Patent Application
20250102207
This application claims priority from German Patent Application No. DE 102023126364.1, filed on Sep. 27, 2023, the entirety of which is hereby incorporated by reference herein.
The invention relates to a collector for a refrigerant circuit in a motor vehicle and a method for producing the collector, as well as the use of the collector in a refrigerant circuit for a motor vehicle.
EP 1 533 580 A1 discloses a condenser for a refrigerant circuit (for an air conditioner) in a motor vehicle, which has a fin-tube block with collector tubes on both sides and a collector. The collector is connected to a collector tube by an intake line and drain line (inlet and outlet holes), and the collector contains a filter (filter unit), sealing means (seal), and drying agent (desiccant bag or hygroscopic substance) for the refrigerant. The filter is integrated in a flow conductor, and ends not far from the intake line. The flow conductor ensures that the drying agent does not get close to the intake line, or that the flow cannot act directly on the desiccant bag. The collector is sealed by two caps that cannot be removed. The condenser, made up of its individual components, and collector are joined to one another in a brazing furnace. The filter and drying agent are placed in the collector after brazing the condenser. The collector is open on at least one end. The open end or ends of the collector are then sealed permanently. The seal is obtained through welding, during which the collector may need to be cooled where it contains the filter. Welding heats up the collector. The filter is made of an appropriate plastic. Plastics become soft at high temperatures and begin to melt. The heat from the welding process can damage the filter. The drying agent can also contain components that are sensitive to heat, which can also be damaged during the welding process. By cooling the part of the collector containing the filter and drying agent, these damages can be avoided. The cooling requires energy during the production of the collector. The heat generated during the welding process creates a hot zone in the material forming the collector. These collectors are frequently made of an aluminum alloy. The high thermal conductivity of aluminum alloys can result in a large hot zone. This hot zone has a negative impact on the material forming the collector. Typical problems arising near hot zones include increased brittleness, cracking in the welds, internal stress, reduced durability and corrosion resistance. The internal stress and the reduced durability that arise can be compensated for by making the walls of the tubes thicker. This can have negative effects, such as in increase in the weight of the collector, and higher costs. When joining the individual components of the condenser to the collector in the brazing furnace, the material forming the collector may become weakened. If the tubes are produced in an extrusion process, the finished tubes are more durable than the material forming the finished collector. The increased durability of the material forming the tubes is lost in a brazing furnace. To compensate for this, it may be necessary to subsequently increase the thickness of the walls of the tubes. This requires more material, making the tubes heavier and more expensive to produce.
The device obtained with the invention that has the features of the independent claims has the advantage that the properties of the material forming the tubes are retained, or substantially retained, and it is possible to avoid heating the filter and the drying agent.
The basis for the invention is a collector for a refrigerant circuit in a motor vehicle. The collector can be used in a refrigerant circuit for a motor vehicle, and it can contain a tube and at least one cap, and have an axial direction. A tube is understood to be an elongated hollow element. The tube can extend in the axial direction. The tube can have a circular cross section. The cross section can also be oval, polygonal, or a combination of geometric shapes. The axial direction is parallel to the outer surface of the tube. The tube can have at least one narrowing, and the at least one cap can have at least one bulge, and the bulge and narrowing can come in contact with one another in order for the cap to seal the tube in the axial direction, preventing the at least one cap from moving axially. This at least one bulge can result in a reduction in the outer diameter of part of the at least one cap. By way of example, the bulge can be a circumferential bead constricting the cap. The bulge can also increase the outer diameter of the at least one cap. By way of example, the bulge can widen the outer diameter of the cap. The interior of the tube can be pressurized when the collector is in use. The narrowing prevents the at least one cap from moving axially. This ensures that the collector obtained with the invention is sealed in a fluid-tight manner. It is possible to test the collector obtained with the invention prior to putting it to use with a significantly higher pressure than that occurring in use. The at least one cap may move axially during the test at a significantly higher pressure, such that at this significantly higher pressure, the collector is no longer sealed. The at least one narrowing can be obtained with a radial compression process. In a first exemplary embodiment, the tube can be open at its ends and have a circular cross section. In this case, the tube in the collector can be sealed at its ends by two caps. In a second exemplary embodiment, the tube can be open at the top and sealed at the bottom. This tube can be produced from a circular base and a sleeve using a welding process. The circular base and sleeve can be made of a metallic material. In another exemplary embodiment, the tube can be open at the top and sealed by crimping at the bottom. In another exemplary embodiment, the tube can be open at the top and sealed at the bottom. The tube and base can form an integral unit. This can be obtained in fabrication processes such as shaping processes and reverse impact extrusion.
