Claims:CLAIMS

We claim:
1. A fan system (100), comprising:

a ring (108) having a first surface (124) encircles and fixedly mounted to a fan (102);

a shroud (112) having a second surface (126) positioned substantially around the ring (108), wherein the first surface (124) and the second surface (126) face each other and together define a clearance (122) between the ring (108) and the shroud (112), and

at least one groove (202, 302) extends along a circumference of either one of the first surface (124) and the second surface (126).

2. The fan system (100) of claim 1, wherein the groove (202, 302) is formed on the first surface (124) of the ring (108).

3. The fan system (100) of claim 2, wherein the groove (202) is formed by at least two spaced-apart ridges (204, 206) extending from the first surface (124).

4. The fan system (100) of claim 3, wherein a projecting edge (204A, 206A) of each ridge (204, 206) lies in a different plane as that of the first surface (124).

5. The fan system (100) of claim 1, wherein the groove (302) is formed by at least two spaced-apart ridges (304, 306) extending from within the first surface (124).

6. The fan system (100) of claim 5, wherein a projecting edge (304A, 306A) of each ridge (304A, 306A) lies in a same plane as that of the first surface (124).

7. The fan system (100) of claim 1, wherein the groove (202, 302) extends helically and continuously over at least a portion along an axial length of the ring (108).

8. The fan system (100) of claim 1, wherein the groove (202, 302) extends helically and discontinuously over at least a portion along an axial length of the ring (108).

9. The fan system (100) of claim 1, wherein the groove (202, 302) has at least one of a V-shaped cross-section, a U-shaped cross section, and a semi-circular cross-section.

10. The fan system (100) of claim 1, wherein the clearance (122) is at least one of an L- shaped clearance and an I-shaped clearance.
, Description:A FAN SYSTEM

TECHNICAL FIELD
The present invention generally relates to a fan system, more particularly to, a fan system for an automobile cooling system.

BACKGROUND
Generally, automobile cooling systems are provided with a heat exchanger along with a fan system. The fan system may induce airflow across the heat exchanger, in-order to increase the rate of heat exchange between the airflow and a coolant flowing in the heat exchanger. The fan system may include a fan coupled to a motor housed in a shroud. The fan has a plurality of blades coupled to an outer ring for inducing airflow across the heat exchanger. The plurality of blades extend radially from the centre of the fan to the outer ring for end support of the blades. As the fan is rotary and the shroud is stationary, a clearance is needed between the outer ring of the fan and the shroud, in-order to avoid any contact between the outer ring of the fan and the shroud, thereby enhancing smooth rotation of the fan. Such clearance provided between the outer ring of the fan and the shroud, may cause backflow of air from the downstream of the fan to the upstream of the fan, which is opposite to the main flow of air. The backflow or leakage of air though the clearance between the tip of the ring and shroud is generally referred as tip leakage.

The efficiency of the fan is dependent in part upon the quantity of air, which moves past the blade tips from the discharge side of the fan to the heat exchanger. Thus, the tip leakage at the clearance need to be reduced significantly. Further, the tip leakage may lead to some acoustic issues such as noise.

In-order to overcome the above mentioned problems, non-contact seals are formed between the outer ring of the fan and the shroud that restricts the backflow of air from the downstream of the fan to the upstream of the fan. Such non-contact seals are formed by the structures of the outer ring of the fan and the shroud facing each other, which induce turbulence in the clearance provided between the outer ring of the fan and the shroud. Although, such turbulence induced in the non-contact seal help in reducing the tip leakage, such seals do not efficiently restrict the tip leakage.

Accordingly, there is a need for an improvement in the seal to avoid the backflow of air through the clearance between the outer ring of the fan and the shroud. In addition, there is a need for a seal between the outer ring of the fan and the shroud, to mitigate acoustic issues.

SUMMARY

In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention.

In view of the foregoing, an embodiment of the invention herein provides a fan system for automobile cooling system. The fan system comprises a ring having a first surface encircles and fixedly mounted to a fan, and a shroud having a second surface positioned substantially around the shroud. The first surface and the second surface face each other and together define a clearance between the ring and the shroud. The fan system further comprises at least one groove extends along a circumference of either one of the first surface and the second surface.

