Refrigerant Compressor

Abstract

The present application relates to a refrigerant compressor (100) for mobile applications, comprising a compressor section (30) formed with a variable compression chamber (39) for receiving and compressing a refrigerant flowing through a working medium circuit, and a motor section (10) in which a brushless electric motor is arranged, comprising a stator (11) and a rotor (12) in driving connection with the compressor section (30). The present application is characterized in that the stator (11) and the rotor (12) are separated from each other in a liquid-tight and / or gas-tight manner by a separating pot (13).

Description

[Technical field]

[0001] The present invention relates to a refrigerant compressor for mobile applications according to the preamble of claim 1. Furthermore, the present invention relates to a motor vehicle, in particular a battery electric vehicle or a fuel cell vehicle, equipped with such a refrigerant compressor. [Background technology]

[0002] A refrigerant compressor of the type mentioned at the outset is known, for example, from the international patent application WO 2017 / 108572 A1. The known refrigerant compressor is intended for use in motor vehicles and comprises a housing with a compressor part and a motor part. A variable compression chamber is formed in the compressor part, which can compress the refrigerant flowing through the working medium circuit. The known refrigerant compressor is driven by a brushless electric motor arranged in the motor part. The electric motor comprises a stator and a rotor, the rotor being connected to the compressor part. In the refrigerant compressor mentioned at the outset, the waste heat of the electric motor generated during operation is generally dissipated by guiding the refrigerant through the motor part before it is fed to the compressor part. The refrigerant flows through the gap between the stator and the rotor and absorbs the heat generated in the electric motor. In this way, the electric motor is cooled.

[0003] The refrigerants used in refrigerant compressors usually contain oil or other flammable components. This is hardly a problem in conventional refrigerant compressors, since they are usually operated at low voltages of 24 or 48 volts. However, new generations of vehicles, especially battery electric vehicles and fuel cell vehicles, use high-voltage systems designed for voltages of 400 or 800 volts. Such high voltages impose correspondingly high demands on the insulation of electrical components. Otherwise, especially in refrigerant compressors, there is a risk of the refrigerant igniting due to sparks. For this reason, efforts are made to insulate the fluid-guiding components as effectively as possible from the refrigerant flow. Summary of the Invention [Problem to be solved by the invention]

[0004] It is therefore an object of the present invention to provide a refrigerant compressor for mobile applications having improved electrical insulation, in particular to enable the refrigerant compressor to operate safely in the environment of a high voltage system of at least 400 V. Furthermore, it is an object of the present invention to provide a motor vehicle equipped with such a refrigerant compressor. [Means for solving the problem]

[0005] According to the invention, the above problem is solved for the refrigerant compressor by the subject matter of claim 1 and for the motor vehicle by the subject matter of claim 13.

[0006] The invention is therefore based on the idea of ​​presenting a refrigerant compressor for mobile applications, comprising a compressor part and a motor part, in which a variable compression chamber is formed for receiving and compressing the refrigerant flowing through a working medium circuit, in which a brushless electric motor is arranged, comprising a stator and a rotor which is drivingly connected to the compressor part, according to the invention the stator and the rotor being separated from each other in a liquid-tight and / or gas-tight manner by a separating pot.

[0007] In brushless electric motors, the stator contains the current carrying coils. To provide a good electrical isolation of these current carrying elements from the compressor section, an isolation pot is provided. The isolation pot separates the stator from the rotor in a liquid-tight manner, thereby forming an additional barrier between the conductive parts and the refrigerant flowing through at least the compressor section.

[0008] In a preferred embodiment of the invention, the refrigerant compressor is a reciprocating piston compressor or a rotary piston compressor, in particular the refrigerant compressor is a scroll compressor having a displacing spiral and an opposing spiral revolving within the compressor section, the displacing spiral and the opposing spiral engaging with each other such that a variable compression chamber is formed between the spirals.

[0009] The separating pot can separate the suction chamber, in which the stator is preferably arranged, from the back pressure chamber in a liquid-tight and / or gas-tight manner. In the refrigerant compressor according to the invention, the suction chamber is preferably not through-flowed by the refrigerant, as in the prior art is provided for cooling the electric motor. In the case of scroll compressors, it is advantageous if the back pressure chamber is arranged on the side of the displacement spiral facing the counter spiral. The precompressed refrigerant can be guided into the back pressure chamber via a corresponding flow passage so that the compressor scroll is pressed against the counter spiral. The pressure in the back pressure chamber thus improves the sealing between the displacement spiral and the counter spiral. The back pressure chamber is usually formed in the motor part, and in the refrigerant compressor according to the invention, the separating pot advantageously ensures that no fluid exchange takes place between the back pressure chamber and the suction chamber. The suction chamber is thereby separated gas-tight from the back pressure chamber.

