Fan wheel and radiator fan module with the fan wheel

Abstract

A fan wheel has a hub cup and a plurality of blades extending radially outward from an outer wall of the hub cup, which is in particular at least substantially cylindrical. Each blade has a leading edge and a trailing edge, wherein for at least one blade, the progression of a relative position of the blade's leading edge and/or the progression of a relative position of the blade's trailing edge has an aperiodically wave-like shape. There is also described a radiator fan module with a fan wheel of the type described above, and a motor vehicle with such a radiator fan module.

Claims

1. A fan wheel, comprising: a hub cup; and a plurality of blades arranged on said hub cup and extending radially outward from an outer wall of said hub cup; each of said blades having a leading edge and a trailing edge; wherein the following applies for at least one of said blades, or for some of said blades, or for all of said blades: a reference line is defined by: a first point on an axis of rotation of the fan wheel; a radial extent through the first point and perpendicular to the axis of rotation; and a second point that bisects an arcuate edge into two equal sections at a transition from said hub cup to said blade, a reference plane is defined by a line displaced parallel to the axis of rotation and a line displaced parallel to said reference line, a displacement, as viewed in a direction of rotation of the fan wheel, being located entirely in front of said blade, wherein an orthogonal projection of said leading edge of said at least one blade and an orthogonal projection of said trailing edge of said at least one blade are mapped in the reference plane; wherein a z-axis is defined in the reference plane by an orthogonal projection of the axis of rotation in the reference plane, which is displaced parallel outward in a radial direction in the reference plane from the orthogonal projection of the axis of rotation around an outer radius of said hub cup; wherein a y-axis is defined in the reference plane by an orthogonal projection of the radial extent in the reference plane; wherein a relative unit radius t(r) is plotted on the y-axis, and is defined as follows: $t\left(r\right)=\frac{r-R_i}{R_a-R_i}$ wherein R.sub.i is an outer radius of said hub cup; R.sub.a is an outer radius of said at least one blade; and r is a distance between the axis of rotation and a sectional plane under consideration, which is at distance r perpendicular from the axis of rotation on the associated reference line, wherein r∈[R.sub.i;R.sub.a] wherein a relative position of said leading edge POS.sub.rel_VK and/or a relative position of said trailing edge POS.sub.rel_HK is plotted on the z-axis; wherein a progression of the relative position of said leading edge POS.sub.rel_VK(t) and/or a progression of the relative position of said trailing edge POS.sub.rel_HK(t) has an aperiodically wave-like shape; wherein the progression of the relative position of said leading edge POS.sub.rel_VK(t) and the progression of the relative position of said trailing edge POS.sub.rel_HK(t) are axisymmetric to each other; and wherein said trailing edge POS.sub.rel_HK(t) extends in a range around a geometrically determined progression of a reflected curve that is +/−20% of a value of the relative position of said leading edge POS.sub.rel_VK(t).

2. The fan wheel according to claim 1, wherein: said hub cup is at least substantially cylindrical and rotationally symmetrical around an axis of rotation of the fan wheel; and R.sub.i is the outer radius of said hub cup and an inner radius of said at least one blade.

3. The fan wheel according to claim 1, wherein the relative position of said leading edge POS.sub.rel_VK(t) is referenced to a third point that is a forward-most point in the direction of rotation of the fan wheel at a transition from said hub cup to said blade; and/or the relative position of said trailing edge POS.sub.rel_HK(t) is referenced to a fourth point, which is a rearward-most point in the direction of rotation of the fan wheel at the transition from the hub cup to said blade.

4. The fan wheel according to claim 1, wherein said blade, viewed in the direction of rotation, is a backward-swept blade.

5. The fan wheel according to claim 1, further comprising a substantially circular outer ring disposed to link respective tips of said plurality of blades together.

6. The fan wheel according to claim 1, wherein: the progression of the relative position of said trailing edge POS.sub.rel_HK(t) has a maximum in a range of 80% to 100% of the relative unit radius t(r) of said blade; and/or the progression of the relative position of said leading edge POS.sub.rel_VK(t) has a minimum in a range of 80% to 100% of the relative unit radius t(r) of said blade.

