CN-122014649-A - Cooling fan shroud with highly skewed stator

Abstract

A cooling fan shroud with highly skewed stators is disclosed. A cooling fan assembly includes a fan, a motor driving the fan, and a shroud enclosing the fan. The shroud has a plenum portion, a barrel portion, a motor-support structure, and a stator that spans an annular region disposed between the barrel and the motor-support structure. The deflection angle of at least one stator of the assembly is highly skewed.

Inventors

• Y.SHEN

Assignees

• 罗伯特·博世有限公司

Dates

Publication Date

20260512

Application Date

20251110

Priority Date

20241108

Claims (14)

1. 1. A cooling fan assembly, comprising: A shroud, comprising: The air is guided to the air chamber, A hollow, cylindrical barrel having a sidewall centered on a barrel axis, the sidewall having an inner diameter, Motor-support structure, and A stator spanning an annular region disposed between the barrel portion and the motor-support structure; A motor supported by the motor support structure, the motor having a motor shaft defining a central axis that coincides with the barrel axis, and A fan at least partially surrounded by the barrel, the fan comprising: A hub which is rotated by the motor and is centered on the central axis, and Blades protruding from the hub and arrayed around the central axis; Wherein, the A projection plane can be drawn perpendicular to the central axis, and upstream of the barrel portion of the shroud, When the stators, the motor-support structure and the barrel are projected onto the projection plane, the projection of at least one of the stators onto the projection plane corresponds to a first stator line extending between the motor-support structure and the barrel sidewall and a second stator line extending between the motor-support structure and the barrel sidewall, and a mid-chord line disposed between and equidistant from each of the first and second stator lines, The chord line of the at least one of the stators intersects the projection of the inner diameter of the barrel at an outer terminus and intersects the projection of the outer portion of the motor-support structure at an inner terminus, The angular displacement from the inner terminus to the outer terminus is in the same angular direction as the direction of rotation of the fan, The deflection angle of the at least one stator is defined between a first radial line and a second radial line, and The deflection angle of the at least one stator is at least equal to the average angular spacing of the stators, Wherein the method comprises the steps of The first radial line extends from the central axis to the outer terminus and the second radial line extends from the central axis to the inner terminus, and The stator average angular spacing corresponds to 360 degrees divided by the number of stators employed in the automotive cooling fan assembly.
2. 2. The cooling fan assembly of claim 1, wherein the skew angle of the at least one stator is at least 70% of the average angular spacing of the stators.
3. 3. The cooling fan assembly of claim 1, wherein the skew angle of the at least one stator is at least 80% of the average angular spacing of the stators.
4. 4. The cooling fan assembly of claim 1, wherein the skew angle of the at least one stator is at least 90% of the average angular spacing of the stators.
5. 5. The cooling fan assembly of claim 1, wherein the at least one stator has an aerodynamic cross section.
6. 6. The cooling fan assembly of claim 5, wherein a chord length of a cross section of the at least one stator increases in the region of the increased stagger angle.
7. 7. The cooling fan assembly of claim 1, wherein the at least one stator has an stagger angle that varies along a chord line of the at least one stator.
8. 8. The cooling fan assembly of claim 1, wherein the at least one stator has an intersection angle that decreases from a midpoint of a chord line of the at least one stator to a point where the chord line intersects the barrel.
9. 9. The cooling fan assembly of claim 1, wherein a cross-section of the at least one stator has a curvature.
10. 10. The cooling fan assembly of claim 1, wherein the at least one stator intersects an auxiliary support structure configured to support the at least one stator.
11. 11. The cooling fan assembly of claim 10, wherein the auxiliary support structure has an inner terminus at the motor-support structure and an outer terminus at the shroud barrel.
12. 12. The cooling fan assembly of claim 1, wherein a middle region of the at least one stator is mechanically connected to a middle region of another stator.
13. 13. The cooling fan assembly of claim 12, wherein the skew angle of the other stator is different than the skew angle of the at least one stator.
14. 14. The cooling fan assembly of claim 12, wherein the at least one stator intersects the other stator at a location spaced apart from both the tip of the at least one stator and the root of the at least one stator.

