Patent Publication Number: US-2017356401-A1

Title: Intake manifold

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a resin-made intake manifold installed to introduce outside air into an internal combustion engine. 
     Description of the Related Art 
     Conventionally an intake manifold is known which filters air taken in by an internal combustion engine from outside, using an air cleaner and then distributes and supplies the air to cylinders of an internal combustion engine (see Patent Document 1: Japanese Patent Laid-Open No. 2013-160177). 
     The intake manifold described in Patent Document 1 distributes and supplies the air filtered by the air cleaner to the cylinders of the internal combustion engine through a chamber. 
     The intake manifold described in Patent Document 1 is provided with air supply ports in a lengthwise direction of the chamber to supply air to the respective cylinders of the internal combustion engine. Because an air inlet is provided at one end of the chamber, the closer the air supply port to the air inlet, the more readily air is drawn in. This produces differences in intake air quantity among the cylinders. 
     Also, to deal with the above-mentioned fact that there are differences among quantities of air drawn into different cylinders, an intake manifold is known which provides an air inlet in a center of a chamber and arranges cylinders evenly on opposite sides of the air inlet by giving consideration to distribution of air quantities drawn into the cylinders (see Patent Document 2: Japanese Patent Laid-Open No. 2005-48735). 
     In configurations of the conventional intake manifolds, an intake port needs to be placed on a lateral side of the chamber due to a layout problem, making it difficult to provide the air inlet in the center of the chamber as with Patent Document 2 by providing a connecting passage adapted to connect the intake port and the chamber in the center of the chamber without changing shape and size greatly. Also, the conventional intake manifolds are constructed by heat-welding plural members formed by resin molding, but with resin molding, the larger a product thickness, the more likely shrinkage is to occur. Thus, to prevent the shrinkage, a recess is formed by intentionally reducing thickness in a relatively thick portion. This produces a dead space around the recess. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the above problem and has an object to provide an intake manifold which can improve distribution of an intake fluid among cylinders of an internal combustion engine without major changes. 
     To solve the above problem, the present invention adopts the following configuration. Note that although reference numerals used in drawings are shown in parentheses to facilitate understanding of the present invention, the present invention is not limited by this. 
     The above and other objects can be achieved according to the present invention by providing an intake manifold ( 1 ) made of resin and including: an intake port ( 21 ) formed by welding together a base member ( 2 ), a port member ( 6 ) having a cavity portion ( 50 ), and a port cover member ( 7 ) and adapted to take in outside air; a chamber ( 10 ) connected with the intake port through a connecting passage ( 25 ) formed by including the cavity portion; and a plurality of discharge ports ( 27 ) connected with one another through a branch passage ( 35 ) branching from the chamber, wherein the connecting passage or the branch passage is formed by including the cavity portion, and a shielding member ( 60 ) adapted to shield the cavity portion and function as a wall surface of the connecting passage is provided in the connecting passage or the branch passage. 
     Also, in the intake manifold according to the present invention, the cavity portion is formed in a portion where the chamber and the connecting passage are connected; the shielding member is formed in a curved shape, being expanded in diameter toward an open end; and a surface of the shielding member is formed smoothly. 
     Also, in the intake manifold according to the present invention, the connecting passage and the branch passage are formed on different planes of the port member; and the cavity portion is formed on one face of the port member, that is, on that face of the port member on which the connecting passage is formed. 
     Also, in the intake manifold according to the present invention, the connecting passage and the branch passage are formed on different planes of the port member; and the cavity portion is formed on another face of the port member, that is, on that face of the port member on which the branch passage is formed. 
     Also, in the intake manifold according to the present invention, the shielding member is provided by being sandwiched between the port member and the base member or between the port member and the port cover member. 
     Also, in the intake manifold according to the present invention, the shielding member is integrated when the port member is welded in contact with both the base member and the shielding member; and when the port member and the base member are placed in contact during welding, a gap is formed between the port member and the shielding member. 
     Also, in the intake manifold according to the present invention, a positioning portion ( 70 ) used to position the shielding member is formed on the base member and part of the shielding member is fitted in the positioning portion. 
