Patent Publication Number: US-2006006641-A1

Title: Flange structure

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a flange structure for use in engine cooling systems and lubricating systems of automobiles and industrial machines.  
      2. Description of Related Art  
      In some cooling system or some lubricating system for an engine, a flange generally called a connector flange is attached to the body, provided with a fluid passage, of a fluid device.  
      Referring to  FIG. 5 , a conventional connector flange  2  is attached to a structure  1  internally provided with a fluid passage  3 . The connector flange  2  is integrally provided with a boss  5 . The connector flange  2  is formed by casting or forging. A connecting tube  5  is fixedly connected to the boss  4  by press fitting. A tube  6  is connected to the connecting tube  5 . The connector flange  2  has a joining surface  7   a  joined to a joining surface  7   b  of the structure  1 . A gasket  8  is held between the joining surface  7   b  of the structure  1  and the joining surface  7   a  of the connector flange  2 , and the connector flange  2  is fastened to the structure  1  with bolts  9 . The joining surfaces  7   a  and  7   b  need to be finished by machining so that the joining surfaces  7   a  and  7   b  may be in close contact with the gasket  8 . Generally, a hole for receiving the connecting tube  5  therein of the boss  4  is formed with its axis extended perpendicularly to the joining surfaces  7   a  and  7   b  to facilitate machining work for forming the hole.  
      Various devices arranged near the connector flange  2  in the cooling system or the lubricating system for the automotive engine in most cases. Usually, the boss  4  is formed in an upper part of the connector flange  2  and the connecting tube  5  is disposed at an elevated level to avoid interference between the connecting tube  5  and a device  50  when the structure  1  is installed.  
      Another conventional connector flange  2  shown in  FIG. 6  is provided with a boss  4  at a position slightly below the center thereof. The boss  4  is extended obliquely upward to prevent interference between a connecting tube  5  attached to the boss  4  and a device  50 .  
      In some cases, a gas-liquid two-phase fluid of a liquid, such as cooling water or lubricating oil, and bubbles of a gas produced by the gasification of the liquid due to increase in the temperature of the liquid or bubbles resulting from inclusion of air in the liquid flows through the fluid passage  3 . Bubbles  51  are liable to accumulate in an upper part of the fluid passage  3  of the structure when the gas-liquid two-phase fluid flows through the fluid passage  3 .  
      Bubbles accumulated in the fluid passage  3  tend to flow into an external tube connected to the connecting tube  5  especially when the connecting tube  5  is connected to an upper part of the connector flange  2  as shown in  FIG. 5 . Those bubbles grow or disappear while the gas-liquid two-phase fluid flows through the tube, causing local pressure change in the gas-liquid two-phase fluid. Such local pressure change generates vibratory force that causes the tube to vibrate. Vibration of the tube generates noise and, when the worst comes to the worst, breaks the tube.  
      Suppose that the tube is included in a cooling system for cooling the engine and the body  1  of the fluid device is a heater core for heating the passenger compartment of an automobile. Then, the cooling water containing bubbles and flowing through the heater core and pipes connected to the heater core generates unpleasant noise and the passenger compartment echoes with the unpleasant noise.  
      Since the tube  5  is connected to a lower part of the connector flange  2  shown in  FIG. 6 , bubbles accumulated in the fluid passage  3  are unable to flow easily into an external tube. Thus, the connector flange  2  has some effect of separating the gas bubbles from the liquid. However, since the boss  4  is extended obliquely upward to avoid interference between the boss  4  and the device  50 , a complicated, expensive casting mold is necessary to form the connector flange  2  by casting or a complicated, expensive forging die is necessary to form the connector flange  2  by forging. Since the axis of the connecting pipe  5  is inclined at an angle to the joining surface  7   a,  troublesome machining work is needed. Consequently, the connector flange  2  needs a high manufacturing cost.  
     SUMMARY OF THE INVENTION  
      Accordingly, it is an object of the present invention so solve the foregoing problems and to provide a flange structure capable of making a connecting tube connected thereto difficult to interfere with devices arranged thereabout, having an improved gas separating function and capable of being manufactured at a greatly reduced manufacturing cost.  
      A flange structure in a first aspect of the present invention includes: a main part having a flange, internally provided with a fluid passage and serving also as a body of a fluid device; a plate member attached to a joining surface of the flange of the main part so as to hold a gasket on the joining surface; and a connecting tube inserted through the plate member into the fluid passage and fixed to the plate member so as to extend obliquely upward toward the outside of the plate member.  
