Impeller for fan

Abstract

The invention relates to an impeller (11) for a fan, comprising two supports (15, 16) and a plurality of impeller blades (17) which are arranged between the two supports (15, 16) and which are connected along a first longitudinal edge (20) to the first support (15) and along a second longitudinal edge (21) to the second support (16). The outer edge (19) of each impeller blade (17) connects the two longitudinal edges (20), (21) and comprises an edge recess (25) at which the outer edge (19) has a local low point (P). The position of the low point (P) is closer to the support (15, 16) in which a higher internal stress or load occurs during operation of the impeller (11).

Description

Technical Field

[0001] This invention relates to an impeller for a fan. During fan operation, the impeller is driven to rotate about a rotational axis, thereby generating a flow, such as a gas flow, particularly an air flow. The fan can be configured as a radial flow fan or a diagonal flow fan. Background Technology

[0002] The impeller has a first support, a second support, and impeller blades arranged between the two supports, wherein the impeller blades are connected to the first support along a first longitudinal edge and to the second support along a second longitudinal edge. Mechanical stress and strength requirements increase with increasing rotational speed, where the total stress can increase quadratically with increasing rotational speed. This can be addressed with a more stable construction, such as having a higher wall thickness, at least in high-stress areas. However, this makes the impeller heavier and more expensive. The fan's energy consumption also increases, especially if the impeller is accelerated to change its rotational speed.

[0003] EP 2942531 A1 shows an impeller for a fan having multiple blades extending between a cover and a chassis. Each blade has a curved trailing edge that is spaced apart from a chord connecting the corner of the trailing edge. However, the trailing edge has a curved extension and no recess.

[0004] DE 112023001908 T5 shows an impeller with blades, each blade having a tip at the rear edge in the middle between supports.

[0005] An impeller with blades is known from DE 112020007795 T5. The trailing edge of the blades is curved but does not include a recess. Summary of the Invention

[0006] The purpose of this invention can be considered as providing an impeller that can withstand increased mechanical stress without increasing the amount of material used.

[0007] This objective is achieved by means of an impeller having the features of claim 1.

[0008] The impeller according to the invention is configured to rotate about an axis of rotation. In the installed state, the impeller is part of a fan, and the fan motor drives the impeller about the axis of rotation to generate a fluid flow, particularly a gas flow, and preferably an air flow. The fan can be a radial fan or a diagonal fan.

[0009] The impeller has a first support and a second support. The supports are arranged at a distance from each other in an axial direction parallel to the axis of rotation. Between the two supports, the impeller has a plurality of impeller blades. The impeller blades are connected to the first support by means of a first longitudinal edge and to the second support by means of a second longitudinal edge. Preferably, the longitudinal edges are curved. More preferably, the longitudinal edges are not congruent when viewed in the axial direction.

[0010] In a preferred embodiment, the attachment of the impeller blades to the support is achieved by means of material bonding or adhesive bonding. This connection between the impeller blades and the support can be achieved, for example, by welding. The impeller blades and / or the support can be made of a metal alloy (e.g., aluminum alloy), a plastic material, or a composite material.

[0011] In this embodiment, the impeller blades and the support portion can be formed as a monolithic body.

[0012] For example, the first support part can be the fan chassis, and the second support part can be the fan cover. The fan motor can be arranged in the mounted state within the area of ​​the fan chassis.

[0013] The two support portions are preferably not flat. The two support portions preferably have different geometries. The first support portion may include one or more ribs to increase strength. The second support portion may have a corrugated geometry.

[0014] Each impeller blade has an inner edge and an outer edge. The inner and outer edges connect two longitudinal edges on opposite sides. The radial distance from the outer edge to the axis of rotation is greater than that from the inner edge.

[0015] In the transition to the first longitudinal edge, the outer edge has a first connection point, and in the transition to the second longitudinal edge, the outer edge has a second connection point. At the first connection point, the first longitudinal edge contacts the first support portion. At the second connection point, the second longitudinal edge contacts the second support portion.

[0016] The outer edge restricts the edge recess of the impeller blade. When viewed from the inner edge to the outer edge, the impeller blade has a reduced length in the region of the edge recess along the corresponding extension direction of the impeller blade. Compared to the virtual connecting line passing through the first and second connection points, the outer edge is at a certain distance from the connecting line in the region of the edge recess. The edge recess preferably starts asymmetrically from a low point, where the distance from the edge recess to the connecting line is longest.

