Abstract
A device for reducing the noise of motor vehicle air conditioning units, having at least one air flow limiting element which projects laterally on an outer circumference of an axial air inlet opening vertically out of an air inlet opening plane and has a surface which limits or blocks a flow path next to the axial air inlet opening, at least two plate-shaped air guiding elements, which are arranged on an inside of a recirculation air flap in mutually spaced parallel planes at right angles to an axis of rotation of the recirculation air flap, and an air flow guiding element which is arranged on a fan tongue and extends radially from the fan tongue at a distance from a fan wheel into a spiral flow channel.
Claims
1. A device for reducing noise of motor vehicle air conditioning units, the device comprising: a radial fan, in which a driven fan wheel draws in air via an axial air inlet opening and the air drawn in is conveyed from an interior of the fan via a fan tongue to an air outlet opening, wherein a recirculation air flap is arranged pivotably at least in some areas over the axial air inlet opening in such a way that an air flow on an inside of the recirculation air flap can be deflected in a direction of the axial air inlet opening, the device further comprising: at least one air flow limiting element which projects laterally on an outer circumference of the axial air inlet opening vertically out of an air inlet opening plane and thereby has a surface which limits or blocks a flow path next to the axial air inlet opening; at least two plate-shaped air guiding elements, which are arranged on the inside of the recirculation air flap in parallel planes at right angles to an axis of rotation of the recirculation air flap; and an air flow guiding element arranged on the fan tongue, which extends radially from the fan tongue at a distance from the fan wheel into a spiral flow channel.
2. The device according to claim 1, wherein the at least one air flow limiting element is arranged in front of the recirculation air flap in a direction of flow of the air drawn in.
3. The device according to claim 1, wherein the at least one air flow limiting element is an integral component of the fan housing or of an air inlet housing.
4. The device according to claim 1, wherein a height of the at least one air flow limiting element projecting vertically out of the air inlet opening plane is less than a highest position of the recirculation air flap above the air inlet opening plane.
5. The device according to claim 1, wherein there are two air flow limiting elements arranged laterally opposite one another on the outer circumference of the axial air inlet opening, the air flow limiting elements arranged opposite one another having sloping sides leading away from one another on their facing narrow sides.
6. The device according to claim 1, wherein a plurality of the plate-shaped air guide elements are arranged on the inside of the recirculation air flap, the plurality of the plate-shaped air guide elements being evenly spaced apart.
7. The device according to claim 1, wherein the plate-shaped air guide elements are integral components of the recirculation air flap.
8. The device according to claim 1, wherein the air flow guiding element has a recess tapering in a direction of the air outlet opening.
9. The device according to claim 1, wherein the air flow guiding element is an integral component of the fan housing in a form of an extension of the fan tongue.
10. The device according to claim 1, wherein the air flow guiding element has a wrap angle related to the fan wheel in a range of 47? and 67?.
11. The device according to claim 1, wherein the air flow guiding element is formed in two parts from an upper air flow guiding element and a lower air flow guiding element, the upper air flow guiding element and the lower air flow guiding element being arranged axially opposite one another.
12. The device according to claim 11, wherein the upper air flow guiding element and/or the lower air flow guiding element has/have a tip pointing into the spiral flow channel with a radius which corresponds to 0.25 times to 0.75 times a radius of the fan tongue.
13. The device according to claim 12, wherein the upper air flow guiding element and/or the lower air flow guiding element on the fan tongue has/have an axial height which corresponds to 0.35 times to 0.75 times an axial height of the fan wheel, an axial height of the tip of the upper air flow guiding element and/or of the lower air flow guiding element corresponds to a maximum of 0.7 times the axial height at the fan tongue.
14. The device according to claim 13, wherein the axial height of the upper air flow guiding element and/or the lower air flow guiding element increases from the tip in a direction of flow.
