Air conditioning system with radial fan

Abstract

The present invention relates to a radial blower (3) for generating an airflow (2) for an air conditioning system (1), in particular for a motor vehicle, comprising a blower wheel (7) having an axial inlet side (8) and a radial outlet side (9), and a housing (10) in which the blower wheel (7) is rotatably arranged about an axis of rotation (11), the housing containing a pressure chamber (14) enclosing the blower wheel (7) at its outlet side (9) in a circumferential direction (13) of the housing (10), the housing having an air inlet (15) at or in which the inlet side (8) of the blower wheel (7) is arranged, and the housing having an air outlet (16) that transitions into an end region (18) of the pressure chamber (14), wherein the housing (10) is connected at a transition (21) between the end region (18) and an initial region (19) of the pressure chamber (14) has a blower tongue (20),and wherein a pressure chamber width (22) measured radially with respect to the axis of rotation (11) increases from the initial region (19) in the circumferential direction (13) along the pressure chamber (14) to the end region (18). Improved performance and lower noise in a compact design can be achieved if the pressure chamber height (23) measured axially with respect to the axis of rotation (11) decreases from the initial region (19) in the circumferential direction (13) along the pressure chamber (14) to the final region (18).

Description

[0001] The present invention relates to a radial fan for generating an air flow for an air conditioning system, having the features of the preamble of claim 1. The invention also relates to an air conditioning system equipped with such a radial fan for conditioning an air flow, preferably in a motor vehicle.

[0002] A generic radial fan is known, for example, from DE 10 2005 012 557 B4 and comprises an impeller designed as a radial fan impeller and accordingly having an axial inlet side or suction side and a radial outlet side or pressure side. The impeller ad is arranged in a housing of the radial fan so as to be rotatable about a rotational axis. The housing has a pressure chamber surrounding the impeller at its outlet side in a circumferential direction of the housing. In this pressure chamber, the pressure increases in the radial direction from a region near the impeller to a radial boundary of the pressure chamber. Furthermore, the housing has an air inlet at which the inlet side of the impeller is arranged. Furthermore, an air outlet is provided on the housing and is arranged at an end region of the pressure chamber.The housing also has a fan blade at a transition between the end region of the pressure chamber and an initial region of the pressure chamber. The housing or its pressure chamber is designed in a spiral or helical shape, so that a pressure chamber width measured radially with respect to the rotation axis increases from the fan blade, i.e. from the initial region of the pressure chamber in a direction of rotation in which the fan wheel rotates during operation of the radial fan, in the circumferential direction along the spiral pressure chamber to the end region of the pressure chamber. In the known radial fan, an air gap is also formed at the edge between a base of the housing opposite the air inlet and an axial end face of the fan wheel facing this base, the gap width of which varies in the circumferential direction.In this way, a cooling air flow can be directed through a cavity defined between the floor and the end face of the impeller facing the floor, in which a drive motor for driving the impeller is arranged. Furthermore, in the known radial fan, the pressure chamber height, measured axially with respect to the rotation axis, increases in the circumferential direction, starting at the fan blade, i.e., at the initial area of ​​the pressure chamber in the direction of rotation of the impeller, in the circumferential direction along the pressure chamber to the end area of ​​the spiral-shaped pressure chamber.

[0003] Another radial fan of this type is known from US 2006 / 0 239 815 A1. There, too, the pressure chamber height increases in the circumferential direction, starting from the fan blade, i.e., from the initial area along the spiral-shaped pressure chamber to the end area. For this purpose, a base opposite the air inlet has a recess in an edge area axially defining the pressure chamber, the depth of which increases in the circumferential direction, or in the direction of rotation of the fan wheel, along the pressure chamber to the air outlet.

[0004] A similar configuration is also shown in EP 1 462 658 B1, from which a conventional radial fan is also known, in which the pressure chamber height in the pressure chamber increases starting from the fan tongue, i.e. from the initial area in the circumferential direction along the spiral-shaped pressure chamber to the end area.

[0005] Other such radial fans are known from DE 10 2005 012 815 A1, from EP 1 178 215 A2 and from US 5 839 879 A.

