Air compressor for conveying air with an air guide path with different channel cross-sections

Abstract

The presented invention relates to an air compressor (100) for conveying air, wherein the air compressor (100) comprises: - a stator (101), - a cover (103) and - an air duct (105), wherein the air guide path (105) is configured to direct a mass airflow along the stator (101), wherein the air duct path (105) comprises a plurality of channels (107) forming a main region (111) extending radially around an inner region (115) of the stator (101) and a plurality of secondary regions (113) extending from the main region (111) towards the inner region (115) of the stator (101), wherein each channel (107) of the plurality of channels (107) differs from each other in its cross-section and wherein the air guide path (105) overlaps the stator (101) at least at the end face.

Description

[0001] The presented invention relates to an air compressor for conveying air, a manufacturing method for an air compressor and a fuel cell system according to the attached claims. State of the art

[0002] Air compressors for conveying air are usually designed to be particularly compact as auxiliary units due to space constraints.

[0003] Due to the compact design, thermal problems arise, particularly in the area of ​​the stator of an electric machine for driving an air compressor. Disclosure of the invention

[0004] Within the scope of the presented invention, an air compressor for conveying air, a manufacturing process for an air compressor, and a fuel cell system are introduced. Further features and details of the invention will become apparent from the respective dependent claims, the description, and the drawings. Features and details described in connection with the air compressor according to the invention naturally also apply in connection with the manufacturing process and the fuel cell system according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always includes, or allows for, reciprocal reference.

[0005] The invention presented here serves in particular to provide a means for the robust operation of an air-conducting system, especially a fuel cell system.

[0006] Thus, according to a first aspect of the presented invention, an air compressor for conveying air is presented.

[0007] The presented air compressor comprises a stator, a casing and an air guide path, wherein the air guide path is configured to direct a mass airflow along the stator, wherein the air guide path comprises a plurality of channels forming a main region extending radially around an inner region of the stator and a plurality of secondary regions extending from the main region towards the inner region of the stator, wherein each channel of the plurality of channels differs from each other in its cross-section and wherein the air guide path superimposes on the stator at least at its end face.

[0008] In the context of the presented invention, an end face is to be understood as a short side of a cylindrical stator.

[0009] In the context of the presented invention, a casing is understood to be a housing, in particular a housing with a bearing shield. Accordingly, the casing can include a bearing shield.

[0010] The presented invention is based on an air guide path comprising a plurality of channels. To form the channels, the air guide path can include air guide elements such as protrusions, indentations, cavities, fins, pin-fin structures, throttle elements, or any other technically suitable form of air guide element. The channels can be integrated into the stator and / or the casing of the air compressor and / or into a cooling device provided in addition to the stator and casing.

[0011] It is provided that individual channels of the plurality of channels overlap the stator at least at its end face, so that an air mass flow is guided along the stator through the channels. This means that the plurality of channels extends, in particular, over the entire length of the stator's end face, especially over the entire length of a short side of the stator, and especially over a winding head of the stator, so that the winding head is cooled by the air guide path, at least at its end face.

[0012] The air mass flowing in the air duct carries away heat radiated by the air compressor, particularly by the stator (e.g., from the bearing shells supporting the stator). Accordingly, thermal energy is transferred from the air compressor, especially the stator, to the air mass flow and carried away, thus cooling the stator and enabling it to withstand particularly high power loads.

[0013] The air duct path can comprise a number, in particular a multitude, of partial air paths, each directing a partial air mass flow to a predetermined location of the air compressor.

[0014] To provide the air mass flow through the air duct, ambient air can flow into the air duct and be guided through the air duct via convection.

[0015] Furthermore, for example, a partial air mass flow can be diverted after the compressor of the air compressor and optionally cooled beforehand, so that the air compressor is cooled more effectively, for example, dynamically with increasing load and correspondingly increasing speed.

[0016] Alternatively, a partial air mass flow from a main air mass flow supplied by a turbine of the air compressor can be directed into the air guide path, so that the stator is cooled more effectively or dynamically with increasing air compressor power. For this purpose, the casing can include at least one inlet opening that introduces an air mass flow into the air guide path or respective channels, and at least one outlet opening that discharges the air mass flow from the air guide path or respective channels.

[0017] According to the invention, the respective channels of the plurality of channels differ from each other in their cross-section.