[0010] In particular, the isolating pot can extend through the gap between the stator and the rotor, in particular the isolating pot houses and separates the rotor in a liquid-tight and gas-tight manner from the stator, which contains the coils through which the current flows.

[0011] In order to achieve good insulation and not affect the electric motor, a preferred embodiment of the invention provides that the separation pot comprises or consists of a non-magnetic material. In particular, the non-magnetic material can comprise or be plastic, stainless steel, aluminum or carbon fiber. The use of plastic or carbon fiber or carbon fiber composite materials is preferred for applications where the weight of the refrigerant compressor needs to be reduced.

[0012] In order to avoid interactions between the conductive parts of the refrigerant compressor, in particular the stator, and the refrigerant, it is advantageous for the working medium circuit to include a compressor inlet opening directly, in particular directly from the outside of the refrigerant compressor, into the compressor section, so that, unlike the prior art, the refrigerant is not guided to the compressor section via the motor section, but is instead introduced directly into the compressor section, which allows for an increased distance between the flow passages guiding the refrigerant and the stator, further reducing the risk of interactions between the working medium circuit and the stator.

[0013] In general, the electric motor of the refrigerant compressor according to the invention can be cooled by a cooling device connected externally to the motor part. In particular, the motor part can have a motor housing connected to or equipped with a cooling device. The cooling device can be, for example, a coolant flow path, which is in contact with the motor housing or includes a cooling flow path formed in the motor housing. In particular, the coolant flow path is preferably separated from the working medium circuit. A thermal connection can be provided, for example, for transferring thermal energy from the refrigerant to the refrigerant. For this purpose, for example, a heat exchanger can be used. A suitable separation between the refrigerant circuit and the working medium circuit is described in the German patent application entitled "Positive Displacement Fluid Machine According to the Spiral Principle" filed by the applicant on the same day.

[0014] In order to achieve good heat dissipation from the coils of the stator to the motor housing, in a preferred variant of the invention, the stator has coils, the head of which is cast with a stator head that is connected to the motor housing. The stator head thus forms a heat conducting element that transfers the heat generated in the coils via the coil head to the motor housing. The motor housing can dissipate this heat passively via the surrounding air or, preferably, via an active cooling device.

[0015] In order to create a good gas-tight seal between the stator and the rotor, it is particularly expedient if the separating pot has a bearing receptacle in which the bearing of the drive shaft is fitted. The drive shaft is preferably connected to the rotor so that it cannot rotate. In order to completely isolate the rotor from the stator, it is advantageous if the separating pot also surrounds the axial end of the drive shaft. This is particularly advantageously achieved if the bearing for the drive shaft is fitted in the separating pot and therefore also if the separating pot surrounds the thrust bearing of the drive shaft.

[0016] The separating pot may furthermore be sealingly connected to a central plate, which separates the motor part from the compressor part. The central plate may in particular be part of the entire housing of the refrigerant compressor. Preferably, the central plate is sealed to the motor part, in particular the motor housing, and to the compressor part, in particular the compressor housing, respectively, by means of seals. In this way, a good and complete sealing of the chamber containing the rotor is achieved. The rotor is thus hermetically separated from its surroundings, in particular the stator.

[0017] In this respect, the central plate can be arranged between the motor housing and the compressor housing. Typically, the motor part can have a motor housing and the compressor part can have a compressor housing. The central plate is preferably arranged between the motor housing and the compressor housing, in particular clamped between them. This provides a good seal and at the same time makes maintenance very easy: since the central plate extends between the motor housing and the compressor housing, the compressor housing can be removed for maintenance without compromising the gas-tight separation between the rotor and the stator by the separating pot.

[0018] A secondary aspect of the present invention relates to a motor vehicle, in particular a battery electric vehicle or a fuel cell vehicle, equipped with a refrigerant compressor as described above. The motor vehicle described herein is preferably a four-wheeled passenger car.

