JP3701770B2 - Intake device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake device for an internal combustion engine, and in particular, a common intake pipe connected to a throttle body and a plurality of branch intake pipes connecting the common intake pipe and a plurality of intake ports of a cylinder head are made of a synthetic resin. The present invention relates to an intake device for an internal combustion engine, which is formed in an intake manifold and a part of a housing of an air cleaner is formed integrally with the intake manifold.
[0002]
[Prior art]
Conventionally, such an intake device is already known, for example, from US Pat. No. 5,259,356.
[0003]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional one, the throttle valve is arranged in the intake pipe arranged at the center of the intake manifold, and it is difficult to support the relatively heavy throttle valve with the intake pipe made of synthetic resin. It is not preferable. The filter element of the air cleaner is formed in a ring shape, and the air introduction port is arranged so as to face a part of the outer periphery of the filter element. In some cases, the function of the filter element is deteriorated due to the partial fouling, and the engine cannot sufficiently exhibit its performance due to long-time operation. Furthermore, since the intake manifold is disposed close to the engine body, the temperature tends to increase, and if the intake air temperature rises as the intake manifold temperature rises, the performance of the internal combustion engine cannot be fully exhibited.
[0004]
The present invention has been made in view of such circumstances, and has ensured sufficient rigidity even though a part of the housing of the air cleaner is integrally formed with the intake manifold made of synthetic resin. It is possible to prevent the filter element from being partially contaminated as much as possible, and to make the time until the function declines relatively long.In addition, by suppressing the temperature rise of the intake manifold, the rise of the intake air temperature is suppressed and the performance of the internal combustion engine is improved. It is an object of the present invention to provide an intake device for an internal combustion engine that can be sufficiently exerted.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a common intake pipe connected to a throttle body and a plurality of branch intake pipes connecting between the common intake pipe and a plurality of intake ports of a cylinder head. In an intake device for an internal combustion engine, which is formed in a manifold and a part of a housing of an air cleaner is formed integrally with the intake manifold, a plurality of upstream branch pipes that constitute an upstream portion of each branch intake pipe And an upstream duct assembly made of a thermoplastic synthetic resin integrally including a common intake pipe that allows the respective upstream branch pipes to communicate with each other, and a plurality of downstream branch pipes constituting a downstream portion of each branch intake pipe And a downstream pipe assembly made of a thermoplastic synthetic resin that is integrally provided with a first pipe connected to the upstream end of the common intake pipe. A flange is integrally provided to be joined to the throttle body, and a second flange connected in common to the downstream end of each upstream branch pipe is integrally provided to be heated and joined to the downstream pipe assembly. 1st and 2nd side wall which continues to 1 and 2nd flange, 3rd side wall which connects between 1st and 2nd side wall in the end along the arrangement direction of each upstream side branch pipe, and the other end of 1st and 2nd side wall A housing main portion formed in a box shape having a rectangular cross section with a fourth side wall connecting between the bottom wall and the bottom wall connecting the lower part of the first to fourth side walls and the substantially central part in the vertical direction of each upstream branch pipe; A cover that is formed integrally with the upper part of the upstream pipe assembly in an arrangement that is biased toward one end along the arrangement direction of each upstream branch pipe, and that cooperates with the housing main part to constitute the housing of the air cleaner. , Unpurified chamber below the housing And a filter element that is partitioned into an upper purification chamber and is sandwiched between the main portion of the housing and attached to the upper portion of the main portion of the housing, and has a lower end that is lower than the upper end of the upstream branch pipe that is raised above the bottom wall. The third side wall is provided with an air introduction port that is disposed at the edge and communicates with the unpurified chamber.
[0006]
According to such a configuration, the main housing portion provided integrally with the upstream pipe assembly in the intake manifold is connected to the first flange provided integrally with the upstream pipe assembly so as to be joined to the throttle body. The housing having a side wall and a second side wall connected to a second flange integrally provided in the upstream side pipe assembly to be heated and bonded to the downstream side pipe assembly, Since the main portion constitutes a part of the housing of the air cleaner, the first and second side walls, that is, the air cleaner, are obtained by joining the throttle body to the first flange and heating and joining the downstream pipe assembly to the second flange. The rigidity of the housing can be increased, and the strength of the entire intake device can be improved. In addition, the bottom wall of the main housing part connects between the central portions in the vertical direction of each upstream branch pipe, and the bottom surface of the main housing part is reinforced by each upstream branch pipe. The bottom surface rigidity can be increased. Further, the housing main part is arranged to be biased toward one end side along the arrangement direction of the respective upstream branch pipes, and the air inlet port is connected to the third side wall connecting the first and second side walls at one end side along the arrangement direction. Is provided, a relatively large space can be secured between the upstream side branch pipe close to the third side wall and the third side wall, which is higher than the upper end of the upstream side branch pipe raised from the bottom wall of the housing main part. Since the lower edge of the air inlet is arranged at a low position, a part of the air introduced from the air inlet into the unpurified chamber can collide with the upper part of the upstream branch pipe and be dispersed in the wide space. Since the dispersed air circulates through the filter element that covers the upper part of the unpurified chamber, the almost uniformly dispersed air circulates through the filter element, thereby preventing partial contamination of the filter element as much as possible and reducing the function. All the way It can be made relatively long time. Furthermore, since the upper part of each upstream branch pipe is arranged facing the housing in the air cleaner, each upstream branch pipe is cooled by the air flowing through the air cleaner, and the intake air due to the proximity to the engine body. An increase in the temperature of the manifold can be avoided as much as possible, an increase in the intake air temperature accompanying an increase in the temperature of the intake manifold can be prevented, and the performance of the internal combustion engine can be fully exerted. In addition, the intake sound radiated from the upper part of the upstream pipe assembly can be blocked by the air layer of the uncleaned chamber and the filter element in the air cleaner to suppress the diffusion of the radiated sound, and a part of the air cleaner and the intake manifold As a result of being integrated, assembly workability can be improved.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.