There can be at least one sealing element placed between the inside of the tube in the collector obtained with the invention and the at least one cap. In another embodiment of the collector, two sealing elements can be placed between the inside of the tube and the at least one cap. The two sealing elements can seal the collector axially in a fluid-tight manner. A fluid-tight seal means that only very small, or negligible, amounts of a medium can pass through the bond. The second sealing element can be on the side of the first sealing element facing away from the cap in the axial direction, and advantageously prevent an ingress of contaminants such as dust in the collector. The two sealing elements can be O-rings made of plastic, for example. In this case, the at least one cap can have two grooves. The O-rings can be placed in the grooves. The two O-rings can bear on the inside of the tube and the surfaces of the grooves. In another embodiment, the two sealing elements can be formed as integral parts of the at least one cap. The at least one cap can be made of plastic, and the two sealing elements can be molded thereto.
Mechanical processing is no longer necessary to obtain a fit between the at least one sealing element and the inside of the tube in the collector obtained with the invention. To be able to seal the collector axially in a fluid-tight manner, the at least one sealing element requires a precise bearing surface on the inside of the tube. This bearing surface must be obtained within very small radial tolerances. When the at least one narrowing is produced, the end of the tube may be fit to the at least one cap such that the bearing surface for the at least one sealing element is obtained. For this reason, any prior processing for obtaining the bearing surface and therefore a precise fit is no longer necessary. The fit refers to the sizing of the two components in relation to one another, which should fit together without subsequent processing.
The tube in the collector can contain a first metallic material that has a constant strength that is the same or greater than the strength of the first material prior to sealing the tube with the at least one cap. The first metallic material can be an aluminum alloy. The strength is understood to be the mechanical durability of the tube before it fails. Breakage or permanent deformation of the tube can result in its failure. Material bonding processes such as welding or brazing can impact the durability of at least parts the tube. When the collector and cap are welded, a hot zone can be formed that significantly reduces the durability. If the collector and cap are brazed in a furnace, the heat can weaken the first material. This weakening of the tube must be compensated for, e.g. by thickening the walls of the tube. This can be avoided with the collector obtained with the invention because the tube can be sealed with at least one cap in a mechanical process. This means it is possible to use a tube with thinner walls, thus reducing the amount of material that is needed. The tube can be produced in an extrusion process. This can increase the durability of the first material. Because sealing the tube with at least one cap does not weaken the first material, this can be exploited in order to further reduce the thickness of the walls. Durability refers to the mechanical strength of a component before it fails. Breakage or permanent deformation can result in failure of the component.
The cap can be made of a single piece. It can be produced in an impact extrusion process. There can be holes therein for the intake line and drain line in the collector obtained with the invention.
The at least one narrowing of the first tube can form a circumferential bead in another embodiment of the collector, and the at least one first bulge on the at least one first cap can be a circumferential constriction. The circumferential constriction can form a circumferential groove on the first cap, while the first narrowing can form a circumferential bead. The circumferential bead can form a groove. The first metallic material can be permanently shaped in a radial compression process. The first cap can have the first bulge prior to sealing the first tube. The at least one first narrowing can be obtained with a radial compression for example, in which the first material is pressed into the first bulge. The at least one first cap can thus be secured in place axially. The load to the at least one cap caused by internal pressure in the collector can thus be advantageously conducted into the tube. In another exemplary embodiment, the first cap can have a circumferential first rim. The diameter of the first rim can be greater than the inner diameter of the first tube. The cap can therefore bear on the rim of the first tube prior to producing the first narrowing, thus preventing the first cap from sliding into the first tube.
In another embodiment of the collector, the at least one second narrowing of the second tube can be a circumferential deformation and the at least one second bulge in the at least one second cap can be a circumferential deformation. The circumferential deformation can have an increasingly smaller diameter in the axial direction. The at least one second cap can have the second bulge prior to sealing the second tube. The at least one second narrowing can thus be produced by a radial compression that fits the first material to the second bulge. The at least one second cap can thus be secured in place axially. The load to the at least one second cap by an even higher pressure inside the collector can thus be better conducted into the tube.
In another embodiment of the collector, the at least one second narrowing of the third tube can be a circumferential deformation, and the at least one second bulge in the at least one second cap can be a circumferential deformation. The third tube can have at least one more, at least partially contiguous circumferential bead on the inside. This at least one circumferential bead can form a circumferential groove obtained through compression. This at least one additional bead can prevent the at least one second cap from sliding into the third tube prior to sealing it. The circumferential deformation of the at least one second cap can have an increasingly smaller diameter in the axial direction.
