Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
  • F04C18/02—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
  • F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
  • F01C21/02—Arrangements of bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
  • F04C29/0021—Systems for the equilibration of forces acting on the pump
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2240/00—Components
  • F04C2240/50—Bearings
  • F04C2240/56—Bearing bushings or details thereof

Definitions

• the invention relates to a screw compressor with a housing in which a main rotor and a secondary rotor are arranged, each having a shaft and a screw rotor.
• Screw compressors are used to compress a gaseous substance, for example air, and to make it available as compressed gas.
• a screw compressor is known in which a main rotor driven by a motor drives a secondary rotor.
• the shafts of the main and secondary rotor are supported radially at both ends by roller bearings.
• the shafts of both rotors are axially supported at one end by several ball bearings.
• These thrust bearings bear the forces that occur due to gas compression between the screw rotors in the axial direction of the main and secondary fers.
• the roller bearings develop heat during operation, which leads to an inhomogeneous heat distribution and thus to stresses in the shaft.
• the object of the invention is to simplify and improve the storage of the main and secondary rotor in a screw compressor.
• the secondary rotor is supported axially on the main rotor. Only the main rotor has an axial bearing part which is supported on an axial bearing part of the housing. The secondary rotor is therefore only supported directly on the housing by radial bearings. However, the secondary runner is no longer supported directly on the housing by its own axial bearing. The axial forces of the secondary rotor are transferred to the screw rotor of the main rotor by its screw rotor. The axial bearing of the main rotor, formed by the axial bearing parts of the main rotor and the housing, absorbs all the axial forces of the main rotor and the secondary rotor. By eliminating the axial bearing between the secondary rotor and the housing, the total effort for mounting the main and secondary rotor is reduced by at least one (axial) bearing.
• An axial bearing supported on the housing is only provided for the main rotor, on which the majority of the axial forces that occur during gas compression act anyway.
• the secondary rotor to which considerably lower axial forces act due to the gas compression, is supported on the screw rotor of the main rotor via the tooth flanks of its screw rotor.
• the main runner expediently has the only axial bearing, since greater axial forces act on the main runner than on the secondary runner. With this configuration, only the relatively low axial forces of the secondary rotor have to be transmitted to the main rotor via the screw rotor teeth.
• the secondary rotor can also be axially supported on the housing with an axial bearing, while the main rotor is axially supported on the secondary rotor via the screw rotors and does not have its own axial bearing with the housing.
• the thrust bearing formed by the thrust bearing parts is a plain bearing.
• the radial bearings can also be designed as plain bearings.
• the axial plain bearing is structurally simpler than roller bearings and thus facilitates cheaper manufacture of the screw compressor.
• Plain bearings also have the advantage of not generating any heat worth mentioning, so that the rotor shafts remain stress-free even at high speeds.
• the plain bearing can with the be lubricated with the same medium that is also used as a lubricant and sealant in the compressor chamber of the screw compressor. Oil or water can serve as a lubricating, lubricating and sealing fluid. However, air can also be used as the sliding bearing fluid.
• a roller bearing is preferably used as the radial bearing on the drive side, since plain bearings are not suitable for absorbing extremely high radial loads.
• the secondary rotor is supported axially on the main rotor exclusively via the meshing teeth of the screw rotors.
• the teeth of the screw rotors can be designed in such a way that very little or no axial forces occur on the secondary rotor, so that these small axial forces of the secondary rotor can be easily transmitted to the main rotor via the screw rotor teeth.
• Another device for transmitting the axial forces from the secondary rotor to the main rotor is not required.
• the secondary runner preferably has an axial tensioning device which axially preloads the secondary runner.
• the axial tensioning device does not have a stop against which the secondary rotor could be supported, but rather applies a constant preload force to the secondary rotor, preferably the secondary rotor shaft, which approximately corresponds to the expected axial load on the secondary rotor due to the gas compression.
• the clamping device thus approximately compensates for the axial forces occurring on the secondary rotor, so that only very little or no axial forces have to be transferred from the secondary rotor to the main rotor.
• the axial tensioning device is a hydraulic tensioning device which acts on the shaft or the screw rotor of the secondary rotor. However, the tensioning device can also be fed with air.
• the axial bearing part of the main rotor is preferably arranged on the screw rotor of the main rotor. Not the shaft of the main rotor, but the screw rotor of the main rotor is supported on the housing.
• the screw rotor, on which the axial forces caused by the pressure generation and the axial forces transmitted by the secondary rotor occur, is therefore mounted directly on the housing, so that the axial forces are supported by another component without transmission. This eliminates the axial load on the shaft due to the axial load forces of the main rotor, so that the shaft is less stressed by corresponding torques and shear forces.
• the axial bearing part of the main rotor is an axial end wall of the screw rotor.
• the axial bearing part of the housing is an annular disk-like running surface, with both axial bearing parts together forming the slide bearing.
• the end wall of the main rotor screw rotor thus forms a bearing surface which is supported on the ring-shaped running surface of the housing.
• the main rotor has, on an axial end face of the screw rotor, a slide bearing disk as an axial bearing part, which forms the slide bearing with an axial bearing part running surface of the housing.
• An annular slide bearing disk is thus provided on one end face of the main rotor rotor and forms a closed radial running surface.
• the screw rotor end wall or the slide bearing disk preferably has essentially radially running grooves for a sliding fluid. Through these grooves, the sliding fluid, which is introduced near the shaft or at the base of the screw rotor, can get further to the outside through the centripetal forces. In this way, a sliding film is generated over the entire radius and circumference of the screw rotor.
• the grooves have an arcuate course, the radially outer end of each groove being bent opposite to the direction of rotation of the rotor. This results in very even lubricant distributions over the entire radius and circumference of the screw rotor.
• the grooves preferably have a T-shaped course, the vertical part being arranged radially and the horizontal part running tangentially in the circumferential direction.
• the T-shaped grooves enable good sliding bearing lubrication in both directions of the main rotor.
• an end face of the secondary rotor screw rotor is axially supported on the slide bearing disk of the main rotor.
• the end face of the rotor teeth of the secondary rotor thus strikes the rotor-side side of the plain bearing disc.
