Filter-and-throttle unit for a scroll compressor, and scroll compressor for a refrigerant circuit

Abstract

Filter-and-throttle units (10) are known which comprise a housing (12) with housing walls (14, 16), and which comprise an opening (18) that acts as a throttle and is formed in one of the housing walls (14, 16). According to the invention, a filter element (24) is situated within the housing walls (14, 16) of the housing (12), as a result of which additional assembly steps are eliminated. Moreover, scroll compressors (26) for refrigerant circuits are known which have an orbiting displacement spiral (78) that engages in a fixed stator spiral (80). Said scroll compressors have an oil return channel (114) via which the high-pressure chamber (92) is fluidically connected to the low-pressure chamber (88), and a gas connection channel (118) via which the counter-pressure chamber (60) is fluidically connected to the high-pressure chamber (92). In order to simplify the assembly of these scroll compressors and extend their lifespan, according to the invention a filter-and-throttle unit (10) is situated in the gas connection channel (118) and / or in the oil return channel (114).

Description

[0001] The invention relates to a filter and throttling unit for a scroll compressor with a housing having housing walls and an opening serving as a throttle or orifice, which is formed in one of the housing walls, as well as a scroll compressor for a refrigerant circuit with a drive, an eccentric unit driven by means of the drive, over which an orbiting displacement spiral is movable which engages in a stationary stator spiral, at least one displacement chamber between the stator spiral and the displacement spiral, a high-pressure chamber into which the at least one displacement chamber opens, a low-pressure chamber which opens into the at least one displacement chamber, an oil return channel through which the high-pressure chamber is fluidically connected to the low-pressure chamber, a back-pressure chamber which is formed on the side of the displacement spiral facing away from the stator spiral, and a gas connection channel.via which the counter-pressure chamber is fluidically connected to the high-pressure chamber.

[0002] Scroll compressors are used primarily for compressing refrigerants in the refrigeration and air conditioning systems of motor vehicles. The expanded refrigerant entering the scroll compressor is in a gaseous state and, at least in electrically driven scroll compressors, typically flows into the housing on the motor side, so that the refrigerant flows through the electric motor. The refrigerant also absorbs oil in the motor compartment, which is necessary for lubrication. This oil is usually separated from the refrigerant in an oil separator on the scroll compressor and returned to the compressor for lubrication. The compressed refrigerant then returns to the refrigerant circuit via an outlet.

[0003] Such scroll compressors are known, for example, from EP 3 404 264 A1 and comprise a high-pressure chamber, a low-pressure chamber, an orbiting displacement spiral, and a stationary stator spiral interacting with the displacement spiral. The orbiting displacement spiral engages with the stator spiral in such a way that displacement spaces are formed between the displacement spiral and the stator spiral, in which the medium to be compressed is received and compressed. A back-pressure chamber is provided between the compressor's bearing housing and the displacement spiral. The pressure prevailing in the back-pressure chamber and acting on the displacement spiral causes a resultant force in the axial direction, which presses the displacement spiral against the stationary spiral, thus sealing the spirals from each other.

[0004] To achieve the required contact pressure in the backpressure chamber, a fluidic connection exists between the high-pressure chamber and the backpressure chamber via a gas connection channel, ensuring that the high-pressure fluid from the high-pressure chamber is also present in the backpressure chamber. A gas connection throttle or orifice is located in the gas connection channel, which controls the mass flow of the fluid entering the backpressure chamber and reduces the pressure.

[0005] Furthermore, the scroll compressor includes an oil return channel that fluidically connects the high-pressure chamber to the low-pressure chamber. Oil intended for lubricating the components within the scroll compressor is separated from the compressed fluid via a separator located in the high-pressure chamber and returned to the low-pressure chamber via the oil return channel, allowing it to be reused for component lubrication. An oil return throttle is installed in the oil return channel to reduce the pressure of the returned oil.

[0006] Furthermore, US patent 2005 / 0129556 A1 discloses a scroll compressor in which, in addition to the throttle, a filter element is arranged in the oil return line to filter contaminants from the oil.

