Positive displacement machine according to the spiral principle

Abstract

The invention relates to a displacement machine according to the spiral principle, in particular a scroll compressor, said machine comprising a housing (100) and a compression assembly (150) which has an electric motor (10), an orbiting displacement spiral (21), a counter spiral (22), and a bearing plate (30), the displacement spiral (21) and the counter spiral (22) engaging into one another in such a way that variable compression chambers are formed between the displacement spiral (21) and the counter spiral (22) in order to receive and compress a working medium flowing through a working medium circuit, and the electric motor (10) being drivingly connected to the displacement spiral (21) by means of a motor shaft (12). The compression assembly (150) is vibrationally decoupled from the housing (100).

Description

[0001] Displacement machine based on the spiral principle

[0002] Description

[0003] The invention relates to a positive displacement machine based on the spiral principle, in particular a scroll compressor, according to the preamble of patent claim 1.

[0004] Positive displacement machines operating according to the scroll principle, especially scroll compressors, are well known in practice. They are typically used as compressors for air conditioning systems in vehicles. Such scroll compressors are generally designed with a compression assembly comprising an electric motor, an orbiting displacement scroll, a counter scroll, and a bearing plate, arranged in a housing. The housing is designed to protect the internal components of the scroll compressor from corrosion.

[0005] The operating principle of the scroll compressor is that the displacement scroll and the counter scroll mesh, forming variable compression chambers between the displacement scroll and the counter scroll. A working fluid flows into these compression chambers and is compressed by the variable compression chambers. The orbiting displacement scroll is driven by the electric motor via a motor shaft that is connected to the displacement scroll.

[0006] Scroll compressors are generally very efficient and run smoothly. However, with the increasing electrification of vehicles, the requirements for smooth running are increasing significantly. In electrically powered vehicles, even small vibrations in individual components lead to noticeable noise development. In conventional vehicles with combustion engines, such noise development is drowned out by the vibrations of the combustion engine itself. In electrically powered vehicles, however, the reduction in moving parts results in a significant reduction in the vibrations emitted by the vehicle's drive system. Consequently, vibrations from other components in the vehicle become more prominent. There is therefore a strong desire to improve other moving components in a vehicle with regard to vibrations and noise emissions. This particularly applies to air conditioning compressors in vehicles.

[0007] The object of the invention is therefore to provide a positive displacement machine according to the spiral principle, in particular a scroll compressor, which is improved with regard to vibrations and noise emissions.

[0008] According to the invention, this object is achieved by the subject matter of patent claim 1.

[0009] The invention is based on the idea of ​​providing a positive displacement machine based on the scroll principle, in particular a scroll compressor, with a housing and a compression assembly. The compression assembly comprises an electric motor, an orbiting displacement scroll, a counter scroll, and a bearing plate. The displacement scroll and the counter scroll engage with each other in such a way that variable compression chambers are formed between the displacement scroll and the counter scroll to accommodate and compress a working fluid flowing through a working fluid circuit. The electric motor is drive-connected to the displacement scroll by means of a motor shaft. According to the invention, the compression assembly is vibration-decoupled from the housing.

[0010] The invention is based on the idea of ​​combining all moving elements of the displacement machine in a compression assembly and decoupling this compression assembly from the housing of the displacement machine so that vibrations caused by the moving parts of the compression assembly are not directly introduced into the housing and transmitted from the housing to other components of the vehicle.

[0011] In this way, the smooth running of the positive displacement machine is significantly improved. An additional positive effect of this design is that the decoupling of the compression assembly from the housing facilitates maintenance of the compression assembly. In particular, the entire compression assembly can be replaced relatively easily. Preferably, non-metallic decoupling elements are arranged between the compression assembly and the housing. The decoupling elements can in particular be designed as O-rings. It is advantageous if the O-rings are made of plastic and / or rubber. The decoupling elements bring about vibration decoupling between the compression assembly and the housing in a particularly simple and cost-effective manner.

