HOUSING FOR A FLOW MACHINE, ESPECIALLY FOR A RADIAL FAN

Description

[0001] The invention relates to a housing for a turbomachine, in particular for a radial fan, according to the preambles of claims 1 and 5.

[0002] Housings for turbomachinery, especially for radial fans, and radial fans themselves are known in the prior art in a variety of designs. Turbomachinery, especially radial fans, typically serves to transport gaseous media, for example air, through a flow system by means of the rotation of an impeller influencing the pressure conditions in the flow system and generating a volume flow.

[0003] Turbomachines, or radial fans, are often used for cooling purposes. One example of their application is the ventilation of automotive seats, where at least one turbomachine, in particular at least one radial fan, is integrated into the seat. The turbomachine generates at least one volume flow that exchanges the air in the area between a passenger and the seat surface, in particular by removing air from the seat surface and / or supplying it to the seat surface.

[0004] In such applications, where people are in the immediate vicinity of a working turbomachine, the focus is on reducing noise emissions while maintaining high fan performance.

[0005] JP 2010-209888 A discloses a radial fan with a helical inlet geometry and a fan wheel. On the inside of the housing, in the area of ​​the fan wheel, the housing has a circumferential recess. The cross-section of the circumferential recess decreases continuously counterclockwise around the circumference.

[0006] JP 2013-57298 discloses a housing with a fan wheel. The fan wheel is arranged at an inlet opening. A recessed area is provided on the inside of the inlet opening.

[0007] JP 2009-41517 A discloses a housing with a fan wheel. The fan wheel is located on the inside of an inlet opening. The housing has a circumferential recess surrounding the inlet opening on the inside.

[0008] US 6,030,286 A discloses a radial fan with a housing and a fan wheel arranged within the housing. The housing has an inlet opening surrounded on the inside by a circumferential recess.

[0009] The turbomachines known from the prior art, especially radial fans, have the disadvantage that, for example, at high volume flows and / or pressure levels, unpleasant noise emissions occur for the passenger(s).

[0010] The present invention is therefore based on the objective of providing a housing for a turbomachine, in particular a housing for a radial fan, preferably for use in an automobile seat, in which noise emission is reduced and high performance values ​​are achieved at the same time.

[0011] The aforementioned problem is solved in a generic housing for a turbomachine according to claim 1 by forming a circumferential recess on an inner side of the housing part, which at least partially surrounds the inlet opening, and by the circumferential recess having a basic cross-section in at least a first arc segment on its circumference and a varying cross-section in at least a second arc segment. Furthermore, the aforementioned problem is solved in a generic housing for a turbomachine according to claim 5 by forming a circumferential projection that at least partially surrounds the inlet opening, and by the circumferential projection having a cross-section that varies along its extent. For example, the circumferential projection has a cross-section that decreases continuously in both circumferential directions starting from a maximum cross-section.

[0012] In particular, it is provided that the circumferential setback and / or the circumferential projection has a cross-section that varies at least sectionally, preferably at least once, over the circumference.

[0013] The circumferential recess and / or projection is formed on the inside of the housing part so that, in the assembled state, it is part of the fluid space or, in the case of the projection, extends into the fluid space. The cross-section of the circumferential recess is preferably substantially U-shaped. The circumferential recess is designed as a recess that is at least partially recessed with respect to the inside of the housing part, particularly in a direction parallel to a central axis of the inlet opening, and extends along the circumference of the inlet opening. The projection is designed as a bulge that is at least partially projecting with respect to the inside of the housing part, particularly in a direction parallel to a central axis of the inlet opening, and extends along the circumference of the inlet opening. Preferably, the circumferential recess and / or projection adjoins the inlet opening directly in the radial direction.For example, it is planned that a circumferential lead extends over part of the circumference and a circumferential step-back extends over another part of the circumference.

[0014] It is further provided that the inlet opening is surrounded by a protrusion on the outer surface of the housing part, and that the curved inlet surface extends at least partially onto the protrusion. The protrusion preferably projects from the outer surface of the housing part as a projection that circumferentially surrounds the inlet opening. The protrusion has a surface that preferably has a continuous cross-section.

[0015] Advantageously, the convexly curved inlet surface extends at least partially onto the bulge, particularly in a region of the bulge that includes a local maximum of the bulge. Preferably, the cross-sectional shape of the bulge corresponds to at least 75% of the shape of a logarithmic spiral. The bulge widens the inlet opening parallel to its central axis, allowing a boundary layer to form earlier. Starting from a surface on the outside of the housing, and particularly in a direction parallel to the central axis of the inlet opening, the bulge preferably has a height between 3 mm and 10 mm, and more specifically 6 mm. Consequently, the bulge and the inlet surface create an advantageous surface geometry in the region of the inlet opening, which has the cross-sectional shape of a logarithmic spiral, particularly a Fibonacci spiral.