15. The device according to claim 14, wherein a radial width of the upper air flow guiding element and/or the lower air flow guiding element increases in the direction of flow.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Further details, features and advantages of embodiments of the invention can be found in the description of exemplary embodiments below with reference to the associated drawings. In the drawings:
[0024] FIG. 1: shows a schematic diagram of an exemplary embodiment of a radial fan for a motor vehicle air conditioning unit according to the prior art,
[0025] FIG. 2: shows a schematic sectional diagram of the exemplary embodiment of a radial fan for a motor vehicle air conditioning unit shown in FIG. 1,
[0026] FIG. 3: shows a schematic diagram of an exemplary embodiment of the device according to the invention,
[0027] FIG. 4A: shows a schematic perspective diagram of an exemplary embodiment of the device according to the invention,
[0028] FIG. 4B: shows a further view of the exemplary embodiment of the device according to the invention shown in FIG. 4A,
[0029] FIG. 5: shows a detail diagram of a recirculation air flap,
[0030] FIG. 6: shows a schematic diagram of an exemplary embodiment of the device according to the invention inside a radial fan, and
[0031] FIG. 7: shows a detail diagram of an exemplary embodiment of the upper air flow guiding element.
DETAILED DESCRIPTION
[0032] Recurring features are labelled with the same reference signs in the figures.
[0033] FIG. 1 shows a schematic diagram of an exemplary embodiment of a radial fan 1 for a motor vehicle air conditioning unit according to the prior art. The radial fan 1 comprises a fan housing 2 with a spiral or screw-shaped inner contour, which is not visible owing to the perspective representation. A drivable fan wheel 3 is arranged in the interior of the fan housing 2. An electric motor can be provided for driving the fan wheel 3. Axially to the rotational axis of the fan wheel 3, the fan housing 2 has an air inlet opening 4, which is partially concealed by a separate air inlet housing 5 in the diagram shown. In the housing interior of the fan housing 2, a flow channel leads along the spiral inner contour via a fan tongue 6 (shown in FIG. 2) to an air outlet opening 7 (see FIG. 2), which opens into a diffuser in the example shown. Air is drawn in via the axial air inlet opening 4 using the driven fan wheel 3. The drawn-in air is conveyed from the fan interior via the fan tongue 6 (see FIG. 2) to the air outlet opening 7. The air is provided from a flow channel or from a flow path which is connected to the air inlet housing 5. The air inlet housing 5 comprises a fresh air inlet 5.1 and a recirculation air inlet 5.2, through which air passes axially into the radial fan 1 without substantial influence of the air flow.
[0034] FIG. 2 shows a schematic sectional diagram of the exemplary embodiment, shown in FIG. 1, of a radial fan 1 according to the prior art for a motor vehicle air conditioning unit. The section runs axially in relation to the rotational axis of the fan wheel 3 through the air inlet housing 5 and through the fan housing 2 to allow a view into a spiral flow channel 14, of the fan tongue 6 and of the fan wheel 3. The axial air inlet opening 4 is formed within an air inlet opening plane 15. Above the axial air inlet opening 4, the air inlet housing 5 is situated, in which a recirculation air flap 5.3 is arranged such that it can pivot over some regions of the axial inlet opening 4. The housing-side transition of the fan tongue 6 into the spiral flow channel 14 to the air outlet opening 7 has a radius.
[0035] FIG. 3 shows a schematic diagram of an exemplary embodiment of the device according to the invention. This is a perspective and transparent view from above of the opening cross section of the axial air inlet opening 4 of the fan housing 2. FIG. 3 thus allows a view into the interior of an air inlet housing (not shown in detail), in which a recirculation air flap 8 and a further flap 9, which can also be referred to as a fresh air flap, are situated. The circular axial air inlet opening 4 is formed within the air inlet opening plane 15. The recirculation air flap 8, which is arranged pivotably on fastening elements 16 above the axial air inlet opening 4, is used to change air flow paths generated by the fan wheel 3 (not shown). The fastening elements 16 are used as flap bearings for the recirculation air flap 8. The pivot region of the recirculation air flap 8 extends over some regions of the opening cross section of the axial air inlet opening 4. The fastening elements 16 can be formed on the air inlet housing or on the air inlet opening plane 15 of the fan housing 2. An inside 12 of the recirculation air flap 8 is designed to deflect an air flow in the direction of the axial air inlet opening 4. According to the design of the recirculation air flap 8, the inside 12 of the recirculation air flap 8 is situated at a distance from the pivot axis of the recirculation air flap 8. The