[0018] Channels with different cross-sections, i.e., different effective cross-sections for guiding an air mass flow, can generate a multitude of partial air mass flows with varying strengths and speeds, so that, for example, a turbulent overall flow forms at the end or outlet of the multitude of channels.

[0019] Alternatively, the cross-section of the respective channels can be designed so differently that a loss of force or velocity of an air mass flow through the air guide path is compensated for along the main area, so that, for example, a laminar overall flow is formed at the end or at the outlet of the multitude of channels.

[0020] It may be provided that at least part of each of the channels forming the secondary areas includes a throttling element that sets a cross-section of each channel.

[0021] To adjust the cross-section of a given channel, the channel may include a material protrusion or a throttling element inserted into the channel.

[0022] A throttling element can, for example, comprise an outer circumference corresponding to the cross-section of a respective channel and a specific inner cross-section, so that the inner cross-section of the throttling element defines or determines an effective cross-section of the channel for guiding an air mass flow.

[0023] In particular, a flow geometry with different cross-sections in respective secondary areas can be implemented by using a multitude of throttle elements with different cross-sections, i.e., different internal cross-sections, in an air guide path with a multitude of channels, each with the same cross-section. For this purpose, the respective throttle elements can be inserted into the respective channels, in particular by gluing, clamping, and / or welding.

[0024] It may also be provided that the throttling element is detachably connected to the respective channel.

[0025] A throttle element that is detachably connected to a respective channel allows for the replacement of the throttle element and, consequently, a change in the flow geometry of the air duct path.

[0026] It may also be provided that throttling elements arranged in the respective channels of the secondary areas successively increase or decrease the effective cross-section of the respective channels in the course of the main area.

[0027] Changes in the secondary areas during the course of the main area can influence the flow behavior of an air mass flow formed at the outlet of the secondary areas, for example by forcing it into a turbulent or a laminar flow motion.

[0028] It may be provided that the air compressor includes a cooling device which forms at least part of the air duct path, wherein the cooling device includes a base body in which at least part of the plurality of channels is formed, wherein the cooling device overlaps the stator at least end-face in an area between a winding head of the stator and the casing and forms the air duct path together with the winding head and / or the casing.

[0029] An additional element in the form of a cooling device, added to the stator and the casing of the air compressor, enables a complex geometry of the air guide path, which directs an air mass flow from a thermally favorable, i.e., particularly cold, point to particularly thermally stressed areas of the air compressor, such as the winding head and / or bearing shells for supporting the stator.

[0030] In particular, a cooling device can interact with the stator and / or the casing to form the air guide path, allowing the air compressor to be designed to be particularly compact.

[0031] The cooling device can be manufactured from a large number of parts, for example, using a 3D printing process or an injection molding process.

[0032] It may also be provided that the cooling device overlaps the winding head at least partially, both at the front and laterally in the direction of the respective stator slots of the stator.

[0033] By overlapping the winding head at the front and sides, the surface area for transferring thermal energy from the winding head to a fluid flowing in the cooling device is maximized, and the winding head is protected at the front and sides from mechanical stress.

[0034] It may also be provided that the base body of the cooling device consists of a material whose thermal conductivity is higher than the thermal conductivity of air and whose electrical conductivity is less than 1% of the electrical conductivity of aluminium.

[0035] A high thermal conductivity of the base body of the cooling device results in a high heat transfer from the winding head to a fluid flowing in the cooling device and a correspondingly good cooling effect or high cooling capacity.

[0036] An electrical conductivity of the base body that is less than 1% of the electrical conductivity of aluminium results in the suppression of eddy currents between the stator shell and the stator, thus maximizing the performance of the air compressor.

[0037] It may also be provided that the base body of the cooling device consists entirely or partially of ceramic.

[0038] Ceramics, such as Al2O3 with a thermal conductivity of 20W / mK or AlN with a thermal conductivity of 170W / mK, have proven to be particularly advantageous for dissipating heat from a winding head and are electrically insulating.

[0039] It may also be provided that at least some of the multiple channels are formed in the casing and / or the stator.

[0040] Channels that run partially or completely within the casing and / or the stator allow for efficient cooling of the casing and / or the stator.

[0041] Furthermore, integrating the respective channels into the casing and / or the stator minimizes the space required for the air compressor.