     Whereas in an intake manifold, a portion having a cavity portion  50  conventionally cannot be used effectively on reasons of injection molding, by providing the connecting passage  25  in the portion having the cavity portion  50  and shielding the cavity portion  50  with the shielding member  60 , the intake manifold according to the present invention allows an intake fluid to be introduced from a center of the chamber  10  and thereby improves distribution of the intake fluid among cylinders of an internal combustion engine. 
     Also, using the configuration of the conventional intake manifold, since the connecting passage  25  is provided in a dead space, an intake manifold can be produced without major changes or capsizing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a schematic diagram showing an appearance of an intake manifold according to a first embodiment; 
         FIG. 2  is an exploded schematic diagram for explaining a structure of the intake manifold according to the first embodiment; 
         FIG. 3  is a schematic diagram showing an example of a connecting passage; 
         FIG. 4  is a bottom view of a port member; 
         FIG. 5  is a plan view of the port member; 
         FIG. 6  is a schematic diagram showing an example of a cavity portion; 
         FIG. 7  is a schematic diagram showing an example of how a shielding member is mounted in the cavity portion; 
         FIG. 8  is a schematic diagram showing an appearance example of the shielding member; 
         FIG. 9A  shows an assembled condition of the shielding member, and is a schematic diagram showing a section in a front-rear direction; 
         FIG. 9B  shows an assembled condition of the shielding member, and is a schematic diagram showing a section in a left-right direction; 
         FIG. 10A  shows an assembled condition of the shielding member, and is an enlarged view of part X in  FIG. 9 ; 
         FIG. 10B  shows an assembled condition of the shielding member, and is a schematic diagram showing arrangement of various members before welding by enlarging part Y in  FIG. 10A ; and 
         FIG. 11  is a schematic diagram showing an assembled condition of a shielding member of an intake manifold according to a second embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will be described hereunder with reference to the accompanying drawings. Note that the embodiments described below are not intended to limit the claimed invention and that a combination of all the features described in the embodiments is not necessarily essential for the solution of the present invention. 
     First, an intake manifold according to a first embodiment will be described with reference to  FIGS. 1 to 10 . 
       FIG. 1  is a schematic diagram showing an appearance of the intake manifold according to the present embodiment;  FIG. 2  is an exploded schematic diagram for explaining a structure of the intake manifold according to the present embodiment;  FIG. 3  is a schematic diagram showing an example of a connecting passage;  FIG. 4  is a bottom view of a port member;  FIG. 5  is a plan view of the port member;  FIG. 6  is a schematic diagram showing an example of a cavity portion;  FIG. 7  is a schematic diagram showing an example of how a shielding member is mounted in the cavity portion;  FIG. 8  is a schematic diagram showing an appearance example of the shielding member;  FIG. 9A  shows an assembled condition of the shielding member, and is a schematic diagram showing a section in a front-rear direction; and  FIG. 9B  shows an assembled condition of the shielding member, and is a schematic diagram showing a section in a left-right direction; and  FIG. 10A  shows an assembled condition of the shielding member, and is an enlarged view of part X in  FIG. 9 ; and  FIG. 10B  shows an assembled condition of the shielding member, and is a schematic diagram showing arrangement of various members before welding by enlarging part Y in  FIG. 10A . 
     As shown in  FIGS. 1 and 2 , the intake manifold  1  includes, for example, a base member  2  and a cover member  5  provided covering upper part of the base member  2 . The cover member  5  is formed by being divided into a port member  6  and a port cover member  7  placed on the port member  6 . 
     The port member  6  is placed between the port cover member  7  placed on an upper side and the base member  2  placed on a bottom side and is assembled by welding the base member  2 , for example, after the port member  6  and the port cover member are welded together. That is, the intake manifold  1  according to the present embodiment is formed by being divided, for example, into three members  2 ,  6 , and  7  and is integrated when the members  2 ,  6 , and  7  are assembled and welded together. 
