Scroll compressor assembly

Abstract

The invention relates to a scroll compressor assembly (1) for generating compressed air for a compressed-air supply system (2) of a vehicle, the scroll compressor assembly having a scroll compressor (3) which has a static spiral (4), a spiral (5) which can orbit about the static spiral, and an inlet and an outlet, wherein: the compressed-air supply system has a supply pressure reservoir (19); an electronically controllable valve device (15) is functionally connected to the inlet and / or to the outlet of the scroll compressor such that the scroll compressor is switchable between two operating modes by means of the valve device; in the first operating mode, ambient air (14) can be drawn in through the inlet; and in the second operating mode, pre-compressed air from the supply pressure reservoir (19) or from the outlet (12) of the scroll compressor can be drawn in through the inlet. According to the invention: two inlets (10, 11) are formed on the scroll compressor; the first inlet (10) is connected at an input side to a first controllable 2 / 2 directional valve (16) by means of which said first inlet can be connected to or shut off with respect to the ambient air; the first inlet (10) is pneumatically connected at an output side to a first inlet chamber (25) formed in the static spiral (4); the second inlet (11) is connected at an input side to a second controllable 2 / 2 directional valve (17) by means of which said second inlet can be connected to or shut off with respect to the supply pressure reservoir (19) or the outlet (12); and the second inlet (11) is connected at an output side to a second inlet chamber (27) formed in the static spiral (4).

Description

[0001] Scroll compressor arrangement

[0002] The invention relates to a scroll compressor arrangement for generating compressed air for a compressed air supply system of a vehicle, comprising a scroll compressor which has a fixed scroll, a scroll which can be orbited around the fixed scroll, and an inlet and an outlet, wherein the compressed air supply system has a supply pressure reservoir, and wherein an electronically controllable valve device is functionally connected to the inlet and / or to the outlet of the scroll compressor in such a way that the scroll compressor can be switched between a first operating mode and a second operating mode by means of the valve device, wherein in the first operating mode ambient air can be sucked in through the inlet, and wherein in the second operating mode air pre-compressed by the scroll compressor can be sucked in from the supply pressure reservoir or from the outlet of the scroll compressor through the inlet.Furthermore, the invention relates to a compressed air supply system with a scroll compressor arrangement having the features of the invention and to a vehicle with such a scroll compressor arrangement.

[0003] Spiral compressors, referred to here as scroll compressors, are known in various designs. According to a common design, two spirals are arranged eccentrically to one another, one of which can perform an orbital or planar movement around a stationary spiral. For this purpose, the orbitable spiral is deflected by means of an eccentric drive in a plane transverse to a geometric center axis. Between them, the two spirals form several chambers whose volume continuously decreases radially inward. As a result, during an orbital movement of the movable spiral around the stationary spiral, air drawn in from the outside is increasingly compressed in the chambers and finally led to a radially inward outlet of the scroll compressor, through which compressed air can be axially discharged.

[0004] The use of scroll compressors in vehicles is already known, for example, for generating compressed air in compressed air supply systems, for temperature control in air conditioning systems, or for increasing the performance of combustion engines. To achieve specific pressure ratios between an intake pressure and an outlet pressure, such as those required for pneumatic braking systems or air suspension systems in commercial vehicles and buses, or to create multiple compression stages with different pressure ratios, conventional scroll compressor arrangements feature two or more pairs of fixed and orbiting scrolls arranged one behind the other in terms of flow and independent of each other. However, such multi-stage scroll compressor arrangements are relatively expensive and complex in design, and also have a comparatively large axial length.

[0005] For example, DE 10 2021 121 424 A1 discloses a two-stage, electrically driven compressor for generating compressed air for a commercial vehicle's compressed air supply system. The two compression stages are each designed as scroll compressors.

[0006] EP 0 777 052 ​​B1 discloses a scroll compressor for a vehicle air conditioning system, comprising a fixed scroll having a central outlet opening and two bypass openings arranged radially spaced from the outlet opening and forming a pair, and comprising a scroll orbitable around the fixed scroll, which engages with the fixed scroll so that a gas is enclosed between the fixed scroll and the orbitable scroll. The scroll compressor is arranged in a gas-tight housing having an inlet and an outlet, which connect the scroll compressor to a vehicle air conditioning system. The inlet admits gas into a low-pressure chamber formed on an intake side and discharges gas compressed in the scroll compressor from a high-pressure chamber formed on an outlet side to the air conditioning system.In addition, a rotatable hollow cylindrical rotary slide valve is arranged, with a valve wall having two slots formed as a pair therein, which can be controlled to the pair of bypass openings in order to prematurely blow off the gas trapped in the compressor and thereby change the displacement of the compressor.

[0007] EP 1 656 503 B1 shows and describes a scroll compressor arrangement for a vacuum system, comprising a scroll compressor, a turbomolecular pump, and two interconnected vacuum chambers. The scroll compressor has two nested spirals, one of which is fixed to the housing, and the other spiral is connected to an eccentric section of a drive shaft and arranged to orbit the stationary spiral. A first inlet and a second inlet are formed on two radially spaced-apart outer sections of the scroll compressor, and an outlet is formed on a central section radially inward and spaced from the inlets.

