Scroll compressor for generating oil-free compressed air

Abstract

A scroll compressor for generating oil-free compressed air, in particular for a compressed air brake system of a lorry, with a drive which is arranged in a housing (4) and is connected to an orbiting displacer scroll (31, 32) which has a displacer scroll bottom (39) and a displacer scroll wall (38), wherein the displacer scroll wall (38) engages into a stationary mating scroll (21, 22), with the result that at least one variable compression chamber (30) is formed between the displacer scroll (31, 32) and the mating scroll (21, 22), wherein a seal element (33) is provided between the displacer scroll (31, 32) and the housing (4), and wherein the seal element (33) is fastened in the displacer scroll bottom (39) and seals against a sliding plate (26) which is connected fixedly to the housing (4). A compressed air brake system with a scroll compressor of this type.

Description

[0001] The invention relates to a scroll compressor for generating oil-free compressed air. The invention further relates to a compressed air brake system with such a scroll compressor.

[0002] Scroll compressors are known from the prior art and are used for various applications. For example, German patent application DE 10 2019 200507 A1 discloses a scroll compressor for refrigerant in a vehicle air conditioning system with a seal between the movable scroll and an intermediate wall of the housing.

[0003] The publication EP 0 798 463 A2 discloses a vacuum pump designed as a scroll compressor. The vacuum pump is used for evacuating containers and operates without oil. For this purpose, the vacuum pump has a scroll compressor comprising an orbiting displacement spiral connected to a drive mechanism, which engages with a stationary counter-spiral. The stationary counter-spiral is fixedly integrated into a housing. The displacement spiral comprises a base and a wall, the wall of which engages in corresponding spaces within the counter-spiral, thus forming a variable compression chamber between the displacement spiral and the counter-spiral.

[0004] To ensure gas tightness, an annular seal is provided in the housing, sealing against the displacer spiral base. Furthermore, the displacer spiral wall and the counter-spiral wall each have spiral grooves into which a spiral seal is inserted, sealing against the displacer spiral base and the housing, respectively, in the area of ​​the bottom end of the counter-spiral wall.

[0005] During operation of the scroll compressor, the displacement spiral orbits, meaning it performs a circular motion above the ring seal. This can cause oil present in the drive segment of the scroll compressor to be drawn by the displacement spiral over the ring seal, allowing oil to enter the compression chamber. Furthermore, the friction between the displacement spiral base and the ring seal can lead to increased wear of the ring seal, potentially creating further leakage points for oil.

[0006] Therefore, with the well-known scroll compressor, there is a risk that the compression chambers will not be kept completely oil-free. This is not critical when used as a vacuum pump, as the gas compressed in the compression chamber and any oil that may have entered it are discharged into the environment. However, in a closed circuit, such as in compressed air brake systems, such oil ingress is critical, as the oil can accumulate in the closed gas circuit.

[0007] The object of the invention is to provide a scroll compressor for generating oil-free compressed air, in which the introduction of oil into the compression zone is efficiently prevented. Furthermore, it is an object of the invention to provide a compressed air braking system with such a scroll compressor.

[0008] According to the invention, this problem is solved with regard to the scroll compressor by the subject matter of claim 1 and with regard to the compressed air brake system by the subject matter of claim 13.

[0009] The invention is based on the concept of providing a scroll compressor for generating oil-free compressed air, particularly for a truck's compressed air brake system, with a drive unit arranged in a housing and connected to an orbiting displacement spiral. The displacement spiral has a base and a wall, the wall of which engages with a stationary counter-spiral, so that at least one variable compression chamber is formed between the displacement spiral and the counter-spiral. According to the invention, a sealing element is provided between the displacement spiral and the housing, the sealing element being fixed in the base of the displacement spiral and sealing against a sliding plate that is rigidly connected to the housing.

[0010] To ensure an efficient and durable oil barrier between the drive area and the compression area of ​​the scroll compressor, the invention provides that the sealing element is fixed in the displacement spiral base and seals against a sliding plate that is fixed in the housing. The sliding plate can be designed to achieve a good seal with minimal friction between the sliding plate and the sealing element. This effectively counteracts excessive wear of the sealing element, resulting in a high level of sealing performance in the long term.