In one embodiment, the groove is formed on the first surface of the ring.

In one embodiment, the groove is formed by at least two-spaced-apart ridges extending from the first surface, where a projecting edge of each ridge lies in a different plane as that of the first surface.

In one embodiment, the groove is formed on the second surface of the ring.

In one embodiment, the groove is formed by at least two spaced-apart ridges extending from within the first surface, where a projecting edge of each ridge lines in a same plane as that of the first surface.

In one embodiment, the groove extends helically and continuously over at least a portion along an axial length of the ring.

In another embodiment, the groove extends helically and discontinuously over at least a portion along an axial length of the ring.

In one embodiment, the groove has at least one of a V-shaped cross-section, a U-shaped cross section, and a semi-circular cross-section.

In one embodiment, the clearance is at least one of an L-shaped clearance and an I-shaped clearance.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein:

FIG. 1 exemplarily illustrates a front perspective view of a fan system, according to an embodiment of the present invention.

FIG. 2 exemplarily illustrates a rear perspective view of the fan system of FIG. 1.

FIG. 3 exemplarily illustrates an exploded, cross-sectional view of a fan and a shroud of the fan system of FIG. 1

FIG. 4 exemplarily illustrates an assembled, cross-sectional view of the fan and the shroud of the fan system of FIG. 1.

FIG. 5 exemplarily illustrates a detailed view of a sealing assembly of the fan system of FIG. 1.

FIG. 6 exemplarily illustrates a detailed view of a sealing assembly, according to another embodiment of the present invention.

FIG. 7 exemplarily illustrates the sealing assembly of FIG. 5 mitigating the back flow of air at the clearance of the fan system of FIG. 1.

FIG. 8 exemplarily illustrates the sealing assembly of FIG. 6 mitigating the backflow of air at the clearance of the fan system of FIG. 1.

FIG. 9 exemplarily illustrates a perspective view of an outer ring of fan system of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

It must be noted that the figures disclose the invention in a detailed enough way to be implemented, the figures helping to better define the invention if needs be. The invention should however not be limited to the embodiment disclosed in the description.

The present invention relates to a fan system that effectively limits backflow of air in a clearance provided between a fan and a shroud of the fan system. Generally, the clearance is provided between the fan and the shroud to enable frictionless and smooth functioning of the fan. The fan induces airflow from the upstream of the fan to the downstream of the fan. As the clearance is provided between the fan and the shroud, a part of the airflow leaks in the clearance due to a pressure difference between downstream of the fan and the clearance. Such leakage of airflow in the clearance is known as tip leakage flow, which is undesirable and may lead to acoustic issues. To overcome such issues, one or more grooves formed on at least one of the fan and the shroud to mitigate the tip leakage flow and associated acoustic issues.

FIG. 1 exemplarily illustrates a front perspective view of a fan system 100, according to an embodiment of the present invention. FIG. 2 exemplarily illustrates a rear perspective view of the fan system 100 of FIG. 1. The fan system 100 is provided along with one or more heat exchangers (not shown in Figures) to induce ambient airflow across the heat exchangers. The heat exchanger generally includes tubes and fins arrangement, in which a coolant flows thereto and enable heat exchange between the coolant and the airflow across the heat exchangers. The coolant exchanges heat with the ambient air through the walls of the tubes and the fins. Further, the heat exchanger is positioned in front of the fan system 100 to induce the airflow across the heat exchanger, thereby increasing the rate of heat exchange between the airflow across the heat exchanger and the coolant flowing in the heat exchanger.