[0008]
1 to 11 show an embodiment of the present invention, FIG. 1 is a longitudinal side view of an engine body and an intake device, and FIG. 2 is a plan view of the intake device as viewed from the direction of arrow 2 in FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2, FIG. 4 is a plan view of the upstream pipe assembly, FIG. 5 is an exploded vertical cross-sectional view of the intake manifold, and FIG. 6 is an enlarged cross-sectional view taken along line 6-6 in FIG. FIG. 7 is a view showing the arrangement of the rod-shaped cores at the time of forming the upstream side pipe assembly, and FIG. FIG. 9 is a longitudinal sectional view taken along line 8-8 in FIG. 9, FIG. 9 is an enlarged sectional view taken along line 9-9 in FIG. 8, and FIG. 10 is an upstream pipe assembly and downstream pipe assembly. FIG. 11 is a cross-sectional view taken along line 11-11 of FIG.
[0009]
First, in FIGS. 1 to 3, the engine body E of an in-line multi-cylinder, for example, in-line 3-cylinder internal combustion engine, is mounted horizontally in a posture inclined forward at a front portion of a vehicle (not shown) and is in a forward inclined posture. In the space generated above the engine main body E, the intake devices 23 connected to the three intake ports 22 provided in the cylinder head 21 of the engine main body E are arranged.
[0010]
The intake device 23 includes an intake manifold 24 made of a thermoplastic synthetic resin, a throttle body 25 connected to the upstream end of the intake manifold 24, and a housing main portion integrally provided on the upper upstream side of the intake manifold 24. 79 is provided with an air cleaner 26 disposed on the upstream side of the intake manifold 24 with 79 as a part of the housing 78, and an air flow tube 27 connecting the air cleaner 26 and the throttle body 25.
[0011]
The intake manifold 24 includes a common intake pipe 30 connected to the throttle body 25 and a plurality of, for example, three first, second, and third branched intake pipes connecting the common intake pipe 30 and the intake ports 22 of the cylinder head 21. The branch intake pipes 31 to 33 are arranged in such a manner that the distance between the branch intake pipes 31 to 33 increases with increasing distance from the common intake pipe 30, and the branch intake pipes 31 to 33 are arranged. The upstream end side of each of the branched intake pipes 31 to 33 is curved so as to be connected to each intake port 22 of the engine body E in a forward leaning posture. Formed.
[0012]
4 to 6, the intake manifold 24 includes an upstream pipe assembly 34 made of a thermoplastic synthetic resin such as 6-nylon and a downstream pipe line made of a thermoplastic synthetic resin such as 6-nylon. The assembly 35 is formed by heating and joining (thermal welding).
[0013]
The upstream-side pipe assembly 34 includes first to third upstream-side branch pipes 31 ₁ , 32 ₁ , 33 ₁ that constitute upstream portions of the branch intake pipes 31 to 33 and extend in a straight line. the upstream branch pipe 31 _to 333 common intake pipe 30 which allowed communication with and extending in a straight line ₁ of the upstream end in common, the first flange 36 provided integrally with the upstream end of the common intake pipe 30, the upstream side And a second flange 37 provided in common and integrally with the downstream ends of the branch pipes 31 _{1 to} 33 ₁ .
[0014]
The second upstream branch pipe 32 ₁ is coaxially connected to the downstream end of the common intake pipe 30, and the first and third upstream branch pipes 31 ₁ , 33 ₁ increase as the distance from the common intake pipe 30 increases. It arrange | positions so that the space | interval between 2 upstream branch pipes 32 ₁ may become large gradually. In other words, the upstream branch pipes 31 _{1 to} 33 ₁ are arranged so as to be widened with an increase in the distance between them as they are separated from the common intake pipe 30.
