Patent Publication Number: US-6904958-B2

Title: Heat exchanger

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based upon and claims priority of Japanese Patent Application No. 11-302705, filed Oct. 25, 1999, the contents being incorporated therein by reference, and a continuation of PCT Application No. PCT/JP00/07471, filed Oct. 25, 2000. 

   TECHNICAL FIELD 
   The present invention relates to a heat exchanger having a mounting member for attaching a blower thereto and suitable for a car radiator. 
   BACKGROUND ART 
   A blower for supplying cooling air to a radiator is generally attached to the radiator via a fan shroud. Therefore, in the prior art, pin-like projections are formed integrally with a radiator tank made of resin, for mounting the blower (fan shroud) thereto. 
   In this regard, as is well-known, the fan shroud covers the blower to support the same and prevent the supplied air from bypassing the radiator. 
   Recently, to reduce industrial waste by improving the recycling ability of car parts including the radiator, car parts improved in recycling ability have been eagerly desired. 
   To satisfy this demand, in the case of conventional radiators (heat exchangers), it is necessary to classify materials thereof into metal and resin because each of them is generally composed of two kinds or more of materials, including at least metal and resin. Accordingly, man-hours for recycling (man-hours necessary for classifying materials) becomes large thereby causing a problem in that the recycling ability is lowered. 
   To solve this problem, the present inventors attempted to form a heat exchanger from metallic (aluminum) components, and found that a sufficient mechanical strength is not obtainable in a header tank resulting in a problem in that the header tank deforms due to inner pressure. 
   Although this problem might be solved by increasing a plate thickness of members constituting the header tank, such a countermeasure would increase the mass (weight) and production cost of the heat exchanger. 
   Also, if the mounting member for attaching the blower (fan shroud) is secured to the header tank as in the above-mentioned conventional structure, stress is concentrated on a joint portion between the mounting member and the header tank when the blower vibrates, for example, due to the oscillation of a car, resulting in a risk of breakage of the header tank. 
   DISCLOSURE OF INVENTION 
   An object of the present invention is to improve the mechanical strength of a header tank while suppressing the increase of mass (weight) and production cost of a heat exchanger. 
   In this regard, when inner pressure is applied to a header tank ( 120 ) having a rectangular cross-section, the header tank ( 120 ) deforms so that a longer side wall surface ( 120   c ) having a larger pressure-receiving area is swollen. 
   Accordingly, to achieve the above object in view of such a point, in one embodiment of the present invention, a heat exchanger comprises a plurality of metallic tubes ( 111 ) through which fluid flows, and a pair of metallic header tanks ( 120 ) of a rectangular cross-section communicating with the plurality of tubes ( 111 ); the header tanks being arranged at lengthwise opposite ends of the tubes ( 111 ) and extending perpendicular to the lengthwise direction of the tubes ( 111 ); wherein the mounting members ( 128 ,  129 ) to which the blower is to be attached are secured to a longer side wall surface ( 120   c ) of the header tank ( 120 ), and reinforcements ( 128   a,    129   a ) are provided in the mounting members ( 128 ,  129 ) on the sides to be in contact with the longer side wall surface ( 120   c ), for strengthening the longer side wall surface ( 120   c ). 
   According to this arrangement, it is possible to mitigate the concentration of stress generated in the joint portions between the mounting member ( 128 ,  129 ) and the longer side wall surface ( 120   c ) caused by the car oscillation and prevent the longer side wall surface ( 120   c ) from being largely deformed. 
   Thus, according to the present invention, by providing the reinforcement in the longer side wall surface ( 120   c ) having a larger pressure-receiving area, it is possible to improve the mechanical strength of the header tank ( 120 ) (particularly, the longer side wall surface ( 120   c )) without the increase in mass (weight) and production cost of the heat exchanger caused by excessive reinforcement, whereby the reliability and the durability of the heat exchanger can be improved. 
   According to another embodiment of the present invention, a heat exchanger comprises a plurality of metallic tubes ( 111 ) through which fluid flows, and a pair of metallic header tanks ( 120 ) of a rectangular cross-section communicating with the plurality of tubes ( 111 ); the header tanks being arranged at lengthwise opposite ends of the tubes ( 111 ) and extending perpendicular to the lengthwise direction of the tubes ( 111 ); wherein concave and convex portions ( 120   e ) are formed in a portion of a longer side wall surface ( 120   c ) of the header tank ( 120 ) by the plastic deformation thereof, and mounting members ( 128 ,  129 ) to which a blower is to be attached are secured to other portions of the longer side wall surface ( 120   c ) having no concave and convex portions ( 120   e ), and wherein reinforcements ( 128   a,    129   a ) are provided in the mounting members ( 128 ,  129 ) on the sides to be in contact with the longer side wall surface ( 120   c ), for strengthening the longer side wall surface ( 120   c ). 