The at least one second cap can have the second bulge prior to sealing the second tube. The at least one second narrowing can be produced with a radial compression that fits the first material to the second bulge. The at least one second cap can thus be secured in place axially. The load to the at least one second cap from a higher pressure inside the collector can thus be conducted into the tube.
In another embodiment of the collector, the fourth tube can have at least one third narrowing. The at least one third narrowing can be a deformation with an indentation on the inside of the fourth tube. The deformation can have an increasingly smaller diameter in the axial direction, which then transitions to a constant diameter. The indentation on the inside of the fourth tube can be slightly slanted, and the third bulge in the at least one third cap can have an axially offset diameter. The at least one third cap can have the third bulge prior to sealing the fourth tube. By this means, the at least one fourth narrowing can be produced through radial compression, fitting the first material to the third bulge. The at least one third cap can thus be secured in place axially. The load to the at least one third cap from an even higher pressure inside the collector can thus be conducted into the tube. In another embodiment, the at least one third cap can have a third circumferential rim. The third rim can have an outer diameter that is as large as the inner diameter of the fourth tube, and the fourth cap can bear on the third rim of the fourth tube. This prevents the at least one third cap from sliding into the tube prior to producing the at least one fourth narrowing.
In another embodiment of the collector, the fifth tube can have at least one fourth narrowing. The at least one fourth narrowing of the firth tube can have two circumferential beads and a circumferential deformation. The two beads can form a groove. A straight section can have the deformation, and the deformation can have a greater outer diameter than the two beads. The at least one fourth bulge on the at least one fourth cap can be a circumferential widening. The outer diameter of the upper and lower ends of the fourth cap be smaller than that of the area therebetween. This results in a fourth bulge in the form of a widening. The at least one fourth cap can have the fourth bulge prior to sealing the fifth tube. The at least one fourth narrowing can be produced by radial compression, fitting the first material to the fourth bulge. The at least one fourth cap can thus be secured in place axially. Two sealing elements can be placed between the widening of the fourth cap and the deformation of the fifth tube. This results in a good seal at high pressures between the widening and the deformation.
In another embodiment of the collector, the sixth tube can have at least one fifth narrowing. By way of example, the fifth narrowing can be on the upper end of the sixth tube. The at least one fifth narrowing can have three straight sections. These three sections can be parallel to the axial direction. The middle section can be a circumferential widening on the sixth tube, thus having a greater outer diameter that the two other sections of the fifth narrowing. The at least one fourth bulge on the at least one fourth cap can be a circumferential widening. The outer diameter of the upper and lower ends of the fourth cap can be smaller than the area therebetween. Consequently, the fourth bulge forms a widening. The at least one fourth cap can have the fourth bulge prior to sealing the sixth tube. The at least one fifth narrowing can be produced through radial compression, fitting the first material to the fourth bulge. The at least one fourth cap can thus be secured in place axially. Because the inner diameter of the sixth tube can be greater than the outer diameter of the fourth bulge, the load to the at least one cap by a higher pressure inside the collector can advantageously be conducted into the sixth tube. Two sealing elements can be placed between the widening of the fourth cap and the middle section of the fifth narrowing in the sixth tube. This advantageously results in a good seal obtained from a high compression between the widening and the deformation.
The at least one cap can contain a second metallic material, or a third material made of plastic. The second metallic material can be an aluminum alloy. The second metallic material can also be steel. In both cases, the at least one bulge can be obtained through a radial compression or impact extrusion. If the at least one cap contains a third material made of plastic, the cap can be produced through injection molding. The at least one sealing element can be advantageously formed directly on the cap. This advantageously reduces the production costs for the cap.
The first material can be deformed near the at least one narrowing. The first material can be a metallic material. Deformation is understood to be a permanent deformation of a metallic material, e.g. though the application of pressure. The at least one narrowing can be easily produced in this manner. The durability of the tube is not impacted by this.
In another exemplary embodiment, at least one filter can be placed inside the tube in the collector. A liquid medium can flow through the collector. Course contaminants and any shavings from the production process can be filtered out of the medium by the filter. The collector can be used with other components in a refrigerant circuit. The filter can protect these other components against damage and contamination. In another exemplary embodiment of the collector, at least one drying agent can be placed inside the tube. The drying agent can be a desiccant bag, for example. The drying agent draws moisture from the medium. This protects the components in the refrigerant circuit against corrosion and potential disruptions in the refrigerant circuit caused by water. In another exemplary embodiment of the collector, at least one filter and one drying agent can be placed inside the tube to filter a medium and draw moisture therefrom.