      In the flange structure according to the present invention, the connecting tube is inserted through an oblique opening formed in the plate member into the main part and is brazed to the plate member.  
      In the flange structure according to the present invention, the connecting tube has a slanting inner end inclined to the axis thereof and is fixed to the plate member with the slanting end facing the bottom of the main part.  
      Preferably, in the flange structure according to the present invention, the oblique opening is formed in a central part of the plate member.  
      Preferably, in the flange structure according to the present invention, the plate member has a uniform thickness.  
      Preferably, in the flange structure according to the present invention, a suction opening is formed in the inner end of the connecting tube extending in the fluid passage. The flange of the main part is provided with bosses provided with internally threaded holes in which bolts for fastening the plate member to the flange are screwed in, and the suction opening is situated near the bosses.  
      Preferably, in the flange structure according to the present invention, the connecting tube has an outer part projecting outside from the plate member, and a resin tube is connected to the outer part of the connecting tube.  
      Preferably, in the flange structure according to the present invention, the outer end of the connecting tube is pressed into the resin tube.  
      Preferably, in the flange structure according to the present invention, a fluid flows in a horizontal direction in the vicinity of the flange in the fluid passage.  
      Preferably, in the flange structure according to the present invention, a joining surface of the flange and a joining surface of the plate member are vertical.  
      Preferably, in the flange structure according to the present invention, the fluid device is a device for circulating a cooling medium used by an engine cooling system for cooling an automotive engine or a device for circulating a lubricating oil used by a lubricating system for an automobile. The fluid device is a heater core for using a cooling medium used by an engine cooling system for cooling an automotive engine for heating.  
      Preferably, in the flange structure according to the present invention, the fluid device is a device for circulating a cooling medium used by an engine cooling system for an industrial machine.  
      In the flange structure according to the present invention, a gas-liquid two-phase fluid flows through the fluid passage.  
      The connecting tube of the flange structure has difficulty in interfering with devices arrange thereabout, the flange structure is capable of separating a gas from a liquid and can be manufactured at a greatly reduced manufacturing cost. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above and other objects, features and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, in which:  
       FIG. 1  is sectional view of a flange structure in a first embodiment according to the present invention;  
       FIG. 2  is a front elevation of the flange structure shown in  FIG. 1 ;  
       FIG. 3  is a sectional view of a flange structure in a second embodiment according to the present invention;  
       FIGS. 4A, 4B  and  4 C are sectional views of assistance in explaining the operation and effect of the flange structure in the second embodiment in comparison with those of the flange structure in the first embodiment;  
       FIG. 5  is a sectional view of a conventional flange structure; and  
       FIG. 6  is a sectional view of another conventional flange structure. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     First Embodiment  
       FIG. 1  shows a flange structure in a first embodiment according to the present invention combined with a main part  10  of a heater core, namely, a fluid device, for heating using cooling water for cooling an automotive engine.  FIG. 2  is a front elevation of the flange structure shown in  FIG. 1 . The main part  10  of the heater core has a fluid passage  12  through which the cooling water flows. A flange  14  having a joining surface is formed at a free end of the main part  10 . This flange structure includes a plate member  16 . The plate member  16  is a flat member and has a uniform thickness, different from the conventional connector flange  2  shown in  FIG. 5  provided with the boss  4 . The plate member  16  is a metal plate formed in a shape corresponding to that of the flange  14  of the main part  10 . A gasket  17  is held between the joining surface of the flange  14  and the plate member  16 . The plate member  16  is fastened to the flange  14  with four bolts  18  as shown in  FIG. 2 .  
      A connecting tube  20  of a metal is attached to the plate member  16  by brazing. A resin tube  23  included in a cooling water circulating system is connected to the connecting tube  20 . The plate member  16  is provided in a substantially central part thereof with an oblique through hole  22 . The connecting tube  20  is inserted through the oblique through hole  22  into the main part  10  and is fixed by brazing to the plate member  20  so as to extend obliquely upward toward the outside. The inner end, namely, the suction end, of the connecting tube  20  is situated near bosses  14   a  protruding from the inner surface of the flange  14 . Internal threads are formed in the bosses  14   a,  respectively. The bolts  18  are screwed in the internally threaded holes of the bosses  14 , respectively. An outer part of the connecting tube  20  extending outside the main part  10  is pressed into the tube  23  included in the cooling water circulating system.  
