Patent ID: 12215690

DESCRIPTION

The scroll compressor according toFIG.1is designed as a two-stage compressor. For this purpose, the scroll compressor has a central drive segment1, which is axially connected on both sides to a respective compressor segment2,3. A first compressor segment2is here designed as a first compressor stage, and the second compressor segment3as a second compressor stage. The first compressor segment2serves to compress an ambient air pressure to a medium air pressure, wherein the second compressor segment3compresses the medium air pressure to a high air pressure.

The drive segment1comprises the drive10, which comprises an electric motor11and a shaft12. The electric motor11is arranged inside of a housing4, which is multipart in design for ease of maintenance. The housing4comprises a drive housing20, two bearing housings23,24that connect to the drive housing20, mating scrolls21,22that likewise form parts of the housing4, and end covers5,6. As a consequence, a first bearing housing23connects to the drive housing20in the direction of the first compressor segment2. The first bearing housing23is fixedly connected with the first mating scroll21, which likewise forms part of the housing4. The first mating scroll21is followed by the first end cover5, which axially closes the housing4. A second bearing housing24is arranged on the opposite side of the drive housing20, and connected with a second mating scroll22. The second mating scroll22is long axially covered by a second end cover6.

The shaft12is mounted in the drive housing20by shaft bearings15. The shaft12has a first shaft end13, which is directed toward the first compressor segment2. Further provided is a second shaft end14, which faces the second compressor segment3. Both shaft ends13,14each have an eccentric pin16, which is arranged in an eccentric bearing17that establishes the connection to the respective displacer scroll31,32. Therefore, the first displacer scroll31is mounted on the eccentric pin16of the first shaft end13via the eccentric bearing17. The second displacer scroll32is mounted on the eccentric pin16of the second shaft end14via the eccentric bearing17.

The displacer scrolls31,32each have a displacer scroll bottom39, from which a displacer scroll wall38extends into the respective mating scroll21,22. This will be exemplarily explained below based onFIG.2, which shows a cutout of the second compressor segment3of the scroll compressor according toFIG.1. The design described below for the first compressor segment2applies analogously to the second compressor segment3. The first displacer scroll31and the second displacer scroll32as well as the first mating scroll21and the second mating scroll22are thus similarly constructed, in particular also with regard to their arrangement relative to each other. They only differ in terms of the volume of a compression chamber30formed between them, which in the second compressor stage, meaning between the second displacer scroll32and the second mating scroll22, is smaller than in the first compressor stage, i.e., between the first displacer scroll31and the first mating scroll21.

Therefore,FIG.2shows the first displacer scroll31, which comprises a displacer scroll bottom39and a displacer scroll wall38. The first displacer scroll31engages into the first mating scroll21, so that the compression chamber30is formed between the displacer scroll wall38and a mating scroll wall28. The compression chamber30is variable, meaning that the orbiting motion of the first displacer scroll31changes the volume of the compression chamber30, thereby performing a compression of the gas located in the compression chamber30, preferably air.

In order to effectively seal the first displacer scroll31and the first mating scroll21against each other, it is provided that the first displacer scroll31and the first mating scroll21each have a scroll groove19, in which a scroll seal18is arranged. The scroll seal18of the first displacer scroll31here forms a seal against a mating scroll bottom29of the first mating scroll21. By contrast, the scroll seal18of the first mating scroll21forms a seal against the displacer scroll bottom39. The scroll seals can each comprise thrust washers, which are arranged between the respective scroll groove19and the displacer scroll bottom39or the mating scroll bottom29.

In order to guide the first displacer scroll31into the orbiting motion, several guide rings37are arranged in the displacer scroll bottom39. The guide rings37accommodate guide pins25, which are fixed in the first bearing housing23. Each guide pin25comprises an anchoring section25a, which is held in a corresponding hole of the first bearing housing23. A guide section25bof the guide pin25engages into the guide ring37. A ledge25cis formed between the guide section25band the anchoring section25a. In particular, the ledge25cis formed by virtue of the guide section25bhaving a smaller diameter than the anchoring section25a.

The anchoring section25ais preferably not completely recessed into the corresponding hole of the first bearing housing23. Rather, the ledge25cof the anchoring section25aprotrudes over the first bearing housing23. The guide ring37rests on the ledge25c. Since the ledge25cprotrudes over the first bearing housing23, a distance is formed between the guide ring37and a sliding plate26that is fixed in the first bearing housing23. As a result, oil that lubricates the drive segment can flow between the guide ring37and the sliding plate26, and thereby lubricate the sliding plate26.

The sliding plate26is preferably ring-shaped in design, and comprises through holes through which the guide pins25can extend. The sliding plate26can be sealed with a ring seal27on a side facing the first bearing housing23. The ring seal27is here arranged in a continuous groove in the first bearing housing23.