[0015]
A flange 39 provided at the downstream end of the throttle body 25 including the throttle valve 38 is fastened to the first flange 36 by a bolt (not shown).
[0016]
In FIG. 7, the upstream side pipe assembly 34 is, for example, injection-molded by a resin mold, and the resin mold includes a plurality of molds (not shown) corresponding to the outer shape of the upstream side pipe assembly 34. ) And the rod-shaped cores 41, 42, 43, 44 mounted in the molds corresponding to the inner surfaces of the first to third upstream branch pipes 31 _{1 to} 33 _{1 and} the inner surface of the common intake pipe 30, respectively. With. Thus, after the molten synthetic resin filled between the molds and the rod-shaped cores 41 to 44 is cured, the rod-shaped cores 41 to 44 are pulled out from the molds, and the molds are separated from each other. By doing so, the formation of the upstream side pipe assembly 34 is completed.
[0017]
Each of the rod-shaped cores 41 to 44 is pulled out of the mold by their axial movement, and the inner surfaces of the second upstream branch pipe 32 ₁ and the common intake pipe 30 are coaxial with the rod-shaped cores 42 and 44. Are pulled out in directions away from each other, and the inner surfaces of the first and third upstream branch pipes 31 ₁ , 33 ₁ are rod-shaped cores 41, 43 extending in an angle with the rod-shaped core 44. formed respectively by the axial movement, the upstream branch pipe 31 _to 333 ₁ of the bifurcation from the common intake pipe 30, the rod-shaped core 41 to 43 is formed by contacting the rod-shaped core 44.
[0018]
The downstream-side pipe assembly 35 includes first to third downstream-side branch pipes 31 ₂ , 32 ₂ , 33 ₂ that form a downstream part of each of the branch intake pipes 31 to 33 and bend, respectively, downstream branch pipe 31 _2, 32 _2, 33 and a third flange 45 provided integrally and in common _to the upstream end, integral and in common to the downstream branch pipe 31 _2, 32 _2, 33 ₂ of the downstream end And a fourth flange 46.
[0019]
The fourth flange 46 is fastened to the side surface of the cylinder head 21 in the engine main body E, and is arranged at the upper portion of the downstream end of the downstream side pipe assembly 35 toward the intake ports 22 of the cylinder head 21. A mounting hole 48 for mounting fuel injection valves 47 for injecting fuel is provided, and a fuel distribution pipe 49 connected in common to the rear end of each fuel injection valve 47 is fastened by a pair of bolts 50. A pair of support bosses 51, 51 are integrally provided.
[0020]
8 and 9 together, the downstream side pipe assembly 35 is, for example, injection-molded by a resin mold, and the resin mold corresponds to the outer shape of the downstream side pipe assembly 35. A plurality of molds (not shown), and curved cores 54, 55, 56 mounted in the respective molds corresponding to the inner surfaces of the first to third downstream branch pipes 31 _{2 to} 33 ₂ , respectively. Is provided. Thus, after the molten synthetic resin filled between the molds and the bending cores 54 to 56 is cured, the bending cores 54 to 56 are pulled out from the molds, and the molds are separated from each other. By doing so, the molding of the downstream side pipe assembly 35 is completed.
[0021]
Curved core 55 corresponding to the second downstream branch pipe 32 _1, in which curved and is formed along the imaginary circle 58 in the plane including the second downstream branch pipe 32 ₁ of the center line curved The bending cores 54 and 56 corresponding to the first and third downstream branch pipes 31 ₂ and 33 ₂ are the virtual circles in a plane parallel to the plane including the center line of the second downstream branch pipe 32 _1. Each of them is curved so as to follow a virtual circle (not shown) having a radius corresponding to 58. Thus, each of the bending cores 54 to 56 is pulled out from the mold toward the upstream end side of each of the downstream branch pipes 31 _{1 to} 33 ₂ so as to rotate around the center C of the virtual circle 58. A molding method for forming the inner surface of the synthetic resin pipe curved by the rotation and drawing of the bending core is already well known, for example, in Japanese Patent Laid-Open No. 6-213087. Moreover, the bending cores 54 to 56 are connected to the connecting portion 57 in common and integrally, and the bending cores 54 to 56 are parallel to each other by a driving means (not shown) connected to the connecting portion 57. They are driven to rotate at the same time along the plane.
[0022]
The second flange 37 of the upstream pipe assembly 34 and the third flange 45 of the downstream pipe assembly 35 are joined to each other by heating and joining. In this heating and joining, as shown in FIG. 10, the joining surface 59 of the second flange 37 to the third flange 45 and the joining surface 60 of the third flange 45 to the second flange 37 include a hot plate 61. Each of the upstream branch pipes 31 is heated by being pressed against both surfaces of the first and second heat pipes 61. After the heating, the hot plate 61 is removed from between the joint surfaces 59 and 60, and the joint surfaces 59 and 60 are brought into close contact with each other. _to 333 ₁ of the arrangement for Ren'nara the upstream end of the downstream branch pipe 31 _{2-33 2} respectively to the downstream end, upstream and downstream conduit assemblies 34 and 35 to be heated to each other, bonding become.