[0042] To integrate the respective channels into the casing and / or the stator, these can be milled into the casing or, for example, a shell surrounding the stator and shaped in a primary forming process.

[0043] It may also be provided that the air guidance path is formed by a number of air guidance elements, which include at least one structure from the following list of structures: channel, intake, recess, protrusion, cavity, air guide plate, cooling fin, pin-fin structure.

[0044] Air guide elements can be arranged as separate components on, for example, the casing, the stator or a base body of a cooling device and / or incorporated into it.

[0045] It may also be provided that the air guidance path runs inclined at an air guidance angle towards the stator.

[0046] An airflow path inclined at an angle towards the stator, where the airflow path is inclined to an auxiliary axis perpendicular to a rotational axis of the stator, particularly one superimposed on the end face of the stator, results in an airflow from a point above the stator towards an inner part of the stator. The airflow path can, for example, be shaped like a snail shell or spiral, so that the airflow path itself already forms a vortex.

[0047] It may also be provided that the numerous secondary areas connect the interior of the stator to the main area via an air-conducting mechanism.

[0048] Through a main area, which is filled with a fresh or cold air mass flow through a number of inlet openings, for example, secondary areas can be supplied with air, which divide the total air mass flow into partial mass flows and, as a result, control the flow behavior of the air mass flow.

[0049] It may also be provided that the air guidance path includes a multitude of secondary areas, each extending from the main area towards the interior of the stator with different flow geometries.

[0050] For example, the secondary areas can be designed in such a way that the partial mass flows are combined at the outlet of the secondary areas to form a vortex that flows through the inner part of the stator.

[0051] In the context of the presented invention, a flow geometry can be understood to mean, for example, an angle to the main area, a length, a thickness, a throttling point, or a path of the air guide elements between respective secondary areas. Accordingly, a specific flow geometry can be used to control the flow pattern of the air mass flowing through the air guide path, for example, by locally accelerating or decelerating it.

[0052] It may also be provided that the flow geometry of the main area changes during its course.

[0053] A main area that changes in its course can, for example, locally accelerate or decelerate an air mass flow passing through the main area, so that, for example, an air mass flow is generated that flows with the same strength or speed everywhere in the main area.

[0054] It may also be provided that the main area forms a circle or is closed at one end.

[0055] A circular main area allows an air mass flow entering the main area to be divided into two opposing and correspondingly strong partial mass flows.

[0056] A main area closed at one end results in a flow of air mass flowing through the main area in only one direction, as it prevents the air mass flow from being divided into two opposing partial mass flows.

[0057] It may also be provided that the air guide path overlaps the winding head both at the front and laterally in the direction of the respective stator slots of the stator, at least in some areas.

[0058] By overlapping the winding head at the front and sides, the surface area for transferring thermal energy from the winding head to a fluid flowing in the cooling device is maximized, and the winding head is protected at the front and sides from mechanical stress.

[0059] It may also be provided that the air duct includes an interface configured to receive the air to be directed through the air duct from an environment and discharge it to the environment, or to receive a partial mass flow of air from a compressor and / or turbine of the air compressor and discharge it to the turbine or the environment.

[0060] An interface, such as a number of inlet channels and a number of outlet channels, allows cold air to be introduced at a point that is particularly thermally favorable, i.e., cold, and air to be expelled at a point that is particularly mechanically favorable, i.e., thermally resilient.

[0061] It may also be provided that a first air guide path is formed at a first end face of the stator and a second air guide path is formed at a second end face of the stator opposite the first end.

[0062] Two air ducts at the respective end faces of the stator require a particularly high cooling capacity to regulate the temperature of the stator, so that it can be subjected to a particularly high power.

[0063] According to a second aspect, the presented invention relates to a manufacturing process for an air compressor.

[0064] The presented manufacturing process comprises providing a stator, providing a shell, providing an air guide path configured to direct a mass airflow along the stator, wherein the air guide path comprises a plurality of channels forming a main region extending radially around an inner region of the stator and a plurality of secondary regions extending from the main region towards the inner region of the stator, and forming at least one throttling element in at least a part of the plurality of channels such that respective channels of the plurality of channels differ from each other in their cross-section, and wherein the air guide path superimposes on the end face of the stator.