7. The fan wheel according to claim 6, wherein: the progression of the relative position of said trailing edge POS.sub.rel_HK(t) has the maximum in a range of 90% to 100% of the relative unit radius t(r) of said blade; and/or the progression of the relative position of said leading edge POS.sub.rel_VK(t) has the minimum in a range of 90% to 100% of the relative unit radius t(r) of said blade.

8. The fan wheel according to claim 7, wherein: the progression of the relative position of said trailing edge POS.sub.rel_HK(t) has a local maximum in a range of 92.5% to 97.5% of the relative unit radius t(r) of said blade; and/or the progression of the relative position of said leading edge POS.sub.rel_VK(t) has a local minimum in a range of 92.5% to 97.5% of the relative unit radius t(r) of said blade.

9. The fan wheel according to claim 6, wherein: the progression of the relative position of said trailing edge POS.sub.rel_HK(t) has no low points or at most one low point in the y-direction after maximum in a radial direction; and/or the progression of the relative position of said leading edge POS.sub.rel_VK(t) has no high points or at most one high point in the y-direction after the minimum in the radial direction.

10. The fan wheel according to claim 1, wherein said trailing edge POS.sub.rel_HK(t) extends in a range around the geometrically determined progression of the reflected curve that is +/−10% of the value of the relative position of said leading edge POS.sub.rel_VK(t).

11. The fan wheel according to claim 1, wherein the progression of the relative position of said leading edge POS.sub.rel_VK(t), as a function of the relative unit radius t(r), satisfies the following condition: ${\mathrm{POS}}_{\mathrm{rel}\_\mathrm{VK}}\left(t\right)=\frac{-\left(A_1{t}^2+A_{2}t\right)\cos \left[2\pi N\left(a\left(1-t\right)+1\right)\left(t+t_0\right)\right]+A_{3}t+A_4}{R_a-R_i}$ $\mathrm{where}\text{:}$ $t_0\in \left[0;0,5\right]$ $N\in \left[1;8\right]$ $a\in \left[-1,5;1,5\right]$ $A_1\in \left[-10;10\right]$ $A_2\in \left[-10;10\right]$ $A_3\in \left[-10;10\right]\mathrm{and}$ $A_4\in \left[-10;10\right].$

12. The fan wheel according to claim 1, wherein the progression of the relative position of said trailing edge POS.sub.rel_HK(t), as a function of the relative unit radius t(r), satisfies the following condition: ${\mathrm{POS}}_{\mathrm{rel}\_\mathrm{HK}}\left(t\right)=\frac{\left(A_1{t}^2+A_{2}t\right)\cos \left[2\pi N\left(a\left(1-t\right)+1\right)\left(t+t_0\right)\right]+A_{3}t+A_4}{R_a-R_i}$ $\mathrm{where}\text{:}$ $t_0\in \left[0;0,5\right]$ $N\in \left[1;8\right]$ $a\in \left[-1,5;1,5\right]$ $A_1\in \left[-10;10\right]$ $A_2\in \left[-10;10\right]$ $A_3\in \left[-10;10\right]\mathrm{and}$ $A_4\in \left[-10;10\right].$

13. The fan wheel according to claim 1 configured for a motor vehicle.

14. A radiator fan module, comprising: a fan cowl formed with a fan wheel recess; a cowl ring bounding said fan wheel recess; a motor holder arranged within said fan wheel recess and mechanically connected with said fan cowl via struts; a motor at least partially held in said motor holder; and a fan wheel according to claim 1 disposed in said fan wheel recess and to be rotationally driven by said motor.

15. The radiator fan module according to claim 14, wherein said motor is an electric motor.

16. The radiator fan module according to claim 14, wherein said struts are arranged in front of said fan wheel, relative to a flow direction.

17. A motor vehicle, comprising a radiator fan module according to claim 14.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1A shows a fan wheel of the prior art in a perspective view of the upper side;

(2) FIG. 1B shows a front view of a blade of the fan wheel known in the art from FIG. 1A, viewed from the reference plane in a perspective view, with the upper side of the fan wheel facing downward.

(3) FIG. 2A shows a fan wheel according to an embodiment of the present invention in a perspective view from the upper side;

(4) FIG. 2B shows a front view of a blade of the fan wheel of FIG. 2A viewed from the reference plane in a perspective view, with the upper side of the fan wheel facing downward.

