Compressor for a motor vehicle

Abstract

The invention relates to a compressor (2) for a motor vehicle, comprising a compressor housing (14) with a low-pressure inlet (50) and a high-pressure outlet (52), as well as with an electric motor drive (4) and with a compressor head (6) coupled thereto via a drive shaft (30), wherein the compressor head (6) comprises a compressor chamber (40) for compressing an oil-fluid mixture and a high-pressure chamber (56) coupled thereto for pulsation damping, as well as a reservoir chamber (58) coupled to the drive shaft (30) as a high-pressure oil reservoir, wherein the high-pressure chamber (56) and the reservoir chamber (58) are separated from each other by a partition (62), wherein an oil separator (68) for separating the oil-fluid mixture is arranged in the partition (62), wherein an inlet (74) of the oil separator (68) is coupled to the high-pressure chamber (56), wherein a The fluid outlet (76) of the oil separator (68) is coupled to the outlet (52),and wherein an oil outlet (80) of the oil separator (68) is coupled to the reservoir chamber (58).

Description

[0001] The invention relates to a positive displacement machine or a rotary compressor, in particular in the form of a scroll or rolling piston compressor for a motor vehicle, which is used in particular for compressing refrigerant in a vehicle air conditioning system.

[0002] Motor vehicles are regularly equipped with air conditioning systems that, with the help of a refrigerant circuit, condition the vehicle interior (passenger compartment), i.e., cool and heat it. In electrically powered or drivable motor vehicles, such as electric or hybrid vehicles, the air conditioning system can also be used to condition the vehicle battery (traction battery). Such systems generally have a circuit in which a refrigerant is carried. The refrigerant, for example R-744 (carbon dioxide, CO2), is heated in an evaporator and compressed by a (refrigerant) compressor. The refrigerant then releases the absorbed heat via a heat exchanger before being fed back to the evaporator via a throttle.

[0003] In electrically or electric-motor-driven refrigerant compressors, the compressor mechanism, electric motor, and motor electronics (electronic control unit, ECU) are typically housed together in a compressor housing. One part of the compressor housing is thus subjected to suction pressure (low-pressure side) and another part to discharge pressure (high-pressure side). The suction gas is also used to cool the electric motor and electronics.

[0004] Scroll compressors are typically used as refrigerant compressors in vehicle air conditioning systems to compress a refrigerant-oil mixture. The resulting gas-oil mixture is separated, with the separated gas being introduced into the air conditioning circuit, while the separated oil is usually fed to the moving parts within the scroll compressor to lubricate them.

[0005] So-called rolling piston compressors are generally not used for automotive applications, but only for stationary applications, such as refrigeration systems and heat pumps.

[0006] In rotary piston compressors, a cylindrical or piston-like compressor rotor rotates completely around an eccentric axis, which is why rolling piston compressors are also called rotary or rotary compressors. A spring-loaded separating or gate valve (vane) is pressed radially from the outside against the outer circumference of the compressor rotor, dividing a compressor chamber into two separate chambers (suction and pressure chamber). When a gaseous refrigerant enters the compressor on the suction side (suction gas), it is pressed against the separating valve by the compressor rotor rolling along the inner wall of the compressor chamber. The rotary movement reduces the volume of the pressure chamber and thus leads to compression of the refrigerant. The separating valve, which moves back and forth with the rhythm of the rotating rotor, seals off the suction and pressure sides, eliminating the need for additional inlet valves (suction valves) for the compressor chamber.Rotary piston compressors therefore achieve a high coefficient of performance and have particularly low noise levels.

[0007] In stationary applications, rotary piston compressors typically have a vertical hollow shaft with radial bores, one open side of which is immersed in an oil pan (oil sump) that acts as an oil reservoir. The oil is sucked upwards through the hollow shaft and, with the help of an oil flinger inside the shaft, continuously supplies the shaft bearings with oil. Another feature of such rotary piston compressors is that the compressor housing, in particular the oil pan, is subjected to a uniform gas pressure. In other words, the compressor housing is subjected to either high or medium pressure. Due to this uniform gas pressure inside the compressor housing, the shaft end faces of the hollow shaft are at the same pressure level, so that no pressure-related axial force acts on the hollow shaft.

[0008] In contrast, refrigerant compressors in vehicle air conditioning systems have a horizontally oriented shaft when installed. Furthermore, such refrigerant compressors do not have a traditional oil pan. Because the electric motor and electronics are cooled by the suction gas, compressor housings in automotive refrigerant compressors do not have a uniform gas pressure inside the housing.