     The base member  2 , port member  6 , and port cover member  7  are formed of thermoplastic synthetic resin such as polyamide group resin or polypropylene group resin. These members  2 ,  6  and  7  are welded together by generating frictional heat through application of vibration to weld surfaces among these members  2 ,  6  and  7  and applying pressure thereto using a pressure jig or slide jig. In addition, in the intake manifold  1  according to the present embodiment, welded portions of the base member  2 , port member  6 , and port cover member  7  are formed by being superposed in a vertical direction on the side of discharge ports  27  in branch passages  35  described later. 
     As shown in  FIGS. 1 and 3 , the chamber  10  is formed inside the intake manifold  1 . As shown in  FIG. 3 , the chamber  10  is connected via the connecting passage  25  with an intake port  21  through which an intake fluid is introduced, and the intake fluid introduced through the intake port  21  is introduced into the chamber  10  via the connecting passage  25 . Also, as shown in  FIGS. 1 and 2 , the chamber  10  is connected via the branch passages  35  with the plural discharge ports  27  connected to the respective cylinders of the internal combustion engine, the intake fluid introduced into the chamber  10  is distributed to the branch passages  35 , and the distributed intake fluid is discharged to the discharge ports  27 . 
     Note that the intake manifold  1  according to the present embodiment described herein is used for a so-called in-line four-cylinder internal combustion engine, in which four cylinders are arranged in line, and thus as many branch passages  35  as there are cylinders, i.e., four branch passages  35  are formed. 
     As shown in  FIGS. 1 to 3 , the intake port  21  is formed by opening to a flange  23  formed protruding toward a lateral end portion of the chamber  10 . Note that the intake manifold  1  is attached to a throttle body (not shown) via the flange  23 , where the throttle body is adapted to control the intake fluid. 
     As shown in  FIG. 3 , the connecting passage  25  includes a linear portion  25   a  extending rectilinearly into the intake manifold  1  and a bent portion  25   b  formed by bending to connect to central part of the chamber  10 . 
     Also, as shown in  FIGS. 1 and 2 , the branch passages  35  are arranged side by side in a line by bending around an upper circumference of the intake manifold  1  and the discharge ports  27  are provided on a downstream side of the branch passages  35 . 
     As shown in  FIGS. 2 and 3 , the intake port  21  and the discharge ports  27  are formed in the base member  2 , on which an inner wall  2   a  and an inner wall  2   b  are formed, where the inner wall  2   a  makes up lower part of the connecting passage  25  along which the intake fluid introduced through the intake port  21  is introduced into the chamber  10  while the inner wall  2   b  makes up lower part of the chamber  10 . 
     On the other hand, as shown in  FIG. 4 , an inner wall  6   a  making up upper part of the connecting passage  25  and an inner wall  6   b  making up upper part of the chamber  10  are formed on an undersurface of the port member  6 . When the base member  2  and the port member  6  are integrated by welding, the connecting passage  25  cylindrical in shape and the chamber  10  with a predetermined space are formed. 
     Also, as shown in  FIGS. 2 and 5 , on a top surface of the port member  6  and an undersurface of the port cover member  7 , grooves  35   a  and  35   b  arranged side by side in a line and forming part of the branch passages  35  are formed curving upward. Consequently, the branch passages  35  cylindrical in shape are formed when the port member  6  and the port cover member  7  are integrated by welding. 
     Also, as shown in  FIGS. 4 and 5 , an opening  35   c  connecting the branch passages  35  and the chamber  10  with each other and an opening  35   d  connecting the branch passages  35  and the discharge ports  27  with each other are formed in the port member  6 . The intake fluid introduced into the chamber  10  is distributed to the branch passages  35  through the opening  35   c  and the intake fluid distributed to the branch passages  35  is discharged to the discharge ports  27  through the opening  35   d.    
     In this way, in the intake manifold  1 , the connecting passage  25  and the branch passages  35  are formed on different planes of the port member  6 , intersecting each other at right angles, the intake port  21  adapted to take in outside air is connected with the chamber  10  through the connecting passage  25 , and the chamber  10  is connected with the plural discharge ports  27  through the branch passages  35 . Thus, the air introduced through the intake port  21  is introduced into the chamber  10  through the connecting passage  25 , distributed to the branch passages  35  by the chamber  10 , discharged to the discharge ports  27 , and distributed to the cylinders of the internal combustion engine. Also, as shown in  FIG. 3 , the connecting passage  25  is connected to a substantially central part of the chamber  10 , and the branch passages  35  branching from the chamber  10  are placed almost evenly on opposite sides of an exit from the connecting passage  25  as shown in  FIG. 5 . This makes it possible to easily improve distribution of intake air to the branch passages  35 . 