Description

Cooling fan shroud with highly skewed stator Background The purpose of an automotive cooling fan assembly is to draw ambient air from the surroundings of the vehicle through one or more heat exchangers. A typical automotive cooling fan assembly includes a fan, a motor, and a shroud. The shroud structure may be a one-piece injection molded portion having an air induction plenum portion that interfaces with the heat exchanger, a circular barrel portion that encloses the fan, a motor support structure, and a plurality of support arms ("stators") that connect the barrel portion to the motor support structure and provide physical support to and centering of the motor support structure. In some cases, the barrel portion is a separate injection molded portion that is attached to the plenum portion. The shroud stator occupies a generally annular space between the inner diameter of the barrel and the outermost portion of the motor support structure. Since the air discharged from the fan flows through this annular region, the stator has the potential to affect the aerodynamic efficiency of the fan and stator system. If the stators are properly designed for the environment in which they operate, it is possible to improve aerodynamic efficiency by recovering energy from the flow. If the stators are not optimized for the environment, they may exhibit aerodynamic blockage that degrades the aerodynamic efficiency of the fan. As motor vehicles evolve, the under-hood space for equipment (including cooling fans) continues to decrease. The tighter under-hood vehicle packaging trend has increased the amount of blockage to fan airflow and has a detrimental effect on fan assembly efficiency. In the event that the vehicle installation creates significant axial obstruction or obstruction to the fan flow field, the flow streamlines following the path of least resistance are forced to become more radial to avoid the axial obstruction. As the flow streamlines become more radial, the stator may no longer be aligned with the previously more axially oriented streamlines. Such a stator that is suboptimal for flow alignment produces an undesirable loss of aerodynamic efficiency. There is a need for a shroud stator design that improves the aerodynamic performance of an automotive cooling fan assembly, especially when the outlet streamlines have a large radial velocity component. Disclosure of Invention A cooling fan assembly includes a fan, a motor, and a shroud. The shroud is an injection molded portion having an air induction plenum portion interfacing with the heat exchanger, a circular barrel portion surrounding the fan, a motor support structure, and a plurality of stators connecting the barrel portion to the motor support structure. In some conditions, the stators described herein improve aerodynamic performance over some prior art stators by reducing the undesirable aerodynamic blockage effects created by surrounding fixed structures in the airflow path, while providing a robust physical structure to support the motor and fan. In particular, the skew angle of at least one stator of the cooling fan assembly is highly skewed, resulting in a shroud stator design that improves the aerodynamic performance of the automotive cooling fan assembly, especially when the outlet streamlines have a large radial velocity component. This can be compared to some prior art stators, which have a thick cross section to exhibit a significant blocking effect, and some other prior art stators, which add additional reinforcement to increase rigidity at the cost of increased aerodynamic blocking (such as a circular stator reinforcement ring). Still other prior art stators have streamlined cross-sections but are not well aligned with the fan effluent over at least a portion of the shroud-barrel annular flow region. Drawings FIG. 1 is a perspective view of a prior art cooling fan assembly. FIG. 2 is a perspective exploded view of the cooling fan assembly of FIG. 1. Fig. 3 is a perspective view of a prior art fan, illustrating three-dimensional components of speed, as viewed from upstream and downstream of the fan. The direction of fan rotation is indicated by the arrow. FIG. 4 is a front view of a prior art cooling fan assembly, as viewed from upstream and downstream of the fan, illustrating the location of section line A- -A. The direction of fan rotation is indicated by the arrow. FIG. 5 is a rear view of a prior art cooling fan assembly, as viewed from downstream and upstream of the motor, illustrating two of the three components of speed. The direction of fan rotation is indicated by the arrow. FIG. 6 is a cross-sectional view of the cooling fan assembly of FIG. 4, as seen along line A-A, illustrating two of the three components of speed. The direction of fan rotation is shown by the solid arrows and the direction of airflow is shown by the broken arrows. Fig. 7A is a front view of a prior art motor support, as viewed from upstream to downstream of the mo