[0006] A radial fan of this type is known from GB 772 888 A and differs from the aforementioned conventional radial fans in that the pressure chamber height, measured axially with respect to the rotation axis, decreases from the initial area in the circumferential direction along the pressure chamber to the end area. In the known radial fan, the pressure chamber height decreases in several steps or jumps from the initial area to the end area in the circumferential direction along the pressure chamber.

[0007] The performance of such a radial blower depends on the achievable speed of the impeller and, in particular, on the diameter of the impeller. The diameter of the impeller thus determines the radial dimensions of the housing, whereby a sufficiently large pressure chamber must be provided in the radial direction within the housing to convert the speed generated by the impeller into pressure.

[0008] However, particularly in vehicle applications, the space available for accommodating the radial fan is often limited, so the housing cannot be dimensioned arbitrarily in the radial direction. However, if the housing is specified in terms of its radial dimension, the diameter of the fan wheel is also limited in conventional designs for the reasons mentioned above. Otherwise, the circumferential flow cross-section of the pressure chamber would be too small, significantly reducing the efficiency of the radial fan.

[0009] The present invention addresses the problem of providing an improved embodiment for a radial fan of the above-mentioned type or for an air conditioning system equipped therewith, which is characterized by a high fan power and low noise emission, particularly in a compact design.

[0010] This problem is solved according to the invention by the subject matter of the independent claim. Advantageous embodiments are the subject matter of the dependent claims.

[0011] The invention is based on the general idea of ​​geometrically designing the pressure chamber such that its axially measured pressure chamber height decreases continuously from the initial region of the pressure chamber at the fan blade, i.e., from the initial region of the pressure chamber in the direction of rotation of the impeller that occurs during operation of the radial fan, in the circumferential direction along the pressure chamber to the end region of the spiral-shaped pressure chamber. However, this means that the pressure chamber has a relatively large axial pressure chamber height in the initial region, which also results in a comparatively large cross-section in the pressure chamber in the initial region. Since the pressure chamber height thus decreases from the fan blade along the pressure chamber to the air outlet, the pressure chamber height in the initial region of the pressure chamber is greater than in the area of ​​the air outlet or in the end region of the pressure chamber located in front of it.However, this means that, compared to a conventional design, in which the pressure chamber height increases in the circumferential direction from the fan blade, i.e., from the initial area along the pressure chamber to the end area, more cross-sectional area can be made available axially within the pressure chamber, which can be used to reduce the radially measured pressure chamber width. In other words, the design presented here allows the use of a larger-diameter impeller in the housing, thus enabling higher air performance and lower noise. The radial reduction in the pressure chamber cross-section, which leads to a high-pressure area near the impeller in the spiral-shaped pressure chamber, is compensated for by an axial enlargement of the pressure chamber cross-section, so that the radial dimensions of the housing can remain the same.In conventional designs, the high-pressure area near the impeller is followed by a low-pressure area in the pressure chamber near the impeller.

[0012] The invention utilizes the finding that the reduced pressure chamber width can be compensated for by the increased pressure chamber height, so that a fan wheel with a larger diameter can be used in a housing than in a housing with the same radial outer dimensions in a conventional design. The invention utilizes the further finding that, particularly in vehicle applications, the radial space available for the housing is more limited than the axial space available for it, so that it is possible, in particular, to axially enlarge the housing in the area of ​​the pressure chamber in order to implement the pressure chamber height profile proposed by the invention.

[0013] In an advantageous embodiment, it can be provided that the decrease in the pressure chamber height and the increase in the pressure chamber width in the circumferential direction along the pressure chamber in the direction of rotation of the impeller are coordinated such that a pressure chamber cross-section extending radially to the axis of rotation increases in the circumferential direction along the pressure chamber. By increasing the pressure chamber cross-section from the fan tongue in the direction of rotation of the fan along the pressure chamber to the air outlet, an increase in the air mass flow can be achieved, which supports the conveying capacity of the fan. For this purpose, the increase in the pressure chamber cross-section along the pressure chamber due to increasing pressure chamber width is designed to be greater than the decrease in the pressure chamber cross-section along the pressure chamber due to decreasing pressure chamber height.

