Ventilation arrangement

Abstract

Ventilation arrangement designed for a vehicle heat exchanger, comprising: a support structure or hood (1) in which a channel (3) is defined having at least one axial first and one axial second region (3a, 3b) each with a smaller and a larger section, wherein these regions are connected to each other by an intermediate connecting region (3c), and a motor-driven blower with a fan wheel (2) rotatably mounted in the channel (3) and having several blades (5) extending between a central hub (4) and a peripheral ring (6); wherein the peripheral ring (6) has a substantially cylindrical main region (6a) to which the radially outer ends of the blades (5) are connected and to which an outwardly diverging end lip (6b) is attached; wherein the arrangement is such that an annular passage (7) is defined between the outer ring (6) of the fan wheel (2) and the wall of the channel (3) of the support structure or hood (1), comprising a first region (7a) extending in one direction with a radial component, which is located between the lip (6b) of the ring (6) of the fan wheel (2) and the intermediate connection area (3c) of the channel (3) is defined, and a substantially axial second area (7b) defined between the cylindrical main area (6a) of the ring (6) of the fan wheel (2) and the second area (3b) of the channel (3); wherein the lip (6b) of the outer ring (6) of the fan wheel (2) has a substantially frustoconical shape; wherein the channel has a third region (3d) extending from the axial second region (3d) of the channel (3) in a direction inclined relative to the axial second region (3b) of the channel (3); and wherein a distal edge of the third region (3d) is arranged in an axial direction of the marginal ring (6) deeper than a lower edge of the substantially cylindrical main region (6a), so that an intake opening (8) is formed between the third region (3d) and the lower edge of the substantially cylindrical main region (6a).

Description

AREA OF INVENTION

[0001] The invention relates to a ventilation arrangement, specifically for a heat exchanger of a motor vehicle, and in particular a ventilation arrangement with a recirculation protection device. BACKGROUND OF THE INVENTION

[0002] The invention specifically relates to a ventilation arrangement of the type comprising: a support structure or hood in which a channel is defined having at least a first and a second axial region, each with a larger and smaller cross-section, the regions being connected to one another by an intermediate connecting region; and a motor-driven blower with a fan wheel rotatably mounted in the channel and having a plurality of blades extending between a central hub and an outer ring. The outer ring has a substantially cylindrical main region to which radially outer ends of the blades are connected and to which an outwardly diverging end lip adjoins. The arrangement is such that an annular passage is defined between the outer ring of the fan wheel and the wall of the channel in the support structure or hood.The annular passage has a first region defined between the lip of the outer ring of the fan wheel and the intermediate connecting region of the channel, extending in a direction with a radial component, and a substantially axial second region defined between the cylindrical region of the outer ring of the fan wheel and the second region of the channel.

[0003] Such ventilation arrangements, in accordance with the state of the art, are in the Fig. Figures 1a to 1d of the accompanying drawings are shown partially and schematically in cross-section. In these figures, the support structure or hood, which is provided for attachment to a heat exchanger, is designated by reference numeral 1, and the impeller of the associated motor-driven blower is designated in its entirety by reference numeral 2. The channel 3 formed in the hood 1 has a first section 3a and a second section 3b, each with a larger and a smaller cross-section, the sections being separated by an intermediate connecting section 3c (see, for example, the Fig. 1a and 1b are connected.

[0004] The fan wheel 2 has a central hub 4 from which several blades 5 extend, their radially outer ends connected to a peripheral ring designated by reference numeral 6. The ring has a substantially cylindrical main section 6a to which the blades 5 are connected and to which a radially outwardly diverging end lip 6b is attached. The annular opening defined between the channel 3 and the ring 6 is designated by reference numeral 7.

[0005] In the variant according to Fig. 1a the lip 6b of the ring 6 of the fan wheel 2 extends approximately in the same general plane as the hood 1, whereas in the embodiment according to Fig. 1b the lip 6b is set back with respect to the general plane and extends into the first area 3a of the canal 3.

[0006] In the variant according to Fig. 1c the lip 6b of the ring 6 of the fan wheel extends beyond the channel 3, at a given distance from the general plane of the hood 1.

[0007] In the variant according to Fig. 1d Finally, the fan wheel 2 is relative to the hood 1 and to the duct 3 essentially as in Fig. 1b is positioned, but the hood 1 has an associated recirculation protection ring 9, also known as an acoustic ring, which extends radially towards the axis of the fan wheel and is partially opposite the fan wheel 2 and in some cases is curved towards the fan wheel 2.