     Also, as shown in  FIGS. 4 and 6 , the cavity portion  50  is formed on the undersurface of the port member  6  to prevent shrinkage during injection molding. The cavity portion  50  is formed being exposed to part of the connecting passage  25  and is provided with an opening  51  on a flow path of the intake fluid flowing in from the intake port  21 . Therefore, part of the intake fluid flows into the cavity portion  50 , obstructing flow of the intake fluid in the connecting passage  25 . 
     According to the present embodiment, the cavity portion  50  is formed where the bent portion  25   b  of the connecting passage  25  is connected to the chamber  10 , ribs  54  for reinforcement are provided in the cavity portion  50 , and inner part of the cavity portion  50  is divided into plural rooms. 
     Also, the intake manifold  1  according to the present embodiment is provided with the shielding member  60  adapted to shield the opening  51  of the cavity portion  50  as shown in  FIG. 7 . As shown in  FIGS. 7 and 8 , the shielding member  60  includes a base body  61  adapted to close the opening  51 , and mounts  63  erected on opposite end portions of the base body  61  and used to mount the base body  61 , shielding the opening  51 . 
     As shown in  FIG. 7 , the surface of the shielding member  60  is formed smoothly, and functions as a wall surface of the connecting passage  25 . Also, in the shielding member  60 , central part of the base body  61  protrudes into the connecting passage  25  and central part of each mount  63  is formed into a curved shape protruding inward and expanded in diameter toward an open end, and consequently flow of the intake fluid passing through the connecting passage  25  is regulated and the intake fluid discharged into the chamber  10  is regulated so as to flow to a periphery of the chamber  10  without stagnating in the central part of the chamber  10 . 
     Note that a connection port between the connecting passage  25  and the chamber  10  is formed into a so-called funnel shape, being expanded in diameter toward an open end to allow the intake fluid in the connecting passage  25  to be smoothly introduced into the chamber  10 . 
     As shown in  FIG. 9 , the shielding member  60  is positioned on the base member  2  and mounted by being sandwiched between the port member  6  and the base member  2 . 
     As shown in  FIG. 10A , a recess  70  (positioning portion according to the present invention) for use to position the shielding member  60  is formed on the base member  2 . An outer peripheral edge of the shielding member  60  is positioned by being fitted into the recess  70  by press fitting or the like and displacement of the shielding member  60  during welding is prevented by the recess  70 . Note that the recess  70  may be formed by corresponding to either the entire outer peripheral edge or only part of the outer peripheral edge of the shielding member  60 . 
     Also, in manufacturing the intake manifold  1 , first the outer peripheral edge of the shielding member is positioned and mounted at the recess  70  of the base member  2  by means of press fitting or the like, and then as shown in  FIG. 10A , a weld surface  72  of the base member  2  and a weld surface  73  of the shielding member  60  are placed in contact with a weld surface  74  of the port member  6  and welded, thereby integrating the members  2 ,  6 , and  60 . 
     Also, by giving consideration to the fact that weld strength between the port member  6  and base member  2  needs to be set higher than weld strength between the shielding member  60  and port member  6 , as well as to manufacturing errors of the members  2 ,  6 , and  60 , shape of the shielding member  60  is designed appropriately such that a gap will be formed between the weld surface  74  of the port member  6  and the weld surface  73  of the shielding member  60  as shown in  FIG. 10B  during assembly of the port member  6  and base member  2  before welding. 
     Consequently, even if some manufacturing errors occur in the members  2 ,  6 , and  60 , the port member  6  and base member  2  can be set to be welded together before the port member  6  and shielding member  60 , making it easy to manage welding allowance. 