[0011] Furthermore, the arrangement of the sealing element in the displacement spiral base increases the ease of maintenance of the scroll compressor according to the invention. In the event of a defect in the seal area, the seal can be quickly replaced by replacing the entire displacement spiral, including the seal located within it. Prior art requires additional steps to replace the sealing element in the housing after removing the displacement spiral. With the invention, this can be done simply and quickly by replacing the displacement spiral with the integrated sealing element. The scroll compressor is therefore ready for use again in a timely manner.

[0012] In a preferred embodiment of the invention, the sliding plate has a harder material than the housing, at least in one contact area with the sealing element. Furthermore, the sliding plate can have a lower roughness on a side facing the sealing element than the surfaces of the housing. Essentially, the sliding plate serves to ensure good contact with the sealing element and to reduce friction between the sliding plate and the sealing element. Since the sealing element orbits with the displacer spiral, i.e., moves across the sliding plate, the harder material of the sliding plate in this area prevents or reduces wear of the sealing element.Therefore, the sliding plate, especially with its harder material in the contact area with the sealing element, forms the basis for a good and, in particular, oil-tight seal between the drive area of ​​the scroll compressor and the compression area. This ensures that oil from the drive area does not enter the compression area. Consequently, the oil-free nature of the generated compressed air is guaranteed.

[0013] As an additional safety barrier, according to the invention a scraper element for removing oil residues from the sliding plate is also attached in the displacement spiral base. Das The wiper element is preferably arranged parallel or concentrically to the sealing element and wipes away any oil residue that may accumulate on the sliding plate in the contact area with the sealing element. This ensures that areas of the sliding plate regularly located in the compression zone do not introduce oil into the compression zone. Such zones arise because the orbiting movement of the displacement spiral defines a contact area on the sliding plate that is sometimes in the compression zone and sometimes in the drive zone. The wiper element removes any oil that may have accumulated on this contact area of ​​the sliding plate, so that sections of the sliding plate that enter the compression zone are oil-free.

[0014] To securely hold the sealing element and / or the wiper element in the displacement spiral, a preferred embodiment of the invention provides that the displacement spiral base has a sealing groove for receiving the sealing element and / or a wiper groove for receiving the wiper element. Additional preload elements can be arranged in the sealing groove and / or the wiper groove, extending between a groove base and the sealing element or the wiper element. These preload elements exert a contact pressure of the sealing element or wiper element against the sliding plate, thus ensuring a permanent seal or wiper function, particularly even when the sealing element and / or the wiper element is somewhat worn.

[0015] A sliding element can also be arranged between the displacement spiral and the sliding plate. This sliding element can be designed as an axial bearing and support the displacement spiral against the sliding plate or the housing. The sliding element preferably comprises a material that slides particularly well on the sliding plate. In particular, the sliding element, together with the sliding plate, reduces friction between the displacement spiral and the housing, resulting in smooth rotation of the displacement spiral. This reduces the energy required to operate the scroll compressor as well as the frictional heat generated during operation.

[0016] The sliding element can be arranged in a recess in the displacer spiral base. This ensures that the sliding element is securely fixed in its predetermined position. Furthermore, this design allows the sliding element to be easily replaced along with the displacer spiral, for example, for repair purposes.

[0017] To further improve the sliding properties of the sliding element, it is designed to be arranged radially within the sealing element and / or the wiper element. Essentially, the sliding element can therefore be located in the oil-lubricated area, particularly in the drive area, of the scroll compressor. This provides additional oil lubrication between the sliding element and the sliding plate, resulting in smooth rotation of the displacement spiral.

[0018] In the scroll compressor according to the invention, guide pins can further be provided that are anchored in the housing and extend through openings in the sliding plate into guide rings arranged in the displacer spiral base. Each guide pin has a shoulder that projects beyond the sliding plate, creating a gap between the respective guide ring and the sliding plate. The combination of guide pin and guide ring is referred to as a "pin-ring" system, which is advantageous for the orbital movement of the displacer spiral. The guide pin, engaging with the guide ring, forces the displacer spiral into the predetermined orbit, which is generated by an eccentric mounting of the displacer spiral on the drive shaft.

