Patent Publication Number: US-6341643-B1

Title: Crossflow fan

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present invention is related to Japanese patent application No. Hei. 11-127980, filed May 10, 1999, the contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention generally relates to a cross-flow fan, and more particularly, to a cross-flow fan, which provides for reduced ventilation resistance. 
     BACKGROUND OF THE INVENTION 
     Presently, there is a conventional technique (Japanese Patent Application Laid-Open No. 8-126125) which uses a cross-flow fan as a cooling fan for a heat exchanger mounted in a vehicle. As shown in FIG. 12, this technique uses a heat exchanger  100  disposed in the path of run wind. A cross-flow fan  110  is disposed toward the vehicle&#39;s rear side with respect to the heat exchanger  100 , so that air passing through the heat exchanger  100  flows from the front side of the vehicle to the rear side. As such, it is possible to cool the heat exchanger  100  by using the run wind generated by movement of the vehicle, in addition to the cooling wind generated by the cross-flow fan  110 . 
     However, when heat exchanger  100  is cooled by using the run wind, the run wind passing through the heat exchanger  100  passes through the inside of a casing  120  of the cross-flow fan  110 . A bladed wheel  130  is contained in the inside of casing  120 , which results in large ventilation resistance. Therefore, it is difficult for the run wind to pass through, thereby resulting in ineffective use of the run wind. The present invention was developed in light of these drawbacks. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a cross-flow fan, which increases the amount of wind sent without increasing the power of the motor. 
     According to a first aspect of the invention, a cross-flow fan for ventilating a heat exchanger sucks air into a casing through the heat exchanger. An opening portion for ventilation is bored into a wall surface of the casing. As a result, ventilation resistance in the casing is decreased. Therefore, air movement therethrough is increased. 
     According to a second aspect of the invention, the casing includes a partition for partitioning the air passage into an intake side and a discharge side. A tongue portion is positioned close to the outer periphery of the bladed wheel as an apex. Also, an opening is bored in the wall surface forming the partition. 
     According to a third aspect of the invention, the partition has roughly a mountain shape formed by the wall surface at the intake side with respect to the tongue portion and the wall surface at the discharge side. The opening is bored in either the wall surface at the intake side or the wall surface at the discharge side. Or, the opening is bored into both surfaces. 
     According to a fourth aspect of the invention, the openings are bored into both the wall surface at the intake side and the wall surface at the discharge side thereby forming the partition. The respective distances between the two openings and the center of a swirl generated inside of the casing at the time of rotation of the bladed wheel are equal to each other. 
     According to a fifth aspect of the invention, the cross-flow fan is disposed at a vehicle&#39;s rear side with respect to the heat exchanger mounted in a vehicle, so that a run wind passing through the heat exchanger can be introduced into the inside of the casing. In this case, since the run wind can pass through the inside and the outside of the casing through the opening portions bored in the casing, it becomes easy for the run wind to escape from the inside of the casing, and an increase of an amount of run wind can be expected. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a side cross-sectional view of a cross-flow fan according to a first embodiment of the present invention; 
     FIG. 2 is an environmental view showing cross-flow fan mounted to a vehicle according to the present invention; 
     FIG. 3A is a partial cross-sectional view of a casing for a cross-flow fan according to the present invention; 
     FIG. 3B is a partial cross-sectional view of a casing for a cross-flow fan according to the present invention; 
     FIG. 4 is a front cross-sectional view of a boiling and cooling apparatus for a cross-flow fan according to the present invention; 
     FIG. 5 is a diagrammatical view of a casing for a cross-flow fan according to the present invention; 
     FIG. 6 is a graphical view illustrating the relationship between ram pressure and air volume for a cross-flow fan according to the present invention; 
     FIG. 7 is a graphical view illustrating the relationship between cooling air movement and static pressure for a cross-flow fan according to the present invention; 
     FIG. 8A is a side cross-sectional view illustrating a cross-flow fan according to a second embodiment of the present invention; 
     FIG. 8B is a partial cross-sectional view of a casing for a cross-flow fan according to the present invention; 
     FIG. 9 is a cross-sectional view of a cross-flow fan according to a third embodiment of the present invention; 
     FIG. 10 is a cross-sectional view of a cross-flow fan according to a fourth embodiment of the present invention; 
     FIG. 11 is a top view of a cross-flow fan according to a fourth embodiment of the present invention; and 
     FIG. 12 is a side view of a cross-flow fan according to the prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1 and 2, a cross-flow fan according to the present invention is shown and described. In FIG. 2, A cross-flow fan (hereinafter referred to as cooling fan  1 ) is illustrated as a cooling means for a boiling cooling apparatus  2  mounted in a vehicle. 