[0009] An oil reservoir on the low-pressure side of the rotary piston compressor is generally not possible due to the small distance between the compressor housing and the electric motor rotor. With an oil reservoir on the low-pressure side, the additional problem arises as to how the oil is to be pumped from the oil reservoir via the hollow shaft to the plain bearing lubrication.

[0010] The compression mechanism of the rotary piston compressor creates a pulsating flow of the compressed gas-oil mixture. Due to the associated (flow) turbulence, it is not possible to provide a steady oil reservoir on the high-pressure side without additional components, free of refrigerant gas bubbles.

[0011] The invention is based on the object of providing a particularly suitable compressor for a motor vehicle. In particular, a rotary piston compressor with a quiet oil reservoir for supplying the hollow shaft or the plain bearings with oil as a lubricant is to be provided.

[0012] The object is achieved according to the invention with the features of claim 1. Advantageous embodiments and further developments are the subject of the dependent claims (subclaims).

[0013] The compressor according to the invention is intended for, and is suitable and configured for, a motor vehicle, in particular for a vehicle air conditioning system. The compressor comprises a compressor housing with a low-pressure or suction-side inlet and a high-pressure or discharge-side outlet. An electric motor drive is arranged in the compressor housing, which drives a (rolling piston) compressor mechanism. During operation, the compressor conveys or compresses a refrigerant, in particular a chemical or natural refrigerant, preferably carbon dioxide (R744).

[0014] The drive comprises an electric motor, in particular a brushless electric motor, which can be powered by motor or control electronics. The electric motor has a stator fixed to the housing and a rotor mounted so that it can rotate or rotate relative to the stator. The stator is wound with a rotating field or stator winding, with the rotor being equipped, for example, with permanent magnet rotor magnets. The rotor is fixedly connected to a motor or drive shaft. The drive shaft is mounted so that it can rotate or rotate in the compressor housing by means of shaft bearings. The drive shaft is preferably mounted on plain bearings.

[0015] The motor electronics are housed in a fluid-tight, pressure-tight electronics compartment of the compressor housing. The inlet is preferably fluidically oriented such that the incoming refrigerant flows along a housing wall of the electronics compartment, thus cooling it. The refrigerant also flows around the electric motor, cooling, in particular, the energized or energizable rotating field or stator winding.

[0016] The drive shaft is connected to a compressor head. The compressor head contains the compressor mechanism, which draws in the refrigerant from the low-pressure side, compresses it, and discharges it from the compressor housing via the high-pressure side.

[0017] The compressor head has a compressor chamber for compressing an oil-fluid mixture and a coupled high-pressure chamber for pulsation damping as well as a reservoir chamber as a high-pressure oil reservoir.

[0018] The compressor mechanism, which has at least one compressor rotor driven eccentrically by the drive shaft, is arranged in the compressor chamber. Furthermore, a spring-loaded separating slide is arranged in the compressor chamber to separate the compressor chamber into a suction chamber and a pressure chamber. This slide is pressed radially against the compressor rotor by a spring element, in particular a compression or helical spring. The compressed medium is expelled in a pulsating manner via an outlet into the high-pressure chamber. To reduce the resulting pulsations (pressure waves in the flowing medium or varying flow velocity), the high-pressure chamber is preferably designed as a pulsation volume (so-called muffler).

[0019] The tribological conditions during operation are crucial for the robustness and service life of a rotary piston compressor. These can be significantly improved through adequate and continuous lubrication. The rotary piston compressor is primarily oil-lubricated and features an integrated oil circuit for a (lubricating) oil. The term "oil" in this context is not limited to mineral oils. Rather, it can also include fully synthetic or semi-synthetic oil, silicone oil, or other lubricants.

[0020] In particular, a mixture of refrigerant (gas) and special oils (e.g., PAG or POE) is used. The oil is then distributed through the flow conditions within the system and within the compressor. Redistribution of the oil into the system components of a connected refrigerant circuit is undesirable and leads to poorer heat transfer and, consequently, to lower system efficiency (COP). The actual purpose of the oil is the compressor chamber and the lubrication or friction reduction between loaded compressor components such as the shaft bearing and the separating vane.