[0007] A filter and throttling system is also known from CN 203035552 U, in which a hollow cylindrical filter element is held in a plastic housing. At the end facing the pressure side, a capillary tube 13 is arranged inside this filter element, through which the inflow occurs and which serves as a throttling element.

[0008] A disadvantage of conventional scroll compressors is that either no filtration of the recirculated gas and oil takes place, or the effort required to manufacture and install the filter element and throttle is very high. Additionally, there is a risk of the filter elements becoming clogged in the recirculation channels.

[0009] The challenge, therefore, is to provide a filter and throttling unit that is easy to manufacture and can be installed in a scroll compressor with minimal effort. Furthermore, clogging of the filter elements within the scroll compressor should be prevented.

[0010] These tasks are solved by a filter and throttling unit with the features of main claim 1 and a scroll compressor for a refrigerant circuit with the features of main claim 8.

[0011] The filter and throttle unit according to the invention for a scroll compressor comprises a housing with housing walls that form an outer wall of the filter and throttle unit and thus define the unit axially and radially. An opening serving as a throttle or orifice is formed in one of these defining walls. Furthermore, a filter element, which is plate-shaped and defines the filter and throttle unit on one axial side, is arranged within the housing walls and thus also bounded at least radially by the housing walls. This allows the filter element to be easily accessed and mounted in the housing. The plate-shaped design creates a surface, particularly in horizontally arranged compressors, that can be positioned perpendicular to the force of gravity, enabling self-cleaning of the filter element without external forces.The filtered-out solids do not adhere to the filter element, even during operation. Accordingly, a single unit consisting of a throttle or orifice and a filter element is created, which can be easily inserted as a whole into a corresponding housing on the scroll compressor, thus significantly simplifying assembly. Furthermore, manufacturing is simplified because the housing wall itself, through its design of the opening, directly serves as the throttle or orifice, eliminating the need for additional components.

[0012] The scroll compressor according to the invention has a drive, which can in particular be an electric motor. This drives an eccentric unit, which is coupled to a displacement spiral, so that it performs an orbiting, i.e., eccentric, rotational movement. The displacement spiral is usually arranged on a sliding disk and engages with a stationary stator spiral. The stator spiral, together with the displacement spiral, defines one or more displacement chambers. As the displacement spiral rotates along the stator spiral, the volume of these chambers is reduced, thus compressing the medium within them. The last displacement chamber opens into a high-pressure chamber, into which the compressed medium flows, for example, via an outlet valve.The scroll compressor additionally features a low-pressure chamber that opens into the outer displacement chamber and serves as an inlet. The entire space in which the electric motor can be located also forms the low-pressure chamber. This chamber is thus comprised of the entire enclosed space of the scroll compressor, in which the fluid to be compressed is in a relaxed state, the same state in which it flows into the scroll compressor. Furthermore, an oil return channel is provided, through which the high-pressure chamber is fluidically connected to the low-pressure chamber. This fluidic connection is typically not direct, but rather via an oil separator chamber.Additionally, the scroll compressor has a backpressure chamber formed on the side of the displacement spiral facing away from the stator spiral. A gas connection channel fluidically connects the backpressure chamber to the high-pressure chamber to generate a backpressure that loads the displacement spiral against the stator spiral. According to the invention, a filter and throttle unit is arranged in the gas connection channel and / or in the oil return channel. This unit comprises a housing with housing walls that externally delimit the filter and throttle unit. An opening serving as a throttle or orifice is formed in one of these delimiting walls of the filter and throttle unit. Furthermore, a plate-shaped filter element is arranged within a space delimited by the housing walls and delimits the filter and throttle unit on one axial side.This design of the filter and throttle unit allows for easy insertion of the unit, consisting of the filter and throttle or aperture, into a corresponding mounting opening in the scroll compressor in a single assembly step. It can be secured by simply pressing it into place. The unit, comprising the throttle or aperture and filter, remains easily accessible and replaceable.

[0013] Regarding the filter and throttle unit, it is advantageous if the housing has an axially limiting housing wall in which the opening serving as a throttle or aperture is formed, and an annular, radially limiting housing wall that extends axially from the axially limiting housing wall. This results in a substantially pot-shaped component whose housing does not require further assembly but can be manufactured as a single piece.