[0012] In general, the compression assembly can be designed to function mechanically independently. The compression assembly thus includes all moving parts of the positive displacement machine. This ensures that the mechanical components that generate vibrations are well decoupled from the housing. The vibrations generated in the compression assembly are therefore not directly transmitted to the housing. This improves smooth running. In particular, the transmission of vibrations to other components, such as a vehicle, is prevented.

[0013] In a preferred embodiment of the positive displacement machine according to the invention, the bearing plate forms an inner housing in which the electric motor is arranged. The bearing plate is therefore not merely designed as a flat plate, but has a housing shape. The bearing plate preferably forms an inner housing, which, as part of the compression assembly, is arranged within the housing and is vibration-decoupled from it. The inner housing consolidates the moving parts of the compression assembly, forming a single, easily manageable unit.

[0014] The bearing plate can be a single-piece or multi-piece design. A single-piece design offers advantages during assembly. In particular, fewer individual parts need to be manufactured, which can reduce manufacturing costs. A multi-piece design increases flexibility during maintenance and repair of the positive displacement machine.

[0015] The bearing plate, especially the inner housing, can be a shaft bearing of the

[0016] The motor shaft is supported by the bearing plate. Consequently, the motor shaft is part of the compression assembly and thus vibration-decoupled from the housing.

[0017] The bearing plate can firmly connect the electric motor, in particular its stator, the shaft bearing, and the counter-volute. The bearing plate thus forms a central component of the compression assembly. Specifically, the bearing plate can form a link between the moving parts of the compression assembly.

[0018] In a preferred variant of the invention, the shaft bearing is designed such that the motor shaft is supported exclusively by the single shaft bearing. In conventional scroll compressors, the motor shaft is usually supported on the one hand on the bearing plate via a first bearing and on the other hand on the bottom of the housing via a second bearing. To avoid metallic contact between the compression assembly and the housing, however, it is advantageous to omit the second bearing. This eliminates a direct vibration-transmitting connection between the motor shaft and the housing. This further prevents the transmission of structure-borne noise.

[0019] To be able to absorb the forces occurring in the motor shaft even with single-sided support, it is preferable for the shaft bearing to be designed as a double-row angular contact ball bearing or as a pair of adjacent single-row angular contact ball bearings. The double-row angular contact ball bearing or the pair of adjacent single-row angular contact ball bearings can each have a U-shaped arrangement. In this way, axial forces acting on the motor shaft are also well absorbed by the shaft bearing.

[0020] Furthermore, it can be provided that the compression assembly, in particular the bearing plate, comprises different materials than the housing. In particular, the bearing plate can be made of a different material than the housing. In this way, a functional separation can be achieved and further improved. The housing has the function of protecting the compression assembly from external influences. For this purpose, the housing is preferably made of a corrosion-resistant material, preferably aluminum. The compression assembly, in particular the bearing plate, forms the mechanical components required for the basic function of the positive displacement machine. This releases forces that must be absorbed by the components of the compression assembly. The bearing plate in particular has to absorb high forces. In this respect, it is advantageous if the bearing plate is made of a solid material, for example steel.It is particularly preferred if the bearing plate and the shaft bearing are made of a material with a similar coefficient of thermal expansion, in particular the same coefficient of thermal expansion. This prevents distortion of the shaft bearing in the bearing plate and also prevents vibrations.

[0021] The invention is explained below using an exemplary embodiment with reference to the accompanying drawing. The single figure shows a longitudinal sectional view through a displacement machine according to the invention.

[0022] The single figure shows a positive displacement machine based on the scroll principle, in particular a scroll compressor. The scroll compressor has a housing 100 enclosing a compression assembly 150. In the embodiment shown here, the housing 100 is formed from a main housing 110 and a housing cover 120. The main housing 110 is essentially pot-shaped and is closed at one axial end by the housing cover 120.

[0023] The compression assembly 150 comprises an electric motor 10 having a stator 13 and a rotor 11. The rotor 11 is rotationally fixedly connected to a motor shaft 12, which is mounted in a shaft bearing 31. The shaft bearing 31 is preferably designed as a double-row angular contact ball bearing and forms the sole bearing for the motor shaft 12. Alternatively, the shaft bearing 31 can also be formed by a pair of adjacent single-row angular contact ball bearings. In any case, the shaft bearing 31 preferably has an O-arrangement so that it can absorb axial forces in both directions.