[0016] In particular, it is provided that the circumferential recess is formed within the bulge, so that with a nearly constant wall thickness of the housing part, a bulge and a circumferential recess are formed simultaneously. For example, in a configuration not covered by the claimed invention, the circumferential recess has a constant cross-section over its entire circumference. The circumferential recess or projection improves the flow characteristics of the housing part in the area of ​​the inlet opening, particularly with constant noise emission and by increasing the pressure at flow rates of 2.5 liters per second and above. The circumferential recess advantageously prevents backflow of fluid.

[0017] It is intended that the circumferential recess and / or the circumferential projection has a cross-section that varies at least section by section along its circumference. The circumferential projection is, in particular, formed integrally with the housing part.

[0018] It is provided that the circular setback in at least one first arc segment on the circumference has a basic cross-section and in at least one second arc segment a varying fill cross-section, in particular that the fill cross-section extends over an arc segment with a central angle between 1° and 359°.

[0019] The basic cross-section is, in particular, the cross-section with the greatest clear width and clear height of the circumferential recess. The clear cross-section in the filling cross-section is reduced compared to the basic cross-section, with the degree of reduction varying across the arc segment of the filling cross-section. The filling cross-section is preferably arranged on the circumference such that it is located below the tongue of the radial fan and below the outlet opening.

[0020] According to a further embodiment, the recessed area in the base cross-section has a free base area (clear cross-section), and the free base area in the fill cross-section is reduced, at least in sections. For example, the base cross-section has a base height, which is reduced in the fill cross-section. The base height is preferably the height of the clear cross-section of the recessed area parallel to the central axis of the inlet opening between the lowest point of the recessed area in the cross-section and the highest point of the recessed area at the transition to the boundary of the inlet opening.

[0021] The reduction of the base height in the filling cross-section can advantageously be specified as a percentage reduction relative to the base height in the base cross-section, particularly where the base height can be reduced to 0 section by section. Specifically, it is provided that the base height is reduced by 100% at at least one or at least two points around the circumference, meaning that the filling cross-section has one or two areas with maximum filling of the recirculation recess.

[0022] According to a further embodiment of the housing, it has proven advantageous if the filling cross-section extends in a polar coordinate system, located on the inside of the housing part, whose pole coincides with a central axis of the inlet opening and whose polar axis is orthogonal to a central axis of an outlet opening of the housing, within an angular range between 120° and 360°, particularly between 135° and 358°. The filling cross-section is thus arranged in a region that is partly located in the area of ​​the outlet opening and predominantly below the outlet opening, so that the filling cross-section is essentially located in the area of ​​the radial fan where the pressure build-up occurs.

[0023] According to a further embodiment of the housing, the filling cross-section, particularly in the radial direction, is provided to have a continuous or discontinuous profile. The profile of the filling cross-section is the area of ​​transition from the recirculation recess to the fluid chamber in the cross-section. Specifically, the profile extends across the width – in the radial direction – of the recirculation recess in the cross-section. The profile in the cross-section is, in particular, linear, arcuate, and / or stepped.

[0024] A further development of the housing provides that the circumferential projection extends along the circumference in at least one arc segment, and in particular that the arc segment has a central angle between 1° and 359°, especially 220°. In particular, the circumferential projection therefore does not extend along the entire circumference, but only along a portion of the circumference, the arc segment. The arc segment has a central angle of approximately 220° and is located in the pressure zone of a radial fan.

[0025] According to a further embodiment, this means in particular that the projecting arc segment extends in a polar coordinate system, which lies on the inside of the housing part, whose pole coincides with a central axis of the inlet opening, and whose polar axis is orthogonal to the central axis of an outlet opening, in an angular range between 120° and 360°, in particular in an angular range between 135° and 355°.

[0026] Particularly in multi-part designs, a further development has shown it to be advantageous for the circumferential projection to be at least partially recessed into the housing part. In such a design, the circumferential projection is, for example, inserted as a separate part into a designated recess in the housing part and attached to it. This allows for smoother transitions between the circumferential projection and the housing part.

[0027] Another embodiment of the housing is characterized in that the housing part is made of a plastic, in particular that the housing part is made in one piece, preferably by injection molding or an additive manufacturing process, in particular 3D printing.

[0028] The housing comprises at least one first housing part with at least one first inlet opening. The housing part can at least partially define at least one fluid chamber for accommodating at least one fan impeller. The housing part is, for example, a housing shell of a two-part housing. The housing or housing part has, in particular, the spiral shape typical for radial fans. In the assembled state, the fluid chamber is thus defined by the first and second housing parts, and the fan impeller is rotatably held between the first and second housing parts. Alternatively, the housing part is a cover element on a one- or multi-part housing. Preferably, the housing part has at least one outlet opening and / or, in the assembled state, at least partially defines an outlet opening of the housing.When installed in a radial fan, for example, air is drawn into the fluid chamber with the fan wheel at the inlet opening and then exits the housing at the outlet opening.