[0008] The walls of the fixed and orbiting scrolls define a first spiral flow path for a gas between the first inlet and the outlet. During operation of this scroll compressor, gas enters the scroll compressor through the first inlet at a first pressure and exits through the outlet at a second pressure, which is higher than the first pressure.

[0009] Furthermore, the walls of the fixed and orbiting scrolls define a second spiral flow path between the second inlet and the outlet, with gas entering the scroll compressor through the second inlet at a third pressure, which is higher than the first pressure and lower than the second pressure, and exiting through the outlet at the second pressure. The first flow path is connected to the second flow path over the entire extent of the second flow path to form a common flow path.

[0010] An inlet of the turbomolecular pump is connected to one of the two vacuum chambers. The first inlet of the scroll compressor is connected to an outlet of the turbomolecular pump to assist it in pumping at the first pressure. The second inlet of the scroll compressor is connected to the other of the two vacuum chambers to pump at the third pressure, which is higher than the first pressure. The radial positioning of the second inlet determines the third pressure at which gas enters the scroll compressor through the second inlet. This pressure is higher the closer this second inlet is located toward the outlet of the scroll compressor.

[0011] The two scrolls mesh with each other, with spiral flights formed between the scrolls narrowing increasingly radially inwards. This means that when the drive shaft of the scroll compressor rotates, the gas drawn in at the two inlets with the first pressure and the third pressure is increasingly compressed in the flights or in the common flow path, and the compressed gas can be extracted at the central outlet of the scroll compressor with the second pressure. This scroll compressor arrangement thus makes it possible to maintain a differentially pumped system consisting of two interconnected chambers at different pressures while being pumped by a single scroll compressor. Although this scroll compressor arrangement compresses a gas with two different inlet pressures via two spaced-apart inlet openings, it is designed as a single-stage compressor with only a single outlet pressure.In addition, the second inlet pressure is fixed by the radial distance of the second inlet to the first inlet.

[0012] DE 10 2020 133 438 A1 discloses a scroll compressor arrangement for a refrigeration system, comprising a scroll compressor having two intermeshing scrolls, both scrolls being arranged rotatably (co-rotating scroll), and the two scrolls being coupled to each other by means of a transmission unit. The scroll compressor has a first inlet and an additional second inlet, as well as an outlet, the first inlet being oriented perpendicular to a rotational axis and the second inlet being oriented parallel to it. Gas drawn in through the two inlets mixes within the scroll compressor and is guided together to the outlet.

[0013] Finally, DE 11 2019 004 801 B4 discloses a compressed air supply system of a vehicle with a scroll compressor for supplying compressed air to an air suspension system, by means of which air springs and / or a storage tank can be supplied with compressed air, but with which it is also possible to return compressed air from the air springs and / or from the storage tank to the inlet of the scroll compressor.

[0014] Against this background, the object of the invention is to present a scroll compressor arrangement with which the operating modes known from DE 11 2019 004 801 B4 can be operated very advantageously.

[0015] This object is achieved with a scroll compressor arrangement having the features of claim 1. Advantageous embodiments and further developments are defined in the dependent claims.

[0016] The invention therefore initially relates to a scroll compressor arrangement for generating compressed air for a compressed air supply system of a vehicle, comprising a scroll compressor which has a fixed scroll, a scroll which can be orbited around the fixed scroll, and an inlet and an outlet, wherein the compressed air supply system has a supply pressure reservoir, and wherein an electronically controllable valve device is functionally connected to the inlet and / or to the outlet of the scroll compressor in such a way that the scroll compressor can be switched between a first operating mode and a second operating mode by means of the valve device, wherein in the first operating mode ambient air can be sucked in through the inlet, and wherein in the second operating mode air pre-compressed by the scroll compressor can be sucked in from the supply pressure reservoir or from the outlet of the scroll compressor through the inlet.

[0017] To achieve the object, this scroll compressor arrangement is provided with a first inlet and a second inlet, the first inlet is connected on the inlet side to a first controllable 2 / 2-way valve by means of which the first inlet can be pneumatically connected to the ambient air or shut off from it, the first inlet is pneumatically connected on the outlet side to a first inlet chamber formed in the stationary spiral, the second inlet is connected on the inlet side to a second controllable 2 / 2-way valve by means of which the second inlet can be pneumatically connected to the supply pressure reservoir or to the outlet or shut off from them, and the second inlet is pneumatically connected on the outlet side to a second inlet chamber formed in the stationary spiral.

[0018] This creates a scroll compressor which, with only one pair of a fixedly arranged spiral and a spiral which can be orbited around the fixed spiral, enables at least two compression stages in two operating modes, so that in a first operating mode a common system pressure for general compressed air consumers in a compressed air system of a commercial vehicle and in a second operating mode an increased system pressure for certain compressed air consumers with increased pressure requirements, such as for a pneumatic brake system of a truck or a bus, can be provided by the scroll compressor.