[0017] Outside the edge recess, the outer edge may extend along the connecting line, or it may extend on the opposite side of the line compared to the edge recess, and may form a so-called edge protrusion. In a preferred embodiment, the outer edge does not extend through the virtual connecting line, so that there is no edge protrusion.

[0018] Due to the edge recesses formed at the outer edges of the impeller blades, the blade stiffness is reduced, but the internal stress in the connection area between the impeller blades and the first and / or second supports is significantly reduced during impeller operation. By doing so, the impeller can be used in fans with higher maximum rotational speeds without increasing the material thickness of the supports and / or impeller blades.

[0019] By means of the construction according to the invention, a minimum increase in rotational speed of 8% to 9% and up to 25% or more can be achieved compared to impellers of comparable size. For smaller sizes with diameters up to 450 mm, the impeller is suitable for rotational speeds ranging from a minimum of 3,500 rpm to a maximum of 4,350 rpm. For impellers with diameters of 500 mm and above, rotational speeds ranging from a minimum of 2,300 rpm to a maximum of 2,900 or 3,000 rpm can be achieved.

[0020] Along their particularly curved extensions between the inner and outer edges, the first longitudinal edges have a first length. Similarly, the second longitudinal edges have a second length from the inner edge to the outer edge. The lengths of the longitudinal edges are measured between connection points, where the longitudinal edges transition to either the inner or outer edge, and where they contact either the first or second support. For the outer edge, these are the first and second connection points as explained above. The inner edge forms a third connection point at its transition to the first longitudinal edge and a fourth connection point at its transition to the second longitudinal edge. Thus, the first longitudinal edge extends between the first and third connection points, and the second longitudinal edge extends between the second and fourth connection points.

[0021] Along the virtual straight line, the first connection point and the second connection point are at a distance that defines the height of the impeller blades.

[0022] The edge recess has a local low point, and preferably only one single local low point. At the local low point, when viewed orthogonally to the connecting line, the outer edge has a low point distance to the connecting line. When viewed parallel to the virtual connecting line, the local low point has a distance defining a first height from the first longitudinal edge. When viewed parallel to the virtual connecting line, the distance between the local low point and the second longitudinal edge defines a second height. The first height and the second height are different from each other.

[0023] Preferably, the low point distance has a minimum amount of 2.5%, 5.0%, 7.5%, or 10% of the first length. Additionally or alternatively, the low point distance may have a maximum amount of 25%, 20%, 15%, or 12.5% ​​of the first length.

[0024] For example, the low point distance may be in one of the following ranges, including the range limits: 2.5% to 25% of the first length, or 2.5% to 20% of the first length, or 5.0% to 15% of the first length, or 7.5% to 12.5% ​​of the first length.

[0025] The first height preferably has a minimum of 5.0%, 7.5%, 10%, or 15% of the impeller blade height. Alternatively or additionally, the first height has a maximum of 40%, 30%, 25%, 20%, or 17.5% of the impeller blade height.

[0026] The first height can preferably be in one of the following ranges, including the range limits: 5.0% to 40% or 7.5% to 30% or 10% to 25% or 10% to 20% or 15% to 20% of the impeller blade height.

[0027] In a preferred embodiment, along the edge recess, the outer edge has a first edge segment curved in a concave manner and a second edge segment curved in a concave manner, these two edge segments preferably being directly adjacent to each other and having different maximum curvatures. In an embodiment, the two edge segments are directly adjacent to each other at a local low point.

[0028] Preferably, the outer edge is constructed to be without edges and / or without steps. In mathematical terms, the extension of the outer edge can be continuous and differentiable.

[0029] In one embodiment, a third edge segment curved in a convex manner may be adjacent to a first edge segment curved in a concave manner. Additionally or alternatively, a fourth edge segment curved in a convex manner may be adjacent to a second edge segment curved in a concave manner.

[0030] Advantageously, at least one of the edge segments that bends in a convex manner (e.g., the third and / or the fourth edge segment) is adjacent to another edge segment that bends in a concave manner (meaning, for example, the fifth edge segment and / or the sixth edge segment that bends in a concave manner).