[0029] Preferably, the housing is designed for single-flow radial fans, i.e., radial fans with at least one central inlet opening, wherein, in the assembled state, the inlet opening is arranged in a plane parallel to the impeller's plane of rotation. Alternatively, the housing is designed for a dual-flow radial fan, i.e., having at least one first inlet opening and at least one second inlet opening. Preferably, the first and second inlet openings are arranged opposite each other, and in particular, are identical. Preferably, the inlet opening is circular.

[0030] It is provided that the circumference of the inlet opening is not merely formed as a material recess in the housing part, but rather that the circumference of the inlet opening is formed, at least in sections, as a convex inlet surface. Preferably, the convex inlet surface extends over the entire circumference of the inlet opening. Consequently, the inlet opening is convex, at least in sections, along its circumference in the direction of a central axis of the inlet opening. In particular, the convex inlet surface extends in cross-section from an outer surface of the housing part to an inner surface of the housing part.

[0031] The boundary layer of a flow in the region of the inlet opening, particularly at its circumference, is advantageously extended by ensuring that the curved inlet surface has at least a partial logarithmic spiral cross-section. This extension of the boundary layer reduces vortex formation and dead water areas, thereby reducing noise emissions or, with the same noise emission, increasing pressure, for example.

[0032] Any logarithmic spiral is suitable as a shape for the cross-sectional surface of the inlet opening, where with each revolution around its center point (which here lies specifically on a circular path around a central axis of the inlet opening), the distance to this center point increases or decreases by the same factor. "In cross-section" here means in any section plane that includes a central axis of the inlet opening. The shape of the inlet surface in cross-section can be mathematically described in polar coordinates using the following formula ( r,φ ) describe: r φ = a ⋅ e kφ

[0033] Here, k is the constant, non-zero slope of the spiral. a and k are elements of the real numbers, and e is Euler's number.

[0034] The cross-section is preferably rotationally symmetrical about the central axis over the entire circumference of the inlet opening. Preferably, a section in the cross-section, which has the shape of a logarithmic spiral, extends from the outside of the housing part to the inside of the housing part. Preferably, the section has at least two different radii.

[0035] It has proven particularly advantageous if the logarithmic spiral is a Fibonacci spiral, especially if the cross-section corresponding to the logarithmic spiral—at least a section of the inlet surface—has at least two different radii of curvature. In particular, these radii of curvature should be in a ratio of approximately 1.618034 to each other. The curved inlet surface preferably corresponds in cross-section to at least a portion of a Fibonacci spiral, especially with a sweeping central angle for the spiral of more than 90°. Mathematically, the shape of the inlet surface can be described in polar coordinates as follows: r φ = a ⋅ e kφ

[0036] The slope is k = 2 ⋅ ln Φ π and Φ = 5 + 1 2

[0037] The shape of the Fibonacci spiral advantageously prevents flow separation in the area of ​​the curved inlet surface, thus reducing noise emission from the fluid flowing through the inlet opening into the fluid space towards the impeller.

[0038] The stability of the housing part can be advantageously increased according to a further embodiment by at least partially surrounding the bulge with a support structure. Preferably, the bulge is completely surrounded by a support structure. The support structure extends on the outside of the housing part and increases its stability. Preferably, the support structure is honeycomb-shaped, so that the inlet opening is surrounded by a plurality of honeycomb-shaped sections. The honeycomb-shaped support structure extends, in particular, parallel to the central axis of the inlet opening.

[0039] Preferably, the height of the support structure – in a direction parallel to the central axis of the inlet opening – is equal to the maximum height of the bulge in this direction, so that the bulge and the support structure are flush with the surface.

[0040] In particular, the developing boundary layer of the flow can be further enlarged, according to a further embodiment, by having the curved inlet surface protrude from the inside of the housing part. The inlet surface is thus extended in cross-section on the inside of the housing part in such a way that it forms a projection on the inside. In the assembled state, the curved inlet surface therefore extends at least partially into the fluid space bounded by the housing part.

[0041] According to a further embodiment of the housing, the inlet surface is provided with at least one local guide projection, in particular that the local guide projection extends in a plane that includes a central axis of the inlet opening. Preferably, a plurality of guide projections are arranged on the inlet surface, which reduce the formation of flow components in the circumferential direction.

[0042] Another embodiment of the housing provides that the inlet surface has at least one recess extending over part of the circumference of the inlet opening. The recess is preferably designed to locally reduce the height of the bulge and / or locally increase the clear cross-section of the inlet opening. The recess also reduces noise emission.