[0019] This is achieved by means of a valve device assigned to the scroll compressor, which can assume several switching positions, via which the first inlet of the scroll compressor can be subjected to the pressure of the sucked-in ambient air and the second inlet to an increased pre-pressure. For this purpose, the valve device can have at least one valve by means of which the second inlet of the scroll compressor can be pneumatically connected to the reservoir pressure vessel of the vehicle's compressed air supply system or to the outlet of the scroll compressor, or can be shut off from it. The valve device can also advantageously have further controllable valve means for varying, in particular limiting, the inlet pressure.

[0020] Accordingly, the scroll compressor arrangement can be operated in two different modes. In a first operating mode, air is drawn in from the environment via the first inlet and compressed in the scroll compressor. At the outlet of the scroll compressor, an outlet pressure and a displacement volume of the generated compressed air are then available, the amount of which is determined by a design-related internal compression ratio of the scroll compressor in conjunction with a speed of the orbiting scroll. The outlet pressure can, for example, be a typical system pressure of a compressed air supply system of a commercial vehicle. In a second operating mode, the scroll compressor generates an increased outlet pressure by feeding pre-compressed air to its second inlet, which is then further compressed in the scroll compressor.The pre-compressed air can be taken, for example, from the storage pressure vessel or another compressed air source, for example an output line connected to the outlet of the scroll compressor.

[0021] Compared to a conventional scroll compressor arrangement with two scroll compressors, a single scroll compressor has a smaller displacement. To still achieve a comparable displacement, the displacement or displacement of the scroll compressor can be structurally increased and / or the speed of a drive of the orbiting scroll can be adjusted to a limited extent, in particular, increased accordingly.

[0022] This design creates a compact, two-stage scroll compressor with two separate inlets for different inlet pressures, which can advantageously be switched between two operating modes. A first inlet chamber associated with the first inlet functions as a first compression stage, and a second inlet chamber associated with the second inlet functions as a second compression stage. Air from the environment can be drawn into the first inlet chamber via the first inlet, with the first 2 / 2-way valve being arranged upstream of the first inlet. Pre-compressed air from the reservoir pressure vessel can be drawn into the second inlet chamber via a reservoir pressure line, with the second 2 / 2-way valve being arranged in the reservoir pressure line.

[0023] Alternatively, pre-compressed air can be drawn in from an outlet pressure line connected to the outlet of the scroll compressor, with the second 2 / 2-way valve located in the outlet pressure line. In principle, an additional, third operating mode is also possible, in which air at different pressures can be drawn in simultaneously via both inlets, which are mixed inside the scroll compressor and further compressed together.

[0024] However, another development of the scroll compressor arrangement according to the invention provides that the two inlets are arranged and / or configured in such a way that pressure equalization between these two inlets is not possible. This ensures that the compressed air supplied to the scroll compressor via the second inlet after the first compression process is not mixed with the ambient air at the lower ambient pressure or escapes into the ambient air at a lower pressure when the first 2 / 2-way valve is open.

[0025] According to another embodiment of this scroll compressor arrangement, it can be provided that it is arranged in a housing, that the first inlet is designed as a first opening in the housing, that a first intake port is arranged in the first opening, which is connected to the first inlet chamber and via which air can be sucked into the first inlet chamber when the first 2 / 2-way valve is open, that the second inlet is designed as a second opening in the housing, and that a second intake port is arranged in the second opening, which is connected to the second inlet chamber and via which air can be sucked into the second inlet chamber when the second 2 / 2-way valve is open.

[0026] Accordingly, in a first operating mode, the scroll compressor can be charged with ambient air via a direct air supply. In the second, alternative operating mode, the scroll compressor can be charged with pre-compressed air from the supply pressure reservoir or from the outlet of the scroll compressor via a direct air supply. This ensures effective air supply to the scroll compressor in both the first and second modes. In either case, both compression stages can be operated independently of each other. In principle, the housing could be omitted entirely if the two inlet chambers were connected to the valve assembly via external connections. At least then, a pressure-tight housing design is not necessary.

[0027] Furthermore, it can be provided that the scroll compressor arrangement is arranged in a housing, that the first inlet is designed as a first opening in the housing, via which, when the first 2 / 2-way valve is open, air can flow into the interior of the housing and can be sucked into the first inlet chamber via the interior of the housing, that the second inlet is designed as a second opening in the housing, in which an intake nozzle is arranged, which is connected to the second inlet chamber, and via which, when the second 2 / 2-way valve is open, air can be sucked into the second inlet chamber.

[0028] Accordingly, a first intake port for the first inlet, which is provided for the first operating mode, can be omitted and the scroll compressor can be charged with the ambient air, which ventilates the housing via the first inlet.

[0029] According to another embodiment of the scroll compressor, a pressure relief valve can be pneumatically arranged between the outlet of the scroll compressor and the supply pressure reservoir and / or between the outlet of the scroll compressor and the first inlet and / or between the outlet of the scroll compressor and the second inlet. This allows the air pressure with which the scroll compressor is precharged in the second operating mode to be easily varied, and prevents excessive overpressure in the scroll compressor and also in the supply pressure reservoir.