[0019] The invention will now be explained in more detail on the basis of an embodiment with reference to the accompanying schematic drawings. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is an exploded view showing a portion of a refrigerant compressor according to a preferred embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view through the refrigerant compressor according to FIG. [Diagram 3] FIG. 3 is a detailed view of FIG. [Figure 4] FIG. 4 is a partial cross-sectional view of the refrigerant compressor according to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] FIG. 1 shows a part of a refrigerant compressor 100 with a motor part 10 and a compressor part 30. The motor part 10 is shown open, in particular the rotor 12 of the electric motor. The rotor 12 is connected non-rotatably with a drive shaft 15, which is supported in a pot-side bearing 16. In the exploded view according to FIG. 1, the separation pot 13 with the bearing receptacle 25 is also visible. The bearing receptacle 25 is designed so that the pot-side bearing 16 can be fitted in. The bearing receptacle 25 is formed integrally with the rotor receptacle 26. The rotor receptacle 26 and the bearing receptacle 25 each have a cylindrical contour, the cross-sectional diameter of the rotor receptacle 26 being larger than the cross-sectional diameter of the bearing receptacle 25. In the assembled state, the rotor receptacle 26 completely accommodates the rotor 12.

[0022] At the axial end of the drive shaft 15 opposite the pot-side bearing 16, a compressor-side bearing 17 can be seen, which is fixed to a center plate 40. The center plate 40 separates the motor section 10 from the compressor section 30. The center plate 40 is fixedly connected to the compressor housing 34 of the compressor section 30.

[0023] 2 shows a cross section of a refrigerant compressor 100. The refrigerant compressor has a motor section 10 including a motor housing 20. An inverter chamber 21 is arranged in the motor housing 20 to accommodate electronic components of an inverter for controlling the stator. The inverter chamber 21 is separated from a motor chamber 28. An electric motor including a stator 11 with a coil 22 is arranged in the motor chamber 28. The coil 22 includes a coil head 23, to which a stator head is preferably cast and connected to the motor housing.

[0024] The electric motor further comprises a rotor 12 arranged coaxially with the stator 11. Between the rotor 12 and the stator 11, a gap 14 is formed, through which the separating pot 13, in particular its rotor container 26, extends. The separating pot 13 divides the motor chamber 28 into a suction chamber 28a containing the stator 11 and a drive chamber 28b in which the rotor 12 and the drive shaft 15 are arranged. A bearing container 25 of the separating pot 13, which accommodates the pot-side bearing 16 of the drive shaft 15, is fixed in an axial holder 29 of the motor housing 20.

[0025] The separation pot 13 extends beyond the rotor 12 and reaches a central plate 40. The central plate 40 has an annular step 41 which projects into the separation pot 13, in particular into the rotor vessel 26, and forms a sealed connection between the separation pot 13 and the central plate 40. The central plate 40 further accommodates a compressor-side bearing 17 which supports a drive shaft 15. The drive shaft 15 extends through the compressor-side bearing 17 and terminates in an eccentric guide 18 which engages in a displacement spiral 31 of the compressor section 30.

[0026] Compressor section 30 further includes a compressor housing 34 connected to a center plate 40. Specifically, center plate 40 is disposed between compressor housing 34 and motor housing 20.

[0027] In the compressor section 30, a displacement spiral 31 and a counter spiral 32 are arranged. The displacement spiral 31, which can be revolved by the drive shaft 15 via an eccentric guide 18, is engaged in the counter spiral 32. The engagement of the displacement spiral 31 in the counter spiral 32 forms at least one variable compression chamber 39, the volume of which varies with the revolving movement of the displacement spiral 31. The refrigerant flows through the compression chamber 39, is compressed by the change in the volume of the compression chamber 39 and is guided with increased pressure into the high pressure chamber 33 via the central outlet opening 35. From the high pressure chamber 33, the refrigerant reaches the working medium circuit via a corresponding outlet.

[0028] 3 shows in detail the connection between the compressor housing 30 and the motor section 10. In particular, a center plate 40 is disposed between the motor housing 20 and the compressor housing 34. A seal 24 is disposed between the center plate 40 and the motor housing 20, and between the center plate 40 and the compressor housing 34, respectively, so that the entire refrigerant compressor 100 is hermetically sealed against the outside. The seal 24 is preferably liquid-tight and / or gas-tight.

[0029] A further seal between the central plate 40 and the compressor section 30 takes place in particular between the central plate 40 and the displacement spiral 31. For this purpose, the central plate 40 has a sliding plate 38 in the area that is rubbed by the revolution movement of the displacement spiral 31. The displacement spiral 31 comprises a sealing groove 36 in which a sliding seal 37 is arranged. The sliding seal 37 has a sliding element 37a and a pressing element 37b. The sliding element 37a slides on the sliding plate 38 and is pressed against it by the pressing element 37. For this purpose, the pressing element 37b can have, for example, an elastic material. The pressing element 37 can be designed, for example, as an O-ring.