[0008] Further ventilation arrangements with a support structure or hood and a fan wheel are known from DE 10 2012 023 454 A1, DE 33 04 297 C2 and DE 38 04 217 A1.

[0009] The hood 1 and the fan wheel 2 are manufactured from thermoplastic polymers using typical molding processes. Their design requires particular attention in that the need for weight reduction must be balanced with the need for adequate strength. The fan wheels are components subjected to high dynamic stresses during operation, and their deformations and movements must be appropriately accounted for to prevent contact with stationary parts. For these reasons, the gaps between the various parts must be dimensioned appropriately. The increased throughput and pressure of the generated airflow at these gaps, which are oversized for safety reasons, are not offset by the resulting increase in noise, higher power consumption, and reduced operating efficiency. BRIEF DESCRIPTION OF THE INVENTION

[0010] Therefore, a ventilation arrangement of the type defined above is desired which can improve the performance characteristics of known solutions according to the state of the art, in particular with regard to a reduction of recirculation flows and noise, a reduction in power consumption and an improvement in overall efficiency.

[0011] The invention provides a ventilation arrangement according to claim 1. Advantageous embodiments are the subject of the dependent claims.

[0012] According to the invention, a ventilation arrangement of the type defined above is proposed, wherein the lip of the outer ring of the fan wheel has a substantially frustoconical shape, preferably with an angle of inclination between 115° and 145°, and wherein, further preferably, the intermediate connection area of ​​the aforementioned channel also has a substantially frustoconical shape, wherein an angle of inclination corresponds at least approximately to that of the lip of the fan wheel.

[0013] Preferably, the lip of the outer ring of the fan wheel has a frustoconical outer surface with a linear profile and an inner surface with a convex profile, in particular a parabolic profile.

[0014] In one embodiment, the support structure or the hood has an associated recirculation protection ring that extends at the end of the first region of the aforementioned channel opposite the second region of that channel. This recirculation protection ring faces the lip of the outer ring of the fan wheel and converges towards the fan wheel at an angle of inclination that is at least similar to that of the lip of the fan wheel.

[0015] Advantageously, an annular projection is provided in the annular passage defined between the outer ring of the fan wheel and the channel of the hood, extending from the connecting zone between the recirculation protection ring and the first area of ​​the aforementioned channel towards the lip of the outer ring of the fan wheel, thereby defining a local constriction in the annular passage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A preferred embodiment of the invention will now be described by way of example, with reference to the accompanying drawings. Identical structures, elements, or parts that appear in more than one figure are generally characterized identically in all figures in which they appear. The dimensions of components and features are chosen for the sake of clarity and are not necessarily drawn to scale. The figures are listed below. The ones already described Fig. Figures 1a to 1d are partial sectional views that schematically represent solutions according to the state of the art; Fig. 2 is a partial sectional view of a ventilation arrangement according to the present invention; Fig. Figure 3 is an enlarged view of part of Fig. 2. DETAILED DESCRIPTION OF THE PREFERRED EXECUTION FORMS

[0017] In the Fig. 2 and Fig. Figure 3, in which the preferred embodiment of the present invention is shown, parts and elements that have already been described are identified by the same reference numerals as used above.

[0018] The ventilation arrangement, which is in the Fig. 2 and Fig. 3 shown also has a support structure or hood 1, which is made of molded plastic and defines a channel 3 in which a fan wheel 2 is mounted, which is driven by an electric motor, for example by a DC motor with or without brushes, in a manner known per se and not described.

[0019] The fan wheel 2 has a central hub 4 from which a plurality of blades 5 extend, their radially outer ends being connected to the cylindrical main section 6a of the outer ring 6, which forms an outwardly diverging lip 6b at one end. The lip 6b is essentially frustoconical, with an inclination angle α (angle of divergence from the axis) between 115° and 145°.

[0020] The channel 3 defined by the hood 1 has an axial first and an axial second region 3a and 3b, which are essentially cylindrical and each have a larger and a smaller cross-section. These regions 3a and 3b of the channel 3 are connected by an intermediate connecting region 3c, which is also essentially frustoconical, with an angle of inclination that corresponds at least approximately to that of the lip 6b of the outer ring 6 of the fan wheel 2. In particular, the intermediate connecting region 3c of the channel 3 is at least approximately parallel to the outer surface of the lip 6b.