     The boiling and cooling apparatus  2  cools heat generating units  3  by repeated boiling and condensation of a refrigerant. As shown in FIG. 4, boiling and cooling apparatus  2  includes a refrigerant tank  4  for storing a liquid refrigerant and a radiator  5  attached to the upper portion of the refrigerant tank  4 . These items are manufactured by integrated soldering. 
     The heat generating units  3  are, for example, IGBT modules of an inverter circuit of an electric car. As such, heat generating units  3  are brought into close contact with and affixed to both surfaces of the refrigerant tank  4  by bolts  6  or the like. 
     The refrigerant tank  4  has thin walls as compared to its width. Refrigerant tank  4  includes a refrigerating chamber  7 , a liquid return passage  8 , a heat insulating passage  9 , and a connecting passage  10 . Refrigerant chamber  7  is formed in the region where the heat generating unit  3  is attached, and is divided into a plurality of passages. 
     Liquid return passages  8  allow condensed liquid, cooled and liquefied by the radiator  5 , to flow. Liquid return passages  8  are provided at both sides of the refrigerant tank  4 . Heat insulating passages  9  insulate a portion between the refrigerant chamber  7  and the liquid return passage  8 . These passages are provided between the refrigerant chamber  7  and the liquid return passage  8 . 
     The connecting passage  10  is a passage for supplying the condensed liquid that has flowed into the liquid return passage  8  to the refrigerant chamber  7 , and is provided at the lower end portion of the refrigerant tank  4 , and mutually communicates with the liquid return passage  8 , the refrigerant chamber  7 , and the heat insulating passage  9 . 
     Radiator  5  has a core portion  11 , an upper tank  12 , and a lower tank  13 . Refrigerant flow control plate  14  is disposed in the inside of the lower tank  13 . Core portion  11  has a plurality of radiating tubes  16  provided side by side between radiating fins  15 . 
     Upper tank  12  is connected with the upper end of each of the radiating tubes  16 . Likewise, each of the respective radiating tubes  16  communicate with each other in the upper tank  12 . 
     Lower tank  13  is connected with the lower end of each of the radiating tubes  16 . Likewise, the respective radiating tubes  16  communicate with each other in the lower tank  13 . 
     The refrigerant flow control plate  14  prevents condensed liquid, liquefied in the radiating tube  16 , from directly dropping into the refrigerant chamber  7 . Refrigerant flow control plate  14  hangs over the refrigerant chamber  7  and the heat insulating passage  9  which opens into the lower tank  13 . 
     Referring to FIG. 1, the cooling fan  1  includes a casing  18  which forms an air passage  17 , a bladed wheel  19  contained in casing  18 , a motor (not shown) for rotating and driving the bladed wheel  19 . Cooling fan  1  is seated at a vehicle&#39;s rear side with respect to the core portion  11  of the radiator  5  (see FIG.  2 ). 
     Casing  18  forms an air passage having an inside wall surface  20  with a stabilizer  20 A (partition portion of the invention), an outside wall surface  21  having a scroll portion  31 , and two side wall surfaces (not shown) covering both outsides of the bladed wheel  19  in the axial direction. An intake port (not shown) of the air passage  17  is attached opposite to the core  11 . A discharge port  25  opens substantially downward. 
     The stabilizer  20 A provided on the inside wall surface  20  is formed to be roughly mountain-shaped. Stabilizer  20 A further has a tongue portion  22  close to the outer periphery of bladed wheel  19  as an apex. Tongue portion  22  divides the air passage  17  in the casing  18  into an intake side and a discharge side. 