[0021] During operation of the refrigerant drive or compressor, a fluid in the form of gaseous refrigerant is introduced through the inlet into the compressor housing. This area of ​​the compressor housing forms the suction or low-pressure side of the rotary piston compressor. Within the compressor housing, the refrigerant is mixed with oil to form a fluid-oil mixture or a refrigerant-oil mixture, and is sucked along the rotor and stator through an opening to the compressor head. The mixture of refrigerant and oil is compressed by the compressor mechanism, with the oil serving to lubricate the at least one compressor rotor, thereby reducing friction and consequently increasing efficiency. The oil also serves as a seal to prevent uncontrolled escape of the refrigerant in the pressure chamber to the suction chamber.

[0022] So-called oil separation systems are designed to separate the oil (which is usually present in the form of droplets within the flowing refrigerant) and retain it within the compressor. For this purpose, the high-pressure side features an oil reservoir formed by a reservoir chamber to collect and calm the separated oil. The reservoir chamber and the high-pressure chamber are spatially separated from each other by a partition wall, with an oil separator, such as a cyclone separator, arranged or integrated into the partition wall as an oil separation system. The collected oil can then be cooled in the reservoir chamber via housing surfaces and returned to relevant friction points of the compressor via an oil return system, particularly pressure-driven.

[0023] The oil separator has an inlet for the fluid-oil mixture or refrigerant-oil mixture, as well as a fluid outlet (refrigerant outlet) and an oil outlet. The oil separator inlet is coupled to the high-pressure chamber, allowing a pulsation-reduced flow into the oil separator. The separated fluid or refrigerant is directed toward the compressor housing outlet via the fluid outlet, with the oil being separated into the reservoir chamber via the oil outlet.

[0024] The compressed mixture of refrigerant and oil is fed into a high-pressure chamber within the compressor housing, forming the high-pressure side. Within the oil separator located in the partition wall, the mixture of refrigerant and oil is set into a rotational motion, for example. Due to its increased inertia and increased mass, the heavier oil is directed toward the walls of the oil separator by centrifugal force. Under the influence of gravity, for example, it is collected in a lower area of ​​the oil separator in the reservoir chamber as an oil collection area. While the refrigerant is discharged upwards or laterally through the outlet, the oil is returned to the electric motor via an oil return line.

[0025] The partition wall with the integrated oil separator creates a particularly suitable compressor, in which, on the one hand, the high-pressure chamber acts as a pulsation dampening chamber, and, on the other hand, the reservoir chamber is designed as a high-pressure-side oil reservoir. The pulsation dampening of the high-pressure chamber thus introduces a fluid-oil mixture with reduced pulsation or turbulence into the oil separator, so that the separated oil subsequently contains fewer dissolved gas bubbles (refrigerant bubbles). This creates a quieter oil reservoir in the reservoir chamber for the integrated oil circuit of the rotary piston compressor. This advantageously increases the lubrication and sealing—and thus the efficiency—of the compressor and its service life.

[0026] "Axial" or an "axial direction" is understood here and below to mean, in particular, a direction parallel (coaxial) to the axis of rotation of the electric motor, i.e., along a longitudinal direction of the drive shaft. Accordingly, "radial" or a "radial direction" is understood here and below to mean, in particular, a direction oriented perpendicular (transverse) to the axis of rotation of the electric motor along a radius of the drive shaft or of the electric motor. "Tangential" or a "tangential direction" is understood here and below to mean, in particular, a direction along the circumference of the hollow shaft or of the electric motor (circumferential direction, azimuthal direction), i.e., a direction perpendicular to the axial direction and the radial direction.

[0027] The compressor is designed, for example, as a scroll compressor or a rotary piston compressor. In the following, the compressor is specifically designed, and also referred to, as a rotary piston compressor without restriction of generality.

[0028] The drive shaft, which is arranged particularly horizontally or horizontally when installed, is preferably designed as a hollow shaft in the rotary piston compressor and is also referred to as such below. The hollow shaft is axially open on both sides, which means that the hollow shaft has an axial bore which opens into a high-pressure side hollow shaft inlet and a low-pressure side hollow shaft outlet. The hollow shaft also has a number of radial bores which are connected to the axial bore. The radial bores are preferably arranged at the level of the shaft bearings. The oil carried in the hollow shaft escapes through the radial bores due to centrifugal force and thus lubricates the shaft or plain bearings of the hollow shaft. The hollow shaft is part of the oil return line, with the oil being returned from the reservoir chamber via the hollow shaft under pressure.