[0030] The pressure relief valve can be adjustable or preset. This allows the maximum pressure to be set variably or fixed, with which the scroll compressor and / or the supply pressure reservoir is filled in the second operating mode. This ensures that the scroll compressor's spirals, a compressed air reservoir, and any compressed air consumers connected directly to the outlet are not subjected to excessively high pressure.

[0031] Furthermore, the scroll compressor can be provided with a bypass opening arranged radially between the at least one inlet and the outlet, which bypass opening is connected to a controllable bypass valve. Using the bypass valve, the bypass opening can be partially or fully opened as needed to change the outlet pressure of the scroll compressor. In particular, this makes it possible to reduce the outlet pressure to the extent permitted by the compressed air consumers of the compressed air supply system. Furthermore, the scroll compressor can be mechanically relieved, especially by protecting a spiral flight near the outlet, which is exposed to the highest pressure load in the second operating mode.

[0032] Another advantageous development of the invention provides that at least one inlet of the scroll compressor is aligned axially parallel to a drive shaft of the orbitable scroll, and that the scroll compressor has at least one axial bearing in the form of a rolling bearing or plain bearing for axially supporting the orbitable scroll, wherein the at least one axial bearing has at least three support points which are arranged asymmetrically distributed in a plane transverse to the drive shaft of the orbitable scroll.

[0033] Precharging the intake side of the scroll compressor with pre-compressed air creates a higher load on its orbiting scroll. In particular, precharging the scroll compressor via an inlet aligned parallel to the drive shaft, which may be intended for the inflow of pre-compressed air, creates an axial compressive load on the orbiting scroll. This can generate a tilting moment that acts on the orbiting scroll in a plane perpendicular to the longitudinal alignment of the drive shaft. This can cause slight deformations in this scroll, leading to sliding contact between the orbiting scroll and the stationary scroll. This can cause premature wear of the scroll compressor and possibly even failure. This load can be advantageously fully compensated or absorbed with an axial thrust bearing.The thrust bearing can, for example, comprise three individual rolling bearings, each with rolling elements guided in a cage. These rolling bearings are positioned in an asymmetrical arrangement so that the orbiting scroll is securely held in a force equilibrium and in its intended path of motion. This ensures the scroll compressor runs smoothly in both operating modes.

[0034] The axial bearing can also be formed on so-called idler shafts, which are coupled to the orbiting spiral in such a way that the orbiting spiral, when driven by the aforementioned eccentric drive, is prevented from rotating and is forced onto its orbiting path. The idler shafts have integrated shoulder bearings or angular contact ball bearings at both axial ends, which are movably guided in guideways. These guideways are formed in a first guide component fixed to the housing and in a second guide component connected to the orbiting spiral.

[0035] It should be noted at this point that a radially oriented inlet on the scroll compressor would be possible. While this would largely prevent axial loading of the orbiting scroll, when the compressor is charged with pre-compressed air, it would exert a significant radial load on the orbiting scroll, which would be transferred essentially in a radially perpendicular direction to the scroll flights and the drive shaft. Such a load would require a bearing acting in the radial direction. Therefore, an axial alignment of the inlets in combination with an axially acting thrust bearing is more advantageous.

[0036] To achieve the stated object, the invention also relates to a compressed air supply system of a vehicle, comprising a scroll compressor arrangement for generating compressed air, comprising a scroll compressor in the scroll compressor arrangement, which has a fixed scroll and a scroll orbitable around the fixed scroll as well as an inlet and an outlet, and comprising a supply pressure reservoir for storing compressed air generated by the scroll compressor.

[0037] According to the invention, this scroll compressor arrangement is provided with the scroll compressor having two inlets, with the scroll compressor arrangement having an electronically controllable valve device which is functionally connected to the two inlets and to the outlet of the scroll compressor, with the scroll compressor arrangement having an electronic control unit or being electrically connected to such an electronic control unit, with the control unit being electrically connected to the valve device and being designed to control the valve device in such a way that the scroll compressor can be switched at least between a first operating mode and a second operating mode, wherein in the first operating mode ambient air can be sucked in through the first inlet, and wherein in the second operating mode air pre-compressed by the scroll compressor can be sucked in from the supply pressure reservoir or from the outlet of the scroll compressor through the second inlet.

[0038] A compressed air supply system according to the invention therefore comprises a scroll compressor which, with only one pair of a fixed scroll and an orbiting scroll, is advantageously suited for generating various system pressures in commercial vehicles, for example, for pneumatic braking systems. The orbiting scroll of the scroll compressor can be driven by an electric motor. The drive speed is variable by means of an electric drive. This allows the compressed air delivery rate to be variably adjusted.

[0039] A valve device of the scroll compressor arrangement has at least two electrically controllable directional control valves. The directional control valves can each be individually switched to an open position and a closed position by means of an electronic control unit. The control unit can be integrated into an existing compressed air supply system, with a function for controlling the valve device additionally being implemented in control software. Alternatively, a dedicated control unit can be assigned to the scroll compressor. Accordingly, the compressed air supply system can be operated using the scroll compressor arrangement in a first mode for applications with a standard compressed air pressure and in a second mode for applications with a high compressed air system pressure. The control unit can switch the compressed air supply system between these two operating modes at any time as needed using the valve device.