[0014] In another preferred embodiment, the filter element is designed as a filter screen, radially limited by a sealing element that is fixed in the housing. The sealing element ensures that no oil or gas can bypass the filter element. The screen provides sufficient filtration efficiency with high durability. Furthermore, the filter screen can be easily secured in the housing via the sealing element.

[0015] Preferably, the housing is designed as a stamped part in which the filter element is positively locked to the sealing element. The stamped part design is particularly cost-effective, as is the positive locking of the filter element to the sealing element. This locking can be achieved, for example, by simply forming the axial end of the annular housing wall.

[0016] In a further embodiment, the sealing element rests with a first axial side against the axially limiting housing wall and with its opposite axial side against a collar of the radially limiting housing wall that extends at least partially radially inwards. In this way, a positive-locking connection between the sealing element and the housing can be established in a simple manner.

[0017] A tight seal is achieved when the sealing element is axially compressed between the collar and the axially limiting housing wall, ensuring that the gas or oil can flow exclusively over the filter element, which is surrounded by the seal.

[0018] It is particularly advantageous if the filter screen is radially overmolded on the outside with a plastic component of the sealing element, so that the filter screen and sealing element can be inserted into the housing as a single unit and secured there, which further simplifies assembly and manufacturing. Alternatively, the filter screen could be inserted between two pressed-in sealing elements inside the housing or secured between the collar and a sealing element.

[0019] In a further embodiment of the scroll compressor according to the invention, the gas connection channel and / or the oil return channel extends at least partially through the stator spiral. These channels can be easily incorporated during the manufacturing of the spiral, so that no additional machining is necessary.

[0020] In a further preferred embodiment, the filter and throttling unit is mounted in the stator spiral. In particular, the filter and throttling unit can simply be inserted into the corresponding channels in the compressor housing before the stator spiral is mounted.

[0021] It is particularly advantageous if the filter and throttling unit is pressed into an inlet opening on a cover plate of the stator spiral, with the filter element being plate-shaped and defining the high-pressure chamber. In this case, the filter element extends at the same height as the wall surface of the stator spiral cover plate that defines the high-pressure chamber, thus forming a common wall surface. This eliminates any space in which the filtered contaminants can settle in front of the filter element. Instead, in the conventional horizontal design of the compressor, these contaminants will always fall back from the surface of the filter element into the high-pressure chamber due to gravity, thereby preventing clogging of the filter element.

[0022] Preferably, the gas connection channel extends from the high-pressure chamber through the stator spiral and a bearing housing component to the back-pressure chamber. This minimizes the number of components that need to be precisely aligned during assembly, allowing for simple channel fabrication.

[0023] Preferably, the high-pressure chamber is connected to an oil separation chamber in which an oil separator is arranged. This enables the separation and return of the oil to the low-pressure chamber, thus minimizing the oil load on downstream components.

[0024] The oil return channel preferably extends from the lowest point of the oil separation chamber through a head housing section, the stator spiral, and the bearing housing section to the low-pressure chamber. This layout and arrangement ensures complete oil return and facilitates simple manufacturing and assembly.

[0025] Preferably, the inlet opening of the gas connection channel is arranged in the direction of gas flow upstream of the oil separator, so that a gas-oil mixture enters the back pressure chamber and thus the bearing housing, ensuring that the bearings and moving parts located there are adequately lubricated.

[0026] This creates a filter and expansion unit, as well as a scroll compressor for a vehicle's refrigerant circuit, that can be easily manufactured and installed. This reduces costs both in the production of the filter and expansion unit and in its assembly on the compressor. Furthermore, the filter element is self-cleaning, which also prevents clogging of the return lines.

[0027] An embodiment of a filter and throttling unit and a scroll compressor according to the invention is shown in the figures and described below. Figure 1 shows a perspective view of a throttle and filter unit according to the invention. Figure 2 shows a side view of the filter and throttling unit according to the invention. Figure 1 in cutaway view. Figure 3 shows a side view of a scroll compressor according to the invention for a refrigerant circuit of a motor vehicle with a [unclear] in the Figures 1 and 2 The filter and throttle unit shown is in cutaway view.