     In this way, whereas in an intake manifold  1 , a portion having a cavity portion  50  conventionally cannot be used effectively on reasons of injection molding, by providing the connecting passage  25  in the portion having the cavity portion and shielding the cavity portion  50  with the shielding member  60 , the intake manifold  1  according to the present invention allows an intake fluid to be introduced from a center of the chamber  10  and thereby improves distribution of the intake fluid among cylinders of an internal combustion engine. 
     Also, using the conventional intake manifold  1 , since the connecting passage  25  is provided in a dead space, the intake manifold  1  can be produced without major changes or upsizing. 
     Next, an intake manifold  1 A according to a second embodiment will be described with reference to  FIG. 11 . In  FIG. 11 , components in common with  FIG. 9  are denoted by the same reference numerals as the corresponding components in  FIG. 9 , and detailed description thereof will be omitted. 
     The present embodiment differs from the above embodiment in that a cavity portion  50 A is provided on the top surface of the port member  6  and that a shielding member  60 A is mounted at a different position on the cavity portion  50 A. 
     That is, in the intake manifold  1 A according to the present embodiment, an opening  51 A of the cavity portion  50 A is formed being exposed to part of the branch passages  35 . A shielding member  60 A adapted to shield the cavity portion  50 A and function as wall surfaces of the branch passages  35  is provided in the branch passages  35 . 
     Also, for example, of four grooves  35   a  arranged side by side in a line and forming part of the branch passages  35  formed on the top surface of the port member  6 , the cavity portion  50 A is formed in part of the two grooves  35   a  on an inner side, and the opening  51 A of the cavity portion  50 A is formed being exposed to part of the branch passages  35 . 
     The shielding member  60 A is attached to the opening  51 A. As shown in  FIGS. 11 , the shielding member  60 A is positioned on the base member  2  and mounted by being sandwiched between the port member  6  and the port cover member  7 . 
     In this way, by providing the branch passages  35  in the portion having the cavity portion  50 A and shielding the cavity portion  50 A with the shielding member  60 A, the intake manifold  1 A according to the present embodiment, can prevent the flow of the intake fluid in the branch passages  35  from being obstructed by the intake fluid which flows into the cavity portion  50 A by being distributed from the chamber  10  to the branch passages  35 , introduce the intake fluid from the center of the chamber  10 , and thereby improve distribution of the intake fluid among the cylinders of the internal combustion engine. 
     Also, using the conventional intake manifold  1 , since the connecting passage  25  is provided in the dead space, the intake manifold  1  which allows the intake fluid to be introduced from the center of the chamber  10  can be produced easily without major changes or upsizing. 
     In the intake manifold  1  according to the present embodiment described above, the cover member  5  is made up of the port member  6  and the port cover member  7  configured separately, but may be made up of a single member as with the base member  2 . Furthermore, the base member  2  may be made up of separate members as with the cover member  5 . 
     Also, the intake manifold  1  according to the present embodiment described above is an intake manifold applied to an in-line four-cylinder internal combustion engine, but the type of internal combustion engine is not limited to this. For example, six Branch passages may be formed to apply the intake manifold  1  to an in-line six-cylinder internal combustion engine. In this way, the shape and number of Branch passages may be increased or decreased as appropriate according to the type of internal combustion engine to which the intake manifold  1  is applied. It will be apparent from the description of the appended claims that any form resulting from such changes or improvements is also included in the technical scope of the present invention. 
     The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. 
     The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 
     The entire disclosure of Japanese Patent Application No. 2016-115577 filed on Jun. 9, 2016 including the specification, claims, drawings and summary is incorporated herein by reference in its entirety. 
     REFERENCE SIGNS LIST 
     
         
           1 ,  1 A Intake manifold 
           2  Base member 
           6  Port member 
           6   a  inner wall 
           7  Port cover member 
           10  Chamber 
           21  Intake port 
           27  Discharge port 
           25  Connecting passage 
           35  Branch passage 
           35   a,    35   b  Groove 
           50 ,  50 A Cavity portion 
           60 ,  60 A Shielding member 
           61  Base body 
           63  Mount 
           72 ,  73 ,  74  Weld surface