[0023]
The bonding surface 59 of the second flange 37 on the upstream side conduit assembly 34 includes a first fitting recess 62, 63, 64 is provided which surrounds the downstream end opening of the upstream-side branch pipe 31 _to 333 _1, respectively The joint surface 60 of the third flange 45 in the downstream pipe assembly 34 is provided with second fitting recesses 65, 66, and 67 surrounding the upstream end openings of the downstream branch pipes 31 _{2 to} 33 ₂ , respectively. It is done.
[0024]
Between the first second fitting recess 65 of the upstream-side branch pipe 31 ₁ of the first mating recess 62 of the downstream end first downstream the upstream end of the branch pipe 31 ₂ nest 68 is sandwiched, the second A nest 69 is sandwiched between the first fitting recess 63 at the downstream end of the upstream branch pipe 32 ₁ and the second fitting recess 66 at the upstream end of the second downstream branch pipe 32 ₂ , and the third upstream side A nest 70 is sandwiched between the first fitting recess 67 at the downstream end of the branch pipe 33 ₁ and the second fitting recess 67 at the upstream end of the third downstream branch pipe 33 ₂ .
[0025]
These inserts 68 to 70 are formed of the same synthetic resin as the upstream and downstream pipe assemblies 34 and 35, for example, 6-nylon, and the upstream and downstream pipe assemblies 34 and 35. It arrange | positions so that it may be pinched | interposed between both the assemblies 34 and 35, without being heated at the time of a heating and joining.
[0026]
The nest 68, communicating hole 71 which allowed to communicating the first upstream-side branch pipe 31 ₁ of the downstream end and the first downstream the upstream end of the branch pipe 31 ₂ is provided in the nesting 69, second upstream branch pipe 32 ₁ is provided with a communication hole 72 that allows the downstream end of 32 _{1 and} the upstream end of second downstream branch pipe 32 ₂ to communicate with each other. The insert 70 has a downstream end of third upstream branch pipe 33 ₁ and a third downstream branch pipe. A communication hole 73 for communicating the upstream end of 33 ₂ is provided.
[0027]
By the way, although the first to third branch intake pipes 31 to 33 are arranged so as to widen away from each other as the distance from the common intake pipe 30 increases, Of the downstream branch pipes 31 _{2 to} 33 ₂ , the curved cores 54 to 56 forming the inner surfaces of the side branch pipes 31 _{2 to} 33 ₂ are rotated along planes parallel to each other. curved core 54, 56 to form the first and third downstream branch pipe 32 _2, 33 ₂ of the inner surface, the first and third upstream corresponding to the first and third downstream branch pipe 32 _2, 33 ₂ It will rotate in a plane that intersects the axis of the side branch 31 _to 333 _1. Therefore, a step portion is necessarily formed between the inner surfaces of the upstream end portions of the first and third downstream branch pipes 31 ₂ and 33 ₂ and the inner surface of the downstream ends of the first and third upstream branch pipes 31 ₁ and 33 _1. Will occur. Therefore, the inner surfaces of the upstream end portions of the first and third downstream branch pipes 31 ₂ and 33 ₂ are located on the outer side of the extension lines of the inner surfaces of the first and third upstream branch pipes 31 ₁ and 33 _1. The housing recesses 74 and 75 corresponding to the stepped portions are formed, the insert 68 interposed between the first upstream and downstream branch pipes 31 ₁ and 31 ₂ , and the third upstream and downstream branch pipes 33 ₁ and 33. _The insert 70 interposed between the _two is housed in the housing recesses 74 and 75 and the inner surfaces of the first and third upstream branch pipes 31 ₁ and 33 ₁ are connected to the first and third downstream branch pipes 31 ₂ and 31 ₂ . Extension portions 68a and 70a that are smoothly connected to the inner surface of 33 ₂ are integrally provided.
[0028]
A housing 78 of the air cleaner 26 is formed in a box shape having an open top and is integrally provided on the upper part of the upstream pipe assembly 34, and a synthetic resin attached to the upper part of the housing main part 79. And a cover 80 made of metal.