[0028] The in the Figures 1 and 2The illustrated filter and throttling unit 10 has a housing 12, which consists of an axially limiting housing wall 14, which in the present embodiment is somewhat thinner in the radially inner region, and an annular housing wall 16 that radially limits the filter and throttling unit 10 and extends axially from the radially outer edge of the axially limiting housing wall 14. This housing can be manufactured particularly easily from sheet metal by stamping and bending.

[0029] In the inner, thinner region of the axially bounding housing wall 14, a narrow opening 18 is formed, serving as a throttle or orifice. Inside the radially bounding housing wall 16, an annular sealing element 20 is clamped and axially compressed between the axially bounding housing wall 14 and an axial end section of the annular radially bounding housing wall 16, which is bent radially inwards and designed as a collar 22. Accordingly, the first axial side of the sealing element 20 rests against the axially bounding wall 14, and the opposite axial side of the sealing element 20 rests against the collar 22.

[0030] A filter element 24, designed as a filter screen, is arranged on the open side of the housing 12. This filter element is plate-shaped, and its radially outer edge is either overmolded by the plastic of the sealing element 20 or axially clamped between two sealing elements 20 or between the collar 22 and the sealing element 20. Accordingly, oil or refrigerant can flow into the housing 12 via the filter element 24, filtering out solids from the oil or refrigerant stream. The oil or refrigerant then flows out of the filter and throttling unit 10 through the opening, which acts as a throttle or orifice. The pressure downstream of the opening 18 is lower than the pressure upstream of the opening 18. The mass flow rate is also significantly reduced by the cross-sectional constriction.

[0031] The figure shows a scroll compressor 26 according to the invention, which has a multi-part compressor housing 28 with a first motor housing part 30 and a head housing part 32 axially adjoining it, wherein the motor housing part 30 surrounds a drive 34 in the form of an electric motor and the head housing part 32 surrounds a compressor chamber 36.

[0032] The drive 34 comprises a stator 38 with windings 40 and an internal rotor 42 with permanent magnets 44, which is mounted on a shaft 46. The shaft 46, and thus the rotor 26, is supported on one side by a ball bearing 48, which is arranged in a receiving opening on an axially limiting rear wall 50 of the motor housing part 30, and on the other side by a second ball bearing 52, which is arranged in a receptacle of a bearing housing part 54, which is attached to the side axially opposite the rear wall 50 in the radial interior of the motor housing part 30. A shaft seal 56 is arranged in the bearing housing part 54 between the rotor 42 and the second ball bearing 52, sealing off a motor compartment 58, in which the drive 34 is arranged, from a back pressure chamber 60, which is formed on the axial side of the bearing housing part 54 opposite the motor compartment 58.

[0033] On the side of the rear wall 50 opposite the electric motor 34, an electronics compartment 62 is formed, in which a circuit board 64 with the power electronics 66 is mounted. This is connected to the windings 40 of the stator 38, so that the stator can be energized in a controlled manner. The power supply to the power electronics 66 is provided via a connector 68, which extends parallel to the motor shaft from the rear wall 50. The electronics compartment 62 is closed by a cover 70.

[0034] An eccentric unit 72 is formed on the end of the shaft 46 facing the compressor chamber 36, on whose output journal 74 an eccentric shaft bearing 76 is arranged, on which an orbiting displacement spiral 78 is eccentrically mounted, which corresponds to a stator spiral 80 which is attached in the head housing part 32 and on the bearing housing part 54, so that when the displacement spiral 78 rotates eccentrically, its walls 82 slide along the walls 84 of the stator spiral 80, forming several displacement chambers 86, thereby reducing the size of the displacement chambers 86 and thus compressing the refrigerant drawn in from a low-pressure chamber 88.The inlet from the low-pressure chamber 88 into the displacement chambers 86 is formed radially between the head housing part 32 and the stationary stator spiral 80, so that the refrigerant is conveyed from the low-pressure chamber 88 radially inwards through the displacement chambers 86 towards an outlet 90, which is formed on a cover plate 91 of the stator spiral 80, into a high-pressure chamber 92 via a check valve 94 designed as a leaf spring element. The low-pressure chamber 88 is supplied with refrigerant via a concealed compressor inlet, through which the refrigerant flows into the motor compartment 58, which serves as the low-pressure chamber 88.