[0065] It may be provided that the air guidance path is supplied by air guidance elements formed in a cooling device and / or the stator and / or the casing.

[0066] To form the air guide path, the respective air guide elements can be formed, for example, in a primary forming process together with the cooling device or the stator or the shell, in particular cast, or inserted into the cooling device or the stator or the shell in a separate forming process, for example by milling.

[0067] According to a third aspect, the presented invention relates to a fuel cell system for converting energy.

[0068] The presented fuel cell system comprises a fuel cell stack and a possible configuration of the presented air compressor for supplying the fuel cell stack with air.

[0069] Advantages described in detail with respect to the air compressor for conveying air according to the first aspect of the invention apply equally to the manufacturing process for an air compressor according to the second aspect of the invention and to the fuel cell system for converting energy according to the third aspect of the invention.

[0070] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination.

[0071] They show: Fig. 1 a schematic representation of a possible design of the presented air compressor in a cutaway side view, Fig. 2 a possible embodiment of the air guide path provided according to the invention in a sectional top view, Fig. 3 a possible design of the presented fuel cell system, Fig. 4. A possible embodiment of the presented manufacturing process.

[0072] In Fig. Figure 1 shows an air compressor 100 for conveying air. The air compressor 100 comprises a stator 101, a casing 103, and an air guide path 105.

[0073] The air duct 105 is configured to guide a mass airflow along the stator 101. For this purpose, the air duct 105 comprises a plurality of channels 107, which form a main area extending radially around an inner region of the stator 101 and a plurality of secondary areas extending from the main area towards the inner region of the stator 101.

[0074] Each of the 107 channels differs in its cross-section.

[0075] The air guide path 105 overlaps the stator 101 at least on its end face 109 and is in this case partially formed by a cooling device 121 which interacts with the stator 101 and the casing 103.

[0076] Air guide elements 123 are formed on the cooling device 121, which form a Fig. The main area 111 shown in section 2 and a multitude of sub-areas 113 form the main area shown.

[0077] In Fig. Figure 2 shows the air duct 105 in a top view. It can be seen that the air duct 105 comprises the main area 111 and the numerous secondary areas 113.

[0078] The main area 111 runs radially or circularly around an inner area 115 of the stator 101.

[0079] The secondary areas 113 connect the main area 111 with the inner area 115, so that an air mass flow flows through an inlet 117 into the main area 111 and further through the secondary area 113 into the inner area 115 of the stator 101, cooling or dissipating heat from the stator at its front and in its inner area 115.

[0080] A first throttling element 203 is arranged in a first channel 201 and a second throttling element 207 is arranged in a second channel 205. The first throttling element 203 and the second throttling element 207 differ in their cross-sectional area.

[0081] Due to the narrower cross-section of the first throttle element 203 compared to the second throttle element 207, an air mass flow through the first throttle element 203 flows more strongly than an air mass flow through the second throttle element 207.

[0082] In Fig. Figure 3 shows a fuel cell system 300 for converting energy.

[0083] The fuel cell system 300 comprises a fuel cell stack 301 and an air compressor 100 according to Fig. 1 to supply the fuel cell stack 301 with air.

[0084] In Fig. Figure 4 shows a manufacturing process 400 for an air compressor.

[0085] The manufacturing process 400 comprises a first provisioning step 401 in which a stator is provided, a second provisioning step 403 in which a casing for receiving the stator is provided, a third provisioning step 405 in which an air guide path is provided which is configured to direct a mass air flow along the stator, the air guide path comprising a plurality of channels forming a main region extending radially around an inner region of the stator and a plurality of secondary regions extending from the main region towards the inner region of the stator.

[0086] Furthermore, the manufacturing process 400 comprises a training step 407 in which at least one throttling element is formed in at least one part of the plurality of channels, such that each channel of the plurality of channels differs from each other in its cross-section, with the air guide path superimposed on the stator face.