[0043] Another embodiment provides that at least one guide element extends from the inlet surface towards a central axis of the inlet opening. The guide element is designed to influence the flow of the incoming fluid in a predetermined manner, for example, its direction. The guide element is designed and configured for flow control. Extending from the inlet surface towards the central axis of the inlet opening, the guide element is supported, for example, by a support element on the inlet surface, particularly on the opposite side of the circumference. It is also provided that the guide element extends beyond the central axis to the opposite side. In this embodiment, one could also speak of two guide elements, each extending towards the central axis, meeting at the central axis, and mutually supporting each other.

[0044] A further development of the housing provides that an inlet ring, at least partially covering the inlet opening, is held to the housing part by a guide element, preferably with two guide elements. The flow entering through the inlet opening is influenced by both the inlet ring and the guide element. The guide element extends radially between the inlet surface and the inlet ring. The largest diameter of the inlet ring is preferably less than or equal to the smallest diameter of the inlet opening. For example, two guide elements are arranged opposite each other or offset from one another on the circumference.

[0045] According to a further development, it has proven particularly advantageous if at least one guide element, preferably all guide elements, has at least one guide surface with a dimension of at least two dimensions. The guide surface serves to deflect the flow, in particular to change its direction. For example, a guide element has two guide surfaces, which are preferably arranged opposite each other – opposite surfaces of the guide element. In particular, the at least one guide surface is curved; preferably both guide surfaces are curved. For example, the curvature corresponds to the shape of a logarithmic spiral, preferably a Fibonacci spiral with at least two different radii of curvature. It is also advantageously provided that the guide surface is inclined in the circumferential direction relative to a central axis of the inlet opening.This means that the guide surface is arranged in such a way that a flow is at least partially deflected into a tangential and / or circumferential direction of a circular path around the central axis.

[0046] According to a further embodiment of the housing, it is preferably provided that more than two guide elements, in particular between five and ten guide elements, are provided, preferably that the guide elements are arranged uniformly or asymmetrically on the circumference of the inlet surface. In the case of a uniform arrangement, the distance on the circumference – in particular the central angle – between all guide elements is identical.

[0047] The guide elements, for example, increase the pressure that can be generated by a radial fan with such a housing, while maintaining a constant volume flow and noise emission. The guide element(s) simultaneously function as a cover grille for the inlet opening and prevent the ingress of solid particles of a certain size.

[0048] In an asymmetrical arrangement, the distance – the central angle – between the guide elements varies around the circumference. In a polar coordinate system, which is located on the outside of the housing part, whose pole coincides with the central axis of the inlet opening and whose polar axis is orthogonal to the central axis of an outlet opening, the guide elements are arranged closer together – the central angles between the guide elements are smaller – in an angular range between 90° and 250°, particularly between 90° and 180° (the pressure range), than in an angular range between 250° and 360°. With uneven spacing of the guide elements, the perceptible noise emission can be advantageously reduced further.

[0049] A particularly advantageous feature of this design is that at least some of the guide elements on the circumference of the inlet surface are spaced apart by distances – or central angles – corresponding to the Fibonacci sequence. Due to insufficient spacing, for example, the first elements of the Fibonacci sequence are not considered. Therefore, preferably, the first distance or central angle between a first and a second guide element corresponds to the seventh element of the Fibonacci sequence, i.e., the number 13; consequently, the first central angle is 13°. All subsequent guide elements on the circumference are spaced such that the distance – the central angle – is the sum of the two preceding distances.In particular, the distance between the first and second guide elements begins with a central angle of 13°, so that a central angle of 21° (13° + 8°) follows between the second and third guide elements. Subsequent central angles are always the sum of the two preceding central angles.

[0050] In particular, it is provided that the guide surfaces are spaced closest to each other on the circumference in the area where the pressure zone is located on the inside of the housing part, in the fluid chamber, especially in the angular range between 90° and 180° in the polar coordinate system described above. This is the area located below the tongue of the radial fan.

[0051] The achievable pressure with constant noise emission can be advantageously increased further by providing, according to a further embodiment, that the inlet ring has a surface oriented towards the circumference of the inlet opening with a cross-section that at least partially has the shape of a logarithmic spiral, in particular a Fibonacci spiral, and / or that the inlet ring has a surface facing away from the circumference of the inlet opening with a cross-section that at least partially has the shape of a logarithmic spiral, in particular a Fibonacci spiral. This causes the flow to adhere to the inlet ring with an advantageous boundary layer in the region of the inlet opening. The surfaces of the inlet ring are those surfaces that are oriented essentially like the inlet surface.

[0052] Preferably, both the inner surface (in cross-section) and the outer surface (in cross-section) of the inlet ring are almost completely designed to have the shape of a Fibonacci spiral, in particular with at least two different radii.

