Intake manifold

Abstract

To prevent requirement of a complicated process in molding.SOLUTION: A first piece 11 constitutes a part of a surge tank 40. A second piece 12, together with the first piece 11, constitutes the surge tank 40. The first piece 11 has an introduction hole 71 for introducing blow-by gas. The first piece 11 has a first flange 11F fixed to the second piece 12. The second piece 12 has a second flange 12F fixed to the first flange 11F. A cover 72 is positioned inside the surge tank 40. The cover 72 defines a gas passage GR extending from the introduction hole 71 to a branch piping side together with an inner surface of the surge tank 40. A part of the cover 72 is sandwiched by the first flange 11F and the second flange 12F.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an intake manifold. [Background technology]

[0002] Patent Document 1 describes an intake manifold. The intake manifold includes a surge tank and a plurality of branch pipes. The surge tank is a part of an intake passage. Each branch pipe extends from the surge tank. Each branch pipe is a pipe that leads the intake passage to each cylinder.

[0003] The intake manifold includes a first piece, a second piece, and a cover. The first piece has an intake port for drawing air into the surge tank and an introduction hole for introducing blow-by gas. The second piece is welded to the first piece. The second piece and the first piece form the surge tank. The second piece also has each branch pipe and an outlet hole for guiding the blow-by gas to each branch pipe. The cover, together with the inner wall of the surge tank, defines a passage for the blow-by gas. The blow-by gas introduced from the introduction hole of the first piece flows to the outlet hole of the second piece through a passage defined by the cover. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3960101 Summary of the Invention [Problem to be solved by the invention]

[0005] In the intake manifold described in Patent Document 1, the cover is integrally molded with the first piece, which may require complex processes for molding the first piece and the cover, or may impose restrictions on the design of the shapes of the first piece and the cover. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an intake manifold comprising a surge tank which is a part of an intake passage, and a plurality of branch pipes which branch off from the surge tank and are respectively connected to each intake port of an internal combustion engine, the intake manifold comprising: a first piece made of resin which constitutes a part of the surge tank; a second piece made of resin which constitutes the surge tank together with the first piece; and a resin cover which is located inside the surge tank, the first piece having an intake port which introduces intake air into the surge tank, an introduction hole which introduces blow-by gas, and a first flange which is fixed to the second piece, the second piece having a second flange which is fixed to the first flange, the cover defines a gas passage which extends from the introduction hole to the branch pipe side together with the inner surface of the surge tank, and a part of the cover is an intake manifold which is sandwiched between the first flange and the second flange.

[0007] According to the above configuration, the cover is fixed by being sandwiched between the first flange and the second flange. Therefore, it is not necessary to forcibly mold the cover as an integral part with the first piece or the second piece. Therefore, there is little risk that the presence of the cover will restrict the shape design of each piece. In addition, the cover can be fixed when the first flange and the second flange are fixed to each other. Therefore, there is no need to go through a complicated process to fix the cover.

[0008] In the above-mentioned intake manifold, the first piece may have a groove recessed on a side opposite to the internal space of the surge tank, and the cover may face the groove. According to the above configuration, the dimension by which the cover protrudes from the inner surface of the first piece can be reduced by the amount that the groove is recessed, and therefore the cover is less likely to obstruct the flow of intake air within the surge tank.

[0009] In the above-described intake manifold, the cover may not be adhered to the surge tank except for a portion sandwiched between the first flange and the second flange. According to the above configuration, the portion of the cover that is not sandwiched between the first flange and the second flange is not bonded to the first piece and the second piece. Therefore, the blow-by gas flowing through the gas passage flows out of the gas passage through a gap between the cover and the inner surface of the surge tank. Therefore, the blow-by gas flowing through the gas passage flows out of the gas passage from a wide range of the gas passage, not from a specific portion of the gas passage. Therefore, the blow-by gas can be guided to a wide range in the surge tank. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an exploded perspective view showing an intake manifold according to one embodiment. [Diagram 2] FIG. 2 is a plan view showing a first piece of the embodiment. [Diagram 3] FIG. 3 is a partial cross-sectional view of the intake manifold taken along line 3-3 in FIG. [Figure 4] 4 is a partial cross-sectional view of the intake manifold taken along line 4-4 in FIG. [Diagram 5] FIG. 5 is a plan view showing a first piece and a cover of a modified example. [Figure 6] FIG. 6 is a partial cross-sectional view of the intake manifold taken along line 6-6 in FIG. [Figure 7] FIG. 7 is a plan view showing a first piece and a cover of a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (One embodiment) Hereinafter, an embodiment of an intake manifold for an internal combustion engine will be described with reference to the drawings.