• the screw rotor, the shaft and the slide bearing disk of the main rotor are integrally formed with one another.
• the main runner can be made from a composite material by casting, spraying, etc. be made in a negative form.
• the plain bearing disc can be formed separately and cast, screwed or otherwise secured to the shaft and / or the screw rotor of the main rotor.
• the slide bearing disk and the main rotor With this separate production of the slide bearing disk and the main rotor, different materials for the shaft, rotor and slide bearing disk can be selected, which can be better adapted to the respective physical requirements of the respective component.
• the screw rotor can, for example, be milled in a conventional manner, for example made of composite material, and the metal plain bearing disc can then be screwed to the screw rotor.
• a special radial bearing running layer is applied to the shaft of the main or secondary rotor.
• the main rotor can, for example, be produced in one piece, and a super sliding material for the radial bearing can then be applied to the shaft. Exemplary embodiments of the invention are explained in more detail below with reference to the figures.
• FIG. 1 shows 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. 5 shows a first embodiment of a main rotor with a separate plain bearing disc
• Fig. 7 shows a second embodiment of the main rotor, which is integrally formed, and
• FIG. 8 shows a third embodiment of a main rotor, on the shaft of which a radial bearing running layer is applied.
• 1 shows a screw compressor 10 which is used to generate an oil-free compressed gas, for example air.
• the screw compressor 10 consists of a housing 12 in which a main rotor 14 and a secondary rotor 16 are arranged axially parallel to one another.
• the main rotor 14 consists essentially of a shaft 18, a screw rotor 20 and a slide bearing disk 22, which serves as an axial bearing part of the main rotor 14.
• the secondary rotor 16 in turn consists essentially of a shaft 24 and the screw rotor 26.
• Both the shaft 24 and the screw rotor 26 of the secondary rotor are each smaller in diameter than the shaft 18 and the screw rotor 20 of the main rotor 14.
• Both the main rotor 14 and the secondary rotor 16 are made in one piece from a composite material.
• the main rotor 14 can be driven via a shaft extension 28 which is led out of the housing 12. This drive is preferably carried out directly via an electric motor aligned axially with the main rotor longitudinal axis.
• the main rotor shaft 18 is supported in the housing 12 with two radial bearings 30, 32.
• the secondary rotor 16 is also mounted in the housing 12 with two radial bearings 34, 36. All radial bearings 30,32,34,36 are designed as plain bearings.
• the space enclosed by the housing 12, in which the main rotor screw rotor 20 and the secondary rotor screw rotor 26 are arranged, is 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 the gas to be compressed can flow into the compression chamber 27.
• the radial bearings 30, 32 and 36 are all constructed identically.
• a sliding fluid namely water, runs through a sliding fluid inlet 38, 39, 41 into an annular groove 44.
• a bearing bush 46 each having three radial bores 48, sits on the shaft 18, 24, surrounded by the annular groove 44 which the lubricating fluid can reach on the outer circumference of the respective shaft 18, 24.
• the sliding fluid is axially distributed along the shaft 18, 24, the sliding fluid flowing in the direction of the compression space 27 passing through an annular groove 50 and collecting channels 52, 54 into a sliding fluid collecting space 57.
• the sliding fluid is injected into the compression chamber 27 via two bores 56, 58.
• the sliding fluid flows along the bearing bush 46 in both axial directions, namely in the direction of a sliding fluid outlet 60 and in the direction of the sliding bearing disk 22.
• the sliding fluid runs through an axial shaft bore 62 and three radial bores 64 of the shaft 24 arranged at 120 ° to one another to the shaft circumference or to the bearing sleeve 47. From there, the sliding fluid runs in the direction of the shaft circumference Compression room 27.
• the main rotor 14 has an axial bearing 15 which is designed as a plain bearing.
• the one axial bearing part of the axial bearing 15 is formed by the slide bearing disk 22, which is arranged on the end face of the screw rotor 20 and axially closes it.
• the other axial bearing part is formed by an annular disk-like running surface 66 of the housing 12.
• the annular disk-like running surfaces 66, 68 of the slide bearing disk 22 and of the housing 12 together form a slide bearing which supports the screw rotor 20 of the main rotor 18 directly on the housing 12.
• the sliding fluid for the axial bearing 15 is fed via an inlet 70 to an annular groove 72 in the main rotor shaft 18, which extends axially as far as the sliding bearing disk 22.
• the sliding fluid is supplied at a pressure of approximately 10 bar, which corresponds approximately to the gas pressure of the compressed gas.
• the plain bearing disc 22 has a plurality of radially and arcuately outwardly tapering grooves 23, through which the centrifugal forces which arise when the main rotor 14 rotates, cause the sliding fluid to come out.
• the sliding fluid emerges from the grooves 23 of the sliding bearing disk 22 and forms a fluid film between the running surfaces 66, 68 of the axial bearing 15, which ensures the sliding bearing.
• the sliding fluid continues to flow outwards and finally reaches the compression space 27.
• the secondary rotor 16 meshes with the teeth 25 of its screw rotor 26 with the teeth 21 of the screw rotor 20 of the main rotor 14. Axial forces of the secondary rotor 16 are transmitted to the teeth 21 of the main rotor 14 via the tooth flanks of the teeth 21 and 25.
• a fluid space 76 is enclosed by a cover 78 of the housing 12, into which the sliding fluid for the radial bearing 34 is introduced through the inlet 40.
• the sliding fluid acts on the end face 74 of the shaft 24 and thereby generates a force on the secondary rotor 16 in the axial direction, which counteracts the axial force acting on the secondary rotor 16 due to the gas pressure generation.
• This arrangement thus acts as a pneumatic clamping device, which axially cushions the secondary rotor 16, but does not have a stop for fixing the secondary rotor 16 in a specific axial position.
• FIG. 3 shows a second embodiment of a slide bearing disk 22 ', in which the slide fluid grooves 84 are arranged in a T-shape.
• the vertical groove 85 is arranged radially and the horizontal groove tangentially.
• FIG. 4 shows a further embodiment of the main rotor 14 ′′, in which, however, no slide bearing washer is provided, but rather the end face 88 of the teeth 25 serves as a slide bearing surface.
• grooves 89 arranged in an arc-like manner in the end face 88 are also provided intended.
• FIG. 5 shows a main rotor 90, which essentially consists of two parts: the shaft 92, which is made in one piece with the screw rotor 94, for example from a composite material or metal, and the slide bearing disk 22 ', which is made from a material good sliding properties.
• the plain bearing disc 22 has four axial driver pins 95 which fit into corresponding bores in the screw rotor 94.
• the slide bearing disk 22 ' is pushed onto the shaft 92 and the driving pin 95 is inserted into the corresponding openings in the screw rotor 94.
• the plain bearing disc 22 ' is then screwed to the screw rotor 94.
• the plain bearing disc can first be manufactured separately and then cast in when the main rotor 90 is cast.
• FIG. 7 shows the main rotor 14 of FIG. 1.
• FIG. 8 shows a main rotor in which a radial bearing race 102 is applied to the shaft 18 on both sides of the screw rotor 26, which has better sliding properties than the shaft material and can consist of so-called super sliding materials.