The fan system 100 includes a fan 102, a motor 110 and a shroud 112. The fan 102 has a plurality of blades 104 extending radially from a central hub 106 to an outer ring or a ring 108 for end support of the plurality of blades 104. The term outer ring 108 and ring 108 are interchangeably used throughout the specification. The plurality of blades 104 may have a definite angled profile for inducing airflow across the heat exchanger. In one example, the fan 102 is coupled to the motor 110 through an output shaft (not shown in Figures) of the motor 110 that transmits rotational movement to the fan 102. The shroud 112 may include a receiving portion 116 adapted to receive the motor 110, and a main body 114. In one embodiment, the receiving portion 116 is connected to the main body 114 of the shroud 112 by means of a plurality of arms 118 to provide support to the receiving portion 116. Further, the plurality of arms 118 is provided in such a way that the plurality of arms 118 is posterior to the plurality of blades 104, so that the plurality of blades 104 may have space to rotate relative to the shroud 112. Thus, the fan 102 along with the motor 110 is housed in the shroud 112 and the plurality of blades 104 can have seamless rotational movement. The shroud 112 is provided with a plurality of mounting features 120 for mounting the fan system 100 to a frame (not shown in Figures) of the heat exchanger. As the plurality of blades 104 rotates in the shroud 112, a main airflow 132 (shown in FIG. 6) is induced from the upstream of the fan 102 to the downstream of the fan 102. As the heat exchanger is provided at the upstream of the fan system 100, the induced airflow 132 passes through the heat exchanger.

FIG. 3 exemplarily illustrates an exploded, cross-sectional view of the fan 102 and the shroud 112 of the fan system 100 of FIG. 1. FIG. 4 exemplarily illustrates an assembled, cross-sectional view of the fan 102 and the shroud 112 of the fan system 100 of FIG. 1.

As the fan 102 along with the motor 110 is fixed in the shroud 112, the fan 102 rotates relative to the shroud 112, inducing the main airflow 132 (shown in FIG. 6) from the upstream of the fan 102 towards the downstream of the fan 102. Further, the clearance 122 is provided between the outer ring 108 of the fan 102 and the shroud 112 to avoid contact between the rotary fan 102 and the stationary shroud 112. The clearance 122 is necessary to enable smooth rotation of fan 102 relative to the shroud 112. Although the clearance 122 between the fan 102 and the shroud 112 enables smooth rotation of the fan 102, the clearance 122 allows a backflow of air 134 (shown in FIG. 6) in a direction opposite to the main airflow 132. The backflow air 134 is a part of the main airflow 132 that branches from the main airflow 132 at the downstream of the fan 102, flows in the clearance 122 and joins back with the main airflow 132 at the upstream of the fan 102, thereby creating an airflow circulation that is undesirable. Further, the backflow of air 134 caused due to the clearance 122 between the fan 102 and the shroud 112 reduces the efficiency of the fan system 100 and leads to some acoustic issues such as noise. The backflow of air 134 is also referred as leakage airflow 134.

As the clearance 122 between the fan 102 and the shroud 112 cannot be avoided, a sealing assembly 200 is provided between the outer ring 108 of the fan 102 and the shroud 112 to mitigate the backflow of air 134 from downstream of the fan 102 to upstream of the fan 102. In one embodiment, the sealing assembly 200 is a non-contact seal.

FIG. 5 exemplarily illustrates a detailed view of the sealing assembly 200, according to one embodiment of the present invention. At least one groove 202 is formed on the ring 108 defines the sealing assembly 200. The outer ring 108 encircles and fixed to the fan 102 having a first surface 124. The shroud 112 positioned substantially around the ring 108 having a second surface 126. The second surface 126 of the shroud 112 faces the first surface 124 of the outer ring 108. In other words, the first surface 124 of the ring 108 and the second surface 126 of the shroud 112 proximate to each other and together define a clearance 122 between the ring 108 and the shroud 112. The clearance 122 is an L-shaped clearance.

The groove 202 is formed by at least two spaced-apart ridges 204, 206 extending from the first surface 124 so that a projecting edge 204A, 206A of ridge 204, 206 lies in a different plane as that of the first surface 124. Further, the arrangement of the fan 102 and the shroud 112 and the ridges 204, 206 on the first surface 124 are formed in such a way to provide the necessary amount of clearance 122 between the shroud 112 and the ring 108 of the fan 102.