     Stabilizer  20 A is formed of wall surface  29  at the intake side with respect to tongue portion  22  and wall surface  27  at the discharge side. Wall surfaces  29  and  27  have opening portions  23  for ventilation. These opening portions  23  are respectively bored at a position separated from the tongue portion  22  by a predetermined distance d. Opening portions  22  may be provided, for example, as shown in FIG.  3 A. Here, opening portions  22  comprise a plurality of small holes provided along the longitudinal direction of the inside wall surface  20 . Alternatively, as shown in FIG. 3B, opening portions  22  comprise a slit-like opening portion provided along the longitudinal direction of the inside wall surface  20 . 
     When bladed wheel  19  is rotated and driven by a motor, air is sucked into the inside of the casing  18  from the front side of the core  11  of the radiator  5  and moves through the core portion  11 . As shown in FIG. 5, the cooling fan  1  generates, inside casing  18 , a simple flow which passes through bladed wheel  19  and travels toward the discharge port  25 , thereby causing a circulation flow (swirl) which circulates inside bladed wheel  19 . 
     Here, where opening portions  23  are bored in the wall surfaces which form the foregoing stabilizer  20 A, the opening portion  23  is preferably bored in the wall surface  29  at the intake side with respect to the tongue portion  22 . Also, opening portion  23  is preferably bored in wall surface  27  at the discharge side. These portions are provided at positions respectively separated from the center of the swirl (circulation flow) by substantially equal distances. 
     The operation of the boiling and cooling apparatus  2  will be described. Refrigerant vapor, boiled by heat from heat generating unit  3 , rises in refrigerant chamber  7  and enters lower tank  13 . The refrigerant vapor is dispersed in lower tank  13  and flows into the respective radiating tubes  16 . The refrigerant vapor rising in the radiating tubes  16  is cooled by cooling air generated by the cooling fan  1  or a run wind generated from running of a vehicle. From this cooling air, radiation tubes radiate latent heat which condenses the refrigerant vapor. 
     The condensed liquid, condensed in the radiating tube  16 , runs along the inner surface of the radiating tube  16  by gravity. After dropping into the lower tank  13  from the discharge tube  16 , the liquid flows into the liquid return passage  8 , and is circulated to the refrigerant chamber  7  through the connecting passage  10 . 
     Next, advantages of the formation of the opening portion  23  in the casing  18  of the cooling fan  1  will be described. First, the relationship between ram air pressure and air movement of the run wind was measured when the opening portion  23  was bored into casing  18  and where the opening portion was not bored. Where the opening portion  23  is bored into casing  18 , as described in the foregoing structure, the opening portion  23  is bored in both the wall surfaces  29  and  27  forming the stabilizer  20 A at the intake side and the discharge side. 
     According to this measurement, as shown in FIG. 6, the result was such that the air movement increased in the case where the opening portions  23  were provided both when the motor was stopped and when the motor was rotating. It is considered that this result was obtained because by boring the opening portions  23  in the casing  18 , ventilation resistance of the casing was lowered, and as a result, the air movement was increased. 
     Subsequently, the relationship between the static pressure and the cooling air movement (static pressure—cooling air movement characteristics) generated by rotation of the bladed wheel  19  was measured where the opening portions  23  are bored in the casing  18  where the opening portion is not bored. The result is graphically illustrated in FIG.  7 . Accordingly, at the same static pressure, the cooling air movement was larger when the opening portions  23  were bored in the casing  18  than when the opening portion  23  was not bored in the casing  18 . 
     Then, where the run wind does not exist and where the opening portion  23  is not bored in casing  18 , an air movement of value Q 1  is generated due to the lower pressure beside the core portion  11 . Where the opening portions  23  are bored in the casing  18 , the air movement becomes Q 2  (Q 2 &gt;Q 1 ) due to further pressure loss at the core portion  11 . Thus, by boring the opening portions  23  in the casing  18 , the cooling air movement is increased from Q 1  to Q 2 . Therefore, when the vehicle is stopped and no run wind exists, the air volume flowing therethrough still is increased. 