[0053] Particularly advantageous results can be achieved if the embodiments of the previously described solution according to the invention are combined with the solution according to the invention described immediately before, i.e., for example, an inlet ring with guide elements is combined with an inlet surface curved in its shape according to a logarithmic spiral.

[0054] It has also proven particularly advantageous to combine the features of the aforementioned solutions, so that the best results are achieved, for example, with a housing in which the inlet surface has the shape of a Fibonacci spiral, the inlet ring is also formed with Fibonacci surfaces, and a circumferential recess with a filling cross-section is present on the inside. A first housing part can advantageously be joined with a known second housing part to form a housing according to the invention.

[0055] Preferably, the housing is used for a radial fan with at least one impeller, wherein the impeller can be driven by a drive means, and wherein the impeller is rotatably arranged in the housing. A radial fan with such a housing is particularly suitable for air conditioning a vehicle seat.

[0056] In detail, there are numerous possibilities for designing and further developing the housing. Reference is made to the claims subordinate to claims 1 and 5, as well as to the following description of preferred embodiments in conjunction with the drawing.

[0057] The drawing shows: Fig. 1 shows a radial fan with an exemplary housing; Fig. 2 shows a section through the exemplary embodiment according to Fig. 1 Fig. 3 an embodiment of a housing part; Fig. 4 a radial fan with an embodiment of a housing; Fig. 5 an embodiment of a housing; Fig. 6 a section through another embodiment of a housing; Fig. 7 an embodiment of a housing; Fig. 8 the embodiment according to Fig. 7 in another view; Figs. 9a to g Exemplary embodiments of filling cross-sections, Figs. 10a to h Exemplary embodiments of circumferential progressions of the filling cross-section, Fig. 11 a radial fan with an exemplary embodiment of a housing, Fig. 12 an exemplary embodiment of a housing part, Fig. 13 the housing part according to Fig. 12 , Fig. 14a to hExemplary cross-sections of the circumferential projection, and Fig. 15a to hExemplary circumferential profiles of the circumferential projection.

[0058] Fig. 1 Figure 1 shows an embodiment of a housing 1 for a radial fan 2. In this embodiment, the housing 1 comprises a first housing part 3 and a second housing part 4. The first housing part 3 and the second housing part 4 are connected to each other. The housing part 3 has an inlet opening 7 through which a fluid, for example air, can flow into a fluid chamber 8 in which a fan wheel 9 is rotatably mounted. The housing 1 also has an outlet opening 10 through which the fluid leaves the radial fan 2 at a higher pressure. The inlet opening 7 has a convex inlet surface 11 on its circumference, which in this embodiment is convex in the direction of the central axis M of the inlet opening 7.

[0059] Fig. 2 shows a section through the embodiment according to Fig. 1 in a plane that completely encompasses the central axis M of the inlet opening 7. The fan wheel 9 is rotatably mounted within the fluid chamber 8 between the first housing part 3 and the second housing part 4. The curved inlet surface 11, which completely surrounds the inlet opening 7, is formed as a Fibonacci spiral with three different radii of curvature in a section between one end 12 of the inlet surface 11 within the fluid chamber 8 and approximately halfway 13, a height 14, a bulge 15. The inlet surface 11 extends partially onto the bulge 15.

[0060] The bulge 15 surrounds the inlet opening 7 along its entire circumference and extends in a direction parallel to the central axis M (see Fig. 1 ) protrudes from an outer surface 16 of the housing part 3. The protrusion 15 has a continuous profile in cross-section over its entire extent, in particular including the inlet surface 11. The curved inlet surface 11 also protrudes with its end 12 on an inner surface 17 of the housing part 3.

[0061] Fig. 3 Figure 1 shows an embodiment of a housing part 3 in a perspective view. The housing part 3 is designed as a cover ring of a housing 1. The inlet opening 7 has a convex inlet surface 11, which extends at least partially onto a bulge 15. The bulge 15 projects from the outer surface 16 in a direction parallel to the central axis M. A plurality of guide projections 18 are arranged in the inlet surface 11, each of which extends substantially in a plane that includes the central axis M of the inlet opening 7, i.e., is not inclined to the central axis M. In particular, the noise generated by the radial fan 2 is further reduced by a recess 19 in the bulge 15 or in the inlet surface 11. The recess 19 extends over a portion of the circumference.