The first displacer scroll31rests on the sliding plate26with a sliding element36. Specifically, a sliding element36in the form of a sliding ring is provided radially inside of the guide pins25, and arranged in a groove in the displacer scroll bottom39. The sliding element36can protrude slightly over the displacer scroll bottom39, so that essentially only the sliding element36slides on the sliding plate26. As a consequence, the displacer scroll bottom39is spaced a distance apart from the sliding plate26. The sliding element36preferably also serves as an axial bearing for the first displacer scroll31. The sliding element36is here lubricated with liquid, preferably lubricated with oil. In general, the shaft bearings15can also be lubricated with oil. However, it is also possible that the shaft bearings15be lubricated with grease.

A sealing system is provided to prevent oil from getting out of the drive segment1and into the first compressor segment2. The sealing system comprises a seal element33and a scraping element34. The seal element33and the scraping element34are each ring-shaped in design, and fastened in corresponding ring grooves in the first displacer scroll31. As evident onFIG.2, a respective preloading element35is arranged in the ring grooves that hold the scraping element34or the seal element33. The preloading element35is arranged between the seal element33or the scraping element34and a groove bottom of the respective groove in the displacer scroll bottom39, and pushes the seal element33or the scraping element34against the sliding plate26. The scraping element34here serves to strip away oil that accumulates on the sliding plate26. The seal element33prevents any oil that might not have been stripped away from getting into the area flooded with compressed air, in particular the compression chamber30.

FIG.3shows a front view of the scroll compressor, in particular the second end cover6. The first end cover5is preferably identical in design, making it possible to reduce production costs.

The respective end cover5,6comprises several fastening holes42, which are arranged regularly distributed over the circumference of the end cover5,6. The fastening holes make it possible to fix the end cover5,6on the respective mating scroll21,22, for example by means of screws.

Each end cover5,6further has an air inlet7and an air outlet8. The air inlet7is connected with an entrance area of the compression chamber30. The air outlet8is connected with an exit area of the compression chamber30. Cooling ports9are further provided on the end cover5,6so that the scroll compressor can be cooled with water. The cooling ports9make it possible to hook up a cooling water pump, so as to form a closed cooling water circuit inside of the housing4.

FIG.4shows a section through the scroll compressor along the E-E line onFIG.3. The section hence does not run along a straight line as a cross section through the scroll compressor, for example like the cross section according toFIG.1. Given the special sectional progression along the E-E line, the air inlet7can thus also be discerned onFIG.4in the area of the first compressor segment2, while it cannot be seen in the cross sectional view according toFIG.1.

The sectional view according toFIG.4is intended to illustrate how the two compressor stages or compressor segments2,3interact with each other. It is provided that the first compressor segment2perform a precompression of the air flowing into the compression chamber30of the first compressor segment2via the air inlet7in the first end cover5. The air is initially compressed to a medium air pressure in the first compressor segment2, and transferred to a compressed air line40via the air outlet8in the first end cover5.

The air is strongly heated by the compression in the first compressor segment2. In order to prevent the scroll compressor from becoming overheated, it is additionally provided for purposes of water cooling via the cooling ports9that the pre-compressed medium pressure air be guided via a heat exchanger41. For this reason, the heat exchanger41is provided in the compressed air line40, so as to extract heat from the medium pressure air and transfer it to another fluid circuit, which can be filled with gas or liquid.

The medium pressure air cooled in this way then passes through the air inlet7in the second end cover6and into the compression chamber30of the second compressor segment3. As evident onFIG.4, the compression chamber30of the second compressor segment3has a smaller volume than the compression chamber30of the first compressor segment2, so as to further compress the medium pressure air to a high-pressure air. The high-pressure air exits the second compressor segment3via the air outlet8in the second end cover6, which is preferably connected with a compressed air brake system of a lorry.

Specifically, the scroll compressor can be configured in such a way that air with an air pressure of 1 bar applied to the air inlet7of the first end cover5be pre-compressed in the first compressor segment2(first compressor stage) to a medium air pressure of between 3.5 and 4 bar, and post-compressed in the second compressor segment3(second compressor stage) to a high air pressure of about 14 bar. Before being fed into the second compressor segment3, the medium pressure air with a medium air pressure of 3.5 to 4 bar is guided via the compressed air line40to the heat exchanger41, and there cooled to prevent the second compressor segment3from overheating.

REFERENCE LIST

1Drive segment2First compressor segment3Second compressor segment4Housing5First end cover6Second end cover7Air inlet8Air outlet9Cooling port10Drive11Electric motor12Shaft13First shaft end14Second shaft end15Shaft bearing16Eccentric pin17Eccentric bearing18Scroll seal19Scroll groove20Drive housing21First mating scroll22Second mating scroll23First bearing housing24Second bearing housing25Guide pin25aAnchoring section25bGuide section25cLedge26Sliding plate27Ring seal28Mating scroll wall29Mating scroll bottom30Compression chamber31First displacer scroll32Second displacer scroll33Seal element34Scraping element35Pre-loading element36Sliding element37Guide ring38Displacer scroll wall39Displacer scroll bottom40Compressed air line41Heat exchanger42Fastening hole