[0031] It is explicitly recommended here that feature numbering is used only for their identification and does not indicate order or priority. For example, mentioning the sixth edge segment does not require the existence of the fifth edge segment as well.

[0032] The location of the edge recess or local low point closer to the first support portion particularly reduces the stress in the connection area between the first support portion and the impeller blades. This is especially advantageous if higher stress occurs in the first support portion than in the second support portion during impeller operation. According to an embodiment, the first support portion can be the impeller chassis and the second support portion can be the impeller cover plate, or alternatively, the reverse. Attached Figure Description

[0033] Advantageous embodiments of the present invention are derived from the dependent claims, description, and drawings. The invention is explained in detail below with reference to the drawings. In the drawings:

[0034] Figure 1 A schematic perspective illustration of a fan having an impeller according to an embodiment of the invention; and

[0035] Figure 2 and Figure 3 A partial illustration of an embodiment of the impeller in the region of the impeller blades is shown in perspective view in each case.

[0036] List of reference numerals in the attached diagram:

[0037] 10 fans

[0038] 11 Impeller

[0039] 12 Electric motors

[0040] 15 First Support Section

[0041] 16 Second Support Section

[0042] 17 Impeller blades

[0043] 18 Inner Edge

[0044] 19 Outer edge

[0045] 20 First longitudinal edge

[0046] 21 Second longitudinal edge

[0047] 25. Edge recess

[0048] 26 First Edge Section

[0049] 27 Second Edge Section

[0050] 28 Third Edge Section

[0051] 29 Fourth Edge Section

[0052] 30 Fifth Edge Section

[0053] Axial direction

[0054] D. Rotation axis

[0055] G connects the straight lines

[0056] H1 First Height

[0057] H2 Second Height

[0058] L1 First Length

[0059] L2 Second Length

[0060] P Local low point

[0061] S Impeller blade height

[0062] T Low point distance

[0063] X1 First connection point

[0064] X2 Second Connection Point

[0065] X3 Third Connection Point

[0066] X4 fourth connection point Detailed Implementation

[0067] exist Figure 1 The image schematically illustrates a fan 10 (e.g., a radial or mixed-flow fan) comprising an impeller 11 according to an embodiment of the invention. The impeller 11 is configured to rotate about a rotation axis D. To enable the impeller to rotate about the rotation axis D, the fan 10 includes an electric motor 12.

[0068] The impeller 11 includes a first support portion 15, a second support portion 16, and a plurality of impeller blades 17. The impeller blades 17 are arranged between the first support portion 15 and the second support portion 16, wherein the two support portions 15 and 16 are spaced apart from each other in an axial direction A parallel to the rotation axis D. The impeller blades 17 are spaced apart from the rotation axis D and extend from an inner edge 18 to an outer edge 19 in a curved manner. The distance from the inner edge 18 of each impeller blade 17 to the rotation axis D is smaller than the distance from its outer edge 19.

[0069] Each impeller blade 17 also includes a first longitudinal edge 20 and a second longitudinal edge 21. The two longitudinal edges 20, 21 are arranged at a distance from each other in the axial direction A, and are preferably not congruent when viewed in the axial direction. Along the first longitudinal edge 20, the impeller blade 17 is connected to the first support 15. Along the second longitudinal edge 21, the impeller blade 17 is connected to the second support 16.

[0070] The first support portion 15 can be a chassis, and the second support portion 16 can be a cover plate, or vice versa. For example, the first support portion 15 is arranged next to the motor 12 of the fan 10, while the second support portion 16 is located on the inflow side of the fan 10, that is, upstream of the first support portion 15.

[0071] A first connection point X1 is formed at the transition from the first longitudinal edge 20 to the outer edge 19. A second connection point X2 is formed at the transition from the second longitudinal edge 21 to the outer edge 19. A third connection point X3 is formed at the transition from the first longitudinal edge 20 to the inner edge 18. A fourth connection point X4 is formed at the transition from the second longitudinal edge 21 to the inner edge 18. At connection points X1 to X4, the longitudinal edge 20 or 21 is connected to a correspondingly allocated support portion 15 or 16.

[0072] The connection between the impeller blade 17 and the supports 15, 16 is achieved by means of a material bonding connection (e.g., welding) according to the example. Alternatively, an adhesive bonding using an adhesive can also be achieved. In a modified embodiment, the two supports 15, 16 and the impeller blade 17 are constructed as a single unit and are therefore seamless.