[0040] Finally, the invention also relates to a vehicle, for example a commercial vehicle, with a compressed air supply system with a scroll compressor arrangement, which is constructed according to one of the device claims. The invention is further explained below with reference to an exemplary embodiment shown in the accompanying drawing. The drawing shows

[0041] Fig. 1 is a schematic representation of a compressed air supply system of a vehicle with a scroll compressor arrangement according to the invention,

[0042] Fig. 2a shows a longitudinal section through a scroll compressor including an eccentric drive shaft and an axial bearing as well as a valve device connected to the scroll compressor according to Fig. 1 in a first working position,

[0043] Fig. 2b is a longitudinal section through the scroll compressor according to Fig. 2a in a second working position,

[0044] Fig. 2c a longitudinal section through the scroll compressor Fig. 2a in a third working position,

[0045] Fig. 3 shows a cross section through a scroll compressor according to the invention with three support points for at least one axial bearing,

[0046] Fig. 4 a compressed air supply system with a scroll compressor arrangement which has a pressure relief valve, and

[0047] Fig. 5 a compressed air supply system with a scroll compressor arrangement which has a bypass valve.

[0048] Some components in the figures are the same and are therefore designated by the same reference numerals.

[0049] Accordingly, the scroll compressor assembly 1 shown in Fig. 1 is a component of a compressed air supply system 2 of a vehicle, for example, a commercial vehicle with a pneumatic braking system. Associated with the compressed air supply system 2 are a supply pressure reservoir 19 for storing compressed air generated by the scroll compressor assembly 1, as well as an electronic control unit 20.

[0050] The scroll compressor arrangement 1 essentially comprises a scroll compressor 3 for generating compressed air and a valve device 15. In the example shown, the valve device 15 includes two electromagnetic 2 / 2-way valves 16, 17, which can each be switched to an open position or a closed position by the electronic control unit 20 via a first electrical connecting line 21 between the first electromagnetic 2 / 2-way valve 16 and the control unit 20 and via a second electrical connecting line 22 between the second electromagnetic 2 / 2-way valve 17 and the control unit 20.

[0051] The scroll compressor 3 essentially consists of a stationary first scroll 4 and a second scroll 5 that can orbit around the stationary scroll 4. The two scrolls 4, 5 are arranged almost coaxially nested within one another, and the orbitable scroll 5 can be deflected by an eccentric drive 6 by means of an eccentric crank 30 (Figs. 2a, 2b, 2c) in a plane transverse to a center axis 7 of the scroll compressor arrangement 1. The eccentric drive 6 (see also Figs. 2a, 2b, 2c) is non-positively connected to the rotor of an electric machine 9 via a drive shaft 8 for driving the orbiting scroll 5. The arrow 28 illustrates the mobility of the orbitable scroll 5 during operation of the scroll compressor 3.

[0052] In the embodiment shown, the scroll compressor 3 has two outlets 10, 11 radially outwardly through which ambient air 14 passed through an air filter 13 can be sucked in. The two inlets 10, 11 are arranged or formed on the fixed scroll 4 at a distance from one another in the circumferential direction of the scroll compressor 3. In addition, a central outlet 12 is formed in the region of the radially inner end of the fixed scroll 4, through which the air compressed by the scroll compressor 3 can be discharged and guided via a pneumatic branch line 35a (Fig. 4) to the supply pressure reservoir 19, a pneumatic line 35 (Fig. 4) to the second inlet 11, and via a third pneumatic line 35b (Fig. 1, Fig. 4) to compressed air consumers not shown.

[0053] Figures 2a, 2b, and 2c each show the scroll compressor 3 according to Fig. 1 in a schematically simplified longitudinal section with different movement positions of the orbiting scroll 5. In these figures, the axial alignment of the two inlets 10, 11 and the one outlet 12, as well as the eccentric drive 6, are clearly visible. The scroll compressor 3 is accordingly arranged in a housing 23 and enclosed by it in a pressure-tight manner. The stationary scroll 4 is immovably connected to the housing 23. The orbiting scroll 5 has a base plate 5a on its side remote from the inlet, which, shown in simplified form, is movably mounted on the housing 23 of the scroll compressor 3 via three rolling bearings 29a, 29b. The housing 23 has a first opening, not designated in more detail, in which a first intake nozzle 24 is fastened, said first intake nozzle 24 connecting the first inlet 10 formed by this opening with a first inlet chamber 25 (see Fig.1) pneumatically connects. The first inlet chamber 25 is formed by opposing walls of the orbiting spiral 5 and the stationary spiral 4 as a first inlet-side spiral passage.

[0054] If the first inlet 10 is intended exclusively for the intake of ambient air 14, a separate intake port 24 can be dispensed with, provided that an inlet opening is provided in the housing 23 through which ambient air 14 can be drawn into the first inlet chamber 25. In any case, the first inlet 10 is pneumatically connected to the outlet of the first 2 / 2-way valve 16 and can be opened or closed to the outside by switching this 2 / 2-way valve 6.