[0029]
Referring also to FIG. 11, the housing main portion 79 is connected to the throttle body 25 so as to be connected to the first flange 36 provided integrally with the upstream side pipe assembly 34 and extends upward. 81, a second side wall 82 extending upwardly connected to a second flange 37 provided integrally with the upstream side pipe assembly 34 to be heated and joined to the downstream side pipe assembly 35, and a downstream pipe The first and second side walls 81 and 82 are substantially parallel to the second upstream branch pipe 32 _{1 at} one end (the right end in FIG. 11) along the arrangement direction of the upstream branch pipes 31 _{1 to} 33 _{1 in} the road assembly 34. A third side wall 83 connected to each other, a fourth side wall 84 connecting the other ends of the first and second side walls 81 and 82 to face the third side wall 83, a lower portion of the first to fourth side walls 81 to 84, and each upstream branch pipe 31 _to 333 ₁ in the vertical direction substantially central In a bottom wall 85 for connecting the, it is formed in a box-shaped cross-section rectangle having an open top. Although not shown, the bottom wall 85 may be provided with a large number of ribs.
[0030]
In addition, the housing main portion 79 is disposed upstream of the upstream branch pipes 31 _{1 to} 33 ₁ in an arrangement that is biased toward one end along the arrangement direction, that is, the third side wall 83 is separated from the third upstream branch pipe 33 _1. The fourth side wall 84 is formed integrally with the upper part of the side pipe assembly 34, and the fourth side wall 84 has an angle with the first upstream branch pipe 31 ₁ extending in a direction that forms an angle with the second upstream branch pipe 32 _1. And is formed so as to be integrally connected to an intermediate portion of the first upstream branch pipe 31 ₁ .
[0031]
The peripheral edge of the filter element 86 is sandwiched between the housing main portion 79 and the cover 80 mounted on the upper portion of the housing main portion 79, and the inside of the housing 78 is below the unpurified inside by the filter element 86. It is divided into a chamber 87 and an upper purification chamber 88.
[0032]
The third side wall 83 is provided with an air introduction port 89 for introducing air into the unpurified chamber 87, and an air introduction pipe 90 extending outwardly with the inner end connected to the air introduction port 89. Provided integrally. Incidentally, the bottom wall 85 of the housing main portion 79 is for connecting the vertically substantially central portion of the upstream-side branch pipe 31 _to 333 _1, the upstream-side branch pipe 31 _to 333 ₁ of the upper bottom wall It is raised above 85. The air inlet 89 Thus is provided on the third side wall 83 with its lower edge so as to be positioned below the upper end of each upstream branch pipe 31 _to 333 _1.
[0033]
The cover 80 is integrally provided with a lead-out pipe 91 communicating with the purification chamber 88 so as to be positioned above the throttle body 25. That is, in the air cleaner 26, the air introduced into the unpurified chamber 87 from the air inlet 89 flows through the filter element 86 and flows upward, and further changes the flow direction by approximately 90 degrees so as to be substantially horizontal from the outlet pipe 91. Will be derived in the direction.
[0034]
The outlet pipe 91 of the air cleaner 26 and the upstream end of the throttle body 25 are connected via an air flow tube 27. The air flow tube 27 includes an expandable chamber 27a extending vertically and an expandable chamber 27a. A bellows-shaped inlet-side connecting pipe 27b that is continuous with the upper end of the expansion chamber 27a and an outlet-side connecting pipe 27c that is continuous with the lower end of the expansion chamber 27a are integrally formed with a synthetic resin in a substantially U shape. The side connection pipe 27b is fitted and connected to the outlet pipe 51, and the outlet side connection pipe 27c is fitted and connected to the upstream end of the throttle body 25.
[0035]
Thus, the portion of the expandable chamber 27a facing the lead-out pipe 51 is formed in a spherical shape so as to reduce the collision of the air flow and enable a smooth flow, and the resonance in the expandable chamber 27a. By the action, the natural frequency in the intake passage in the intake device 23 can be adjusted, and it is possible to contribute to the improvement of the output torque in the low / medium speed rotation region of the engine.
[0036]
Next, the operation of this embodiment will be described. In the intake manifold 24, in addition to the common intake pipe 30 extending in a straight line, each of the branched intake pipes 31 to 33 connected in common to the common intake pipe 30 is provided. The upstream branch pipes 31 _{1 to} 33 ₃ that extend in a straight line and the curved downstream branch pipes 31 _{2 to} 33 ₂ are formed on the cylinder head 21 of the engine body E that is in a forward inclined posture. The pipe shape from the common intake pipe 30 of the connected intake manifold 24 to the downstream end of each branch intake pipe 31 to 33 can be simplified.
[0037]
In addition, the inner surfaces of the upstream branch pipes 31 _{1 to} 33 _{1 in} the upstream pipe assembly 34 are formed by the axial movement of the rod-shaped cores 41 to 43, and the inner surface of the common intake pipe 30 is also the rod-shaped core 40. Therefore, the upstream side pipe assembly 34 is easily formed, and the inner surfaces of the downstream side branch pipes 31 _{2 to} 33 _{2 in} the downstream side pipe assembly 35 are curved. Since it is formed by pulling out by rotation of the cores 54 to 56, it is easy to form the downstream side pipe assembly 35, and both assemblies 34, 35 can be manufactured with high accuracy and low cost.