[0019] To minimize friction, it is advantageous that the guide pins have a shoulder that protrudes beyond the sliding plate. This creates a gap between the guide ring and the sliding plate, thus reducing friction in this area. Furthermore, the gap between the guide ring and the sliding plate allows for oil lubrication of the sliding plate.

[0020] In a particularly preferred embodiment of the invention, the drive is arranged between a first displacement spiral and a second displacement spiral. The scroll compressor can therefore be designed as a multi-stage, and in particular a two-stage, scroll compressor. This allows for pre-compression in a first compression stage and post-compression in a second compression stage, enabling the achievement of particularly high pressures. This is especially advantageous for generating compressed air for compressed air brake systems, particularly in trucks.

[0021] Therefore, in a preferred embodiment, the drive is provided with a shaft with two ends, the first end being connected to the first displacement spiral and the second end to the second displacement spiral. The displacement spirals thus share the same drive, which increases the efficiency of the scroll compressor and advantageously reduces its size. Such a two-stage scroll compressor is therefore particularly compact.

[0022] The first positive displacement spiral can form a first compressor stage with a first counter-spiral, and the second positive displacement spiral can form a second compressor stage with a second counter-spiral. The compressor stages can be coupled together, so that, for example, the first compressor stage performs pre-compression and the second compressor stage performs post-compression. This allows for particularly high pressures, which are especially advantageous for generating compressed air, particularly for the compressed air braking systems of trucks. The coupling of the first and second compressor stages can be achieved via external lines. However, it is also possible to integrate the lines for coupling the two compressor stages into the housing of the scroll compressor.In any case, it is preferably provided that a heat exchanger is arranged between the first compressor stage and the second compressor stage, which removes heat from the pre-compressed compressed air, so that cooled, pre-compressed compressed air is supplied to the second compressor stage.

[0023] In particular, the first compressor stage can be configured to compress the air from a suction pressure to an intermediate air pressure. The suction pressure can be, for example, around 1 bar, while the intermediate air pressure is in the range of 3.5 bar to 4 bar. The second compressor stage can then perform a higher compression from the intermediate air pressure to a high air pressure. Thus, the intermediate air pressure, which is preferably between 3.5 bar and 4 bar, is compressed to a high air pressure in the range of approximately 14 bar.

[0024] The first and second shaft ends are preferably each equipped with a radial bearing, in particular an eccentric bearing. The radial or eccentric bearing can be designed as a plain bearing, ball bearing, or needle bearing. A compensating mechanism can be arranged between the first shaft end and the first displacer spiral and / or between the second shaft end and the second displacer spiral, which reduces vibrations and the resulting noise during the orbiting movement of the displacer spiral. Such a compensating mechanism comprises a counterweight that is arranged eccentrically on the axis of rotation of the orbiting displacer spiral and can oscillate about this axis. The compensating mechanism is designed such that the oscillation is automatically regulated by centrifugal forces.The balancing mechanism compensates for gas forces and manufacturing tolerances, thereby reducing vibrations and noise during operation of the scroll compressor.

[0025] A compensation mechanism, which can be used particularly preferably for the scroll compressor according to the invention, is described, for example, in the subsequently published German patent application 10 2020 121 442.1, the content of which, in particular in connection with the embodiment described therein, is to be referenced. Fig. 2 , is fully referenced.

[0026] In a further embodiment of the invention, a spiral seal is provided between the displacer spiral wall and the counter spiral, as well as between the counter spiral wall and the displacer spiral. This ensures a good seal between the displacer spiral and the counter spiral, creating a closed, essentially leak-free variable compression chamber. The spiral seal can also compensate for manufacturing tolerances and pressure fluctuations in the compression chamber. Therefore, the scroll compressor does not require a back-pressure chamber, which typically uses pressure from the compression chamber to press the orbiting displacer spiral against the counter spiral. Eliminating the back-pressure chamber saves installation space, resulting in a particularly compact scroll compressor.