[0029] The compressor housing has an outlet chamber volume arranged between the compressor chamber and the outlet, which is separated into the high-pressure chamber and the reservoir chamber by the partition wall. In an advantageous embodiment, the partition wall and the oil separator are designed as a pre-assembled unit, which is installed in the compressor housing to form the high-pressure chamber and the reservoir chamber. In other words, the gas volume on the high-pressure side is separated into two sub-volumes by the partition wall or by the unit. The partition wall is preferably inserted axially into the compressor housing to separate the outlet chamber volume. The partition wall expediently has a circumferential sealing element for radially sealing the high-pressure chamber and the reservoir chamber against the inner wall of the compressor housing.This makes the compressor housing and the outlet chamber volume particularly simple to construct, which simplifies the assembly and manufacture of the rotary piston compressor.

[0030] Since the partition wall is located on the high-pressure side of the rotary piston compressor, it has sufficient mechanical stability to prevent deformation of the partition wall during compressor operation. In a suitable embodiment, the partition wall is designed as a die-cast part, particularly an aluminum die-cast part, or as a plastic part, particularly an injection-molded part.

[0031] An additional or further aspect of the invention provides for a riser pipe to be arranged between the oil outlet of the oil separator and the reservoir chamber. The riser pipe opens into the reservoir chamber. The riser pipe ensures the highest possible filling level of the reservoir chamber with oil. In other words, it ensures that the high-pressure side oil reservoir is filled as completely as possible, so that sufficient oil is always available for the oil return via the hollow shaft.

[0032] In a preferred embodiment, the riser pipe is integrated into the partition wall. The riser pipe is preferably constructed in one piece, i.e., monolithic, with the partition wall, or is molded onto or into it. This achieves a particularly advantageous structural functional integration of the partition wall. In particular, the partition wall thus essentially fulfills three functions: separation of the oil reservoir (reservoir chamber) and pulsation damping (high-pressure chamber), oil separation, and ensuring a desired fill level in the oil reservoir.

[0033] The orientation or angle of the riser pipe relative to the oil separator or to a direction of gravity depends on the position of the compressor housing outlet. The riser pipe is preferably oriented as upright as possible to ensure the highest possible fill level in the oil reservoir. In a suitable orientation, the riser pipe is essentially vertical, i.e., oriented parallel to the direction of gravity. Alternatively, the riser pipe has an angle as acute or shallow as possible, less than 45°, for example, 0° to 45°, in particular approximately 30°, relative to the direction of gravity. For example, the riser pipe can have an inclination in a range of ± 45°.

[0034] In a practical development, the partition wall has a cylindrical channel in which the oil separator is located or inserted. Preferably, the channel is open axially at the end face toward the outlet of the compressor housing, with the fluid outlet of the oil separator oriented toward this end face. The channel and the oil separator located therein establish a fluid and pressure connection between the high-pressure chamber and the reservoir chamber.

[0035] For this purpose, the channel has a first channel inlet leading from the high-pressure chamber into the channel, with the inlet of the oil separator being arranged at the first channel inlet. The channel further has a second channel inlet leading from the reservoir chamber into the channel. Preferably, fluid or coolant that was dissolved in the separated oil is led from the oil reservoir back into the channel, in particular to the inlet of the oil separator. The channel further has a channel outlet leading from the channel volume to the reservoir chamber or to the riser pipe, which is arranged in the region of the oil outlet of the oil separator.

[0036] In an advantageous embodiment, the second channel inlet from the reservoir chamber and the channel outlet into the reservoir chamber or into the riser pipe are arranged offset from one another in the direction of gravity, wherein the second channel inlet is arranged in particular above the channel outlet in the direction of gravity.

[0037] Preferably, the separated oil is fed into the riser pipe via the channel outlet. The oil is poured into the reservoir chamber from above via the riser pipe, counter to gravity, allowing the fluid to settle and defoam. In particular, bubbles (fluid or refrigerant) rise from the fluid or oil sump to the surface and are guided back to the oil separator inlet through the second channel inlet located above. This ensures that, if possible, only fluid or oil is returned via the hollow shaft.

[0038] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. In the drawings: Fig. 1 shows a schematic representation of a rotary piston compressor, Fig. 2 in a perspective sectional view, a section of an outlet chamber volume of the rotary piston compressor which is divided by a partition wall assembly into a high-pressure chamber and a reservoir chamber, Fig. 3 in a perspective sectional view of the outlet chamber volume, with the partition wall assembly having an integrated riser pipe, Fig. 4 in perspective view the partition wall assembly with a view of a high-pressure chamber side, Fig. 5 in perspective view the partition assembly with a view of a reservoir chamber side, Fig. 6 shows a perspective view of a partition wall assembly in a partially disassembled state, and Fig. 7 shows the partition wall assembly in perspective sectional view.