[0038]
By the way, the joint surface 59 of the second flange 37 in the upstream pipe assembly 34 and the joint surface 60 of the third flange 45 in the downstream pipe assembly 35 are heated and joined to each other. There is a risk that flash generated at the time of joining may protrude from the inner surfaces of the connecting portions of the upstream branch pipes 31 _{1 to} 33 ₁ and the downstream branch pipes 31 _{2 to} 33 ₂ . However wherein the the joining surfaces 59 and 60, the first fitting recess 62 to 64 surrounding the downstream end opening of the upstream-side branch pipe 31 _to 333 _1, downstream the upstream end of the branch pipe 31 _{2-33 2} 2nd fitting recessed parts 65-67 surrounding each opening part are provided, and the synthetic resin inserts 68, 65, 63, 64, 67 are sandwiched between the fitting recessed parts 62, 65; 63, 66; 69 and 70 are arranged, so that even if a flash occurs during the heating and joining, the flashes are prevented from entering the branch intake pipes 31 to 33 by the inserts 68 to 70. Therefore, it is possible to prevent the variation in the inner surface shape of each of the branched intake pipes 31 to 33 from being caused by flashes, thereby contributing to the improvement of the intake performance. It should be noted that the flash that protrudes outward from the joint surfaces 59 and 60 during the heating and joining does not affect the intake performance and may be left as it is.
[0039]
Moreover, the joint surface 59 of the upstream side pipe assembly 34 of both the joint surfaces 59 and 60 is formed continuously to the second side wall 82 which is a part of the housing main portion 29 constituting the housing 28 of the air cleaner 26. Therefore, the joint strength at both joint surfaces 59 and 60 can be improved, and the joint reliability of both the pipe assemblies 34 and 35 can be improved.
[0040]
Further, the inner surfaces of the downstream branch pipes 31 _{2 to} 33 ₂ of the downstream pipe assembly 35 are respectively formed by being drawn by the rotation of the bending cores 54 to 56 in planes parallel to each other. Pulling out by rotation of each of the bending cores 54 to 56 can be performed simultaneously by a common driving means, and the downstream side pipe assembly 35 can be formed more easily.
[0041]
On the other hand, despite the fact that each of the branch intake pipes 31 to 33 is in a divergent arrangement, the first and second curved cores 54 to 56 are rotated along planes parallel to each other. The curved cores 54 and 56 that form the inner surfaces of the third downstream branch pipes 31 ₂ and 33 ₂ are rotated on a plane that intersects the axis of the first and third upstream branch pipes 31 ₁ and 33 _1. Therefore, a step portion is necessarily formed between the inner surfaces of the upstream end portions of the first and third downstream branch pipes 31 ₂ and 33 ₂ and the inner surface of the downstream ends of the first and third upstream branch pipes 31 ₁ and 33 _1. Will occur. However, the inner surfaces of the upstream end portions of the first and third downstream branch pipes 31 ₂ and 33 ₂ are located on the outer side of the extension lines of the inner surfaces of the first and third upstream branch pipes 31 ₁ and 33 _1. Storage recesses 74, 75 are formed, and nested 68, interposed between the first upstream and downstream branch pipes 31 ₁ , 31 _{2 and} between the third upstream and downstream branch pipes 33 ₁ , 33 ₂ , 70 is integrally provided with extensions 68a and 70a that are accommodated in the accommodating recesses 74 and 75, respectively. Therefore, the inner surfaces of the first and third upstream branch pipes 31 ₁ , 33 ₁ are smoothly connected to the inner surfaces of the first and third downstream branch pipes 31 ₂ , 33 ₂ , and the upstream branch pipes 31 ₁ , The air flow from 33 ₁ to the downstream branch pipes 31 ₂ and 33 ₂ can be made smooth, and the intake performance can be further improved.
[0042]
Further, the housing 78 of the air cleaner 26 includes a housing main portion 79 provided integrally with the upstream side pipe assembly 34 and a cover 80 attached to the upper portion of the housing main portion 79. The portion 79 has first and second side walls 81 and 82 that extend upwardly from the first and second flanges 36 and 37 included in the upstream side pipe assembly 34 and are formed in a rectangular box shape. Is. Accordingly, not only can the rigidity of the joint portion of the throttle body 25 to the first flange 36 be increased, but also the rigidity of the joint portion of the upstream side and downstream side pipe assemblies 34 and 35 can be increased. The rigidity of the two side walls 81 and 82, that is, the housing 78 of the air cleaner 26 can be increased, and the strength of the entire intake device 23 can be improved.