Claims

[1] Air compressor (100) for conveying air, the air compressor (100) comprising: - a stator (101), - a shell (103) and - an air guide path (105), wherein the air guide path (105) is configured to guide an air mass flow along the stator (101), wherein the air guide path (105) comprises a plurality of channels (107) forming a main region (111) extending radially around an inner region (115) of the stator (101) and a plurality of secondary regions (113) extending from the main region (111) towards the inner region (115) of the stator (101), wherein respective channels (107) of the plurality of channels (107) differ from one another in their cross-section and wherein the air guide path (105) overlies the stator (101) at least on the front side. [2] Air compressor (100) according to claim 1, characterized bythat at least a part of respective channels (107) forming the secondary regions (113) comprises a throttle element (202, 207) which adjusts a cross-section of a respective channel (107). [3] Air compressor (100) according to claim 2, characterized by that the throttle element (203, 207) is detachably connected to the respective channel (107). [4] Air compressor (100) according to one of the preceding claims, characterized by that throttle elements (203, 207) arranged in respective channels (107) of the secondary regions (113) successively enlarge or reduce an effective cross-section of the respective channels (107) in the course of the main region (111). [5] Air compressor (100) according to one of the preceding claims, characterized byin that the air compressor (100) comprises a cooling device (121) which forms at least part of the air guide path (105), wherein the cooling device (121) comprises a base body in which at least part of the plurality of channels (107) is formed, wherein the cooling device (121) overlies the stator (101) in a region between a winding head of the stator (101) and the casing (103) at least on the end face and forms the air guide path (105) together with the winding head and / or the casing (103). [6] Air compressor (100) according to one of the preceding claims, characterized by that at least a part of the plurality of channels (107) is formed in the casing (103) and / or the stator (101). [7] Air compressor (100) according to one of the preceding claims, characterized bythat the air guide path (105) is formed by a number of air guide elements (123) which comprise at least one structure from the following list of structures: channel, receptacle, recess, protuberance, cavity, air guide plate, cooling fin, pin-fin structure. [8] Air compressor (100) according to one of the preceding claims, characterized by that the air guide path (105) is inclined by an air guide angle in the direction of the stator (101). [9] Air compressor (100) according to one of the preceding claims, characterized by that respective channels (107) forming the plurality of secondary regions (113) connect the inner region (115) of the stator (101) to respective channels (107) forming the main region (111) in an air-conducting manner. [10] Air compressor (100) according to one of the preceding claims, characterized bythat the air guide path (105) comprises a plurality of secondary regions (113), each of which extends with mutually different flow geometries from the main region (111) in the direction of the inner region (115) of the stator (101). [11] Air compressor (100) according to one of the preceding claims, characterized by that a flow geometry of the main area (111) changes over the course of the main area (111). [12] Air compressor (100) according to one of the preceding claims characterized by that the main area (111) forms a circle or is closed at one end. [13] Air compressor (100) according to one of the preceding claims, characterized by that the air guide path (105) overlaps a winding head of the stator (101) both at the front and laterally in the direction of respective stator slots of the stator (101) at least in some areas. [14] Air compressor (100) according to one of the preceding claims, characterized byin that the air guide path (105) comprises an interface (109) which is configured to receive air to be guided through the air guide path (105) from an environment and to release it to the environment or to receive a partial air mass flow of a compressor and / or a turbine of the air compressor and to release it to the turbine or the environment. [15] Air compressor (100) according to one of the preceding claims, characterized by that a first air guide path is formed at a first front end of the stator (101) and a second air guide path is formed at a second front end of the stator (101) opposite the first end. [16] Manufacturing method (400) for an air compressor, the manufacturing method (200) comprising: - Providing (401) a stator (101), - providing (403) a cover (103), - Providing (405) an air guide path (105) configured to guide an air mass flow along the stator (101), wherein the air guide path (105) comprises a plurality of channels (107) forming a main region (111) extending radially around an inner region (115) of the stator (101) and a plurality of secondary regions (113) extending from the main region (111) toward the inner region (115) of the stator (101), - forming (407) at least one throttle element (203, 207) in at least some of the plurality of channels (107), so that respective channels (107) of the plurality of channels (107) differ from one another in their cross section and wherein the air guide path (105) overlaps the stator (101) on the front side. [17] Manufacturing method (400) according to claim 16, characterized bythat the air guide path (105) is provided by air guide elements (123) formed in a cooling device (121) and / or the stator (101) and / or the casing (103). [18] Fuel cell system (300) for converting energy, the fuel cell system (300) comprising: - a fuel cell stack (301), - an air compressor (100) according to one of claims 1 to 15 for supplying the fuel cell stack (301) with air.

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