[0039] Corresponding parts and sizes are always provided with the same reference symbols in all figures.

[0040] The Fig. Figure 1 shows a schematic and highly simplified representation of a compressor 2 according to the invention, which is installed, for example, as a refrigerant compressor in a refrigerant circuit (not shown in detail) of a motor vehicle's air conditioning system. The refrigerant pumped is, for example, R744. The compressor 2 is designed, for example, as a rotary piston compressor and is also referred to as such below.

[0041] The modularly constructed electromotive refrigerant or rotary piston compressor 2, for example, has an electric (electromotive) drive (drive module) 4 and a compressor head (compressor module) 6 coupled to it. Between the drive 4 and the compressor head 6, a bearing plate (center plate) 8 is provided as a mechanical interface, by means of which the compressor head 6 is connected to the drive 4.

[0042] The bearing plate 8 forms an intermediate wall between a drive housing 10 and a compressor head housing 12. The bearing plate 8, the drive housing 10, and the compressor head housing 12 form a compressor housing 14 of the rotary piston compressor 2. The compressor head 6 is connected (joined, screwed) to the drive 4, for example, by means of flange connections distributed around the circumference and extending in an axial direction A of the rotary piston compressor 2.

[0043] A compressor-side housing section of the drive housing 10 is designed as a motor housing or motor compartment 16 for accommodating an electric motor 18 and is closed on the one hand by an integrated housing partition 20 to an electronics compartment (electronics housing) 24 provided with a housing cover 22 and containing motor electronics (electronics) (not shown in detail) that controls the electric motor 18, and on the other hand by the bearing plate 8. The drive housing 10 has, in the area of ​​the electronics housing 16, a connection section (not shown in detail) for electrically contacting the electronics 18 with an on-board electrical system of the motor vehicle.

[0044] The electric motor 18, which is particularly brushless, has a housing-mounted or stationary stator 26, which is equipped with a rotating field winding. The rotating field winding is connected to the electronics by means of vias through the (housing) partition 20. The electric motor 18 further has a rotor 28, which is rigidly connected to a drive or motor shaft 30. The drive shaft 30 is designed as a hollow shaft and is also referred to as such below.

[0045] “Axial” or an “axial direction A” is understood here and below to mean, in particular, a direction parallel (coaxial) to the axis of rotation of the electric motor 18, i.e., along the longitudinal direction of the rotary piston compressor 2. Correspondingly, “radial” or a “radial direction” is understood here and below to mean, in particular, a direction oriented perpendicular (transverse) to the axis of rotation of the electric motor 18 along a radius of the electric motor 18. “Tangential” or a “tangential direction” is understood here and below to mean, in particular, a direction along the circumference of the electric motor (circumferential direction, azimuthal direction), i.e., a direction perpendicular to the axial direction and the radial direction. In the figures, the direction of gravity (direction of gravity) is denoted by g and is shown as an example.

[0046] The hollow shaft 30 has a central axial bore 32, which opens into a compressor head-side (hollow shaft) inlet 34 and an electric motor-side (hollow shaft) outlet 36 on the shaft end face or shaft end. The hollow shaft 30 also has a number of axially distributed radial bores (not shown in detail). These bores extend through the hollow shaft 30, starting from the bore 32, in a radial direction and are open toward the outer circumference of the hollow shaft 30.

[0047] The compressor head 6 has a (rolling piston) compressor mechanism. In the exemplary embodiment, the compressor mechanism is particularly designed in two stages, with two compressor rotors 38a, 38b being eccentrically joined to the hollow shaft 30. The compressor rotors 38a, 38b are arranged in a compressor chamber 40. A valve plate 42, fixed to the housing, is arranged between the compressor rotors 38a, 38b, which divides the compressor chamber 40 into a first sub-chamber 40a facing a low-pressure side 44 and a second sub-chamber 40b facing a high-pressure side 46.

[0048] Arranged in each of the subchambers 40a, 40b are one of the compressor rotors 38a, 38b and a spring-loaded separating vane (not shown in detail) for separating the subchambers 40a, 40b into a suction chamber and a pressure chamber, respectively. The separating vanes are pressed radially against the respective compressor rotor 38a, 38b by means of a spring element, in particular a compression or helical spring. Subchamber 40a is fluidly connected to the motor chamber 16 forming the low-pressure side 44 of the compressor housing 14, as well as to subchamber 40b. Subchamber 40b is correspondingly fluidly connected to subchamber 46a and an outlet chamber volume 48 forming the high-pressure side 46 of the compressor housing 14.