(5) FIG. 3 shows a fan wheel of the prior art in a perspective view for illustrating a reference plane;

(6) FIG. 4 shows the progression of the relative position of the leading edge POS.sub.rel_VK(t) and the relative position of the trailing edge POS.sub.rel_HK(t) over the relative unit radius of a fan wheel according to an embodiment of the present invention;

(7) FIG. 5 shows a comparison of a fan wheel previously known in the art with a fan wheel according to an embodiment of the present invention; and

(8) FIG. 6 shows a radiator fan module with the fan wheel according to the present invention, according to the second aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(9) Referring now to the figures of the drawing in detail and first, particularly, to FIGS. 1A and 1B, there is shown in FIG. 1A a prior art fan wheel 1 in a perspective view from the upper side and in FIG. 1B a front of a blade 30 of the prior art fan wheel from the reference plane in a perspective view, with the upper side (corresponding to the suction side) of the fan wheel 1 pointing downwards.

(10) According to FIGS. 1A, 1B, 2A, 2B and 3, the fan wheel 1 has a hub cup 10 which is rotationally symmetrical about an axis of rotation R. At the hub cup 10, a plurality of blades 30 are arranged, which extend radially outward from a cylindrical outer wall 12 of the hub cup 10. A direction of rotation D is indicated by an arrow in FIGS. 1A and 2A. Accordingly, the direction of rotation is counterclockwise. A main flow direction of the supplied air is marked with HSR. The fan wheel 1 has an at least substantially circular outer ring 20 which links the tips of the blades 30 together.

(11) With regard to FIG. 1B (and FIG. 2B), it should be noted that the position of the axis of rotation R, with regard to its distance from the cylindrical outer wall 12 of the hub cup 10 or the inner edge of the blade 30 (characterized by the points P3 and P4), is not true to scale; in other words, the orientation is binding, but the position is not.

(12) As may be seen in FIGS. 1A and 1B, the prior art blades 30 have flat or curved leading edges VK and flat or curved trailing edges HK in an orthogonal projection.

(13) FIG. 2A shows a fan wheel 1 according to one embodiment of the present invention in a perspective view, and FIG. 2B shows a front view of a blade 30 of the fan wheel of FIG. 2A viewed from the reference plane E_REF, in a perspective view.

(14) Compared to embodiments of a fan wheel 1 according to the prior art (see FIGS. 1A and 1B), the fan wheel 1 according to an embodiment of the present invention as shown in FIGS. 2A, 2B has blades 30 with an aperiodic wave-shaped trailing edge HK.

(15) As regards the perspective of the sectional view, reference is made to the following statements regarding FIG. 3.

(16) FIG. 3 shows a fan wheel 1 from the prior art in a perspective view for illustrating a reference plane E_REF.

(17) In the following, the viewing plane for the description of the leading edge VK and trailing edge HK will be defined. The fan wheel shown in FIG. 3 does not have any blade geometry according to this invention, which is not relevant to the description of the reference plane E_REF, because the statements relevant thereto apply in the same way for embodiments of the invention.

(18) Starting from the axis of rotation R, a reference line G_REF is defined by a first point P1 on the axis of rotation R of the fan wheel 1, a radial extent E is defined by the first point P1, perpendicular to the axis of rotation R, and a second point P2, which bisects an arcuate edge at the transition from the hub cup 10 to the blade 30 into two equal sections. In other words: The radius is determined that passes through the point P2. The point P2 represents the center of the transition edge from hub cup 10 to blade 30, in particular from the edge of the blade 30 facing the bottom of the cup. Another at least substantially identical definition of P2 may be derived via an angle: Two auxiliary radii are required, the first auxiliary radius passing through P1 and a third point P3 on the transitional edge between the cylindrical outer wall and the blade, and a second auxiliary radius passing through a fourth point P4 on the transitional edge from the hub cup 10 to the blade 30, and the line is constructed that bisects the angle enclosed between the two auxiliary radii. The point at which the aforementioned bisector intersects the cylindrical outer wall 12, in particular at an outer side thereof, is P2. Starting from G_REF, a reference plane E_REF is defined by a line displaced parallel to the axis of rotation R and a line displaced parallel to the reference line G_REF, the displacement being such that, viewed in the direction of rotation D of the fan wheel 1, it is located entirely in front of the blade 30, On the reference plane E_REF are mapped an orthogonal projection of the leading edge VK of the blade 10 and an orthogonal projection of the trailing edge HK of the blade 10. The viewing direction B shows the view in FIGS. 1B and 2B respectively of a blade segment of the fan wheel 1.