[0024] The shaft bearing 31 is preferably the only shaft bearing 31. Specifically, the motor shaft 12 is supported only by the single shaft bearing 31. In particular, on a side opposite the single shaft bearing 31, the motor shaft 12 is free of bearings or bearingless. The motor shaft 12 is thus supported in a cantilevered manner by the single shaft bearing 31. In this context, the motor shaft 12 is referred to as a floating bearing.

[0025] The motor shaft 12 is also spaced apart from a housing base 101 of the housing 100. In particular, there is no direct contact between the motor shaft 12 and the housing base 101. This prevents vibrations from the rotational movement of the motor shaft 12 from being transmitted into the housing 100. An inverter housing can also be arranged on the housing base 101. The housing base 101 can also form a wall of the inverter housing. In both cases, the interior of the inverter housing forms a resonance chamber or resonance body, which can amplify sound emissions. By decoupling the motor shaft 12 from the housing base 101 and thus from the inverter housing, such sound emissions are reduced.

[0026] The shaft bearing 31 is pressed into a bearing plate 30. The bearing plate 30 separates a drive chamber of the compression assembly 150 from a compression chamber. The electric motor 10 is arranged in the drive chamber. The compression chamber comprises a displacement spiral 21, which rests on the bearing plate 30 or a sliding plate (not shown) arranged on the bearing plate 30. The displacement spiral 21 engages a counter spiral 22, which is also arranged in the compression chamber. The counter spiral 22 is firmly connected, in particular screwed, to the bearing plate 30.

[0027] To achieve a good seal between the displacement spiral 21 and the bearing plate 30, the displacement spiral has a sealing groove 23. The sealing groove 23 preferably extends annularly around the longitudinal axis of the motor shaft 12 through the bottom of the displacement spiral 21. A seal is accommodated in the sealing groove 23, which is not shown in the figure for reasons of clarity.

[0028] An anti-rotation mechanism 40 is provided radially within the sealing groove 23. The anti-rotation mechanism 40 comprises a plurality of distributed pins 41, which are fixedly arranged in the bearing plate 30. The pins 41 protrude beyond the bearing plate 30 and engage in bores 42 formed in the displacement spiral 21. The bores 42 have a cross-sectional diameter that is significantly larger, in particular several times larger, than the diameter of the pins. The anti-rotation mechanism 40, also referred to as a pin / ring mechanism, prevents the displacement spiral 21 from rotating about its central axis. Rather, it forces the displacement spiral into an orbiting motion. The displacement spiral 21 is driven by the motor shaft 12, which is in contact with the displacement spiral 21 via a balancing mechanism 14 and an eccentric bearing 15.The balancing mechanism 14 essentially comprises a counterweight that compensates for dynamic imbalances of the displacer scroll 21 and thus causes the compression chambers between the displacer scroll 21 and the counter scroll 22 to be sealed.

[0029] As can be seen from the figure, the bearing plate 30 forms an inner housing 32 in which the electric motor 10 is arranged. In particular, the bearing plate 30 continues in a cylindrical shape and accommodates the stator 13 of the electric motor 10. The stator 13 is preferably firmly connected to the inner housing 32. The inner housing 32 has a plurality of grooves 33, which preferably extend in a ring shape around the longitudinal axis of the motor shaft 12. A total of four grooves 33 are provided, with three grooves 33 opening radially outwards, whereas one groove 33 is open towards an axial end of the inner housing 32. Decoupling elements 34, which are in contact with the housing 100, are arranged in all grooves 33. The decoupling elements 34 are preferably formed as O-rings made of plastic and / or rubber.

[0030] The inner housing 32 has a clearance relative to the housing 100. Specifically, a gap is provided between the inner housing 32 and the housing 100. The decoupling elements 34 bridge this gap and keep the inner housing 32 at a distance from the housing 100. Thus, there is no metallic contact between the inner housing 32 and the housing 100, thereby achieving sound decoupling.