[0014] According to the invention, the pressure chamber height decreases continuously in the circumferential direction from the initial area of ​​the pressure chamber to the end area of ​​the pressure chamber. Such a continuous decrease is advantageous with regard to the pressure distribution around the impeller circumference and noise development.

[0015] Additionally, the pressure chamber height can be provided to decrease continuously in the circumferential direction along the pressure chamber from the initial area of ​​the pressure chamber to the end area of ​​the pressure chamber. In particular, this eliminates circumferential sections with a constant pressure chamber height between the initial area of ​​the pressure chamber and the end area of ​​the pressure chamber. This measure leads to improved delivery performance of the radial fan.

[0016] According to an advantageous embodiment, the housing can have, on an axial end face opposite the air inlet, a base spatially distant from the air inlet, i.e., distal or motor-side, which has a recess in an edge region associated with the pressure chamber and axially delimiting the pressure chamber. The recess's axially measured depth decreases in the circumferential direction along the pressure chamber from the initial region of the pressure chamber to the end region of the pressure chamber. This recess forms a component of the pressure chamber, so that its depth forms a component of the pressure chamber height. In other words, the additional pressure chamber height is created by an outwardly oriented axial extension of the pressure chamber, in which a corresponding recess is provided on the inside in the edge region of the distant motor-side base.For example, a drive motor for driving the fan wheel can be located in the area of ​​the remote engine-side base. However, this motor is not affected by the modified geometry of the engine-side base because it is arranged radially within the edge area. In principle, the increased pressure chamber height can also be increased in the area of ​​a base containing the air inlet and located close to it, i.e., the proximal or air inlet-side base. This, however, leads to an increase in the axial dimension of the radial fan or the air conditioning system equipped with it.

[0017] According to an advantageous development, the housing can have, on an axial end face having the air inlet, a base located close to the air inlet, i.e., proximal or on the inlet side, which has an edge region associated with the pressure chamber. The edge region is spaced axially from a plane lying axially between the motor-side base and the air inlet-side base and extending perpendicular to the axis of rotation, said distance being constant in the circumferential direction along the pressure chamber from the initial region of the pressure chamber to the end region of the pressure chamber. In this way, the decrease in the pressure chamber height from the initial region of the pressure chamber to the end region of the pressure chamber in the circumferential direction along the pressure chamber is realized exclusively by the recess in the edge region of the motor-side base. This simplifies the design and implementation of the radial fan presented here.

[0018] According to another advantageous development, a radially measured width of the recess can increase analogously to the pressure chamber width in the circumferential direction along the pressure chamber. This allows for efficient use of the pressure chamber cross-section enlarged by the recess.

[0019] In another advantageous development, a central region of the motor-side base associated with the impeller can form a sealing gap to the impeller. For example, a corresponding contour can be formed in the motor-side base, which is shaped complementarily to at least an edge region of an axial end face of the impeller facing the motor-side base. In particular, the impeller can axially dip with its axial end face facing the motor-side base into an annular step formed in the central region. The sealing gap can be constant in the circumferential direction. However, it can preferably be provided that the sealing gap is larger in the end region of the pressure chamber than in the beginning region of the pressure chamber, whereby a cooling air flow is guided through a cavity formed between the motor-side base and the axial end face of the impeller facing it.

[0020] In another advantageous embodiment, a step can be formed in the area of ​​the fan blade, at which a smaller pressure chamber height in the end region of the pressure chamber abruptly or gradually transitions into a larger pressure chamber height in the beginning region of the pressure chamber. This step in the height progression of the pressure chamber allows maximum use of the available installation space, since the fan blade represents the boundary or separation between the beginning region of the pressure chamber and the end region of the pressure chamber. Thus, on the one hand, the maximum pressure chamber height can be arranged directly at the fan blade in the beginning region of the pressure chamber, while on the other hand, the minimum pressure chamber height can also be arranged directly at the fan blade in the end region of the pressure chamber.

[0021] In an advantageous further development, the above-mentioned step can be formed in the edge region of the engine-side floor, which simplifies the realization of the step.

[0022] According to another embodiment, the pressure chamber can merge tangentially into the air outlet at the end of the pressure chamber. This design leads to reduced flow resistance and thus efficient blower performance.