pivot region permits pivoting between at least two positions. In a first position of the recirculation air flap 8, fresh air operation is made possible, wherein air is deflected from a fresh air opening in the direction of the axial air inlet opening 4. In a second position of the recirculation air flap 8, recirculation air operation can be realised, wherein air is drawn in from a flow path for recirculation air and deflected in the direction of the axial air inlet opening 4. The recirculation air flap 8 is pivotable in the pivot region between the first and second positions, wherein the inside 12 of the recirculation air flap 8 in the first and in the second position is positioned for example at an angle of 45? in relation to the air inlet opening plane 15. On the inside, seven plate-shaped air guiding elements 11 are arranged in mutually spaced parallel planes oriented at right angles to the recirculation air pivot axis. A detail diagram of the recirculation air flap 8 is shown in FIG. 5. The further flap 9 is arranged opposite the recirculation air flap 8 inside a flow channel for fresh air. Two air flow limiting elements 10 extend vertically out of the air inlet opening plane 15 next to the axial air inlet opening 4. The air flow limiting elements 10 are arranged next to the opening cross section of the axial air inlet opening 4 such that they are situated between the recirculation air flap 8 and the further flap 9. The surfaces of the plate-shaped air flow limiting elements 10 each limit air flows along the air inlet opening plane 15 next to the axial air inlet opening 4. The flow paths next to the opening cross section of the axial air inlet opening 4 are thus blocked along the air inlet opening plane 15. The height of the plate-shaped air flow limiting elements 10 extends at least over the height of the fastening elements 16, which are provided to hold the recirculation air flap 8 over the air inlet opening plane 15. A fastening of the plate-shaped air flow limiting elements 10 can be provided on the inlet opening plane 15 and/or on the inner walls of the air inlet housing (not shown in detail here). It can also be provided for the plate-shaped air flow limiting elements 10 to be designed as integral components of the air inlet housing, so that it is possible to retrofit existing systems by exchanging an air inlet housing having the plate-shaped air flow limiting elements 10.
[0036] FIG. 4A shows a schematic perspective diagram of an exemplary embodiment of the device according to the invention. The perspective diagram of the exemplary embodiment of the device according to the invention shows the recirculation air flap 8 above the opening cross section of the axial air inlet opening 4. The pivot region of the recirculation air flap 8 extends over some regions of the opening cross section of the axial inlet opening 4, wherein the fastening elements 16 for attaching the recirculation air flap 8 are arranged outside the edge region of the axial air inlet opening 4. The fastening elements 16 which are provided for holding the recirculation air flap 8 and for realising the pivoting function of the recirculation air flap 8 are situated on the air inlet opening plane 15 of the axial air inlet opening 4. Next to the opening cross section of the axial air inlet opening 4, two opposing air flow limiting elements 10 extend vertically out of the air inlet opening plane 15 outside the pivot region of the recirculation air flap 8. The plate-shaped air flow limiting elements 10 are arranged with their narrow sides opposite one another so that the surfaces of the long sides of the air flow limiting elements 10 extend from the edge of the axial air inlet opening 4 to the edge of the air inlet opening plane 15. This arrangement limits or blocks flows which would flow past along the axial air inlet opening 4 without the arrangement of the air flow limiting elements 10 next to the opening cross section. The air flow limiting elements 10 can thus be understood as shutters which limit the flow cross section via the opening cross section of the axial air inlet opening 4 in some regions. The air flow limiting elements 10 are dimensioned such that they protrude beyond the fastening elements 16 in their orientation at right angles to the air inlet opening plane 15. The facing narrow sides of the opposing air flow limiting elements 10 are designed as sloping sides 17.
[0037] The further flap 9 is arranged pivotably inside the flow channel for fresh air.
[0038] FIG. 4B shows a further view of the exemplary embodiment of the device according to the invention shown in FIG. 4A. In this FIG. 4B, the device according to the invention is shown in a side view in section through the air inlet housing 5, wherein one of two air flow limiting elements 10 can be seen. The air flow limiting element 10 extends vertically out of the air inlet opening plane 15. The height of the air flow limiting element 10 is dimensioned such that it protrudes beyond the fastening element 16 of the recirculation air flap 8.