[0062] Fig. 4 Figure 1 shows a radial fan 2 with an exemplary embodiment of a housing 1 in a perspective view. In this exemplary embodiment, the housing part 3 has an inlet ring 20 that at least partially covers the inlet opening 7. The exemplary embodiment in Fig. 1 also shows an inlet ring 20. The inlet ring 20 is designed according to Fig. 4 of ten guide elements 21 on the housing part 3 and according to Fig. 1 held by three guide elements 21 on the housing part 3. The guide elements 21 have a first guide surface 22a and a second guide surface 22b with a dimension of at least two dimensions. According to Fig. 4 The guide surfaces 22a and 22b are inclined relative to the central axis M. According to Fig. 1 and Fig. 4 The guide elements are evenly distributed and spaced apart on the circumference surrounding the inlet opening 7. The guide elements 21 are arranged on the inlet surface 11 and extend radially towards the inlet ring 20.

[0063] Fig. 5 Figure 1 shows an embodiment of a housing 1 from the outside 16. The housing 1 has an inlet ring 20, which is held on the housing part 3 by seven guide elements 21, partially covering the inlet opening 7. Some of the guide elements 21 are spaced apart from each other on the circumference of the inlet opening 7 or the inlet surface 11 such that the distances A1 to A5 – the central angles – are in the Fibonacci sequence. This means that, starting from a first distance A1, which is based on a central angle of 13° – the seventh element of the Fibonacci sequence – and a distance A2, which is based on a central angle of 21° – the sum of 8° and 13° – the subsequent distances always correspond to the sum of the two preceding distances or central angles.Consequently, the central angle of distance A3 is the sum of the central angles of A1 and A2, the central angle of A4 is the sum of the central angles of A2 and A3, and the central angle of A5 is the sum of the central angles of A3 and A4. Due to the uneven distribution of the guide elements 21 around the circumference, as shown, the pressure can be increased with the same noise level, particularly at flow rates between two and four liters per second.

[0064] According to Fig. 5 In a polar coordinate system, which is located on the outside 16 of the housing part 3, whose pole P coincides with the central axis M of the inlet opening 7, and whose polar axis PA is orthogonal to the central axis MA of the outlet opening 10, the first guide element 21 is arranged at a distance A1 to the second guide element 21 at an angle of approximately 90°.

[0065] According to the exemplary embodiment of the Fig. 1 and Fig. 2 The inlet ring 20 has a surface 23 oriented towards the inlet surface 11, which is in Fig. 2 The cross-section shown, in particular between an end 20a and a section end 23a before the sign of the curvature of the surface in the cross-section changes, has the shape of a Fibonacci spiral. Furthermore, a surface 24 of the inlet ring 20 facing away from the inlet surface 11 also has, in cross-section, in part, in particular between the end 20a and a section end 24a at the transition to the end face of the inlet ring, the shape of a Fibonacci spiral, in particular with at least two different radii. By means of such a design of the inlet ring 20, the pressure of the radial fan 2 can be increased at almost all volume flows while maintaining the same noise level.

[0066] Fig. 6 Figure 1 shows an embodiment of a housing 1 for a radial fan 2. The fan wheel 9 is rotatably mounted within the fluid chamber 8 between the first housing part 3 and a second housing part 4. On the inner side 17 of the housing part 3, opposite the bulge 15, a circumferential recess 25 is formed, completely surrounding the inlet opening 7. In the section shown, the circumferential recess 25 is designed such that the wall thickness in the area of ​​the inlet surface 11 and the bulge 15 is almost constant. The circumferential recess 25 allows the pressure to be increased compared to embodiments without a circumferential recess 25, particularly at flow rates exceeding two liters per second, while maintaining the same noise level. In this embodiment, an inner flank 31 of the circumferential recess 25 is parallel to the central axis M of the inlet opening 7.

[0067] Fig. 7 and Fig. 8 Figure 17 shows an embodiment of a housing part 3 from the inside. Fig. 8 Figure 1 shows the embodiment in a perspective view. The circumferential recess 25 extends over the entire circumference of the inlet opening 7. In a first arc segment 26 along the circumference, the circumferential recess 25 has a basic cross-section 27, which is, for example, Fig. 6 The second arc segment 28 of the circular recess 25 has a filling cross-section 29 whose cross-section differs from and varies with the basic cross-section 27. In the illustrated embodiment, the filling cross-section 29 extends over a second arc segment 28 with a central angle of approximately 220°. In a polar coordinate system oriented on the inside 17 of the housing part 3, whose pole P coincides with the central axis M of the inlet opening 7, and whose polar axis PA1 is orthogonal to a central axis MA1 of the outlet opening 10 of the housing 1, the illustrated filling cross-section 29 – with its sum of central angles of 220° – is arranged in an angular range between 138° and 358°. The filling cross-section 29 is shown as a dashed line in Fig. 8a for illustrative purposes only; it is not a section.