[0055] The housing 23 also has a second opening with a second intake port 26 arranged therein, which pneumatically connects the second inlet 11 formed by this opening with a second inlet chamber 27 (see Fig. 1). The second inlet chamber 27 is formed as a second inlet-side spiral passage by opposing walls of the stationary scroll 4 and the orbiting scroll 5.

[0056] The second inlet 11 is provided here for the intake of pre-compressed air and is pneumatically connected to the outlet of the second 2 / 2-way valve 17. By switching this second 2 / 2-way valve 17, the second inlet 11 can be connected to or shut off from a compressed air line 18, 35. In the example shown in Fig. 1, the input side of the second 2 / 2-way valve 17 is pneumatically connected to the supply pressure reservoir 19 via the connecting line 18.

[0057] As Figures 2a, 2b, and 2c show, the three-part axial bearing, of which only the two axial bearings 29a, 29b are visible in the selected illustration, is provided for the axial support of the orbiting spiral 5. The rolling elements 37, 38 of the axial bearings 29a, 29b roll, in simplified form, against a frontal rear wall 31 of the base plate 5a of the orbiting spiral 5 and an immediately adjacent inner wall 32 of the housing 23. The rolling elements 37, 38 of the axial bearings 29a, 29b are each held in a cage 33a, 33b, which are arranged perpendicular to the longitudinal extension of the two spirals 4, 5 according to the spatial axes X, Y, Z of a Cartesian coordinate system shown in Fig. 3 and support the orbitable spiral 5 axially, i.e., in the Z direction of the coordinate system. Thus, forces and moments acting in the axial direction on the orbitable spiral 5 are transmitted to the housing 23.

[0058] As can be seen in a schematic cross-section of the scroll compressor 3 shown in Fig. 3 according to the previous figures, three support points A, B, C are provided on the axial inner side of the housing 23, against which the rolling elements 37, 38 of the three axial bearings 29a, 29b are supported, arranged asymmetrically to one another. The two associated support points A, B of the three support points A, B, C are also marked by arrows in Figures 2a, 2b, 2c.

[0059] As already mentioned above, the axial bearing can also be formed on so-called idler shafts, which are coupled to the base plate 5a of the orbitable spiral 5 in such a way that the orbitable spiral 5, when driven by the aforementioned eccentric drive, is prevented from rotating and is forced along its assigned orbitable path. The idler shafts each have an integrated shoulder bearing or angular contact ball bearing at their two axial ends, which are movably guided in guideways. These guideways are formed in a first guide component fixed to the housing and in a second guide component connected to the base plate 5a of the orbitable spiral 5. Axial forces acting on the orbitable spiral 5 can be transmitted to the housing 23 via the shoulder bearings of the idler shafts.

[0060] The operation of the scroll compressor arrangement 1 is as follows:

[0061] By energizing the electric motor 9, the orbiting spiral 5 is moved in an orbit around the stationary spiral 4. The two spirals 4, 5 mesh with each other, so that spiral passages formed between the spirals 4, 5 increasingly narrow radially inward. As a result, air 14 drawn in from the outside is increasingly compressed in these passages and finally discharged via the outlet 12. Figures 2a to 2c show different movement positions of the orbiting spiral 5, with the movement position shown in Fig. 2b corresponding to the position in Fig. 1.

[0062] In a first operating mode, the first inlet 10 is opened under the control of the control unit 20 and the second inlet 11 is closed, so that ambient air 14 is sucked into the first inlet chamber 25 via the air filter 13 and compressed by the movement of the orbiting scroll 5. For example, the scroll compressor 3 can be designed to deliver a displacement of 250 l / min and an outlet pressure of 13.5 x 10 5 to generate Pa.

[0063] In a second operating mode, the first inlet 10 is closed under the control of the control unit 20 and the second inlet 11 is opened, so that pre-compressed air from the storage reservoir 19 with a pressure of, for example, 13.5 x 10 5 Pa into the second inlet chamber 27 and is further compressed when the orbiting spiral 5 moves. With a constant delivery volume of 250 l / min, for example, an output pressure of 18.5 x 10 5Pa can be generated, which can then be used for pneumatic consumers with an increased pressure requirement.

[0064] Fig. 4 shows a scroll compressor arrangement 1.1 according to a second embodiment, with a second scroll compressor 3.1 and a second electronically controllable valve device 15.1. A second pneumatic connecting line 35 is connected to the outlet 12 of the scroll compressor 3.1, by means of which line, the outlet 12 is pneumatically connected to the second inlet 11 via the second 2 / 2-way valve 17. This allows the scroll compressor 3.1 to be precharged on the inlet side in the second operating mode using its own outlet pressure. Furthermore, a branch line 35a connects the outlet 12 of the scroll compressor 3.1 to the inlet of the supply pressure reservoir 19. This allows the supply pressure reservoir 19 to be ventilated with the outlet pressure generated in the second operating mode.

[0065] If only compressed air generated in the first operating mode is to be stored in the supply pressure reservoir 19, this can be achieved by means of a third electromagnetic 2 / 2-way valve 41, which is arranged in the branch line 35a and is brought into its closed position by the control unit 20 via a third electrical connecting line 42 before the second operating mode begins.