      Referring to  FIG. 1 , bubbles are formed in the cooling water due to increase in the temperature of the cooling water heated by heat generated by the engine and resulting from inclusion of external gas, such as air, in the cooling water as the cooling water is circulated continuously. Consequently, a gas-liquid two-phase fluid flows in the fluid passage  12 . Then, bubbles  51  are accumulated in an upper space of the fluid passage  12  in the main part  10  of the heater core. Since the bubbles  51  tend to rise in the cooling water, a lower part of the fluid passage  12  has a lower bubble density.  
      In the conventional connector flange  2  shown in  FIG. 5 , the boss  4  is formed in an upper part of the connector flange  2  and the connecting tube  5  is disposed at an elevated level. Therefore, bubbles  51  accumulated in the fluid passage  12  are easily sucked into the connecting tube  20 . In the flange structure in the first embodiment, the connecting tube  20  is fixed to the plate member  16  so as to extend obliquely upward toward the outside so that the inner end of the connecting tube  20  is at a lower position in the fluid passage  12 . Therefore, the bubbles  51  accumulated in the fluid passage  12  can hardly be sucked into the connecting tube  20 .  
      Since the connecting tube  20  is extended obliquely upward toward the outside, the connecting tube  20  will not interfere with a device  50  disposed near the main part  10 . Thus the flange structure in the first embodiment has a function to prevent interference between the connecting tube  20  and the device  50  and a function to separate the bubbles  51  from the cooling water that flows into the connecting tube  20 .  
      Since the flange structure employs the plate member  16  that can be easily made by a simple blanking process instead of the connector flange formed by a casting or forging process, the flange structure can be manufactured at a very low manufacturing cost.  
      Since the oblique opening  22  is formed in the central part of the plate member  16 , the connecting tube  20  can be stably brazed to the plate member  20 . Since the plate member  16  has a uniform thickness, the plate member  16  can be formed easily.  
     Second Embodiment  
      A flange structure in a second embodiment according to the present invention will be described with reference to  FIG. 3 . The flange structure in the second embodiment is similar the flange structure in the first embodiment and hence parts of the second embodiment like or corresponding to those of the first embodiment are denoted by the same reference characters and the description thereof will be omitted.  
      The flange structure in the second embodiment differs from the flange structure in the first embodiment only in the shape of the inner end of a connecting tube  30  included therein.  
      Referring to  FIG. 3 , the connecting tube  30  has a slanting inner end  30   a  contained in a plane inclined to the axis of the connecting tube  30 . The slanting inner end  30   a  improves a function to separate gas from liquid. The connecting tube  30  is inserted through an oblique opening  22  formed in a plate member  16  into a main part  10 . The connecting tube  30  is fixed by brazing to the plate member  16  such that the slanting inner end  30   a  faces the bottom of the main part  10 .  
      The function and effect of the flange structure in the second embodiment will be described in comparison with those of the flange structure in the first embodiment with reference to  FIGS. 4A, 4B  and  4 C.  FIGS. 4A and 4C  show the connecting tube  20  of the first embodiment and  FIG. 4B  shows the connecting tube  30  of the second embodiment.  
      When the connecting tube  20  is extended deep into the main part  10 , it is possible that the inner end of the connecting tube  20  extends over the boss  14   a  and interferes with the boss  14   a  if the boss  14   a  is so formed as to protrude into the extension of the connecting tube  20 . Interference between the connecting tube  20  and the boss  14  can be avoided by situating the inner end of the connecting tube at an elevated level as shown in  FIG. 4A . However, the bubbles  51  are able to flow into the connecting pipe  20  more easily when the inner end of the connecting tube  20  is situated at an elevated level as shown in  FIG. 4A  than when the inner end of the connecting tube  20  is situated at a low level as shown in  FIG. 4C .  
      Since the slanting inner end of the connecting tube  30  of the second embodiment faces the bottom of the main part  10 , the connecting tube  30  will not interfere with the boss  14   a.  Since the slanting inner end of the connecting tube  30  opens into the fluid passage  12  at a low level as compared with the inner end of the connecting tube  20 , contained in a plane perpendicular to the axis of the connecting tube  20  as shown in  FIG. 4B . Consequently, the cooling water that flows into the connecting tube  30  has a lower bubble density. Thus the flange structure in the second embodiment has an improved function to separate gas from liquid.  
      Although the invention has been described in its preferred embodiments with a certain degree of particularity, obviously many changes and variations age possible therein. It is therefore to be understood that that the present invention may be practiced otherwise than as specifically described herein without departing from the scope and spirit thereof.