[0012] <Overall composition> As shown in Fig. 1, the intake manifold 10 includes an intake pipe 30 for drawing in air from outside the vehicle. The intake pipe 30 includes a main body 31 and an upstream flange 33. The main body 31 is substantially cylindrical. Therefore, the main body 31 includes an intake port 32 for introducing intake air into a surge tank 40, which will be described later.

[0013] The upstream flange 33 protrudes from the outer peripheral surface of the main body 31. The upstream flange 33 is located at the end of the main body 31 on the intake port 32 side. The upstream flange 33 has a plurality of bolt holes 34. Each bolt hole 34 penetrates the upstream flange 33. A cylindrical throttle body is fixed to the intake manifold 10 by inserting a bolt into the bolt hole 34. The throttle body houses a throttle valve for adjusting the amount of intake air. That is, intake air from outside the vehicle passes through the throttle body and flows into the intake manifold 10 via the intake port 32 of the intake pipe 30.

[0014] The intake manifold 10 includes a surge tank 40. The surge tank 40 is part of the intake passage of the internal combustion engine. The surge tank 40 suppresses intake pulsation. The surge tank 40 is connected to the end of the main body 31 opposite the intake port 32. The surge tank 40 is cylindrical overall. The surge tank 40 is elongated in the direction along the axis along which the main body 31 extends.

[0015] The intake manifold 10 includes four branch pipes 50. The branch pipes 50 are aligned along the extension direction of the surge tank 40. Each branch pipe 50 extends in a curved manner along the side of the surge tank 40 so as to surround the surge tank 40.

[0016] The intake manifold 10 has a downstream flange 61. The downstream flange 61 protrudes outward from the outer surface of each branch pipe 50. In addition, the downstream flange 61 connects the four branch pipes 50 together. The downstream flange 61 is located at the end of each branch pipe 50 opposite the surge tank 40.

[0017] The downstream flange 61 has a plurality of gasket grooves 62 and a plurality of bolt holes 63. Each gasket groove 62 is recessed in the end face of the downstream flange 61. Each gasket groove 62 surrounds the opening of each branch pipe 50. When the intake manifold 10 is connected to an intake port of the internal combustion engine, a gasket (not shown) is fitted into the gasket groove 62 to ensure sealing. Each bolt hole 63 penetrates the downstream flange 61. The intake manifold 10 is fixed to the internal combustion engine by inserting a bolt into the bolt hole 63. As a result, each branch pipe 50 branches off from the surge tank 40 and is connected to each intake port of the internal combustion engine. Note that in the drawings, only some of the gasket grooves 62 and some of the bolt holes 63 are labeled.

[0018] As shown in Fig. 2, the intake manifold 10 has an introduction hole 71 for introducing blow-by gas into the surge tank 40. As shown in Fig. 3, the introduction hole 71 penetrates the surge tank 40. The introduction hole 71 is connected to a blow-by gas passage (not shown).

[0019] As shown in Fig. 1, the intake manifold 10 has a cover 72. The cover 72 is located inside the surge tank 40. As shown in Fig. 3, the cover 72, together with the inner surface of the surge tank 40, defines a gas passage GR that extends from the introduction hole 71 to the side of each branch pipe 50, i.e., to the left side in Fig. 3.

[0020] As shown in Fig. 4, the portion of the inner surface of the surge tank 40 that defines the gas passage GR is a groove 41. The groove 41 is recessed toward the opposite side to the cover 72 compared to other portions. As shown in Fig. 2, the groove 41 is generally located between the branch pipe 50 that is closest to the suction port 32 among the four branch pipes 50 and the branch pipe 50 adjacent to the branch pipe 50. The groove 41 is elongated in a direction perpendicular to the axis along which the four branch pipes 50 are arranged.

[0021] As shown in Fig. 1, the cover 72 is plate-shaped. The cover 72 faces the inner surface of the groove 41 of the inner surface of the surge tank 40. Also, as shown in Fig. 4, the cover 72 is substantially flush with the portion of the inner surface of the surge tank 40 that is not the groove 41. In other words, the cover 72 does not protrude inward from the inner surface of the surge tank 40.

[0022] <Split structure> 1, the intake manifold 10 is composed of a plurality of pieces made of resin. Specifically, the intake manifold 10 includes a first piece 11, a second piece 12, and a third piece 13.