[0027] Preferably, a first spiral seal is arranged in a spiral groove of the displacer spiral wall, which is open towards the counter spiral. A second spiral seal can be arranged in a spiral groove of the counter spiral wall, which is also open towards the displacer spiral. Essentially, the spiral grooves in both the displacer spiral wall and the counter spiral wall accommodate and secure the respective spiral seal. To reduce friction between the displacer spiral and the counter spiral, each spiral seal can be assigned a thrust washer. The thrust washer is preferably arranged between the respective spiral seal and the displacer spiral or the counter spiral, thus reducing the friction between the displacer spiral and the counter spiral. The thrust washer is pressed against the displacer spiral or counter spiral by the spiral seal.Counter-spiral is compressed so that a sealing function and a sliding function are achieved on the one hand.

[0028] In a preferred embodiment of the scroll compressor according to the invention, the drive and / or the housing and / or the counter-spiral are water-cooled. Water cooling is particularly efficient and enables rapid and effective heat dissipation, allowing the scroll compressor to operate at exceptionally high pressures. This is especially advantageous for compressed air brake systems in trucks. Particular attention can be paid to the cooling of the housing, especially on the high-pressure or outlet side of the scroll compressor. In this area, particularly in the area of ​​the second compressor stage, the high-pressure compression can generate exceptionally high temperatures, which can be effectively dissipated by water cooling. Additionally, it is advantageous to cool the compressed air generated in the scroll compressor.Preferably, a heat exchanger is provided between the first and second compressor stages to remove heat from the compressed air, which is compressed to a medium pressure. This allows pre-cooled, medium-pressure air to enter the second compressor stage, where it is further compressed to high pressure.

[0029] A secondary aspect of the invention relates to a compressed air braking system, particularly for a truck, with a scroll compressor as described above. Such compressed air braking systems can be used not only in trucks, but also, for example, in buses or construction equipment such as excavators, rollers, self-propelled cranes, and the like. In any case, such a compressed air braking system is particularly suitable for vehicles with a gross vehicle weight exceeding 5 tons.

[0030] The invention is explained in more detail below using an exemplary embodiment with reference to the accompanying schematic drawings. These show Fig. 1 shows a cross-sectional view through a scroll compressor according to a preferred embodiment of the invention; Fig. 2 shows a section C from the scroll compressor according to the invention. Fig. 1 ; Fig. 3 a front view of the scroll compressor according to Fig. 1 ; and Fig. 4 a sectional view of the scroll compressor according to Fig. 1 along line EE from Fig. 3 . The scroll compressor according to Fig. 1 The scroll compressor is designed as a two-stage compressor. It features a central drive segment 1, to which two compressor segments 2 and 3 are axially connected on either side. The first compressor segment 2 serves as the first compressor stage, and the second compressor segment 3 as the second compressor stage. The first compressor segment 2 compresses ambient air pressure to an intermediate air pressure, while the second compressor segment 3 compresses the intermediate air pressure to a high air pressure.

[0031] The drive segment 1 comprises the drive 10, which includes an electric motor 11 and a shaft 12. The electric motor 11 is arranged within a housing 4, which is designed in multiple parts for ease of maintenance. The housing 4 comprises a drive housing 20, two bearing housings 23, 24 adjoining the drive housing 20, counter-spirals 21, 22, which also form part of the housing 4, and end covers 5, 6. A first bearing housing 23 adjoins the drive housing 20 in the direction of the first compressor segment 2. The first bearing housing 23 is rigidly connected to the first counter-spiral 21, which also forms part of the housing 4. The first end cover 5 follows the first counter-spiral 21 and axially closes the housing 4. A second bearing housing 24 is arranged on the opposite side of the drive housing 20 and is connected to a second counter-spiral 22.The second counter-spiral 22 is covered longitudinally by a second end cover 6.

[0032] The shaft 12 is supported in the drive housing 20 by shaft bearings 15. The shaft 12 has a first shaft end 13, which is directed towards the first compressor segment 2. A second shaft end 14 is also provided, which faces the second compressor segment 3. Both shaft ends 13 and 14 each have an eccentric pin 16, which is arranged in an eccentric bearing 17 that connects to the respective displacement spiral 31 and 32. Thus, the first displacement spiral 31 is supported on the eccentric pin 16 of the first shaft end 13 via the eccentric bearing 17. The second displacement spiral 32 is supported on the eccentric pin 16 of the second shaft end 14 via the eccentric bearing 17.