[0068] Fig. 9a bis Fig. 9g Figures 2 show exemplary embodiments of the basic cross-section 27 and the filling cross-section 29 of the circumferential recess 25. The reduced cross-section compared to the basic cross-section 27 is shown in the Fig. 9b bis Fig. 9g Hatched for the sake of simplicity; it is not a different material. Fig. 9a shows the reversible step 25 with a basic cross-section 27, which in cross-section has a free base area 30 with a basic height GH, which is measured on the inner flank 31 between an imaginary plane on the inside 17 and the point 30 furthest away from it along the central axis M or the inner flank 31 in the basic cross-section 27.

[0069] Fig. 9b bis Fig. 9g Figure 1 shows exemplary embodiments of the filling cross-section 29 with different profiles 33 in the base area over the width of the circumferential setback 25. The profiles 33 have, particularly in the radial direction starting from the central axis M, either a continuous, arc-shaped profile in cross-section ( Fig. 9c, 9e ), a linear progression ( Fig. 9b, 9d, 9f ) or a stepped progression ( Fig. 9g). Fig. 9b bis Fig. 9g Each shows a section in the area of ​​maximum reduction of the free base area 30. Starting from the maximum reduction of the free base area 30 shown, it increases again in both circumferential directions, with a continuous increase of the free base area 30 while maintaining the same profile 33 - the hatched area is reduced starting from the maximum area shown.

[0070] Fig. 10a bis Fig. 10h Examples of the fill cross-sectional area 29 shown are expressed as a percentage along the ordinate axis. The value of 100% applies to all examples. Fig. 9b bis 9g shown; starting from this maximum value, the calculation in the Fig. 10a bis Fig. 10h The depicted course over the circumference. On the abscissa axis, the circumference is represented by the angle in a coordinate system according to Fig. 7 illustrated. The exemplary implementations of the Fig. 10d , 10e und 10f shown are embodiments with at least two second arc segments 28 with a varying fill cross-section 29, which is at least locally on the circumference of one of the profiles of the Fig. 9b bis Fig. 9g exhibits, namely at the maxima shown. The exemplary embodiments of the Fig. 10a, 10b, 10c , 10g und 10h shown are embodiments in which the second arc segment, 28 with the filling cross-section 29 extends almost completely over the entire circumference.

[0071] Fig. 11 Figure 1 shows an embodiment of a housing 1 for a radial fan 2. The inlet surface 11 has the same features as in the embodiment shown in Figure 2. Fig. 1 The inlet opening 7 has a cross-sectional shape around its entire circumference that corresponds to the shape of the Fibonacci spiral, specifically with three different radii. The inlet surface 11 extends at least partially onto a bulge 15 that surrounds the inlet opening 7. On the outer surface 17 of the housing part 3, the bulge 15 is surrounded by a honeycomb-shaped support structure 5, the height of which corresponds to the height 14 – see figure. Fig. 2 - corresponds to the bulge 15. The support structure 5 is formed integrally with the housing part 3 and serves in particular to stabilize the housing part 3. In this embodiment, the support structure extends over the entire surface of the outer surface 16.

[0072] Fig. 12 and Fig. 13 Figure 1 shows an embodiment of a housing part 3 from the inside 17. The inlet opening 7 is partially surrounded along its circumference by a circumferential projection 6, which extends over a projection arc segment 34 that sweeps a central angle of approximately 250° - see Figure 1. Fig. 12 In a coordinate system according to the Fig. 7 The projecting arc segment 34 is arranged at an angle between 135° and 25°. The circumferential projection 6 is shown hatched for illustrative purposes only. In this embodiment, the circumferential projection 6 is formed integrally with the housing part 3. In the assembled state, the circumferential projection 6 is located essentially within the pressure zone of a radial fan 2, which advantageously influences its performance characteristics.

[0073] Fig. 14a bis 14h Examples of circumferential projections 6 are shown in cross-section, specifically at a point with the maximum area of ​​the circumferential projection in the cross-section. Starting from the ones shown in the Fig. 14a bis Fig. 14h In the depicted areas, the area of ​​the circumferential projection 6 decreases continuously in cross-section or exhibits a profile that is in the Fig. 15a bis 15h is shown. The following are in Fig. 14a bis Fig. 14h The sections shown are at the absolute maximum of the Fig. 15a bis Fig. 15h The angle specifications of the Fig. 15a bis Fig. 15h refer to a coordinate system according to Fig. 7 .

[0074] In the exemplary embodiments of the Fig. 14a bis Fig. 14h The circumferential projection 6 is designed as a separate part and is inserted into and fastened in a recess 35 in the housing part 3. The circumferential projections 6 shown have a polygonal and / or at least partially convex cross-section. A maximum height 36, exemplified in Fig. 14a und 14gThe circumferential projection 6 is preferably chosen such that the gap between a fan wheel 9 and the maximum height 36 is between 1 mm and 5 mm.