[0021] As in Fig. As can be seen more clearly in Figure 3, an annular passage 7, designated by reference numeral 7, is formed between the outer ring 6 of the fan wheel 2 and the wall of the channel 3. The passage 7 comprises a first region 7a, defined between the lip 6b of the ring 6 and the intermediate connection region 3c of the wall of the channel 3. This first region 7a of the annular passage 7 extends in a direction that forms an angle relative to the axis of the ventilation arrangement and therefore has a radial component. The passage 7 also comprises a substantially axial second region 7b, defined between the cylindrical main region 6a of the ring 6 and the second region 3b of the wall of the channel 3.

[0022] In the illustrated embodiment, the wall of the channel 3 has a third region 3d, which adjoins the second region 3b on the opposite side of regions 3a and 3c. This third region 3d extends axially beyond the outer ring 6 of the fan wheel 2 and also has a frustoconical shape that converges away from the drive wheel 2. The third region 3d of the wall of the channel 3 has an angle of inclination that also corresponds at least approximately to that of the intermediate connecting region 3c and the lip 6b of the ring 6.

[0023] A ring-shaped intake opening, which is located in Fig. 3, which is marked with reference numeral 8, is defined between the distal edge of the third region 3d of the wall of the channel 3 and the lower edge of the substantially cylindrical main region 6a of the ring 6.

[0024] In the embodiment described in the Fig. 2 and Fig. As shown in Figure 3, a recirculation protection ring 9 is associated with the support structure or hood 1. This ring 9 extends at the upper end of the first region 7a of the channel 7 on the opposite side of the second region 7b of the channel 7. The recirculation protection ring 9 has a distal region 9a that is opposite the lip 6b of the outer ring 6 of the fan wheel 2. This distal region 9a of the ring 9 has at least an approximate frustoconical shape that converges towards the fan wheel 2, with an angle of inclination that, on average, corresponds at least approximately to that of the aforementioned lip 6b.

[0025] The lip 6b of the outer ring 6 of the fan wheel 2 has a frustoconical outer surface 6c with a substantially linear profile and an inner surface 6d with a convex profile, in particular a parabolic profile ( Fig. 3).

[0026] The recirculation protection ring 9 advantageously has a concave, preferably parabolic, inner surface 9b and a convex, also preferably parabolic, outer surface 9c. A further region 7c of the passage 7 is defined between the inner surface 6d of the lip 6b of the ring 6 and the inner surface 9b of the recirculation protection ring 9.

[0027] In the annular passage 7, an annular projection 10 extends from the connecting zone between the recirculation protection ring 9 and the first area 3a of the channel 3 towards the lip 6b of the outer ring 6 of the fan wheel 2. The annular projection 10 creates a local constriction in the annular passage relative to the distal edge of the lip 6b.

[0028] Although, as in the Fig. 2 and Fig. As shown in Figure 3, the recirculation protection ring 9 and the annular projection 10 are formed in one piece with the support structure or hood 1. However, it is also advantageous to form them separately from the support structure or hood 1 in order to simplify the associated forming processes and, in particular, to avoid the need to produce undercut parts.

[0029] During operation, the rotation of the fan wheel 2 induces an airflow through the duct 3 of the hood 1, as indicated by the flow lines shown in Fig. 3 are represented by the dashed lines.

[0030] A small fraction of the induced airflow runs around the outer ring 6 of the fan wheel 2, as shown by the flow line F in Fig.3 indicated. This airflow penetrates through the intake opening 8, the areas 7b, 7a and then the area 7c of this passage into the annular passage 7.

[0031] With the ventilation arrangement according to the invention, which is implemented as described above, the airflow through the annular passage defined between the outer ring of the fan wheel and the wall of the hood's duct can be reduced to a minimum. It is also possible to reduce the gaps between the outer ring of the fan wheel, the duct wall of the hood, and the recirculation protection ring.

[0032] It is understood that the support structure or hood 1 refers to a hood or a support structure that acts as a hood, allowing the airflow to be directed through the duct 3. The hood 1 can also act as a support structure, for example, to support the blower.

[0033] It is obvious that the embodiments and design details described above with reference to an example that does not limit the invention can be varied extensively without leaving the scope of the invention as defined by the attached claims.

[0034] Verbs such as "to include", "to exhibit", "to contain", and "to have", as well as their variations in the description and claims of this application, are to be understood in an inclusive sense. They indicate that the mentioned element or feature is present, but do not preclude the presence of further elements or features.