[0033] The displacement spirals 31, 32 each have a displacement spiral base 39, from which a displacement spiral wall 38 extends into the respective counter-spiral 21, 22. This is illustrated below by way of example. Fig. 2 explained, which shows a section of the second compressor segment 3 of the scroll compressor according to Fig. 1 The design described below for the first compressor segment 2 applies analogously to the second compressor segment 3. The first displacement spiral 31 and the second displacement spiral 32, as well as the first counter-spiral 21 and the second counter-spiral 22, are therefore similarly constructed, particularly with regard to their arrangement relative to each other. They differ only in the volume of a compression chamber 30 formed between them, which is smaller in the second compressor stage (i.e., between the second displacement spiral 32 and the second counter-spiral 22) than in the first compressor stage (i.e., between the first displacement spiral 31 and the first counter-spiral 21).

[0034] Fig. 2 Figure 1 shows the first displacer spiral 31, which comprises a displacer spiral base 39 and a displacer spiral wall 38. The first displacer spiral 31 engages with the first counter-spiral 21, so that the compression chamber 30 is formed between the displacer spiral wall 38 and a counter-spiral wall 28. The compression chamber 30 is variable, meaning that the orbiting motion of the first displacer spiral 31 causes the compression chamber 30 to change its volume, thus compressing the gas, preferably air, contained in the compression chamber 30.

[0035] To ensure a good seal between the first displacer spiral 31 and the first counter-spiral 21, each of the first displacer spiral 31 and the first counter-spiral 21 is provided with a spiral groove 19 in which a spiral seal 18 is arranged. The spiral seal 18 of the first displacer spiral 31 seals against a counter-spiral base 29 of the first counter-spiral 21. Conversely, the spiral seal 18 of the first counter-spiral 21 seals against the displacer spiral base 39. The spiral seals can each include thrust washers arranged between the respective spiral groove 19 and the displacer spiral base 39 or the counter-spiral base 29, respectively.

[0036] To guide the first displacer spiral 31 in its orbiting motion, several guide rings 37 are arranged in the displacer spiral base 39. The guide rings 37 accommodate guide pins 25, which are fixed in the first bearing housing 23. Each guide pin 25 comprises an anchoring section 25a, which is held in a corresponding bore in the first bearing housing 23. A guide section 25b of the guide pin 25 engages in the guide ring 37. A shoulder 25c is formed between the guide section 25b and the anchoring section 25a. The shoulder 25c is formed, in particular, by the fact that the guide section 25b has a smaller diameter than the anchoring section 25a.

[0037] The anchoring section 25a is preferably not fully recessed into the corresponding bore of the first bearing housing 23. Rather, the shoulder 25c of the anchoring section 25a projects beyond the first bearing housing 23. The guide ring 37 rests on the shoulder 25c. Because the shoulder 25c projects beyond the first bearing housing 23, a gap is formed between the guide ring 37 and a sliding plate 26, which is fixed in the first bearing housing 23. This allows oil lubricating the drive segment 1 to flow between the guide ring 37 and the sliding plate 26, thus lubricating the sliding plate 26.

[0038] The sliding plate 26 is preferably ring-shaped and includes through-holes through which the guide pins 25 can extend. On one side facing the first bearing housing 23, the sliding plate 26 can be sealed with a ring seal 27. The ring seal 27 is arranged in a circumferential groove in the first bearing housing 23.

[0039] The first displacer spiral 31 rests on the sliding plate 26 with a sliding element 36. Specifically, a sliding element 36 in the form of a sliding ring is provided radially within the guide pins 25 and is arranged in a groove in the displacer spiral base 29. The sliding element 36 may project slightly beyond the displacer spiral base 39, so that essentially only the sliding element 36 slides on the sliding plate 26. The displacer spiral base 39 thus has a gap to the sliding plate 26. The sliding element 36 preferably also serves as an axial bearing for the first displacer spiral 31. The sliding element 36 is liquid-lubricated, preferably oil-lubricated. In general, the shaft bearings 15 can also be oil-lubricated. However, it is also possible for the shaft bearings 15 to be grease-lubricated.