   According to this arrangement, it is possible to mitigate the concentration of stress generated in the joint portions between the mounting member ( 128 ,  129 ) and the longer side wall surface ( 120   c ) caused by the car oscillation and further effectively prevent the longer side wall surface ( 120   c ) from being largely deformed. 
   Thereby, also in this embodiment, it is possible to improve the mechanical strength of the header tank ( 120 ) (particularly, the longer side wall surface ( 120   c )) without the increase in mass (weight) and production cost of the heat exchanger, whereby the reliability and the durability of the heat exchanger can be improved. 
   The present invention will be better understood with reference to the following description of the preferred embodiments of the present invention and the attached drawings. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a front view of a radiator according to a first embodiment of the present invention; 
       FIG. 2  is a sectional view taken along a line A—A in  FIG. 1 ; 
       FIG. 3   a  is a front view of a first or second member in the first embodiment,  FIG. 3   b  is a bottom view of  FIG. 3   a,  and  FIG. 3   c  is a side view of  FIG. 3   b;    
       FIG. 4  is a sectional view of a header tank according to the first embodiment of the present invention; 
       FIG. 5   a  is a sectional view of an upper mounting member, and  FIG. 5   b  is a perspective view of a lower mounting member; 
       FIG. 6  is a perspective view of the header tank according to the first embodiment of the present invention; 
       FIG. 7  is a wire diagram showing the deformation of the header tank; 
       FIG. 8  is a front view of a radiator according to a second embodiment of the present invention; 
       FIG. 9  is a sectional view of an upper mounting member according to a third embodiment of the present invention; 
       FIG. 10  is a sectional view of a lower mounting member according to a fourth embodiment of the present invention; and 
       FIGS. 11   a  and  11   b  are sectional views, respectively, of mounting members according to modifications of the present invention. 
   

   BEST MODES FOR CARRYING OUT THE INVENTION 
   (First Embodiment) 
   In this embodiment, a heat exchanger according to the present invention is applied to a car radiator, and  FIG. 1  is a front view of the heat exchanger (radiator)  100  as seen from a downstream side of air flow. 
   Reference numeral  111  denotes a plurality of tubes in a flat shape for circulating coolant water, which are formed by the extrusion or drawing of aluminum stocks. Reference numeral  112  denotes a fin, made of aluminum, disposed between the adjacent tubes  111  for facilitating the heat exchange between air and coolant water, which is formed in a wave shape (a corrugated shape) by roller shaping. A radiator core  110  for cooling the coolant water by the heat exchange between the coolant water and the air is constituted by the fins  112  and the tubes  111 . 
   First and second header tanks  121 ,  122  made of aluminum are provided at lengthwise opposite ends of the tubes  111  and extend perpendicular to the lengthwise direction of the tubes  111  and communicate with a plurality of tubes  111 , wherein the first header tank  121  located at one lengthwise end of the tubes  111  (a left end as seen in  FIG. 1 ) operates to distribute the coolant water flowing out of an engine (not shown) to a plurality of tubes  111 , while, the second header tank  122  located at the other lengthwise end of the tubes  111  (a right end as seen in  FIG. 1 ) operates to collect the coolant water after the heat-exchange and direct the same to the engine. In this regard, the first and second header tanks  121 ,  122  will be hereinafter referred to as a header tank  120  as a whole. 
   A cross-sectional shape of the header tank  120  is of a rectangular shape, as shown in  FIG. 2 , having a longer side in the direction parallel to the lengthwise direction of the tube  111  (that is, in the direction perpendicular to the direction of air flow). In this embodiment, this rectangular shape is flattened to have a longer side L 1  of 40 mm or more and a shorter side L 2  of 35 mm or less. 
   As shown in  FIGS. 3   a  to  3   c,  the header tank  120  is formed by fixing first and second members  120   a,    120   b,  each shaped to have an L-shaped cross section by the press, with each other by the brazing, wherein, as shown in  FIG. 4 , first and second ribs  123 ,  124  are provided on the shorter side surface of the first and second members  120   a,    120   b  by the plastic deformation of part of the first and second members  120   a,    120   b  (the header tank  120 ) protruding toward the interior of the header tank  120  caused by burring (pressing). 