[0043]
Further, the fourth side wall 84 which is a part of the housing main portion 79 is integrally connected so as to intersect the first upstream branch pipe 31 ₁ at an angle, and is reinforced by the first upstream branch pipe 31 ₁ . Thus, the rigidity of the fourth side wall 84 can be increased. Further, the bottom wall 85 of the housing main portion 79 connects the substantially central portions of the upstream branch pipes 31 _{1 to} 33 _{1 in} the vertical direction, and the bottom surface of the housing main portion 79 has the upstream branch pipes 31 _{1 to} 33. would be reinforced by _1, it is possible to enhance the bottom surface rigidity of the main housing portion 79. Therefore, the rigidity of the housing main portion 79, that is, the housing 78, can be further enhanced in combination with the high rigidity of the first and second side walls 81, 82.
[0044]
The housing main portion 79 is arranged so as to be biased to one end side along the arrangement direction of the upstream branch pipes 31 _{1 to} 33 ₁ , and the third side wall 83 located at one end side along the arrangement direction has air on the third side wall 83. since inlet 89 is provided, it is possible to secure a relatively large space between the upstream-side branch pipe 33 ₁ and the third side wall 83 closer to the third side wall 89. Moreover, since the lower end edge of the air inlet 89 is disposed at a position lower than the upstream upper end of the branch pipe 31 _to 333 ₁ which is raised from the bottom wall 85, air from the air inlet 89 is introduced into the unpurified chamber 87 partially caused to collide with the upper portion of the upstream-side branch pipe 33 ₁ can be dispersed to the large space, because the dispersed air flows through the filter element 86 that covers the upper side of the unpurified chamber 87, substantially uniformly The dispersed air will flow through the filter element 86. Therefore, it is possible to prevent the partial contamination of the filter element 86 as much as possible and to make the time until the function is lowered relatively long.
[0045]
Further, since the upstream-side branch pipe 31 _to 333 ₁ of the upper is disposed facing to the housing 78 in the air cleaner 26, the upstream-side branch pipe 31 _to 333 ₁ is cooled by air flowing through the air cleaner 26 Therefore, an increase in the temperature of the intake manifold 23 due to the proximity to the engine body E is avoided as much as possible, and an increase in the intake air temperature accompanying an increase in the temperature of the intake manifold 23 is prevented, so that the performance of the internal combustion engine is sufficient. Can be demonstrated.
[0046]
By the way, although the intake manifold 24 tends to radiate intake sound due to being made of synthetic resin, the intake sound radiated from the upper part of the upstream side pipe assembly 34 in the intake manifold 24 is upstream. The air cleaner 26 located above the side pipe assembly 34 is blocked by the air layer of the unpurified chamber 87 and the filter element 86, and the diffusion of radiated sound can be suppressed.
[0047]
Furthermore, since a part of the air cleaner 26 and the intake manifold 24 are integrated, the assembling workability of the intake device 23 can be improved.
[0048]
Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.
[0049]
For example, instead of the air flow tube 27 having the expansion chamber 27a, a simple duct connecting the air cleaner 26 and the throttle body 25 is used, and a resonator chamber is connected to an intermediate portion of the duct via an opening / closing control valve. Also good. The respective upstream branch pipe 31 _to 333 ₁ Oyohi each downstream branch pipe 31 _2-33 nested 68-70 so as to be interposed between the _second upstream-side conduit assembly 34 and the downstream conduit assembly However, the present invention is also applicable to those in which the upstream and downstream pipe assemblies 34, 35 are heated and joined without using such inserts 68-70. is there.
[0050]
【The invention's effect】
As described above, according to the present invention, the main portion of the housing is formed in a rectangular box shape having the first and second side walls connected to the first and second flanges, respectively, and integrated with the upstream side pipe assembly. As a result, the rigidity of the housing of the first and second side walls, that is, the air cleaner can be increased, the strength of the entire intake device can be improved, and the bottom surface of the main portion of the housing is reinforced by each upstream branch pipe. Thus, the bottom rigidity of the main portion of the housing can be increased.
[0051]
Moreover, since the housing main part is arranged to be deviated to one end side along the arrangement direction of each upstream branch pipe and the air introduction port is provided in the third side wall on one end side along the arrangement direction, the upstream side near the third side wall is provided. A relatively large space can be secured between the side branch pipe and the third side wall, and the lower end edge of the air inlet is arranged at a position lower than the upper end of the upstream side branch pipe raised from the bottom wall of the housing main portion. As a result, a part of the air from the air introduction port collides with the upper part of the upstream branch pipe and is distributed in the wide space to be guided to the filter element. As a result of the circulation, it is possible to prevent the partial fouling of the filter element as much as possible and to make the time until the function is lowered relatively long.
[0052]
In addition, since the upper part of each upstream branch pipe faces the housing in the air cleaner, each upstream branch pipe is cooled by the air flowing through the air cleaner to avoid the intake manifold temperature rise as much as possible. It is possible to prevent the intake air temperature from rising due to the temperature rise and to fully demonstrate the performance of the internal combustion engine.