[0040] To prevent oil from the drive segment 1 from entering the first compressor segment 2, a sealing system is provided. The sealing system comprises a sealing element 33 and a wiper element 34. The sealing element 33 and the wiper element 34 are each ring-shaped and are fastened in corresponding annular grooves in the first displacement spiral 31. As shown in Fig. 2 As can be seen, a preload element 35 is arranged in each of the annular grooves that hold the wiper element 34 or the sealing element 33. The preload element 35 is positioned between the sealing element 33 or the wiper element 34 and a groove base of the respective groove in the displacer spiral base 39 and presses the sealing element 33 or the wiper element 34 against the sliding plate 25. The wiper element 34 serves to wipe off any oil that collects on the sliding plate 26. The sealing element 33 prevents any unwiped oil from entering the compressed air-filled area, in particular the compression chamber 30.

[0041] Fig. 3 Figure 1 shows a front view of the scroll compressor, in particular the second end cover 6. The first end cover 5 is preferably identical in design, so that manufacturing costs can be reduced.

[0042] The end cap 5, 6 each includes several fastening holes 42, which are regularly distributed around the circumference of the end cap 5, 6. The fastening holes allow the end cap 5, 6 to be fixed to the respective counter spiral 21, 22, for example by means of screws.

[0043] Furthermore, each end cover 5, 6 has an air inlet 7 and an air outlet 8. The air inlet 7 is connected to an inlet area of ​​the compression chamber 30. The air outlet 8 is connected to an outlet area of ​​the compression chamber 30. To enable water cooling of the scroll compressor, cooling connections 9 are also provided on the end covers 5, 6. The cooling connections 9 allow a cooling water pump to be connected to form a closed cooling water circuit within the housing 4.

[0044] Fig. 4 shows a cross-section through the scroll compressor along line EE. Fig. 3 The section therefore does not run in a straight line as a cross-section through the scroll compressor, like the cross-section according to, for example, Fig. 1 . Due to the special cutting pattern along line EE, in Fig. 4 Therefore, the air inlet 7 is also recognizable in the area of ​​the first compressor segment 2, whereas in the cross-sectional view according to Fig. 1 is not visible.

[0045] The sectional view according to Fig. 4 This is intended to illustrate how the two compressor stages or compressor segments 2 and 3 interact. The first compressor segment 2 is designed to pre-compress the air flowing into the compression chamber 30 of the first compressor segment 2 via the air inlet 7 in the first end cover 5. In the first compressor segment 2, the air is initially compressed to an intermediate pressure and then transferred to a compressed air line 40 via the air outlet 8 in the first end cover 5.

[0046] The compression in the first compressor segment 2 causes the air to heat up considerably. To prevent overheating of the scroll compressor, in addition to water cooling via the cooling connections 9, the pre-compressed medium-pressure air is routed through a heat exchanger 41. The heat exchanger 41 is therefore provided in the compressed air line 40. It extracts heat from the medium-pressure air and transfers it to another fluid circuit, which may be filled with gas or liquid.

[0047] The cooled medium-pressure air then enters the compression chamber 30 of the second compressor segment 3 via the air inlet 7 in the second end cover 6. As in Fig. 4As can be seen, the compression chamber 30 of the second compressor segment 3 has a smaller volume than the compression chamber 30 of the first compressor segment 2 in order to further compress the medium-pressure air to high-pressure air. The high-pressure air leaves the second compressor segment 3 via the air outlet 8 in the second end cover 6, which is preferably connected to a compressed air brake system of a truck.

[0048] Specifically, the scroll compressor can be designed such that air with an air pressure of 1 bar at the air inlet 7 of the first end cover 5 is pre-compressed to an intermediate air pressure between 3.5 bar and 4 bar in the first compressor segment 2 (first compressor stage) and then further compressed to a high air pressure of approximately 14 bar in the second compressor segment 3 (second compressor stage). Before being fed into the second compressor segment 3, the intermediate-pressure air with an intermediate air pressure of 3.5 bar to 4 bar is routed via the compressed air line 40 to the heat exchanger 41 and cooled there to prevent overheating of the second compressor segment 3. Reference symbol list