FIG. 6 exemplarily illustrates a detailed view of a sealing assembly 300, according to another embodiment of the present invention. At least one groove 302 is formed on the ring 108 defines the sealing assembly 300. The groove 302 is formed by at least two spaced–apart ridges 304, 306 extending from within the first surface 124 so that a projecting edge 304A, 306A of each ridge 304, 306 lies in a same plane as that of the first surface 124. Since the projecting edge 304A, 306A of the ridge 304, 306 lies in the same plane as that on the first surface 124 of the ring 108, the necessary clearance 122 may be formed between the fan 102 and shroud 112 without considering the height of the ridges 304, 306 on the ring 108 of the fan 102. The height of the ridges 304, 306 is measured from the first surface 124 to the projecting edge 304A, 306A of the ridges 304, 306 in a direction perpendicular to the first surface 124 of the ring 108.

The groove 202, 302 extends helically and continuously over at least a portion along an axial length of the ring 108. In another embodiment, the groove 302, 202 may extend helically and discontinuously over at least a portion along the axial length of the ring 108. In one example, the groove 202, 302 is a helical groove. In another example, the groove 202, 302 is a left-handed helical groove. In yet another example, the groove 202, 302 is right-handed helical groove. The groove 202, 302 may be a left-handed helical groove or a right-handed helical groove depending on the direction of rotation of the fan 102. In one embodiment, the groove 202, 302 extends helically and continuously in a direction opposite that of the direction of rotation of the fan 102. For example, the groove 202, 302 employed may be a left-handed helical groove if the fan 102 rotates in clockwise direction. In another example, the groove 202, 302 employed may be a right-handed helical groove if the fan 102 rotates in an anti-clockwise direction. In another embodiment, the groove 202, 302 may also extend in a same direction as that of the direction of rotation of the fan 102. For example, the groove 202, 302 employed may be a right-handed helical groove if the fan 102 rotates in clockwise direction. In another example, the groove 202, 302 employed may be a left-handed helical groove if the fan 102 rotates in an anti-clockwise direction.

FIG. 7 exemplarily illustrates the sealing assembly 200 mitigating the backflow of air 134 at the clearance 122 of the fan system 100 of FIG. 1. The sealing assembly 200 includes one or more grooves 202 formed on the first surface 124 of the ring 108. The clearance 122 includes a first opening 136 adapted to ingress the backflow of air 134 into the clearance 122 and a second opening 138 adapted to egress the backflow of air 134 from the clearance 122.

The backflow air 134 entering the clearance 122 flows from the downstream of the fan towards the upstream along the groove 202. The groove 202 having a helical configuration provides a longest flow path and allows the backflow air 134 to flow along the longest flow path. The pressure of backflow air 134 may decrease as backflow air 134 passes along each helical turn of groove 202. The backflow air 134 proximal to the first opening 136 have a high pressure (P2) compared to the pressure (P1) of backflow air 134 proximal to the second opening 138. Thus, the pressure drop prevents backflow air 134 from reaching the upstream of the fan 102. Further, the second opening 138 has a bell mouth configuration to provide further resistance to the backflow air 134 and prevent the backflow air 134 from rejoining with the main airflow 132. Resulting, at least part of backflow air 134 locked at the clearance 122, which induces resistance, shown by imaginary dotted lines 146, and restricts further entry of backflow of air 134 in the clearance 122.

FIG. 8 exemplarily illustrates the sealing assembly 300 mitigating the backflow of air 134 at the clearance 122 of the fan system 100 of FIG. 1. The sealing assembly 300 includes one or more grooves 302 formed on the first surface 124 of the ring 108. The clearance 122 includes a first opening 136adapted to ingress the backflow of air 134 into the clearance 122 and a second opening 138adapted to egress the backflow of air 134 from the clearance 122. As the backflow of air 134 flows along the groove 302, resistance 140 is induced in the backflow of air 134, thereby by restricts further backflow of air 134 in the clearance 122.