[0049] The rotary piston compressor 2 has a (refrigerant) inlet or (refrigerant) supply 50 for connection to the refrigerant circuit and a (refrigerant) outlet 52. The inlet 50 is formed in an area of ​​the drive housing 10 facing the electronics compartment 24. The outlet 52 is formed on a bottom of a compressor head housing 12 in the area of ​​the outlet chamber volume 48. When connected, the inlet 50 connected to the motor compartment 18 forms the low-pressure or suction side 44 (suction gas side), and the outlet 52 forms the high-pressure or pump side (pump side) of the rotary piston compressor 2.

[0050] The hollow shaft 30, which is arranged particularly horizontally or horizontally in the installed state, is rotatably or rotatably mounted in the compressor housing 14 by means of three shaft bearings. The shaft bearings, not shown in detail, are each preferably designed as plain bearings. One shaft bearing is arranged in a bearing seat connected to the motor compartment 16, which is formed on the housing base or on the intermediate wall 20 of the drive housing 10. The second shaft bearing is received in the bearing plate 8 delimiting the partial chamber 38a, wherein the third shaft bearing is arranged in a bearing plate 53 that delimits the partial chamber 40b from the outlet chamber volume 48.

[0051] For example, in the Fig. As shown in more detail in Figure 2, a partition assembly 54 is inserted into the compressor head housing 14, which divides the outlet chamber volume 48 or the high-pressure side 46 into a high-pressure chamber 56 and a reservoir chamber 58. An axial bore 60 of the compressor head housing 14, which extends laterally past the high-pressure chamber 56, opens into the reservoir chamber 58.

[0052] The partition wall assembly 54 has a disc- or plate-shaped partition wall (separating disk) 62. A sealing element 64 is provided on the outer periphery of the partition wall 60, which radially seals the partition wall 62—and thus the high-pressure chamber 56 and the reservoir chamber 58—against the inner walls of the compressor head housing 12.

[0053] A cylindrical channel 66 is introduced or molded into the partition wall 62, which is particularly designed as a die-cast part, and in which an oil separator 68 is arranged. The high-pressure chamber 56 is coupled to the outlet of the compression chamber 40 and the channel 66. The channel 66 is coupled to the high-pressure chamber 56, to the outlet 52, and to the reservoir chamber 58.

[0054] The channel 66 is connected to the high-pressure chamber 56 by a channel inlet (not shown in detail). The channel 66 is open axially at the end face toward the outlet 52 of the compressor head housing 12 with respect to a channel longitudinal axis, wherein the oil separator 68, in the installed state, extends at least partially into the compressor head housing 12 or into the outlet 52 (cf., for example, Fig. 2). The channel 66 further has two fluid connections to the reservoir chamber 58 in the form of a channel outlet 70 and a channel inlet 72.

[0055] The compressed oil-refrigerant mixture is introduced from the compressor chamber 40 into the high-pressure chamber 56 as a pulsation dampening volume. From there, the pulsation-damped oil-refrigerant mixture flows through the channel inlet into channel 66, where it is fed radially and / or tangentially into an inlet 74 of the oil separator 68. The oil separator 68 is designed, for example, as a cyclone separator and separates the flowing oil-refrigerant mixture into a refrigerant gas stream, which is discharged via a fluid outlet 76 to the outlet 52, and into droplet-shaped oil 78, which is separated into the channel 66 via an oil outlet 80.

[0056] The separated oil 78 collects due to gravity at a bottom of the channel 66 opposite the outlet 52. In the bottom region, a bore oriented radially to the channel 66 and parallel to the axial direction A is introduced as a channel outlet 70, through which bore the oil 78 flows into the reservoir chamber 58. The oil 78 is collected and calmed in the reservoir chamber 58 designed as a (high-pressure) oil reservoir, with gaseous refrigerant dissolved in the separated oil 78 escaping from the oil 78 as bubbles (defoaming) and being returned via the channel inlet 72 to the inlet 74 of the oil separator 68. For this purpose, the channel inlet 72 is arranged above the channel outlet 70 in the direction of gravity g in the installed state. Preferably, the channel inlet 72 is arranged flush with the inlet 74 with respect to the direction of gravity g.The separated and returned refrigerant is discharged through the fluid outlet 76 and via the outlet 52 from the compressor housing 14.