[0023] An air conditioning system according to the invention, which is preferably used in a motor vehicle for air conditioning an air flow, comprises at least one radial fan of the type described above. Furthermore, such an air conditioning system can be equipped with at least one heating device for heating the air flow and / or with at least one cooling device for cooling the air flow.

[0024] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

[0025] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0026] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0027] They show, schematically, Fig. 1 a highly simplified cross-section of an air conditioning system in the area of ​​a radial fan according to section lines I in Fig. 3, Fig. 2 an axial section of the radial fan according to section lines II in Fig. 1 in the area of ​​a fan blade, Fig. 3 an axial section of the air conditioning system in the area of ​​the radial fan according to section lines III in Fig. 1.

[0028] According to the Fig. 1 to 3 comprises an air conditioning system 1, with the aid of which an air flow 2 indicated by arrows can be air-conditioned and which is used in particular in a motor vehicle, a radial fan 3 for generating the air flow 2. In addition, the air conditioning system 1 can have at least one in Fig. 1 indicated cooling device 4 for cooling the air flow 2 and at least one in Fig. 1 indicated heating device 5 for heating the air flow 2. The cooling device 4 and the heating device 5 are according to Fig. 1 is conveniently arranged downstream of the radial fan 3. The air conditioning system 1 can be Fig. 3 upstream of the radial fan 3 have at least one air filter 6 for filtering the air flow 2.

[0029] The radial fan 3 has a fan wheel 7, which is designed as a radial fan wheel and accordingly has an axial inlet side 8 and a radial outlet side 9. Furthermore, the radial fan 3 has a housing 10, in which the fan wheel 7 is arranged such that it can rotate about a rotation axis 11. The rotation axis 11 defines a Fig. 2 and Fig. 3 each indicated by a double arrow axial direction 12, which extends parallel to the rotation axis 11. Also refers to Fig. 1 by a double arrow indicated circumferential direction 13 of the housing 10 to the rotation axis 11. The housing 10 contains a pressure chamber 14, which largely encloses the impeller 7 at its outlet side 9 in the circumferential direction 13. Furthermore, the housing 10 has a Fig. 3 recognizable air inlet 15 and one in Fig. 1. The inlet side 8 of the impeller 7 is arranged at the air inlet 15. In another embodiment, the impeller 7 can also be designed such that the inlet side 8 protrudes into the air inlet 15, i.e., is arranged at least partially therein.

[0030] In addition, Fig. 3, a drive motor 37 is indicated by a broken line, which is connected to the impeller 7 via a drive shaft 38. The drive motor 37 serves to rotate the impeller 7 in the direction of rotation 17. The impeller motor 37 is connected to a housing wall 25 that is remote from the air inlet 15, i.e., distal thereto, which can also be referred to as the remote or distal or motor-side base 25.

[0031] According to Fig. 1, the impeller 7 has a direction of rotation 17 during operation of the radial fan 3, indicated by an arrow. The air outlet 16 is connected to the pressure chamber 14 in such a way that it merges into an outlet-side end region 18 of the pressure chamber 14. The pressure chamber 14 also has a starting region 19. The pressure chamber 14 merges from the starting region 19 to the end region 18 in the direction of rotation 17 of the impeller 7. Furthermore, the housing 10 is equipped with a fan tongue 20, which separates the end region 18 from the starting region 19 in the housing 10 and is accordingly arranged in the pressure chamber 14 at a transition 21 in the direction of rotation 17 between the end region 18 and the starting region 19. The fan tongue 20 forms a quasi contactless seal of the housing 10 with respect to the fan wheel 7 and thus determines the flow direction of the air flow 2 along the pressure chamber 14 in the direction of rotation 17 when the fan wheel 7 rotates.

[0032] The initial region 19 of the pressure chamber 14 can also be referred to as the post-tongue region 19 due to its position, since it begins at the fan tongue 20. In contrast, the end region 18 of the pressure chamber 14 can also be referred to as the outlet region 18 due to its position, since it merges into the air outlet 16.