   A through-hole  123   a  is formed at a top of the respective first ribs  123  in the first member  120   a,  bored through the top wall in the thickness direction, and the tube  111  is inserted thereinto. 
   In this regard, since the sole difference between the first member  120   a  and the second member  120   b  is whether or not there is the through-hole  123   a,  the second ribs  124  are arranged on the opposite side from joint portions  120   f  of the header tank  120  with the tubes  111  at a pitch P 2  approximately equal to that P 1  of the tubes  111  in a state wherein both the members  120   a,    120   b  and tubes  111  have been jointed together by brazing (that is, a state wherein the radiator  100  has been completed). As shown in  FIGS. 2 and 3 , each of the members  120   a,    120   b  has grasping sections  120   d  for grasping the other member and rigidly brazing both the members  120   a,    120   b  with each other. 
   In  FIG. 1 , reference numeral  125  denotes an entrance pipe to be connected to a coolant water exit of the engine, and reference numeral  126  denotes an exit pipe to be connected to a coolant water entrance of the engine. On a longer side wall surface  120   c  of the header tank  120 , mounting members  128 ,  129  are provided for attaching a blower (fan shroud) as already described in BACKGROUND ART. As shown in  FIG. 6 , both of the mounting members  128 ,  129  are brazed on the midpoint M of the longer side wall surface  120   c  of the header tank  120  in the direction perpendicular to the lengthwise direction of the header tank  120  (i.e. on a line passing a middle point of the length L 1  of the longer side). 
   In this regard, the upper mounting member  128  is a pin-like projection as shown in  FIG. 5   a  and, in the wall surface  120   c  side of the mounting member  128 , has a tapered section  128   a,  integrally formed of an aluminum stock, whose cross-sectional area increases as approaching the wall surface  120   c.  The tapered section  128   a  has an oval (elliptic) cross-sectional shape, as shown in  FIG. 6 , extending in the lateral direction (the longer side direction) perpendicular to the lengthwise direction (the upper/lower direction) of the header tank  120 . 
   Accordingly, the tapered section  128   a  extends in the direction perpendicular to the lengthwise direction (in the longer side direction) of the header tank  120  to cross the median (center line) of the wall surface  120   c,  as a result, such a structure functions as a reinforcement for strengthening the longer side wall surface  120   c.  In addition, a female-threaded hole  128   b  to be engaged with a bolt is formed in a tip portion of the mounting member  128 . 
   On the other hand, the lower mounting member  129  is formed of an aluminum stock by the extrusion or the drawing so that rectangular flange sections  129   a  are integrally provided on the distal and proximal ends thereof as shown in  FIG. 5   b,  wherein the proximal flange section  129   a  located in the wall surface  120   c  side functions as a reinforcement for strengthening the longer side wall surface  120   c.    
   In this connection, the fan shroud (blower) is assembled to the radiator  100  (header tank  120 ) in the manner that the lower portion of the fan shroud (not shown) is secured to the mounting member  129  by the insertion engagement thereof with a U-shaped groove of a hook (stay) provided on the lower portion of the fan shroud, while the upper portion thereof is fixed to the mounting member  128  by the bolt. 
   In  FIG. 1 , reference numeral  130  denotes a water inlet (filler neck) for replenishing coolant water, and reference numeral  131  denotes a radiator cap of a well-known pressurized type for closing the water inlet  130 . Reference numeral  140  denotes a side plate extending parallel to the lengthwise direction of the tube  111  at each of opposite ends of the radiator core  110  to form a reinforcement of the latter. 
   Characteristics of this embodiment will be described below. 
   When the inner pressure is applied to the header tank  120  having a rectangular cross section, the header tank  120  is deformed to swell the longer side wall surface  120   c  having a larger pressure-receiving area, as shown in FIG.  7 . 
   Contrarily, according to this embodiment, since the tapered section  128   a  and the flange section  129   a  are provided as the reinforcement for the mounting members  128 ,  129 , respectively, on the sides to be in contact with the longer side wall surface  120   c,  it is possible to prevent the longer side wall surface  120   c  from being largely deformed, while mitigating the concentration of stress generated in the joint portions between the mounting member  128 ,  129  and the longer side wall surface  120   c  caused by the car oscillation. 
