89) extend arcuately.
11. The screw-type compressor of claim 9, characterized in that the grooves (84) are T-shaped.
12. The screw-type compressor one of claims 1-11, characterized in that a front face of the screw-type rotor (26) of the secondary rotor assembly is supported axially in abutment on the plain bearing disc (22) of the primary rotor assembly (14).
13. The screw-type compressor of one of claims 1-12, characterized in that the screw-type rotor (20), the shaft (18) and the plain bearing disc (22) of the primary rotor assembly (14) are formed integrally.
14. The screw-type compressor of one of claims 1-12, characterized in that the plain bearing disc (22') is cast, screwed or fastened in any other manner to the shaft (92) or the screw-type rotor (94) of the primary rotor assembly (90).
15. The screw-type compressor of one of claims 1-14, characterized in that a special radial bearing running layer (102) is applied onto the shaft (18) of the primary rotor assembly and/or the secondary rotor assembly (14, 16).

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