[0023] The first piece 11 constitutes a part of the suction pipe 30, a part of the surge tank 40, and a part of each branch pipe 50. The first piece 11 has a suction port 32 and an introduction hole 71. The first piece 11 also has a groove 41. The introduction hole 71 of the first piece 11 opens at the bottom surface of the groove 41.

[0024] Furthermore, the first piece 11 has a first flange 11F fixed to the second piece 12. The first flange 11F extends along the outer edges of the surge tank 40 and each branch pipe 50 in the first piece 11.

[0025] The second piece 12 constitutes a part of the suction pipe 30, a part of the surge tank 40, and a part of each branch pipe 50. The second piece 12 is fixed to face the first piece 11, and thereby defines the internal space of the surge tank 40 together with the first piece 11. The second piece 12 has a second flange 12F fixed to the first flange 11F of the first piece 11.

[0026] The second flange 12F extends along the outer edges of the surge tank 40 and the branch pipes 50 in the second piece 12. The second flange 12F is welded to the first flange 11F, and thus they are fixed to each other.

[0027] The third piece 13 constitutes a part of each branch pipe 50. The third piece 13 is located on the opposite side of the first piece 11 from the second piece 12. The third piece 13 is fixed facing the first piece 11, and thereby defines a downstream portion of the internal space of each branch pipe 50 together with the first piece 11. The third piece 13 is shaped so as not to block the introduction hole 71.

[0028] The cover 72 is located between the first piece 11 and the second piece 12. A portion of the cover 72 is sandwiched between the first flange 11F and the second flange 12F. Specifically, as shown in FIG. 3, both ends of the cover 72 in the longitudinal direction are sandwiched between the first flange 11F and the second flange 12F. This fixes the cover 72 to the first piece 11 and the second piece 12. Note that when the first piece 11 and the second piece 12 are heat-welded, a portion of the cover 72 may also be heat-welded thereto.

[0029] On the other hand, the portion of the cover 72 that is not sandwiched between the first piece 11 and the second piece 12 is not bonded to the first piece 11 and the second piece 12. Therefore, as shown in FIG. 4, a small gap G is provided between the cover 72 and the edge of the groove 41. In other words, the gas passage GR is not a completely sealed space. Therefore, the blow-by gas that has entered the gas passage GR from the introduction hole 71 flows out of the gas passage GR from the gap G between the cover 72 and the groove 41. Note that in FIG. 4, the gap G between the cover 72 and the edge of the groove 41 is exaggerated.

[0030] <Operation of the embodiment> Blow-by gas generated as the internal combustion engine runs flows from inside the crankcase through a blow-by gas passage to the inlet hole 71 of the surge tank 40. The blow-by gas that reaches the inlet hole 71 flows through the gas passage GR defined by the cover 72 and the inner surface of the groove 41. The blow-by gas flowing through the gas passage GR gradually flows out of the gas passage GR through the gap G as it flows downstream.

[0031] <Effects of the embodiment> (1) According to the above embodiment, the cover 72 is fixed by being sandwiched between the first flange 11F and the second flange 12F. Therefore, it is not necessary to forcibly mold the cover 72 as an integral part with the first piece 11 or the second piece 12. Therefore, the presence of the cover 72 is unlikely to restrict the shape design of each piece. In addition, the cover 72 can be fixed when the first flange 11F and the second flange 12F are fixed to each other. Therefore, a complicated process is not required to fix the cover 72.

[0032] (2) According to the above embodiment, the gas passage GR is defined by the groove 41 of the surge tank 40 and the cover 72. The dimension by which the cover 72 protrudes from the inner surface of the first piece 11 can be reduced by the amount that the groove 41 is recessed. Particularly in the above embodiment, the cover 72 is substantially flush with the portion of the inner surface of the surge tank 40 other than the groove 41. Therefore, the cover 72 is less likely to obstruct the flow of intake air inside the surge tank 40.

[0033] (3) According to the above embodiment, the portion of the cover 72 that is not sandwiched between the first piece 11 and the second piece 12 is not bonded to the first piece 11 and the second piece 12. Therefore, the blow-by gas flowing through the gas passage GR flows out from a wide range of the gas passage GR through the gap G to the outside of the gas passage GR, not from a specific portion of the gas passage GR. Therefore, the blow-by gas can be guided to a wide range within the surge tank 40.