[0031] The counter-volute 22 also has grooves 33, each of which accommodates a decoupling element 34. The counter-volute 22, together with the inner housing 32 and the components arranged in the inner housing 32, forms the compression assembly 150, which is mounted completely acoustically decoupled from the housing 100. The mounting is achieved via the decoupling elements 34, which are arranged in the grooves 33.

[0032] The figure also shows that one of the grooves 33 in the counter-volute 22 is open toward a free axial end of the housing cover 120. The axially open groove 33 of the inner housing 32 is open in the opposite direction, i.e., toward the free end of the main housing 110. This ensures that the compression assembly 150 is decoupled from the housing 100 not only radially but also axially on both sides. The second groove 33 in the counter-volute 22 is open radially outward, i.e., toward the inner surface of the housing cover 120.

[0033] The figure also shows that the compression assembly 150 is mechanically independent. All mechanical processes of the scroll compressor therefore take place within the compression assembly 150. The sole function of the housing 100 is to form the corresponding fluid chambers for guiding the working fluid to be compressed and to protect the compression assembly 150 from external environmental influences.

[0034] Reference symbol

[0035] 10 Electric motor

[0036] 11 Rotor

[0037] 12 Motor shaft

[0038] 13 Stator

[0039] 14 Compensation mechanism

[0040] 15 eccentric bearings

[0041] 21 Displacement spiral

[0042] 22 Counter spiral

[0043] 23 Sealing groove

[0044] 30 bearing plate

[0045] 31 shaft bearings

[0046] 32 inner casings

[0047] 33 grooves

[0048] 34 Decoupling element

[0049] 40 Anti-rotation mechanism

[0050] 41 pen

[0051] 42 bore

[0052] 100 housings

[0053] 101 Case back

[0054] 110 Main body

[0055] 120 housing cover

[0056] 150 compression assembly

Claims

Claims Displacement machine according to the spiral principle, in particular scroll compressor, with a housing (100) and a compression assembly (150) comprising an electric motor (10), an orbiting displacer spiral (21), a counter spiral (22) and a bearing plate (30), wherein the displacer spiral (21) and the counter spiral (22) interlock in such a way that variable compression chambers are formed between the displacer spiral (21) and the counter spiral (22) in order to receive and compress a working medium flowing through a working medium circuit, and wherein the electric motor (10) is connected to the displacer spiral (21) by means of a motor shaft (12) and is characterized by the fact that the compression assembly (150) is vibrationally decoupled from the housing (100).A positive displacement machine according to claim 1 is characterized by the fact that non-metallic decoupling elements (34), in particular O-rings, preferably made of plastic and / or rubber, are arranged between the compression assembly (150) and the housing (100). A positive displacement machine according to claim 1 or 2 is characterized by the fact that the bearing plate (30) forms an inner housing (32) in which the electric motor (10) is arranged. A positive displacement machine according to any one of the preceding claims is characterized by the fact that the bearing plate (30) is formed in one piece or in multiple parts. A positive displacement machine according to any one of the preceding claims is characterized by the fact that the bearing plate (30), in particular the inner housing (32), supports a shaft bearing (31) of the motor shaft (12). A displacement machine according to claim 5 is characterized by the fact that the bearing plate (30) rigidly connects the electric motor (10), in particular its stator (13), the shaft bearing (31), and the counter-spiral (22). A displacement machine according to any of the preceding claims is characterized by the fact that the shaft bearing (31) is designed such that the motor shaft (12) is supported exclusively by the single shaft bearing (31). A displacement machine according to claim 7 is characterized by the fact that the shaft bearing (31) is formed as a double-row angular contact ball bearing or as a pair of adjacent single-row angular contact ball bearings in an O-arrangement. A displacement machine according to any of the preceding claims is characterized by the fact that the compression assembly (150), in particular the bearing plate (30), comprises or is formed from materials other than the housing (100).Displacement machine according to one of the preceding claims is characterized by the fact that the housing (100) has a corrosion-resistant material, in particular aluminium, or is formed therefrom.

Images