(19) A coordinate system consisting of a z-axis and y-axis is spanned in the reference plane E_REF. This is significant for the description of the progression of the relative position of the leading edge POS.sub.rel_VK(t) and the progression of the relative position of the trailing edge POS.sub.rel_HK(t). The z-axis is defined by an orthogonal projection of the axis of rotation R in the reference plane E_REF, which in a second step is displaced in parallel outward in the reference plane E_REF in the radial direction from the orthogonal projection of the axis of rotation R about an outer radius R.sub.i of the hub cup 10. In other words: The z-axis is unchanged in orientation, but is displaced in parallel in two steps, i.e. a first time through orthogonal projection onto the reference plane E_REF and then through displacement by R.sub.i in the reference plane E_REF. This means that the z-axis passes through the orthogonal projection of P2 onto E_REF. The y-axis is defined through an orthogonal projection of the radial extent E in the reference plane E_REF. The origin of this y-z coordinate system is defined by the intersection of the two axes.

(20) A relative unit radius t(r) is plotted on the y-axis, and is defined as follows:

(21) $t\left(r\right)=\frac{r-R_i}{R_a-R_i}$
wherein R.sub.i is an outer radius of the hub cup 10, which corresponds in particular at least substantially to an inner radius of the blade 30; R.sub.a is an outer radius of the blade 30; and r is the distance between the axis of rotation R and the sectional plane S under consideration, which is perpendicular at the distance r perpendicular from the axis of rotation R along the associated reference line G_REF, where
r∈[R.sub.i;R.sub.a].

(22) FIG. 4 shows the progression of the relative position of the leading edge POS.sub.rel_VK(t) and the relative position of the trailing edge POS.sub.rel_HK(t) over the relative unit radius of a fan wheel according to an embodiment of the present invention.

(23) The horizontal axis corresponds to the y-axis described above, and the vertical axis corresponds to the z-axis described above. The relative unit radius t(r) is plotted on the horizontal axis.

(24) The progression of the relative position of the leading edge POS.sub.rel_VK(t) and the progression of the relative position of the trailing edge POS.sub.rel_HK(t) are respectively plotted on the vertical axis in standardized form.

(25) The relative position of the leading edge POS.sub.rel_VK(t) is given by

(26) ${\mathrm{POS}}_{{\mathrm{rel}}_{—}\mathrm{VK}}\left(t\right)=\frac{-\left(A_1{t}^2+A_{2}t\right)\cos \left[2\pi N\left(a\left(1-t\right)+1\right)\left(t+t_0\right)\right]+A_{3}t+A_4}{R_a-R_i}$
and the relative position of the trailing edge POS.sub.rel_HK(t) is given by

(27) ${\mathrm{POS}}_{{\mathrm{rel}}_{—}\mathrm{HK}}\left(t\right)=\frac{\left(A_1{t}^2+A_{2}t\right)\cos \left[2\pi N\left(a\left(1-t\right)+1\right)\left(t+t_0\right)\right]+A_{3}t+A_4}{R_a-R_i}$
wherein respectively t.sub.0 describes an offset of the relative unit radius for setting the vertex at the hub cup, N describes the number of oscillations over the axial unit radius, a describes an oscillation coefficient for scaling the wavelength and setting the position of the, in particular local, extremum (i.e. minimum for the leading edge, maximum for the trailing edge), A.sub.1 describes a quadratic polynomial coefficient, A.sub.2 describes a linear polynomial coefficient, A.sub.3 describes an axial threading coefficient, i.e. for adjusting the linear progression of the leading or trailing edge from the hub cup to the blade tip or outer ring, and A.sub.4 describes a relative base deflection (“start” deflection) of the leading or trailing edge of the hub cup. The functions described above describe the aperiodic wave-like shape of the progression of the relative position of the leading edge POS.sub.rel_VK(t) and the trailing edge POS.sub.rel_HK(t).