[0073] A virtual connecting line G extends through a first connecting point X1 (the transition from the first longitudinal edge 20 to the outer edge 19) and a second connecting point X2 (the transition from the second longitudinal edge 21 to the outer edge 19). Along the connecting line G, the distance between the first connecting point X1 and the second connecting point X2 defines the impeller blade height S. Along the first longitudinal edge 20, the impeller blade 17 has a first length L1 between the first connecting point X1 and the third connecting point X3. Along the second longitudinal edge 21, the impeller blade 17 has a second length L2 between the second connecting point X2 and the fourth connecting point X4.

[0074] Compared to the virtual connecting line G, the outer edge 19 is recessed at at least one location, and therein it defines the edge recess 25. The edge recess 25 is constructed in a concave manner when viewed from the connecting line G, and includes a local low point P.

[0075] A local low point P has a distance T from the low point of the connecting line G in a direction orthogonal to the connecting line G. When viewed parallel to the connecting line G, the distance of low point P from the first connecting point X1 defines a first height H1, and the distance from the low point P to the second connecting point X2 defines a second height H2. The sum of the first height H1 and the second height H2 is equivalent to the impeller blade height S. The first height H1 is particularly smaller than the second height H2.

[0076] Preferably, the first height H1 has an absolute value that is at least 5.0%, at least 7.5%, at least 10%, or at least 15% of the impeller blade height S. Preferably, the first height H1 has an absolute value that is at most 40%, at most 30%, at most 25%, at most 20%, or at most 17.5% of the impeller blade height S. The indicated minimum and maximum values ​​can be arbitrarily combined with each other.

[0077] Preferably, the low point distance T has a minimum of 2.5%, a minimum of 5.0%, a minimum of 7.5%, or a minimum of 10% of the first length L1. More preferably, the low point distance T has a maximum of 25%, a maximum of 20%, a maximum of 15%, or a maximum of 12.5% ​​of the first length L1. The minimum and maximum values ​​can be arbitrarily combined with each other.

[0078] Preferably, the outer edge 19 includes only a single low point P, whose low point distance T is within the indicated range. Preferably, the outer edges 19 have a profile that defines only a single low point P; or if multiple local low points P exist, the low points P have different low point distances T from each other.

[0079] exist Figure 2 and Figure 3 In the embodiment illustrated, starting from a low point P, the outer edge has a first edge segment 26 on the side facing the first longitudinal edge and a second edge segment 27 on the side facing the second longitudinal edge. The first edge segment 26 and the second edge segment 27 are concave and preferably have different amounts of maximum curvature. Preferably, the maximum curvature of the first edge segment 26 is higher than the maximum curvature of the second edge segment 27.

[0080] Optionally, in addition to the first edge segment 26 and the second edge segment 27, the outer edge 19 may also include additional edge segments, such as a third edge segment 28 and / or a fourth edge segment 29. Figure 2 The third edge segment 28 may be adjacent to the first edge segment 26 and / or the fourth edge segment 29 may be adjacent to the second edge segment 27. When viewed from the virtual connecting line G, the third edge segment 28 and the fourth edge segment 29 are constructed in a convex manner.

[0081] As an alternative, the outer edge 19 may be supplemented with additional edge segments that can be curved concavely when viewed from the connecting line G, such as a fifth edge segment 30. The fifth edge segment 30 may be adjacent to the fourth edge segment 29 and / or the second connecting point X2.

[0082] In the Figure 2In a modification of the embodiment illustrated in the figure, which has concave and convex edge segments, the impeller blade 17 may also have an outer edge 19 having only concave edge segments (e.g., first edge segment 26 and second edge segment 27). Thus, starting from the low point P, edge segments 26, 27 may extend to either the first connection point X1 or the second connection point X2.

[0083] The present invention relates to an impeller 11 having two supports 15, 16 and a plurality of impeller blades 17 arranged between the two supports 15, 16 and connected to the first support 15 along a first longitudinal edge 20 and to the second support 16 along a second longitudinal edge 21. The outer edge 19 of each impeller blade 17 connects to the two longitudinal edges 20, 21 and includes an edge recess 25, at which the outer edge 19 has a local low point P. The low point P is located closer to the supports 15, 16 where higher internal stress or load occurs during operation of the impeller 11.