   Thus, according to this embodiment, by providing the reinforcement in the longer side wall surface  120   c  having a larger pressure-receiving area, it is possible to improve the mechanical strength of the header tank  120  (particularly, the longer side wall surface  120   c ) without the increase in mass (weight) and production cost of the radiator  100  caused by excessive reinforcement, whereby the reliability and the durability of the radiator  100  can be improved. 
   Also, since the tapered section  128   a  of the mounting member  128  constituting the reinforcement has a cross-sectional area which becomes larger approaching the wall surface  120   c,  the concentration of stress to the proximal end of the mounting member  128  can be assuredly mitigated. 
   In addition, since the tapered section  128   a  strengthens the longer side wall surface  120   c  by extending toward the opposite sides of the longer side direction of the header tank  120  while crossing the median (a center line) of the wall surface  120   c,  it is possible to further assuredly strengthen the longer side wall surface  120   c  having a larger pressure-receiving area. 
   Since the tapered section  128   a  and the flange section  129   a,  constituting the reinforcement, are formed integrally with the mounting members  128 ,  129 , respectively, it is possible to reduce the production cost of the mounting members  128 ,  129  having the reinforcement. 
   (Second Embodiment) 
   While the reinforcement for strengthening the longer side wall surface  120   c  is provided solely by the tapered section  128   a  of the mounting member  128  and the flange section  129   a  of the mounting member  129  in the first embodiment, according to the present embodiment as shown in  FIG. 8 , a plurality of ribs (concave and convex portions)  120   e  arranged in the lengthwise direction of the header tank  120  are provided by plastically deforming portions of the longer side wall surface  120   c  during pressing (plastically deforming) the first and second members  120   a,    120   b,  and the remaining part of the longer side wall surface  120   c  having no ribs  120   e  (an area in which a pitch P 3  of the rib  120   e  is larger than that P 4  in the other area in this embodiment) has the mounting member  128  or  129  attached thereto. 
   According to such an arrangement, the ribs  120   e  constitute the reinforcement for strengthening the longer side wall surface  120   c,  in addition to the tapered section  128   a  of the mounting member  128  and the flange section  129   a  of the mounting member  129 , whereby the mechanical strength of the longer side wall surface  120   c  having a larger pressure-receiving area can be uniformly increased as a whole. 
   (Third Embodiment) 
   While the tapered section  128   a  of the mounting member  128  constituting the reinforcement is formed in integral with the mounting member  128  in the above-mentioned embodiments, a flange section  128   c  constituting a reinforcement is formed separately from a mounting member  128  and then brazed to the mounting member  128  for incorporating with the mounting member  128  in the present embodiment, as shown in FIG.  9 . 
   In this regard, the flange section  128   c  is shaped to be an oval shape and secured to a longer side wall surface  120   c  so that a major axis of the oval shape thereof coincides with the longer side direction of the header tank  120 . 
   Also, although the flange section  128   c  is not in a tapered shape in  FIG. 9 , the periphery wall portion of the flange section  128   c  may be tapered so that a cross-sectional area thereof increases as approaching the wall surface  120   c.    
   (Fourth Embodiment) 
   As shown in  FIG. 10 , according to the present embodiment, a wall thickness t of a flange section  129   a  of a mounting member  129  constituting the reinforcement becomes larger and a tapered section  129   b  is provided so that the cross-sectional area of the flange section  129   a  increases as approaching the wall surface  120   c.    
   Thereby, it is possible to assuredly mitigate the concentration of stress to the proximal portion of the mounting member  129 . 
   (Other Embodiments) 
   While the periphery wall portion of the tapered section  128   a  or  129   b  varies in an arcuate manner in each of the above-mentioned embodiments, in the present embodiments, the periphery wall portions of the tapered sections may linearly vary as shown in  FIGS. 11   a  and  11   b.    
   INDUSTRIAL APPLICABILITY 
   In the above embodiments, the radiator is a so-called cross-flow type wherein the length of the header tank  120  extends in the upper/lower direction and the length of the tube  111  extends in the horizontal direction. However, the present invention is similarly applicable to a so-called down-flow type radiator wherein the length of the header tank  120  extends in the horizontal direction and the length of the tube  111  extends in the upper/lower direction. 
   Although the present invention is applied to a radiator in the above embodiments, the present invention should not be limited thereto but also applicable to other types of heat exchangers such as a condenser or a duplex heat exchanger in which a condenser and a radiator are integral with each other. 
   The present invention has been described in detail above with reference to the specific embodiments. However, it will be understood that a person with ordinary skill in the art can make various changes and modifications based on the above description without departing from a scope and spirit of the present invention.