[0053]
In addition, the intake sound radiated from the upper part of the upstream pipe assembly is blocked by the air layer of the uncleaned chamber and the filter element in the air cleaner to suppress the diffusion of the radiated sound, and part of the air cleaner and the intake manifold are integrated. As a result, the assembly workability can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of an engine body and an intake device.
FIG. 2 is a plan view of the intake device as seen from the direction of arrow 2 in FIG.
3 is a cross-sectional view taken along line 3-3 of FIG.
FIG. 4 is a plan view of an upstream duct assembly.
FIG. 5 is an exploded vertical sectional view of an intake manifold.
6 is an enlarged sectional view taken along line 6-6 of FIG.
FIG. 7 is a diagram showing the arrangement of rod-shaped cores when forming an upstream side pipe assembly.
8 is a longitudinal cross-sectional view of the downstream pipe assembly and the bending core for explaining the formation of the inner surface of the downstream branch pipe by the bending core, and is a cross-sectional view taken along line 8-8 in FIG. .
9 is an enlarged cross-sectional view taken along line 9-9 of FIG.
FIG. 10 is a simplified perspective view for explaining heating and joining of the upstream side pipe assembly and the downstream side pipe assembly.
11 is a cross-sectional view taken along line 11-11 in FIG.
[Explanation of symbols]
21 ... Cylinder head 22 ... Intake port 23 ... Intake device 24 ... Intake manifold 25 ... Throttle body 26 ... Air cleaner 30 ... Common intake pipes 31, 32, 33 ... Branch intake pipes 31 ₁ , 32 ₁ , 33 ₁ ... Upstream branch pipes 31 ₂ , 32 ₂ , 33 ₂ ... Downstream branch pipes 34. Road assembly 36 ... first flange 37 ... second flange 78 ... housing 79 ... housing main part 80 ... cover 81 ... first side wall 82 ... second side wall 83 .... Third side wall 84 ... Fourth side wall 85 ... Bottom wall 86 ... Filter element 87 ... Unpurified chamber 88 ... Purified chamber 89 ... Air inlet

Claims (1)

A common intake pipe (30) connected to the throttle body (25) and a plurality of branch intake pipes (31, 32) connecting the common intake pipe (30) and a plurality of intake ports (22) of the cylinder head (21). , 33) is formed in the intake manifold (24) made of synthetic resin, and a part of the housing (78) of the air cleaner (26) is formed integrally with the intake manifold (24). The intake manifold (24) includes a plurality of upstream branch pipes (31 ₁ , 32 ₁ , 33 ₁ ) constituting the upstream portion of each branch intake pipe (31 to 33) and the upstream branch pipes (31 ₁ to 31 ₁ ). 33 ₁ ) an upstream side pipe assembly (34) made of a thermoplastic synthetic resin integrally provided with a common intake pipe (30) that allows the common intake pipe (30) to communicate with each other, and a downstream part of each branch intake pipe (31 to 33). Composing The downstream branch pipe downstream conduit assembly of thermoplastic synthetic resin comprising a (31 _2, 32 _2, 33 ₂₎ integral with (35), but the heating, become joined, upstream conduit assemblies (34) is provided with a first flange (36) that is commonly connected to the upstream end of the common intake pipe (30) so as to be joined to the throttle body (25), and each upstream branch pipe (31 ₁ to 31- 33 ₁ ), a second flange (37) connected in common to the downstream end is integrally provided to be heated and joined to the downstream pipe assembly (35), and the first and second flanges (36, 37). The first and second side walls (81, 82) that are connected to each other, and the first and second side walls (81, 82) connected at one end along the arrangement direction of the upstream branch pipes (31 _{1 to} 33 ₁ ). The side wall (83) is connected to the other end of the first and second side walls (81, 82). A side wall (84), cross out with lower and bottom wall for connecting the vertically substantially central portion of the upstream-side branch pipe (31 _to 333 ₁₎ of the first to fourth side walls (81 to 84) (85) The upstream pipe assembly (34) is arranged in such a manner that the housing main part (79) formed in a rectangular box shape is biased toward one end along the arrangement direction of each upstream branch pipe (31 _{1 to} 33 ₁ ). ) And a cover (80) which forms a housing (78) of the air cleaner (26) in cooperation with the housing main portion (79), and the uncleaned chamber below the housing (78). (87) and a filter element (86) partitioned into an upper purification chamber (88) is sandwiched between the housing main portion (79) and mounted on the upper portion of the housing main portion (79), and the bottom wall (85 ) Of the upstream branch pipe (31 _{1 to} 33 ₁ ) An air intake system for an internal combustion engine, wherein a lower end edge is disposed at a position lower than the upper end, and an air introduction port (89) leading to the unpurified chamber (87) is provided in the third side wall (83).

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