In another embodiment of the collector obtained with the invention, a connecting plate can be attached to the tube. The collector can be used with other components in a refrigerant circuit. The collector can be advantageously attached to other components in the refrigerant circuit by the connecting plate. The collector could be attached to one of the components with clamps, for example. The collector could also be attached to one of the components with a press fit or with threaded fasteners. Holes can be formed in the connecting plate and/or the tube for the intake line and drain line for the collector. The other components can be, e.g., a condenser, expansion valve, compressor, or evaporator. The components can be used in a refrigerant circuit in the following manner: a condenser can be used to precipitate a refrigerant, a collector can be used to collect and store refrigerant, an expansion valve can be used to depressurize the refrigerant, an evaporator can be used to evaporate the refrigerant, and a compressor can be used to pressurize the refrigerant.
In another embodiment of the collector obtained with the invention, the at least one cap can be attached to a connecting plate. The collector can be used with other components in a refrigerant circuit. The collector can be attached to other components in the refrigerant circuit by the connecting plate. The collector could be attached to one of the other components with clamps. It could also be attached to one of the other components with a press fit or threaded fasteners. Holes can be formed in the connecting plate and/or the at least one cap for the intake line and drain line for the collector.
The method for producing the collector according to the embodiments described above can contain the following steps. In a first step, the tube can be produced with the connecting plate. The tube can be extruded with the connecting plate from a metallic material such as an aluminum alloy. The connecting plate could also be subsequently attached to the tube in a reverse impact extrusion process or welded thereto. The intake and drain lines can be produced in the next step. This can be obtained by drilling a hole in the tube. Two seals can then be placed on a first cap. The first cap can then be placed in the next step on the lower end of the tube. A rim on the cap or a bead in the tube prevents the first cap from slipping into the tube. A first narrowing can be subsequently formed at the lower end of the tube. This first narrowing can be formed by a radial compression process. It could also be formed in a spinning process. A bearing surface can also be formed inside the tube for the two seals that holds them in place such that the lower end of the tube is sealed by the cap against liquids and dust. At least one filter and/or at least one drying agent can then be placed in the tube in the next step. Two seals can subsequently be placed on a second cap. The second cap can then be placed in the next step on the upper end of the tube. A rim on the cap or a bead in the tube can prevent the second cap from slipping into the tube. A second narrowing can then be formed on the upper end of the tube. The second narrowing can be formed in a radial compression process. It could also be formed in a spinning process. A bearing surface for the two seals can also be formed inside the tube that holds them in place such that the lower end of the tube is sealed by the cap against liquids and dust.
The refrigerant circuit in the invention for a motor vehicle can contain the following components: a condenser for precipitating a refrigerant, a collector obtained with the invention for collecting and storing the refrigerant, an expansion valve for depressurizing the refrigerant, an evaporator for vaporizing the refrigerant, a compressor for pressurizing the refrigerant, and the connecting lines through which a refrigerant is conducted into and out of the refrigerant circuit. One possible refrigerant is R1234yf. Other possible refrigerants are carbon dioxide (R744), propane (R290) or R134a. Heat can be drawn out of the interior of a motor vehicle by the evaporator and discharged into the environment through the condenser. The collector obtained with the invention increases the efficiency of the refrigerant circuit in various environmental conditions by storing refrigerant and releasing it as needed. The collector can be designed such that the liquid and gaseous phases of the refrigerant can be separated therein by gravity. Various environmental conditions can be understood to be the different seasons. Because the refrigerant circuit is closed and can only contain one collector, the refrigerant circuit is self-regulating. The refrigerant circuit can contain a pressurized portion obtained with the condenser and a depressurized portion obtained with the evaporator. The refrigerant is significantly more pressurized in the pressurized portion than in the depressurized portion. In a first exemplary embodiment, the collector obtained with the invention can be placed in the pressurized portion downstream of the condenser. The evaporated refrigerant in the condenser may not be entirely liquified through pressurized cooling, such that it still contains evaporated portions. Placing the collector downstream of the condenser ensures that only fully liquified refrigerant exits the collector. The temperature of the refrigerant exiting the collector may still be further reduced. The temperature of the refrigerant can be lowered further in a supercooling segment of the condenser, or in another (internal) heat exchanger.
In a second exemplary embodiment, the collector obtained with the invention can be placed in a depressurized area downstream of the evaporator. The liquid refrigerant may not be entirely evaporated in the evaporator, and may still contain liquid portions. Placing the collector downstream of the evaporator ensures that only fully evaporated refrigerant can exit the collector.
The specification can be readily understood with reference to the following Numbered Paragraphs:
| Number | Date | Country | Kind |
|---|---|---|---|
| 102023126364.1 | Sep 2023 | DE | national |