Applications Claiming Priority (3)

Publications (2)

Family

ID=7844952

Family Applications (1)

Country Status (11)

Cited By (1)

Families Citing this family (18)

Family Cites Families (14)

• 1997
  • 1997-10-08 DE DE19744466A patent/DE19744466C2/de not_active Expired - Fee Related
• 1998
  • 1998-10-08 EP EP98955416A patent/EP1019633B1/fr not_active Expired - Lifetime
  • 1998-10-08 JP JP2000515118A patent/JP2001519503A/ja active Pending
  • 1998-10-08 CN CN98809971A patent/CN1274410A/zh active Pending
  • 1998-10-08 KR KR1020007003769A patent/KR20010030985A/ko not_active Application Discontinuation
  • 1998-10-08 WO PCT/EP1998/006389 patent/WO1999018355A1/fr not_active Application Discontinuation
  • 1998-10-08 US US09/529,116 patent/US6312239B1/en not_active Expired - Fee Related
  • 1998-10-08 DE DE59806955T patent/DE59806955D1/de not_active Expired - Fee Related
  • 1998-10-08 AT AT98955416T patent/ATE231220T1/de not_active IP Right Cessation
  • 1998-10-08 AU AU12265/99A patent/AU743902B2/en not_active Ceased
  • 1998-10-08 RU RU2000111494/06A patent/RU2212564C2/ru not_active IP Right Cessation
  • 1998-10-08 ES ES98955416T patent/ES2191976T3/es not_active Expired - Lifetime

Non-Patent Citations (1)

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