[0034] (Other embodiments) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0035] The shape of the gas passage GR is not limited to the example of the above embodiment. In the example shown in FIG. 5, the gas passage GR branches into a plurality of passages. Specifically, the gas passage GR has an upstream passage GRU including an introduction hole 71, a first branch passage GR1 branching from the upstream passage GRU, a second branch passage GR2 branching from the upstream passage GRU, and a third branch passage GR3 branching from the upstream passage GRU. The upstream passage GRU extends in an L-shape as a whole. Specifically, the upstream passage GRU has a first portion U1 and a second portion U2. The first portion U1 includes the introduction hole 71, and extends in a direction perpendicular to the first axis, where the axis along which the plurality of branch pipes 50 are arranged is defined as the first axis. The second portion U2 is connected to an end of the first portion U1 that is closer to the branch pipe 50. The second portion U2 extends along the first axis. All of the first branch passage GR1 to the third branch passage GR3 are connected to the second portion U2. The first branch passage GR1 to the third branch passage GR3 extend from the second portion U2 in a direction perpendicular to the first axis. The first branch passage GR1 to the third branch passage GR3 are arranged at equal intervals in the direction along the first axis. According to this modification, the blow-by gas flowing from the introduction hole 71 into the gas passage GR is distributed in the direction along the first axis by the multiple branch passages. Therefore, the blow-by gas flowing into each branch pipe 50 can be made uniform. The number of the multiple branch passages is not limited to three.

[0036] 6, the gas passage GR may be defined by a wall 142 protruding from the inner surface of the surge tank 40 and a cover 172. In other words, instead of a groove 141 being recessed in the inner surface of the surge tank 40, a space is defined by the opposing walls 142. The cover 172 has a cover body 172A and two walls 172B protruding from the cover body 172A. The two walls 172B are located between a pair of opposing walls 142. In this way, the gas passage GR has a complicated structure formed by the two walls 142 and the two walls 172B, a so-called labyrinth structure.

[0037] Furthermore, the gas passage GR does not have to be a space extending in a straight line. In the example shown in Fig. 7, a flat cover 272 covers substantially the entire portion of the inner surface of the surge tank 40 that is constituted by the first piece 11. The cover 272 also has a plurality of outlet holes 273 for guiding the blow-by gas from the gas passage GR. When the cover 272 covers a reasonably wide area in this manner, providing the outlet holes 273 makes it easier for the blow-by gas to flow.

[0038] The number of branch pipes 50 is not limited to four. It may be three or less, or five or more, depending on the number of cylinders of the internal combustion engine to which the intake manifold 10 is attached. The shape of the downstream flange 61 is not limited to the example in the above embodiment, and may be changed as appropriate to suit the shape of the internal combustion engine to which the intake manifold 10 is attached.

[0039] The shape of the cover 72 is not limited to the example in the above embodiment. It does not have to be plate-shaped. It is sufficient that the cover 72 defines the gas passage GR together with the inner surface of the surge tank 40. Therefore, the cover 72 may face the inner surface of the second piece 12 to define the gas passage GR.

[0040] The shape of the intake manifold 10 is not limited to that of the present embodiment. For example, the branch pipe 50 may open in the same direction as the intake port 32. Also, the branch pipe 50 may be straight and not curved. [Explanation of symbols]

[0041] 10…Intake manifold 11...First piece 11F…First flange 12…Second piece 12F…Second flange 13…Third piece 30…Suction pipe 32…Intake port 40…Surge tank 41,141…Groove 50…Branch piping 71...Inlet hole 72,172,272…Cover GR…Gas passage

Claims

1. An intake manifold comprising a surge tank which is a part of an intake passage, and a plurality of branch pipes which branch off from the surge tank and are respectively connected to each intake port of an internal combustion engine, A first piece made of resin that constitutes a part of the surge tank; a second piece made of resin that constitutes the surge tank together with the first piece; A resin cover is provided inside the surge tank. the first piece has an intake port for introducing intake air into the surge tank, an introduction hole for introducing blow-by gas, a first flange fixed to the second piece, and a groove recessed on a side opposite to the internal space of the surge tank, the second piece has a second flange fixed to the first flange, the cover defines, together with an inner surface of the surge tank, a gas passage extending from the inlet to the branch pipe, a portion of the cover is sandwiched between the first flange and the second flange, The cover faces an inner surface of the groove, A gap is provided between the cover and the edge of the groove, The cover is flush with the inner surface of the first piece except for the groove. Intake manifold.

2. The cover is not bonded to the surge tank except for a portion sandwiched between the first flange and the second flange.

2. The intake manifold of claim 1.

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