[0057] During compressor operation, the refrigerant is drawn into the motor compartment 16 through the inlet 50. The refrigerant flows along the partition wall 20, allowing the motor electronics to be cooled through the partition wall 20. Furthermore, the refrigerant flows around the rotating field winding of the stator 26, cooling it.

[0058] To lubricate the shaft bearings, a lubricant or oil (e.g., PAG or POE) is added to the refrigerant within the motor compartment 16 or in the low-pressure side 44 of the compressor housing 14. The fluid flow delivered by the rotary piston compressor 2 is thus a mixture of the gaseous refrigerant and the liquid, droplet-like oil.

[0059] The refrigerant-oil mixture is drawn through corresponding openings in the bearing plate 8 into the suction chamber of the sub-chamber 40a and compressed by the first compressor rotor. The compressed refrigerant-oil mixture is introduced into the suction chamber of the sub-chamber 40a, where it is further compressed by the second compressor rotor. The oil also serves to lubricate the two separating vanes, thus reducing friction and consequently increasing efficiency. The oil also serves to seal the suction and pressure chambers separated by the separating vanes, preventing uncontrolled escape via the separating vanes. After this two-stage compression, the compressed refrigerant-oil mixture is introduced into the high-pressure chamber 56 or the high-pressure side 46 of the compressor housing 14.

[0060] The pulsations of the compressed refrigerant-oil mixture are dampened by the volume of the high-pressure chamber 56, and the refrigerant-oil mixture is introduced into channel 66. The oil is separated from the refrigerant by the oil separator 68. The refrigerant is expelled via outlet 52, with the oil 78 being collected in the reservoir chamber 58 and conveyed back to the low-pressure side 44 via the oil return line for lubrication of the shaft bearings.

[0061] The reservoir chamber 58 is in the Fig. 2, the oil 78 is at least partially filled with the separated oil 78. Due to the pressure difference between the high-pressure side 46 and the low-pressure side 44, the oil 78 flows through the bore 60. The bore 60 is arranged at a bottom of the reservoir chamber 58 with respect to the direction of gravity g.

[0062] For example, a throttle element (not shown in detail) can be arranged in the bore 60, which expands the (static) high pressure of the oil 78 to the low pressure level of the low-pressure side 44. The low-pressure oil 78 is then guided via a radial bore 82 into a receptacle 84 arranged between the compressor chamber 40 and the high-pressure chamber 56, where it enters the hollow shaft inlet 34. The reservoir chamber 58 is thus coupled or connected to the hollow shaft inlet 34 of the hollow shaft 30 via the bores 60, 82 and the receptacle 84.

[0063] The oil 78 flows axially through the bore 32 to the hollow shaft outlet 36. The radial bores are arranged at the level of the shaft bearings, so that the oil 78 is propelled from the bore 32 through the radial bores by centrifugal force, thus lubricating the shaft bearings. The excess oil 78 exits the hollow shaft outlet 36 into the engine compartment 16 or the low-pressure side 46, where it is mixed again with the refrigerant.

[0064] Below is a second embodiment of the partition wall assembly 54 based on the Fig. 3 to 7 are explained in more detail.

[0065] In this embodiment, the partition 62 of the partition assembly 54 includes an additional riser tube 86 connecting the channel outlet 70 to the reservoir chamber 58.

[0066] The Fig. 4 and Fig. The partition wall 62 shown individually in Figure 5 is designed in particular as a die-cast part, for example as an aluminum die-cast part, wherein the channel 66 and the riser pipe 86 are formed integrally, i.e. one-piece or monolithic, onto the partition wall 62.

[0067] The riser pipe 86 ensures that the reservoir chamber 58 is filled with oil 78 as high as possible ( Fig. 3). In other words, it is ensured that the high-pressure side oil reservoir is filled as completely as possible, so that sufficient oil 78 is always available for the oil return via the hollow shaft 30.

[0068] As particularly in Fig.As can be seen in Figure 5, the riser pipe 86 is oriented at an angle W to a channel's longitudinal direction. In this embodiment, the channel 66 is arranged substantially parallel to the direction of gravity g in the installed state, so that the riser pipe 86 is oriented obliquely or inclined to the direction of gravity g. In this embodiment, the riser pipe 86 has an angle W of approximately 30°.

[0069] The separated oil 78 is fed into the riser pipe 86 via the channel outlet 70. The oil 78 is poured into the reservoir chamber 58 "from above" via the riser pipe 86, counter to the direction of gravity g, so that improved settling and defoaming can take place.