(28) It will be apparent that the progression of the relative position of the trailing edge POS.sub.rel_HK(t) has a maximum, in particular a local maximum, in the range of 80% to 100%, in particular 90% to 100%, in particular 92.5% to 97.5%, of the relative unit radius t(r) of the blade (30), and the progression of the relative position of the leading edge POS.sub.rel_VK(t) has a minimum, in particular a local minimum, in the range of 80% to 100%, in particular 90% to 100%, in particular 92.5% to 97.5%, of the relative unit radius t(r) of the blade (30).

(29) As may also be seen from the exemplary embodiment of FIG. 4, the progression of the relative position of the trailing edge POS.sub.rel_HK(t) in the y-direction has no or at most one low point after the, in particular local, maximum, and/or the progression of the relative position of the leading edge POS.sub.rel_VK(t) in the y direction has no or at most one high point after the, in particular local, minimum.

(30) As may also be seen from FIG. 4, the progression of the relative position of the leading edge POS.sub.rel_VK(t) and the progression of the relative position of the trailing edge POS.sub.rel_HK(t) are at least substantially axisymmetric to each other, and in particular the trailing edge POS.sub.rel_HK(t) extends around a geometrically unambiguously determined progression of a reflected curve in a range that is +/−20%, in particular +/−10%, of the value of the relative position of the leading edge POS.sub.rel_VK(t).

(31) In the exemplary embodiment of FIG. 4, the progression of the relative position of the leading edge POS.sub.rel_VK(t), as a function of the relative unit radius t(r), satisfies the following condition:

(32) ${\mathrm{POS}}_{{\mathrm{rel}}_{—}\mathrm{VK}}\left(t\right)=\frac{-\left(A_1{t}^2+A_{2}t\right)\cos \left[2\pi N\left(a\left(1-t\right)+1\right)\left(t+t_0\right)\right]+A_{3}t+A_4}{R_a-R_i}$$\mathrm{where}\text{:}$$t_0\in \left[0;0,5\right]$$N\in \left[1;8\right]$$a\in \left[-1,5;1,5\right]$$A_1\in \left[-10;10\right]$$A_2\in \left[-10;10\right]$$A_3\in \left[-10;10\right]\mathrm{and}$$A_4\in \left[-10;10\right].$

(33) In the exemplary embodiment of FIG. 4, the progression of the relative position of the trailing edge POS.sub.rel_HK(t), as a function of the relative unit radius t(r), satisfies the following condition:

(34) ${\mathrm{POS}}_{{\mathrm{rel}}_{—}\mathrm{HK}}\left(t\right)=\frac{\left(A_1{t}^2+A_{2}t\right)\cos \left[2\pi N\left(a\left(1-t\right)+1\right)\left(t+t_0\right)\right]+A_{3}t+A_4}{R_a-R_i}$$\mathrm{where}\text{:}$$t_0\in \left[0;0,5\right]$$N\in \left[1;8\right]$$a\in \left[-1,5;1,5\right]$$A_1\in \left[-10;10\right]$$A_2\in \left[-10;10\right]$$A_3\in \left[-10;10\right]\mathrm{and}$$A_4\in \left[-10;10\right].$

(35) The progression of the relative position of the leading edge POS.sub.rel_VK(t) shown in FIG. 4 results at least substantially, in particular absolutely, from the following parameters: t.sub.0=0.04 N=4 a=0 A.sub.1=0 A.sub.2=2 A.sub.3=4 and A.sub.4=0

(36) The progression of the relative position of the trailing edge POS.sub.rel_HK(t) shown in FIG. 4 results at least substantially, in particular absolutely, on the basis of the following parameters: t.sub.0=0.04 N=4 a=0 A.sub.1=0 A.sub.2=2 A.sub.3=−5 and A.sub.4=0

(37) FIG. 5 shows a comparison of a fan wheel 1 previously known in the art with a fan wheel 1 according to an embodiment of the present invention.