Claims

1. A housing (1) for a turbomachine, in particular for a radial fan (2), having at least one housing part (3), wherein the housing part (3) has at least one inlet opening (7), wherein a fluid space (8) for receiving at least one fan wheel (9) is at least partially delimited by the housing part (3), wherein the inlet opening (7) is surrounded on an outer side of the housing part (3) by a bulge (15), wherein a curved inlet surface (11) extends at least partially on the bulge (15), and wherein a circumferential recess (25) at least partially circumferentially surrounding the inlet opening (7) is formed on an inner side (17) of the housing part (3), wherein the circumferential recess (25) has a base cross-section (27) along the circumference in at least one first arc segment (26) and a varying fill cross-section (29) in at least one second arc segment (28).

2. The housing (1) according to claim 1, wherein the circumferential recess (25) has a free base area (30) in the base cross-section (27), and wherein the free base area (30) is reduced in the fill cross-section (29).

3. The housing (1) according to claim 1 or 2, wherein the fill cross-section (29) extends in an angular range between 120° and 360°, in particular in an angular range between 135° and 355°, in a polar coordinate system that lies on the inner side (17) of the housing part (3), whose pole (P) coincides with a central axis (M) of the inlet opening (7), and whose polar axis (PA1) is orthogonal to the central axis (MA1) of an outlet opening (10).

4. The housing (1) according to any one of claims 1 to 3, wherein the fill cross-section (29) has a continuous or discontinuous profile (33), in particular has a linear, arcuate and / or stepped profile (33).

5. A housing (1) for a turbomachine, in particular for a radial fan (2), having at least one housing part (3), wherein the housing part (3) has at least one inlet opening (7), wherein a fluid space (8) for receiving at least one fan wheel (9) is at least partially delimited by the housing part (3), wherein the inlet opening (7) is surrounded on an outer side of the housing part (3) by a bulge (15), and wherein a curved inlet surface (11) extends at least partially on the bulge (15), wherein a circumferential projection (6) at least partially surrounding the inlet opening (7) is formed on an inner side (17) of the housing part (3), and wherein the circumferential projection (6) has a cross-section that varies over its extent.

6. The housing (1) according to claim 5, wherein the circumferential projection (6) extends in at least one projection arc segment (34) along the circumference, in particular wherein the projection arc segment (34) has a central angle between 1° and 359°, in particular 220°.

7. The housing (1) according to claim 6, wherein the projection arc segment (34) extends in an angular range between 120° and 360°, in particular in an angular range between 135° and 355°, in a polar coordinate system that lies on the inner side (17) of the housing part (3), whose pole (P) coincides with a central axis (M) of the inlet opening (7), and whose polar axis (PA1) is orthogonal to the central axis (MA1) of an outlet opening (10).

8. The housing (1) according to any one of claims 5 to 7, wherein the circumferential projection (6) is at least partially recessed into the housing part (3).

9. The housing (1) according to any one of claims 1 to 8, wherein the housing part (3) is formed from a plastic, in particular wherein the housing part (3) is formed in one piece, preferably by means of injection molding or an additive manufacturing process, in particular 3D printing.

10. The housing (1) according to any one of claims 1 to 9, wherein the inlet opening (7) has at least in sections a curved inlet surface (11), and wherein the curved inlet surface (11) has at least partially the shape of a logarithmic spiral in cross-section.

11. The housing (1) according to any one of claims 1 to 10, wherein the inlet opening (7) has at least in sections a curved inlet surface (11), and wherein at least one guide element (21) extends from the inlet surface (11) in the direction of a central axis of the inlet opening (7), in particular wherein more than one guide element (21), in particular between two and ten guide elements (21), are provided, preferably wherein at least a portion of the guide elements (21) are spaced apart on the circumference of the inlet surface (11) with spacings (A1, A2, A3, A4, A5) that relate to one another according to the Fibonacci sequence.

12. The housing (1) according to any one of claims 5 to 8, wherein a circumferential recess (25) at least partially circumferentially surrounding the inlet opening (7) is formed on an inner side (17) of the housing part (3), in particular characterized by the characterizing portion of at least one of claims 2 to 4.

13. The housing (1) according to any one of claims 1 to 4, wherein a circumferential projection (6) at least partially circumferentially surrounding the inlet opening (7) is formed on an inner side (17) of the housing part (3), in particular characterized by the characterizing portion of at least one of claims 5 to 8.

14. A turbomachine, in particular a radial fan (2), having at least one fan wheel (9), wherein the fan wheel (9) is drivable by a drive means, and wherein the fan wheel (9) is rotatably arranged in a fluid space (9) of a housing (1), wherein the housing (1) is configured according to any one of claims 1 to 13.

15. A ventilated vehicle seat having at least one radial fan (2), wherein the radial fan (2) is configured according to claim 14.