[0066] In order not to overload the scroll compressor 3.1 as well as the supply pressure reservoir 19 and the compressed air consumers possibly connected to the outlet 12 of the scroll compressor 3.1 via a third pneumatic line 35b, a pressure relief valve 36 is arranged in the second pneumatic connecting line 35, which limits the line pressure to a maximum pressure, for example to a pressure of 18.5 x 10 5Pa. The permissible maximum pressure can be adjusted, for example, via a spring preload of the pressure relief valve 36.

[0067] Fig. 5 shows a third embodiment of a scroll compressor arrangement 1.2 with a third scroll compressor 3.2 and a third electronically controllable valve device 15.2. A bypass opening 40 is formed therein, radially between the two inlets 10, 11 and the outlet 12 of this scroll compressor 3.2, which bypass opening is connected to a controllable bypass valve 43. The bypass valve 43 is designed as a fourth electromagnetic 2 / 2-way valve and is electrically connected to the electronic control unit 20 via a fourth electrical connecting line 44. The control unit 20 can actuate the bypass valve 43 to control the outlet pressure of the scroll compressor 3.2 as needed, in particular to reduce the outlet pressure in the second operating mode, in which the scroll compressor 3.2 is already charged with pre-compressed air, even before it leaves the outlet 12 of the scroll compressor 3.2. For this purpose, compressed air is released into the environment as needed.

[0068] List of reference symbols (part of the description)

[0069] 1 First scroll compressor arrangement

[0070] 1.1 Second scroll compressor arrangement

[0071] 1.2 Third scroll compressor arrangement

[0072] 2 compressed air supply system

[0073] 3 First scroll compressor

[0074] 3.1 Second scroll compressor

[0075] 3.2 Third scroll compressor

[0076] 4 Fixed spiral

[0077] 5 Orbitable Spiral

[0078] 5a Base plate of the orbitable spiral

[0079] 6 Eccentric drive

[0080] 7 Geometric center axis of the scroll compressor

[0081] 8 Drive shaft of the orbiting spiral

[0082] 9 Electric machine of the eccentric drive

[0083] 10 First inlet of the scroll compressor

[0084] 11 Second inlet of the scroll compressor

[0085] 12 Outlet of the scroll compressor

[0086] 13 air filters

[0087] 14 Ambient air

[0088] 15 First electronically controllable valve device

[0089] 15.1 Second electronically controllable valve device

[0090] 15.2 Third electronically controllable valve device

[0091] 16 First controllable 2 / 2-way valve of the valve assembly

[0092] 17 Second controllable 2 / 2-way valve of the valve device

[0093] 18 First pneumatic connecting line

[0094] 19 Supply pressure reservoir

[0095] 20 Electronic control unit

[0096] 21 First electrical connecting line

[0097] 22 Second electrical connecting cable

[0098] 23 housings

[0099] 24 First intake manifold at the first inlet

[0100] 25 First inlet chamber of the scroll compressor

[0101] 26 Second intake port at the second inlet 27 Second inlet chamber of the scroll compressor

[0102] 28 Arrow as mobility symbol on the orbitable spiral 5

[0103] 29a First thrust bearing

[0104] 29b Second thrust bearing

[0105] 30 eccentric crank

[0106] 31 Back wall of the base plate of the orbiting spiral

[0107] 32 Inner wall of the housing

[0108] 33a Cage of the first axial bearing 29a

[0109] 33b Cage of the second axial bearing 29b

[0110] 35 Second pneumatic connecting line

[0111] 35a branch line

[0112] 35b Third pneumatic line

[0113] 36 Pressure relief valve

[0114] 37 rolling elements

[0115] 38 rolling elements

[0116] 40 Bypass opening

[0117] 41 Third controllable 2 / 2-way valve of the valve device

[0118] 42 Third electrical connecting line

[0119] 43 Fourth controllable 2 / 2-way valve of the valve assembly, bypass valve

[0120] 44 Fourth electrical connecting line

[0121] A First support point, for the first axial bearing 29a

[0122] B Second support point, for the second axial bearing 29b

[0123] C Third support point, for the third axial bearing x, y, z spatial axes of a coordinate system