The backflow air 134 entering the clearance 122 flows from the downstream of the fan towards the upstream of the fan along the groove 302. The groove 302 having a helical configuration provides a longest flow path and allows the backflow air 134 to flow along the longest flow path. The pressure of backflow air 134 may decrease as backflow air 134 passes along each helical turn of the groove 302. The backflow air 134 proximal to the first opening 136 have a high pressure (P2) compared to the pressure (P1) of backflow air 134 proximal to the second opening 138. Thus, the pressure drop prevents backflow air 134 from reaching the upstream of the fan 102. Further, the second opening 138 has a bell mouth configuration to provide further resistance to the backflow air 134 and prevent the backflow air 134 from rejoining with the main airflow 132. Resulting, at least part of backflow air 134 locked at the clearance 122, which induces resistance, shown by imaginary dotted lines 140, and restricts further entry of backflow of air 134 in the clearance 122.

FIG. 9 exemplarily illustrates a perspective view of the ring 108 of the fan system 100 of FIG. 1. The fan 102 is adapted to rotate in clockwise direction, represented by arrow 142 and induces main airflow 132, represented by arrows, from the upstream of the fan 102 to the downstream of the fan 102. At least a part of the air from the main airflow 132 flows back into the clearance 122 as leakage airflow 134, represented by dotted arrows. The provision of groove 202 at the clearance 122 induces turbulence in the leakage airflow 134. The turbulence mitigates the leakage airflow 134 through the clearance 122 between the outer ring 108 and the shroud 112 of the fan system 100. Further, the groove 202 extending in a direction opposite to that of the direction of rotation of the fan 102, for example, a right-handed helical groove rotates along with the fan 102. In another example, the helical groove may be the groove 302. The groove 202 induces resistance on the leakage airflow 134 entering the clearance 122, which redirects at least part of the leakage airflow 134 back again the main airflow 132 at the downstream side of the fan 102 thereby mitigating the leakage airflow 134 and associated acoustic issues.
In another embodiment, the fan 102 may be adapted to rotate in anti-clockwise direction (not shown in Figures) and may have groove 202, 302 extending in a direction opposite to that of the direction of rotation of fan 102, for example, a left-handed helical groove. The rotation of the fan 102 may induce main airflow 132 from the upstream of the fan 102 to the downstream of the fan 102. At least a part of the air from the main airflow 132 may flow back into the clearance 122 as leakage airflow 134. The groove 302, 202 induces resistance on the leakage airflow 134 entering the clearance 122, which redirects at least part of the leakage airflow 134 back again the main airflow 132 at the downstream side of the fan 102 thereby mitigating the leakage airflow 134 and associated acoustic issues.

The leakage airflow 134 entering the clearance 122 flow along the helical groove. The helical configuration of the groove 202, 302 allows the leakage airflow 134 to enter smoothly without causing abrupt changes in the pressure of the airflow 134. Thereafter, the leakage airflow 134 traces along the helical path of groove 202, 302 towards the upstream side of the fan 102. As the leakage flow traces and flows along each helical turn, the pressure of the leakage flow also decreases. The pressure drop prevents backflow air 134 from reaching the upstream of the fan 102. Further, the second opening 138 has a bell mouth configuration to provide further resistance to the backflow air 134 and prevent the backflow air 134 from rejoining with the main airflow 132. Resulting, at least part of the leakage flow may die off losing the energy and at least part of backflow air is locked at the clearance 122, which induces resistance and restricts further entry of backflow of air 134 in the clearance 122. Thereby, the present invention reduces tip losses and increases efficiency of the fan system 100. The longest flow path also provides highest possible resistance to the backflow air 134.

Although the sealing assembly 200, 300 of the present invention is explained with respect to the fan system 100, the sealing assembly 200, 300 can be used in any other systems as far as the system includes grooves formed in a clearance provided between two surface of the elements of the system and fluid flowing in the clearance.

All the above-described embodiments are just to explain the present invention while more embodiments and combinations thereof might exist. Hence, the present invention should not be limited to the above-described embodiments alone.