[0030] In Fig. 4, the pneumatic or gas-tight sealing of the rotor by the separator pot 13 is again shown, with the stator-side components of the refrigerant compressor 100 omitted for clarity. It can be clearly seen that the separator pot 13 is fixedly connected in a liquid-tight manner to the central plate 40, in particular to its annular step 41. The separator pot 13, in particular the rotor vessel 26, extends beyond the rotor 12 and also includes the counterweight 27. The rotor vessel 26 merges into the bearing vessel 25, completely surrounding the pot-side bearing 16 and also extending beyond the axial end face of the drive shaft 15. In this way the entire rotor assembly is hermetically isolated.

[0031] 4 also clearly shows the back pressure chamber 19, which is arranged between the compressor-side bearing 17 and the displacement spiral 31. The back pressure chamber 19 is arranged inside the drive chamber 28b, which is hermetically separated via the separation pot 13 from the stator-side components of the refrigerant compressor 100, in particular the suction chamber 28a. [Explanation of symbols]

[0032] 100 Refrigerant compressor 10 Motor section 11 Stator 12 Rotor 13 Separation pot 14 void 15 Drive shaft 16 Pot side bearing 17 Compressor side bearing 18 Eccentric guide 19 Back Pressure Chamber 20 Motor housing 21 Inverter Room 22 Coil 23 Coil head 24 Seal 25 Axial receptors 26 Rotor Container 27 Counterweight 28 Motor Room 28a Suction chamber 28b Drive room 29 Axial holder 30 Compressor section 31 Displacement Spiral 32 Opposing Spiral 33 High Pressure Chamber 34 Compressor housing 35 Central exit opening 36 Seal groove 37 Sliding seal 37a Sliding element 37b Pressing element 38 Sliding Plate 39 Compression chamber 40 Center Plate 41 Annular step

Claims

1. A refrigerant compressor (100) for mobile applications, comprising a compressor section (30) and a motor section (10), the compressor section (30) being formed with a variable compression chamber (39) for receiving and compressing a refrigerant flowing through a working medium circuit, the motor section (10) being provided with a brushless electric motor including a stator (11) and a rotor (12) in driving connection with the compressor section (30), A refrigerant compressor (100) characterized in that the stator (11) and the rotor (12) are separated from each other liquid-tight and / or gas-tight by a separation pot (13).

2. 2. The refrigerant compressor (100) of claim 1, wherein the refrigerant compressor (100) is a reciprocating piston compressor, a rotary piston compressor, or a scroll compressor, and the scroll compressor in the compressor section (30) has an orbiting displacing spiral (31) and an opposing spiral (32) that engage with each other such that a variable compression chamber (39) is formed between the spirals.

3. 3. The refrigerant compressor (100) according to claim 1 or 2, characterized in that the separation pot (13) liquid-tightly and / or gas-tightly separates a suction chamber (28a) in which the stator (11) is arranged from a back pressure chamber (19).

4. 4. The refrigerant compressor (100) according to any one of claims 1 to 3, characterized in that the separation pot (13) extends through a gap (14) between the stator (11) and the rotor (12).

5. Refrigerant compressor (100) according to any one of claims 1 to 4, characterized in that the separation pot (13) comprises or consists of a non-magnetic material.

6. 6. The refrigerant compressor (100) of claim 5, wherein the non-magnetic material comprises or is plastic, stainless steel, aluminum or carbon fiber.

7. 7. The refrigerant compressor (100) according to claim 1, characterized in that the working medium circuit includes a compressor inlet opening directly into the compressor section (30), in particular directly from the outside of the refrigerant compressor.

8. The refrigerant compressor (100) according to any one of claims 1 to 7, characterized in that the electric motor (10) can be cooled by a cooling device externally connected to the motor section (10).

9. 9. The refrigerant compressor (100) according to claim 1, wherein the stator (11) has a coil (22), and a stator head (23) connected to a motor housing (20) is cast on a coil head (23) of the coil (22).

10. 10. The refrigerant compressor (100) according to claim 1, wherein the separation pot (13) has a bearing container (25) in which a pot-side bearing (16) of the drive shaft (15) is fitted.

11. 11. The refrigerant compressor (100) according to claim 1, characterized in that the separation pot (13) is sealingly connected to a central plate (40) separating the motor part (10) from the compressor part (30), the central plate (40) being sealed by seals (24) to the motor part (10), in particular to the motor housing (20), and to the compressor part (30), in particular to the compressor housing (34), respectively.

12. The refrigerant compressor (100) of claim 11, wherein the center plate (40) is disposed between the motor housing (20) and the compressor housing (34).

13. A motor vehicle, in particular a battery electric vehicle or a fuel cell vehicle, comprising a refrigerant compressor (100) according to any one of the preceding claims.

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