Claims

Patent claims 1. Scroll compressor arrangement (1, 1.1, 1.2) for generating compressed air for a compressed air supply system (2) of a vehicle, with a scroll compressor (3, 3.1, 3.2) which has a fixed spiral (4), a spiral (5) which can be orbited around the fixed spiral, and an inlet and an outlet, wherein the compressed air supply system (2) has a supply pressure reservoir (19), and wherein an electronically controllable valve device (15, 15.1, 15.2) is functionally connected to the inlet (10, 11) and / or to the outlet (12) of the scroll compressor (3, 3.1, 3.2) in such a way that the scroll compressor (3, 3.1, 3.2) can be switched between a first operating mode and a second operating mode, wherein in the first operating mode ambient air (14) can be sucked in through the inlet (10, 11), and wherein in the second operating mode by the scroll compressor (3, 3.1, 3.2) pre-compressed air from the supply pressure reservoir (19) or from the outlet (12) of the scroll compressor (3, 3.1, 3.2) can be sucked in through the inlet (10, 11), characterized in that on the scroll compressor (3, 3.1, 3.2) a first inlet (10) and a second inlet (11) are formed, the first inlet (10) being connected on the inlet side to a first controllable 2 / 2-way valve (16) by means of which the first inlet (10) can be pneumatically connected to the ambient air (14) or shut off therefrom, the first inlet (10) being pneumatically connected on the outlet side to a first inlet chamber (25) formed in the stationary spiral (4), the second inlet (11) being connected on the inlet side to a second controllable 2 / 2-way valve (17) by means of which the second inlet (11) can be pneumatically connected to the supply pressure reservoir (19) or to the outlet (12) or shut off therefrom, and the second inlet (11) being connected on the outlet side to a second inlet chamber formed in the stationary spiral (4) (27) is pneumatically connected.

2. Scroll compressor arrangement according to one of the preceding claims, characterized in that the two inlets (10, 11) are arranged or designed in such a way that pressure equalization between these two inlets (10, 11) is not possible.

3. Scroll compressor arrangement according to one of the preceding claims, characterized in that it is arranged in a housing (23), that the first inlet (10) is designed as a first opening in the housing (23), that in the first opening a first intake port (24) is arranged, which is connected to the first inlet chamber (25) and via which air can be sucked into the first inlet chamber (25) when the first 2 / 2-way valve (16) is open, that the second inlet (11) is designed as a second opening in the housing (23), and that a second intake port (26) is arranged in the second opening, which is connected to the second inlet chamber (27), and via which air can be sucked into the second inlet chamber (27) when the second 2 / 2-way valve (17) is open.

4. Scroll compressor arrangement according to one of the preceding claims, characterized in that it is arranged in a housing (23), that the first inlet (10) is designed as a first opening in the housing (23), through which, when the first 2 / 2-way valve (16) is open, air can flow into the interior of the housing and can be sucked into the first inlet chamber (25) via the interior of the housing, that the second inlet (11) is designed as a second opening in the housing (23), in which an intake nozzle is arranged, which is connected to the second inlet chamber (27) and through which, when the second 2 / 2-way valve (17) is open, air can be sucked into the second inlet chamber (27).

5. Scroll compressor arrangement according to one of the preceding claims, characterized in that a pressure relief valve (36) is arranged pneumatically between the outlet (12) of the scroll compressor (3.1) and the supply pressure reservoir (19) and / or between the outlet (12) of the scroll compressor (3.1) and the first inlet (10) and / or between the outlet (12) of the scroll compressor (3.1) and the second inlet (11).

6. Scroll compressor arrangement according to one of the preceding claims, characterized in that the scroll compressor (3.2) has a bypass opening (40) arranged radially between the at least one inlet (10, 11) and the outlet (12), which is connected to a controllable bypass valve (43).

7. Scroll compressor arrangement according to one of the preceding claims, characterized in that at least one inlet (10, 11) of the scroll compressor (3, 3.1, 3.2) is aligned axially parallel to a drive shaft (8) of the orbitable spiral (5), and that the scroll compressor (3, 3.1, 3.2) has at least one axial bearing (29a, 29b) in the form of a rolling bearing or plain bearing for axially supporting the orbitable spiral (5). wherein the at least one axial bearing (29a, 29b) has at least three support points (A, B, C) which are arranged asymmetrically distributed in a plane transverse to the drive shaft (8) of the orbitable spiral (5).

8. Compressed air supply system (2) of a vehicle, with a scroll compressor arrangement (1, 1.1, 1.2) for generating compressed air, with a scroll compressor (3, 3.1, 3.2) in the scroll compressor arrangement, which has a fixed spiral (4) and a spiral (5) orbitable around the fixed spiral as well as an inlet (10, 11) and an outlet (12), and with a supply pressure reservoir (19) for storing compressed air generated by the scroll compressor (3, 3.1, 3.2), characterized in that the scroll compressor (3, 3.1, 3.2) has two inlets (10, 11), that the scroll compressor arrangement (1, 1.1, 1.2) has an electronically controllable valve device (15, 15.1, 15.2), which is functionally connected to the two inlets (10, 11) and to the outlet (12) of the scroll compressor (3, 3.1, 3.2), that the scroll compressor arrangement (1, 1.1, 1.2) has an electronic control unit (20) or is electrically connected to such a control unit, that the control unit (20) is electrically connected to the valve device (15, 15.1, 15.2) and is designed to control it in such a way that the scroll compressor (3, 3.1, 3.2) can be switched at least between a first operating mode and a second operating mode, wherein in the first operating mode, ambient air (14) can be sucked in through the first inlet (10), and wherein in the second operating mode, air pre-compressed by the scroll compressor (3, 3.1, 3.2) can be sucked in from the supply pressure reservoir (19) or from the outlet (12) of the scroll compressor (3) through the second inlet (11).

9. Vehicle, such as a commercial vehicle or passenger car, with a compressed air supply system (2) which is constructed according to one of the device claims.

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