Claims

1. An impeller (11) for a fan (10), comprising: -First support section (15), - The second support (16) is arranged to be spaced a certain distance from the first support (15) when viewed in parallel with the axis of rotation (D) of the impeller (11). - A plurality of impeller blades (17) extending between the supports (15, 16) and attached to the first support (15) by means of a first longitudinal edge (20) and to the second support (16) by means of a second longitudinal edge (21), wherein the outer edge (19) of each impeller blade (17) extends between a first connection point (X1) at the transition to the first longitudinal edge (20) and a second connection point (X2) at the transition to the second longitudinal edge (21), and wherein the outer edge (19) restricts an edge recess (25) compared to a virtual connecting line (G) extending through the connection points (X1, X2), and wherein the outer edge (19) has a greater distance to the axis of rotation (D) of the impeller (11) compared to the inner edge (18) of the same impeller blade (17) connecting the two longitudinal edges (20, 21) on the opposite side of the outer edge (19). The first longitudinal edge (20) includes a first length (L1), wherein the impeller blade height (S) is defined by a distance measured parallel to the connecting line (G) between the first connection point (X1) and the second connection point (X2), wherein the edge recess (25) includes a local low point (P), the local low point (P) including a low point distance (T) orthogonal to the connecting line (G) measured from the low point of the connecting line (G), wherein a first height (H1) defines the distance between the local low point (P) measured parallel to the connecting line (G) and the first longitudinal edge (20), and a second height (H2) defines the distance between the local low point (P) measured parallel to the connecting line (G) and the second longitudinal edge (21), wherein the first height (H1) is less than the second height (H2).

2. The impeller according to claim 1, wherein, The low point distance (T) has a minimum of 2.5%, 5.0%, 7.5%, or 10% of the first length (L1).

3. The impeller according to claim 1 or 2, wherein, The low point distance (T) has a maximum of 25%, 20%, 15%, or 12.5% ​​of the first length (L1).

4. The impeller according to any one of the preceding claims, wherein, The low point distance (T) has an amount of 2.5% to 25% of the first length (L1), or an amount of 2.5% to 20% of the first length (L1), or an amount of 5.0% to 15% of the first length (L1), or an amount of 7.5% to 12.5% ​​of the first length (L1).

5. The impeller according to any one of the preceding claims, wherein, The first height (H1) has a minimum amount of 5.0%, 7.5%, 10%, or 15% of the impeller blade height (S).

6. The impeller according to any one of the preceding claims, wherein, The first height (H1) has a maximum of 40%, 30%, 25%, 20%, or 17.5% of the impeller blade height (S).

7. The impeller according to any one of the preceding claims, wherein, The first height (H1) has an amount of 5.0% to 40%, 7.5% to 30%, 10% to 25%, 10% to 20%, or 15% to 20% of the impeller blade height (S).

8. The impeller according to any one of the preceding claims, wherein, Along the edge recess (25), the outer edge (19) includes a first edge segment (26) curved in a concave manner and a second edge segment (27) curved in a concave manner, the first edge segment (26) and the second edge segment (27) being adjacent to each other and having different maximum curvatures.

9. The impeller according to claim 8, wherein, The first edge segment (26) and the second edge segment (27) are adjacent to the local low point (P) of the edge recess (25).

10. The impeller according to claim 8 or 9, wherein, The third edge segment (28), which is curved in a convex manner, is adjacent to the first edge segment (26), which is curved in a concave manner.

11. The impeller according to any one of claims 8 to 10, wherein, The fourth edge segment (29), which is curved in a convex manner, is adjacent to the second edge segment (27), which is curved in a concave manner.

12. The impeller according to claim 10 or 11, wherein, Another edge segment (30) that is curved in a concave manner is adjacent to at least one of the edge segments (28, 29) that are curved in a convex manner.

13. The impeller according to any one of the preceding claims, wherein, The stress that occurs during operation is higher in the first support (15) than in the second support (16).

14. The impeller according to any one of the preceding claims, wherein, The support (15, 16) and the impeller blade (17) are connected to each other by means of material bonding and / or adhesive bonding, or the support (15, 16) and the impeller blade (17) form a single unit.

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