(38) There are shown: a pressure coefficient ψ, which describes the total pressure gradient generated by the fan wheel between the upstream and downstream sides as a dimensionless characteristic independent of the effective fan wheel diameter D.sub.W, the air density ρ and the rotational speed n, the total pressure gradient Δp.sub.t generated by the fan wheel (consisting of static and dynamic components) between the upstream and downstream side of the same:

(39) 0$\psi =\frac{2\Delta p_t}{{\pi }^2\rho D_w^2{n}^2}$ a coefficient of performance λ, which describes an input power ρ as a dimensionless characteristic, independent of the effective fan wheel diameter D.sub.W, the air density P.sub.wel and the rotational speed n:

(40) $\lambda =\frac{8P_{\mathrm{wel}}}{{\pi }^4\rho D_w^5{n}^3}$ For the input power P.sub.wel, here the shaft power of the electric motor is used; corresponding losses (heat, friction, etc.) of the electric motor are not taken into account.

(41) There is also shown: a total efficiency η, which relates the input power P.sub.wel to the generated total pressure gradient Δp.sub.t across the supplied volumetric flow {dot over (V)}.

(42) $\eta =\frac{\Delta p_t\stackrel{.}{V}}{P_{\mathrm{wel}}}$

(43) On the x-axis of the diagram, a volume coefficient φ is plotted, which describes the supplied volumetric flow {dot over (V)} as a dimensionless characteristic, independent of the effective fan wheel diameter DW and the rotational speed n:

(44) $\phi =\frac{4\stackrel{.}{V}}{{\pi }^2{D}_w^{3}n}$

(45) In other words: The indicated characteristic numbers are nondimensionalized with pi π, the air density ρ in kg/m.sup.3, the effective diameter (D.sub.W=2R.sub.a) in m and the rotational speed n in 1/s. In this way, comparability with non-identical fan wheels is provided for.

(46) As is apparent, with almost the same performance (similar coefficient of performance) a higher pressure coefficient (=>total pressure increase) is achieved, yielding a significant increase in efficiency in the relevant volume coefficient range.

(47) FIG. 6 shows a radiator fan module 100 with the fan wheel 1 according to the present invention, according to the second aspect of the present invention.

(48) The radiator fan module 100 has a fan cowl 2; a fan wheel recess 40 is formed in the fan cowl 2, and is bounded by a cowl ring 42. A motor holder (hidden by the hub cup 10) is arranged within the fan wheel recess 40 and is mechanically connected with the fan cowl 2 via struts 44. A motor (likewise hidden by the hub cup 10), in particular an electric motor, is at least partially held in the motor holder. A fan wheel 1 is arranged in the fan wheel recess 40 and is driven rotationally by the motor. The fan wheel 1 corresponds to an embodiment of a fan wheel 1 according to the present invention. The detailed configuration of the fan wheel 1 has been described above. According to the embodiment of FIG. 6, the struts 44 are arranged before the fan wheel in the flow direction, with the flow direction running perpendicularly out from the illustration of FIG. 6.

(49) Although exemplary embodiments have been explained in the foregoing specification, it should be noted that numerous modifications are possible. In particular, such a configuration of the fan cowl according to the invention is also suitable for dissipating waste heat from components of a purely electrically powered vehicle. It should additionally be noted that the exemplary embodiments are merely examples that are not intended to limit the scope, applications and structure in any way. Rather, the preceding description gives the person of ordinary skill in the art a guide for implementing at least one exemplary embodiment, and various changes, in particular with regard to the function and arrangement of the components described, may be made without departing from the scope of the patent, as set forth in the Claims and equivalent feature combinations.

(50) The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: 1 Fan wheel 2 Cowl 10 Hub cup 12 (Cylindrical) outer wall of the hub cup 10 20 Outer ring 30 Blade 40 Fan wheel recess 42 Cowl ring 44 Struts 100 Radiator fan module HK Trailing edge VK Leading edge B Line of vision D Direction of rotation E Radial extent E_REF Reference plane G_REF Reference line HSR Main flow direction P1 First point P2 Second point P3 Third point P4 Fourth point POS.sub.rel_VK(t) Relative position of the leading edge POS.sub.rel_HK(t) Relative position of the trailing edge r Distance between axis of rotation R and section plane S R Axis of rotation R.sub.a Outer radius of the blade 30 R.sub.i Outer radius of the hub cup 10 S Section plane y y-axis z z-axis