[0035] Certain features of the invention, which for the sake of clarity have been described in connection with separate embodiments, may also be combined in only one embodiment. Conversely, various features which for the sake of brevity have been described in one embodiment may likewise be present separately or in suitable subcombinations. REFERENCE MARK LIST: 1 hood 2 fan wheels 3-channel 3a first area (channel) 3b second area (channel) 3c Intermediate connection area 3D third area 4 hub 5 shovels 6 edge ring 6a essentially cylindrical main area 6b Lippe 6c Outer surface (lip) 6d Inner surface (lip) 7 annular passage 7a first area (passage) 7b second area (passage) 7c further area (passage) 8 Intake opening 9 Recirculation protection ring 9a distal area (protective ring) 9b Inner surface (protective ring) 9c Outer surface (protective ring) 10 ring-shaped protrusion

Claims

[1] Ventilation arrangement designed for a vehicle heat exchanger, comprising: a support structure or hood (1) in which a channel (3) is defined having at least one axial first and one axial second region (3a, 3b) each with a smaller and a larger section, wherein these regions are connected to each other by an intermediate connecting region (3c), and a motor-driven blower with a fan wheel (2) rotatably mounted in the channel (3) and having several blades (5) extending between a central hub (4) and a peripheral ring (6); wherein the peripheral ring (6) has a substantially cylindrical main region (6a) to which the radially outer ends of the blades (5) are connected and to which an outwardly diverging end lip (6b) is attached; wherein the arrangement is such that an annular passage (7) is defined between the outer ring (6) of the fan wheel (2) and the wall of the channel (3) of the support structure or hood (1), comprising a first region (7a) extending in one direction with a radial component, which is located between the lip (6b) of the ring (6) of the fan wheel (2) and the intermediate connection area (3c) of the channel (3) is defined, and a substantially axial second area (7b) defined between the cylindrical main area (6a) of the ring (6) of the fan wheel (2) and the second area (3b) of the channel (3); wherein the lip (6b) of the outer ring (6) of the fan wheel (2) has a substantially frustoconical shape; wherein the channel has a third region (3d) extending from the axial second region (3d) of the channel (3) in a direction inclined relative to the axial second region (3b) of the channel (3); and wherein a distal edge of the third region (3d) is arranged in an axial direction of the marginal ring (6) deeper than a lower edge of the substantially cylindrical main region (6a), so that an intake opening (8) is formed between the third region (3d) and the lower edge of the substantially cylindrical main region (6a). [2] Ventilation arrangement according to claim 1, wherein the lip (6b) of the fan wheel (2) has a frustoconical outer surface (6c) with a linear profile and an inner surface (6d) with a convex profile, in particular a parabolic profile. [3] Ventilation arrangement according to claim 2, wherein the convex profile of the inner surface (6d) is a parabolic profile. [4] Ventilation arrangement according to claim 1, 2 or 3, wherein the third region (3d) of the channel (3) extends axially beyond the ring (6) of the fan wheel (2) and has a substantially frustoconical shape which converges in the direction away from the fan wheel (2) and has an angle of inclination which corresponds at least approximately to that of the intermediate connection region (3c) of the channel (3). [5] Ventilation arrangement according to one of the preceding claims, wherein the support structure or hood (1) has an associated recirculation protection ring (9) which extends at the end of the first region (3a) opposite the second region (3b) of the duct (3) and is opposite the lip (6b) of the fan wheel (2); wherein the recirculation protection ring (9) converges towards the fan wheel (2) with an angle of inclination which on average corresponds to that of the lip (6b). [6] Ventilation arrangement according to claim 5, wherein the circulation protection ring (9) has an outer surface (9c) with a convex profile and an inner surface (9b) with a concave profile. [7] Ventilation arrangement according to claim 6, wherein the convex profile of the outer surface (9c) of the recirculation protection ring (9) is parabolic. [8] Ventilation arrangement according to claim 6 or 7, wherein the concave profile of the inner surface (9c) of the recirculation protection ring (9) is parabolic. [9] Ventilation arrangement according to claim 6, 7 or 8, wherein an annular projection (10) is provided in the annular passage (7) which extends from the connecting zone between the recirculation protection ring (9) and the first area (3a) of the channel (3) towards the lip (6b) of the edge ring (6) of the fan wheel (2) and thereby defines a local constriction in the annular passage (7).

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