[0039] FIG. 5 shows a detail diagram of an exemplary embodiment of the recirculation air flap 8. The detail diagram of the recirculation air flap 8 shows seven plate-shaped air guiding elements 11, which are arranged on the inside 12 of the recirculation air flap 8 in mutually spaced parallel planes at right angles to the recirculation air pivot axis. The parallel, spaced-apart plate-shaped air guiding elements 11 help to reduce circulation of the air flowing in an upper part of the axial air inlet opening 4 in front of the recirculation air flap 8 above the fan wheel 3. The plate-shaped air guiding elements 11 have a right-angled triangle shape.
[0040] FIG. 6 shows a schematic diagram of the device according to the invention inside a radial fan 1. The transparent diagram allows a view into the interior of the fan housing 2, of the fan wheel 3, the region of the fan tongue 6 and into a portion of the spiral flow channel 14. Reference sign 13 denotes an air flow guiding element, which is formed in two parts from an upper air flow guiding element 13.1 and a lower air flow guiding element 13.2. In the region of the fan tongue 6, the upper air flow guiding element 13.1 and the lower air flow guiding element 13.2 in the form of moulded parts, which can also be referred to as noses, are arranged on the fan tongue 6 opposing one another in the spiral flow channel 14. The air flow guiding elements 13.1 and 13.2 have different geometries and extend radially from the fan tongue 6 at a distance from the fan wheel 3 into the spiral flow channel 14. At comparatively high counterpressures, this design of the fan tongue 6 with the air flow guiding elements 13.1 and 13.2 arranged thereon results in the advantageous effect that only a small amount of air passes out of the spiral flow channel 14 through the blades of the fan wheel 3 back into the axial air inlet opening 4. Advantageously, the conveyed air thus passes with a lower resistance into a diffuser adjoining the fan housing 2.
[0041] FIG. 7 shows a detail diagram of an exemplary embodiment of the upper air flow guiding element 13.1 in a first view A), which is a radial view from above, and in a second view B), which is an axial view from above. View A) shows the axial height of the upper air flow guiding element 13.1, which increases in the direction of flow from a tip 13.1.1. On a side 13.1.2 facing the fan tongue 6, the upper air flow guiding element 13.1 has an axial height B which corresponds to 0.35 times to 0.75 times the axial height of the fan wheel 3. The axial height A of the tip 13.1.1 of the upper air flow guiding element 13.1 pointing into the spiral flow channel 14 corresponds to a maximum of 0.7 times the axial height B of the upper air flow guiding element 13.1. The axial height thus increases from the tip 13.1.1 to the side 13.1.2.
[0042] At the tip 13.1.1, the upper air flow guiding element 13.1 has a radius D which corresponds to 0.25 times to 0.75 times the radius formed on the side 13.1.2 facing the fan tongue 6. The radius E corresponds to the radius at the fan tongue 6. The radius D at the tip 13.1.1 is thus smaller than the radius of the fan tongue 6.
[0043] The upper air flow guiding element 13.1 has a wrap angle C related to the fan wheel 3 in the range of 47? and 67?.
[0044] The radial width of the upper air flow guiding element 13.1 increases in the direction of flow, i.e., from the tip 13.1.1 in the direction of the side 13.1.2 facing the fan tongue 6.
LIST OF REFERENCE NUMERALS
[0045] 1 Radial fan [0046] 2 Fan housing [0047] 3 Fan wheel [0048] 4 Axial air inlet opening [0049] 5 Air inlet housing [0050] 5.1 Fresh air inlet [0051] 5.2 Recirculation air inlet [0052] 5.3 Recirculation air flap [0053] 6 Fan tongue [0054] 7 Air outlet opening [0055] 8 Recirculation air flap [0056] 9 Flap/fresh air flap [0057] 10 Air flow limiting element [0058] 11 Plate-shaped air guiding elements [0059] 12 Inside [0060] 13 Air flow guiding element [0061] 13.1 Upper air flow guiding element [0062] 13.1.1 Tip [0063] 13.1.2 Side facing fan tongue 6 [0064] 13.2 Lower air flow guiding element [0065] 14 Spiral flow channel [0066] 15 Air inlet opening plane [0067] 16 Fastening elements [0068] 17 Sloping sides [0069] A Axial height [0070] B Axial height [0071] C Wrap angle [0072] D Radius [0073] E Radius