[0049] 1 Drive segment 2 First compressor segment 3 Second compressor segment 4 Housing 5 First end cover 6 Second end cover 7 Air inlet 8 Air outlet 9 Cooling connection 10 Drive 11 Electric motor 12 Shaft 13 First shaft end 14 Second shaft end 15 Shaft bearing 16 Eccentric pin 17 Eccentric bearing 18 Spiral seal 19 Spiral groove 20 Drive housing 21 First counter spiral 22 Second counter spiral 23 First bearing housing 24 Second bearing housing 25 Guide pin 25a Anchoring section 25b Guide section 25c Shoulder 26 Sliding plate 27 Ring seal 28 Counter spiral wall 29 Counter spiral base 30 Compression chamber 31 First displacer spiral 32 Second displacer spiral 33 Sealing element 34 Wiper element 35 Preload element 36 Sliding element 37 Guide ring 38 Displacement spiral wall 39 Displacement spiral base 40 Compressed air line 41 Heat exchanger 42 Mounting hole

Claims

1. A scroll compressor for the production of oil-free compressed air, in particular for an air brake system of a lorry, comprising a drive arranged in a housing (4) and connected to an orbiting displacement spiral (31, 32) comprising a displacement spiral base (39) and a displacement spiral wall (38), wherein the displacement spiral wall (38) engages with a stationary counter-spiral (21, 22) so that, between the displacement spiral (31, 32) and the counter spiral (21, 22), at least one variable compression chamber (30) is formed, wherein a sealing element (33) is provided between the displacement spiral (31, 32) and the housing (4), and wherein the sealing element (33) is fixed in the displacement spiral base (39) and seals against a sliding plate (26) which is firmly connected to the housing (4), characterized in that a scraper element (34) is attached to the displacement spiral base (39) for scraping oil residues from the sliding plate (26).

2. The scroll compressor according to claim 1, characterized in that the sliding plate (26) comprises a harder material than the housing (4) at least in a contact region with the sealing element (33).

3. The scroll compressor according to any one of the preceding claims, characterized in that the positive displacement spiral base (39) comprises a sealing groove for receiving the sealing element (33) and / or a scraper groove for receiving the scraper element (34).

4. The scroll compressor according to any one of the preceding claims, characterized in that a sliding element (36) is arranged between the displacement spiral (31, 32) and the sliding plate (26).

5. The scroll compressor according to claim 4, characterized in that the sliding element (36) is arranged radially within the sealing element (33) and / or the scraper element (34) .

6. The scroll compressor according to any one of the preceding claims, characterized in that guide pins (25) are anchored in the housing (4), which extend through openings in the sliding plate (26) into guide rings (37) which are arranged in the displacement spiral base (39), wherein the guide pins (25) each comprise a shoulder (25c) which projects over the sliding plate (26) so that there is a distance between the respective guide ring (37) and the sliding plate (26).

7. The scroll compressor according to any one of the preceding claims, characterized in that the drive is arranged between a first displacement spiral (31) and a second displacement spiral (32).

8. The scroll compressor according to claim 7, characterized in that the drive comprises a shaft (12) with two shaft ends (13, 14), wherein a first shaft end (13) is connected to the first displacement spiral (31), and a second shaft end (14) is connected to the second displacement spiral (32).

9. The scroll compressor according to claim 7 or 8, characterized in that the first displacement spiral (31) with a first counter spiral (21) forms a first compressor stage and the second displacement spiral (32) with a second counter spiral (22) forms a second compressor stage.

10. The scroll compressor according to any one of the preceding claims, characterized in that a spiral seal (18) is provided between the displacement spiral wall (28) and the counter spiral (21, 22) as well as between the counterspiral wall (28) and the displacement spiral (31, 32).

11. The scroll compressor according to claim 10, characterized in that a first spiral seal (18) is arranged in a spiral groove (19) of the displacement spiral wall (38) which is open towards the counter spiral (21, 22), and a second spiral seal (18) is arranged in a spiral groove (19) of the counter spiral wall (28) which is open towards the displacement spiral (31, 32).

12. The scroll compressor according to any one of the preceding claims, characterized in that the drive and / or the housing (4) and / or the counter spiral (21, 22) are water-cooled.

13. An air brake system, in particular of a lorry, with a scroll compressor according to any one of the preceding claims.

Images