     Where the run wind is generated, since the static pressure of the cooling fan  1  is lowered by the ram pressure, the apparent pressure loss of the core portion  11  is decreased. As a result, where the opening portion  23  is not bored in the casing  18 , the air volume becomes Q 3  (Q 3 &gt;Q 1 ) due to the apparent pressure loss of the core portion  11 . Thus, the air volume is increased by Q 3 −Q 1 . Where the opening portions  23  are bored in the casing  18 , the air volume becomes Q 4  (Q 4 &gt;Q 2 ) due to the apparent pressure loss of the core portion  11 . Thus, the air volume is increased by Q 4 −Q 2 . Here, when the increase of the air volume due to the run wind is compared when the opening portions  23  are bored in the casing  18  and when the opening portion is not bored, the following relation is obtained. 
     
       
           Q   4 − Q   2 &gt; Q   3 − Q   1   
       
     
     That is, where the opening portions  23  are bored in the casing  18 , the increase of the air volume due to the run wind becomes larger. 
     In the cooling fan  1  of the first embodiment, since opening portions  23  are bored in both the wall surfaces  29  and  27 . Even where the run wind does not exist (for example, in the state of idling), the air volume can be increased without raising the output of the motor. Where the cooling fan receives run wind and the opening portion  23  is not bored in the casing  18 , the increase of air volume due to run wind becomes large. As a result, it is possible to effectively use the run wind and realize an increase of air movement. In other words, when the cooling air movement for ventilation of the core portion  11  is made equal to where the opening portion  23  is not bored in the casing  18 , the output of the motor can be decreased. As a result, a smaller motor can be used. Moreover, noise is also reduced. 
     In the above measurement, even where run wind does not exist, the air volume of the fan was increased by boring the opening portions  23  in both wall surfaces  29  and  27 . However, the fan characteristics are greatly changed according to the position where the opening portion  23  is bored. As a result, it is possible that the air movement of the fan might become lower than when opening portion  23  is not bored in casing  18 . However, since it is possible to effectively use the run wind and to increase air movement by boring opening portion  23  in the casing  18 , it is not always necessary to limit the positioning of the opening portions  23  to the two wall surfaces  29  and  27 . 
     As shown in FIG. 8A and 8B, a second embodiment of the present invention is shown and described. In this embodiment, the opening portion  23  is bored in only wall surface  29 . 
     In FIG. 9, a third embodiment of the present invention is shown and described. In this embodiment, stabilizer  20 A of casing  18  is made of one partition wall. The opening portion  23  is bored in the partition wall. 
     In a fourth embodiment of the present invention, as shown in FIG.  10  and FIG. 11, the opening portion  23  is bored at a position other than on the wall surface forming the stabilizer  20 A of the casing  18 . In FIG. 10, although the opening portions  23  are shown bored at a plurality of places in the casing  18 , this illustration shows only positions where the opening portions  23  can be bored. Thus, it is not necessary to bore the opening portions  23  at all these positions. Instead, the opening may be bored in only one place. However, preferable the scroll portion  31  of the outside wall surface  21  is excluded. 
     As shown in FIG. 11, where the opening portion  23  is bored into a slanted surface  33 , which forms the intake port of the casing  18 , air blown out from the opening portion  23  hits against motor  24 . As a result, motor  24  is air-cooled. 
     In the cross-flow fan of the present invention, as described in the first embodiment, although the increase of air volume can be realized by using vehicle run wind, it is not always necessary to use the fan for a heat exchanger which is mounted in the vehicle and receives the run wind. Moreover, the heat exchanger using the cross-flow fan is not limited to the boiling and cooling apparatus  2  (core portion  11 ) shown in the first embodiment. Instead, the cross-flow fan can be used for various heat exchangers, for example, a heat exchanger for a freeze cycle, a heat exchanger used for a hot water circuit, or the like. 
     While the above-described embodiments refer to examples of usage of the present invention, it is understood that the present invention may be applied to other usage, modifications and variations of the same, and is not limited to the disclosure provided herein.