[0035] A sliding disk 96 is arranged between the bearing housing part 54 and the stator spiral 80, as well as the orbiting displacer spiral 78. This sliding disk 96 is clamped in its radially outer region between the head housing part 32 and the motor housing part 30. This sliding disk 96 also has openings through which several pins (not visible in the figure) project from the bearing housing part 54 into corresponding receptacles 98 of the orbiting displacer spiral 78. Sliding bushings 100 are arranged on these receptacles, providing additional sliding support for the displacer spiral 78. Furthermore, the displacer spiral 78 has a sliding and sealing ring 104 on the side facing the sliding disk 96, arranged in a circumferential groove 102. Accordingly, the displacer spiral 78 is slidably guided relative to the shaft 46 and the bearing housing part 54.

[0036] The high-pressure chamber 92 of the scroll compressor 26 is fluidically connected to an oil separation chamber 106, in which an oil separator 108 is arranged in the form of a cyclone, so that the lighter, gaseous refrigerant flows to a compressor outlet 110, while the liquid and heavier oil is separated from the refrigerant in the cyclone and drips to a lowest point of the oil separation chamber 106, which is formed by a bottom 112.

[0037] To remove the oil that has settled in the oil separator chamber 106, the beginning of an oil return channel 114 is provided at the bottom 112 of the oil separator chamber 106. This channel fluidically connects the oil separator chamber 106, and thus the high-pressure chamber 92, with the low-pressure chamber 88 or the engine compartment 58. The oil return channel 114 extends through the head housing part 32, the stationary stator spiral 80, the sliding disc 96, and through the bearing housing part 54 into the engine compartment 58.

[0038] According to the invention, the filter and throttle unit 10 is fitted, in particular pressed into, an inlet opening 116 of the oil return channel 114 on the cover plate 91 of the stator spiral 80, so that the oil is returned to the engine compartment 58 with reduced pressure and filtered.

[0039] Furthermore, a gas connection channel 118 extends from the high-pressure chamber 92 through the stator spiral 80, the sliding disk 96 and through the bearing housing part 54 into the counter-pressure chamber 60, in which a pressure is accordingly reduced compared to the high-pressure chamber 92, but increased compared to the low-pressure chamber 88, whereby the orbiting displacer spiral 78 is loaded against the stator spiral 80, which leads to an improved seal between the end faces of the orbiting displacer spiral 78 and the stationary stator spiral 80.

[0040] To adjust this pressure, a filter and throttling unit 10 according to the invention is also located at an inlet opening 120 in the gas connection channel 118 on the cover plate 91 of the stator spiral 80. The opening 18 of this unit is appropriately sized and can be pressed into the inlet opening 120. Additionally, the filter element 24 prevents the ingress of contaminants into the counter-pressure chamber 60, thereby protecting the ball bearings 52, eccentric shaft bearings 76, sliding bushings 100, sliding disc 96, and sliding and sealing ring 104 located therein.

[0041] The filter surface of the filter element 24 is located approximately in the same plane as the cover plate 91 of the stator housing part 80 at both the inlet opening 120 of the gas connection channel 118 and the inlet opening 116 of the oil return channel 114. This prevents filtered contaminants from settling in and clogging the oil return channel 116 or the gas connection channel 120, instead allowing them to fall into the high-pressure chamber 92 due to gravity. This results in self-cleaning. Consequently, the functionality of the oil return channel 116 and the gas connection channel 120 is maintained for a long time. Furthermore, the filter and throttle units 10 can be easily removed and replaced, as they are readily accessible and easy to install and remove. Different desired back pressures can also be set using filter and throttle units 10 with different opening widths.

[0042] It should be clear that the scope of protection is not limited to the described embodiment, but that various modifications are conceivable. For example, the scroll compressor can have any type of drive, or the housing divisions can be changed. Furthermore, the filter and throttle unit can be attached to the inlet openings in a manner other than press-fitting.