[0070] The claimed invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can also be derived therefrom by those skilled in the art within the scope of the disclosed claims without departing from the subject matter of the claimed invention. In particular, all individual features described in connection with the various exemplary embodiments can also be combined in other ways within the scope of the disclosed claims without departing from the subject matter of the claimed invention.

[0071] For example, the compressor 2 can also be designed as a scroll compressor with corresponding nested scroll parts, whereby the design of the partition wall 62 is transferable accordingly. The key difference in a scroll compressor is the design of the oil return from the reservoir chamber 58 to the low-pressure side 44, since no hollow shaft extending through the compressor mechanism is provided. In a scroll compressor, the oil return is integrated, in particular, into the compressor housing 14, in particular into the compressor head housing 12 or into the housing walls. List of reference symbols 2 compressors / rotary piston compressors 4 Drive 6 Compressor head 8 Bearing shield 10 drive housing 12 Compressor head housing 14 Compressor housing 16 Engine compartment 18 electric motor 20 Housing partition 22 Housing cover 24 Electronics compartment 26 Stator 28 Rotor 30 Drive shaft / hollow shaft 32 bore 34 Hollow shaft inlet 36 Hollow shaft outlet 38a, 38b Compressor rotor 40 Compressor chamber 40a, 40b subchamber 42 Valve plate 44 Low pressure side 46 High pressure side 48 outlet chamber volume 50 admission 52 Outlet 53 Bearing shield 54 Partition assembly 56 High pressure chamber 58 Reservoir chamber 60 holes 62 Partition wall 64 Sealing element 66 channel 68 oil separators 70 sewer inlet 72 sewer outlet 74 Entrance 76 Fluid outlet 78 Oil 80 Oil outlet 82 radial bore 84 recording 86 riser pipe A axial direction g direction of gravity W angle

Claims

[1] Compressor (2) for a motor vehicle, comprising a compressor housing (14) with a low-pressure side inlet (50) and a high-pressure side outlet (52) as well as with an electric motor drive (4) and with a compressor head (6) coupled thereto via a drive shaft (30), - wherein the compressor head (6) has a compressor chamber (40) for compressing an oil-fluid mixture and a high-pressure chamber (56) coupled thereto for pulsation damping as well as a reservoir chamber (58) coupled to the drive shaft (30) as a high-pressure oil reservoir, - wherein the high-pressure chamber (56) and the reservoir chamber (58) are separated from each other by a partition wall (62), - wherein an oil separator (68) is arranged in the partition wall (62) for separating the oil-fluid mixture, - wherein an inlet (74) of the oil separator (68) is coupled to the high-pressure chamber (56), - wherein a fluid outlet (76) of the oil separator (68) is coupled to the outlet (52), and - wherein an oil outlet (80) of the oil separator (68) is coupled to the reservoir chamber (58). [2] Compressor (2) according to claim 1, characterized by that the partition wall (62) and the oil separator (68) are a pre-assembled assembly (54) which is arranged in the compressor housing (14) to form the high-pressure chamber (56) and the reservoir chamber (58). [3] Compressor (2) according to claim 1 or 2, characterized by that the partition wall (62) is designed as a die-cast part. [4] Compressor (2) according to one of claims 1 to 3, characterized by that a riser pipe (86) is arranged between the oil outlet (80) of the oil separator (68) and the reservoir chamber (58). [5] Compressor (2) according to claim 4, characterized by that the riser pipe (86) is integrated into the partition wall (62). [6] Compressor (2) according to claim 4 or 5, characterized bythat the riser pipe (86) is oriented parallel to a direction of gravity (g). [7] Compressor (2) according to one of claims 1 to 6, characterized by that the partition wall (62) has a cylindrical channel (66) in which the oil separator (68) is seated. [8] Compressor (2) according to claim 7, characterized by that the channel (66) is open axially at the end face to the outlet (52), wherein a first channel inlet opens from the high-pressure chamber (56) into the channel (66), wherein a second channel inlet (72) opens from the reservoir chamber (58) into the channel (66), and wherein a channel outlet (70) couples the channel (66) to the reservoir chamber (58). [9] Compressor (2) according to claim 8, characterized by that the second channel inlet (72) and the channel outlet (70) are arranged offset from one another in the direction of gravity (g). [10] Compressor (2) according to claim 9, characterized bythat the second channel inlet (72) is arranged above the channel outlet (70) in the direction of gravity (g).

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