[0033] According to Fig. 1, the pressure chamber 14 has a pressure chamber width 22 measured radially with respect to the rotation axis 11, which, however, is not constant in the circumferential direction 13, but increases starting from the fan tongue 20 from the initial region 19 in the direction of rotation 17 to the end region 18 along the pressure chamber 14. Preferably, the pressure chamber width 22 increases steadily and continuously, whereby in the cross section of the Fig. 1 results in a spiral or snail shape for the housing 10 or for the pressure chamber 14. Preferably, the air outlet 16 is attached tangentially to the housing 10, preferably molded onto it, so that the pressure chamber 14 merges tangentially into the air outlet 16 in the end region 18.

[0034] Furthermore, the pressure chamber 14 has Fig. 3 a pressure chamber height 23 measured axially, i.e. parallel to the rotation axis 11, which decreases starting from the fan tongue 20 in the direction of rotation 17 from the initial area 19 to the final area 18 along the pressure chamber 14. The pressure chamber height 23 advantageously decreases steadily and continuously. Preferably, the decrease in the pressure chamber height 23 and the increase in the pressure chamber width 22 along the pressure chamber 14 can be coordinated with one another in such a way that a pressure chamber cross-section 24 extending radially to the rotation axis 11, which in Fig. 1 is indicated by a broken line, also increases in the direction of rotation 17 along the pressure chamber 14. This means that the increase in the pressure chamber cross-section 24 due to the increasing pressure chamber width 22 is designed to be greater than the decrease in the pressure chamber cross-section 24 due to the decreasing pressure chamber height 23.

[0035] According to Fig. 3, the housing 10 has, on an axial end face opposite the air inlet 15, a motor-side base 25 which is remote from the air inlet 15 and which can also be referred to as a distal base 25. The air inlet 15 is in turn arranged in a base 26 located on the air inlet 15, which is opposite the motor-side base 25 and which can also be referred to as a proximal base 26. The motor-side base 25 has a recess 28 in an edge region 27 assigned to the pressure chamber 14. The recess 28 extends in the circumferential direction 13 within the edge region 27. The recess 28 has an axially measured depth 29 which decreases in the circumferential direction 13 or in the direction of rotation 17 along the pressure chamber 14 from the initial region 19 to the end region 18 or, alternatively, can also be constant in sections.The recess 28 forms a component of the pressure chamber 14, so that the cross-section of the recess 28 forms a component of the pressure chamber cross-section 24. The depth 29 of the recess 28 also forms a component of the pressure chamber height 23.

[0036] In the example of Fig. 3, the inlet-side base 26 is arranged or configured with respect to a plane 30 extending perpendicular to the rotation axis 11 and located axially between the engine-side base 25 and the inlet-side base 26 such that an axial distance 31, which the inlet-side base 26 has on an inner side 32 facing the pressure chamber 14 in an edge region 40 associated with the pressure chamber 14, relative to this plane 30, is constant in the circumferential direction 13 along the pressure chamber 14 from the initial region 19 to the end region 18. For this purpose, the inner side 32 expediently extends parallel to the plane 30, at least in the edge region 40.

[0037] According to Fig. 3, the recess 28 also has a radially measured width 33. This width can expediently increase, like the pressure chamber width 22, in the direction of rotation 17 along the pressure chamber 14. In particular, the recess 28 advantageously extends over the entire edge region 27, thereby maximizing the available radial space.

[0038] Out of Fig. 3 also shows that a sealing gap 36 can be formed between a central region 34 of the motor-side base 25 assigned to the fan wheel 7 and an axial end face 35 of the fan wheel 7 facing the motor-side base 25.

[0039] According to the Fig. 1 and Fig. 2, a step 39 is formed at the transition 21 from the end region 18 in the direction of rotation 17 to the initial region 19. The step 39 is accordingly also located in the area of ​​the fan tongue 20, which in the section of the Fig. 2 is not recognizable. At level 39, therefore, a Fig. 2 indicated smaller pressure chamber height 23', which is present in the end area 18, abruptly into a larger pressure chamber height 23", which is present in the initial area 19. The step 39 is according to Fig. 2 is integrally formed in the edge region 27 of the motor-side base 25. The step 39 simultaneously forms a boundary of the recess 28 in the circumferential direction 13, opposite to the direction of rotation 17.