Claims

1. A filter and throttle unit (10) for a scroll compressor (26) comprising a housing (12) having housing walls (14, 16), an opening (18) which serves as a throttle and which is formed in one of the housing walls (14, 16), characterized in that a filter element (24) is arranged within the housing walls (14, 16) of the housing (12), which filter element is of plate-shaped design and delimits the filter and throttle unit (10) to an axial side.

2. The filter and throttle unit for a scroll compressor according to Claim 1, characterized in that the housing (12) has an axially delimiting housing wall (14), in which the opening (18) which serves as a throttle or orifice is formed, and has an annular, radially delimiting housing wall (16) which extends axially from the axially delimiting housing wall (14).

3. The filter and throttle unit for a scroll compressor according to one of claims 1 or 2, characterized in that the filter element (24) is formed as a filter screen which is delimited radially by a sealing element (20) which is fastened in the housing (12).

4. The filter and throttle unit for a scroll compressor according to claim 3, characterized in that the housing (12) is formed as a punched part in which the filter element (24) is fastened in a form-fitting manner by the sealing element (20).

5. The filter and throttle unit for a scroll compressor according to Claim 4, characterized in that the sealing element (20) bears with a first axial side against the axially delimiting housing wall (14) and bears with its opposite axial side against an at least partially radially inwardly extending collar (22) of the radially delimiting housing wall (16).

6. The filter and throttle unit for a scroll compressor according to claim 5, characterized in that the sealing element (20) is pressed axially between the collar (22) and the axially delimiting housing wall (16).

7. The filter and throttle unit for a scroll compressor according to one of claims 3 to 6, characterized in that the filter element (24) is encapsulated radially on the outside with a plastic of the sealing element (20).

8. A scroll compressor (26) for a refrigerant circuit comprising a drive (34), an eccentric unit (72) which can be driven by means of the drive (34) and by means of which an orbiting displacement spiral (78) which engages in a stationary stator spiral (80) can be moved, at least one displacement space (86) between the stator spiral (80) and the displacement spiral (78), a high-pressure chamber (92) into which the at least one displacement space (86) opens, a low-pressure chamber (88) which opens into the at least one displacement space (86), an oil return duct (114) by means of which the high-pressure chamber (92) is fluidically connected to the low-pressure chamber (88), a counter-pressure chamber (60) which is formed on that side of the displacement spiral (78) which faces away from the stator spiral (80), a gas connection duct (118) by means of which the counter-pressure chamber (60) is fluidically connected to the high-pressure chamber (92), characterized in that a filter and throttle unit (10) according to one of the preceding claims is arranged in the gas connection duct (118) and / or in the oil return duct (114).

9. The scroll compressor for a refrigerant circuit according to claim 8, characterized in that the gas connection duct (118) and / or the oil return duct (114) extend at least in sections through the stator spiral (80).

10. The scroll compressor for a refrigerant circuit according to claim 9, characterized in that the filter and throttle unit (10) is fastened in the stator spiral (80).

11. The scroll compressor for a refrigerant circuit according to claim 10, characterized in that the filter and throttle unit (10) is pressed into an inlet opening (116, 120) on a cover disc (91) of the stator spiral (80), wherein the filter element (24) is of plate-shaped design and delimits the high-pressure chamber (92).

12. The scroll compressor for a refrigerant circuit according to one of claims 8 to 11, characterized in that the gas connection duct (118) extends from the high-pressure chamber (92) through the stator spiral (80) and a bearing housing part (54) to the counter-pressure chamber (60).

13. The scroll compressor for a refrigerant circuit according to one of claims 8 to 12, characterized in that the high-pressure chamber (92) is connected to an oil separation chamber (106) in which an oil separator (108) is arranged.

14. The scroll compressor for a refrigerant circuit according to one of claims 8 to 13, characterized in that the oil return duct (114) extends from a lowest point of the oil separation chamber (106) through a head housing part (32), the stator spiral (80) and the bearing housing part (54) to the low-pressure chamber (88).

15. The scroll compressor for a refrigerant circuit according to one of claims 8 to 14, characterized in that the inlet opening (120) of the gas connection duct (118) is arranged upstream of the oil separator (108) in the flow direction of the gas.

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