Claims

[1] Radial fan for generating an air flow (2) for an air conditioning system (1), in particular of a motor vehicle, - with a fan wheel (7) having an axial inlet side (8) and a radial outlet side (9), - with a housing (10) in which the impeller (7) is arranged to rotate about a rotation axis (11), which contains a pressure chamber (14) surrounding the impeller (7) at its outlet side (9) in a circumferential direction (13) of the housing (10), which has an air inlet (15) on or in which the inlet side (8) of the impeller (7) is arranged, and which has an air outlet (16) which merges into an end region (18) of the pressure chamber (14), - wherein the housing (10) has a fan tongue (20) at a transition (21) between the end region (18) of the pressure chamber (14) and a starting region (19) of the pressure chamber (14), - wherein a pressure chamber width (22) measured radially with respect to the rotation axis (11) increases from the initial region (19) in the circumferential direction (13) along the pressure chamber (14) to the end region (18), - wherein a pressure chamber height (23) measured axially with respect to the rotation axis (11) decreases from the initial region (19) in the circumferential direction (13) along the pressure chamber (14) to the end region (18), characterized by that the pressure chamber height (23) decreases continuously from the initial region (19) to the end region (18) in the circumferential direction (13) along the pressure chamber (14). [2] Radial fan according to claim 1, characterized by that a pressure chamber cross-section (24) extending radially to the rotation axis (11) increases in the circumferential direction (13) along the pressure chamber (14). [3] Radial fan according to claim 1 or 2, characterized bythat the pressure chamber height (23) decreases continuously from the initial region (19) to the end region (18) in the circumferential direction (13) along the pressure chamber (14). [4] Radial fan according to one of claims 1 to 3, characterized by in that the housing (10) has, on an axial end face opposite the air inlet (15), a motor-side base (25) which is remote from the air inlet (15) and which has, in an edge region (27) associated with the pressure chamber (14), a recess (28) whose axially measured depth (29) decreases in the circumferential direction (13) along the pressure chamber (14) from the initial region (19) to the end region (18), the recess (28) forming a component of the pressure chamber (14) and the depth (29) forming a component of the pressure chamber height (23). [5] Radial fan according to claim 4, characterized bythat the housing (10) has, on an axial end face having the air inlet (15), an inlet-side base (26) which is close to the air inlet (15) and which has an edge region (40) assigned to the pressure chamber (14) and which has an axial distance (31) from a plane (30) lying axially between the remote motor-side base (25) and the nearby inlet-side base (26) and extending perpendicular to the axis of rotation (11), which is constant in the circumferential direction (13) along the pressure chamber (14) from the starting region (19) to the end region (18). [6] Radial fan according to claim 4, characterized byin that the housing (10) has, on an axial end face having the air inlet (15), an inlet-side base (26) which is close to the air inlet (15) and which has an edge region (40) assigned to the pressure chamber (14) and which has an axial distance (31) to a plane (30) lying axially between the remote motor-side base (25) and the nearby inlet-side base (26) and extending perpendicular to the axis of rotation (11), which is initially constant in the circumferential direction (13) along the pressure chamber (14) from the starting region (19) to the end region (18) and then continuously decreases. [7] Radial fan according to one of claims 4 to 6, characterized by that a radially measured width (33) of the recess (28) increases in the circumferential direction (13) along the pressure chamber (14). [8] Radial fan according to one of claims 4 to 7, characterized bythat a sealing gap (36) is formed between a central region (34) of the remote engine-side base (25) assigned to the fan wheel (7) and the fan wheel (7). [9] Radial fan according to one of claims 1 to 8, characterized by that in the region of the fan tongue (20) a step (39) is formed, at which a smaller pressure chamber height (23') of the end region (18) abruptly changes into a larger pressure chamber height (23") of the initial region (19). [10] Radial fan according to claims 4 and 9, characterized by that the step (39) is formed integrally in the edge region (27) of the removed engine-side base (25). [11] Radial fan according to one of claims 1 to 10, characterized by that the pressure chamber (14) in the end area (18) merges tangentially into the air outlet (16). [12] Air conditioning system for conditioning an air flow (2), preferably in a motor vehicle, - with at least one radial fan (3) according to one of the preceding claims, - with at least one heating device (5) for heating the air flow (2).

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