JPH078809Y2 - exhaust manifold - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an improvement of an exhaust manifold attached to an automobile engine.

[Conventional technology]

BACKGROUND ART Conventionally, as an exhaust manifold for an automobile engine of this type, as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 57-186, a plurality of pipe lines communicating with a plurality of exhaust ports of the engine are integrally formed by casting. What is formed is known.

However, this cast exhaust manifold is heavy due to its wall thickness, and has a large heat capacity, so that there is a problem that the heat of the exhaust gas is taken away and the activity of the catalytic converter provided on the downstream side is reduced.

Therefore, recently, a method of connecting a metal pipe to each of a plurality of exhaust ports of the engine has been adopted. This will be described with reference to FIG. 5. In the figure, reference numeral 1 is a pipe-made exhaust manifold connected to an inline 6-cylinder engine 2, and the pipe-made exhaust manifold 1 has a head flange 3 at one end thereof. It is composed of six metal pipes 4 to 9 which are separately connected to the six exhaust ports of the engine 2.

Then, the other end side of each metal pipe 4 to 5 is superposed on the wall surface facing the adjacent metal pipes 4 to 9, respectively, and the cut portion 10 is superposed on the wall surface, and the collecting portion 12 is formed. It has a structure in which is inserted into the flange 11 and welded. In the figure,
Reference numeral 13 is an exhaust pipe connected to the collecting portion 12.

[Problems to be solved by the device]

However, in the conventional structure in which the cutout portion 10 is provided at one end of each of the metal pipes 4 to 9 as described above, and the gathering portion 12 is welded to the flange 11 by superimposing the cutout portions 10, vibrations of the exhaust system for a long time and Due to the thermal expansion of the metal pipes 4 to 9, the welded portions of the flange 11 and the collecting portion 12, the overlapping portions of the cutout portions 10, or the connecting portions of the head flange 3 and the metal pipes 4 to 9 are damaged. I was afraid.

The present invention has been devised in view of such an actual situation, and has an exhaust manifold that has strength to withstand vibration of an exhaust system and reduces stress concentration on a collecting portion and a head flange due to thermal expansion of a metal pipe. The purpose is to provide.

[Means for Solving the Problems]

In order to achieve such an object, the present invention comprises six metal pipes separately connected to each exhaust port of an in-line 6-cylinder engine and assembled on the downstream side to be connected to one exhaust pipe. In an exhaust manifold for an automobile engine, two central pipes of the metal pipe are formed in a substantially straight shape, and a downstream end portion of the straight metal pipe and two pipes respectively arranged outside the downstream end portion. The downstream ends of the metal pipes addressed to each of the three are respectively assembled, and the downstream ends of the respective metal pipes are formed so that the cross-sectional shape of each assembly is triangular, and each assembly is It is welded to a middle-fork type bifurcated assembly member connected to the exhaust pipe.

[Action]

According to the present invention, even if the vibration of the exhaust system is propagated to the exhaust manifold through the exhaust pipe, the cantilever structure of the collecting portion by the straight metal pipes and the downstream end portion of each metal pipe are provided. The strength of the triangular structure works together to prevent damage to the metal pipe assembly.

Further, even if the straight metal pipe expands and contracts due to thermal expansion, the bent portions of the outer metal pipes absorb the expansion and contraction, respectively, and connect the metal pipe with the head flange and the assembly member. Reduces stress concentration on parts.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The same elements as those in the conventional example shown in FIG. 5 are designated by the same reference numerals.

In FIG. 1, reference numeral 14 is a pipe-made exhaust manifold (hereinafter referred to as “pipe manifold”) connected to an in-line 6-cylinder engine 2 and is the pipe manifold.
14 has 6 of the engine 2 through the head flange 3 at one end.
It consists of six metal pipes 15 to 20 which are separately connected to one exhaust port, and the two metal pipes 17 and 18 arranged at the center are substantially straight as shown in FIG. 1 or 2. Formed on the metal pipe 17,18
The metal pipes 15 and 16 and the metal pipes 19 and 20 for the two pipes, which are respectively arranged on the outer sides of the pipes, are bent as shown in FIG. 3, and the downstream end portions 151, 161, 191, 201 of the metal pipes 17, It has a structure in which three downstream end portions 171 and 181 are gathered to the left and right respectively.

The metal pipes 15 to 17 will be described as an example. As shown in FIG. 4, the downstream end portions 151, 161, and 171 of the metal pipes 15 to 17 have two sides with one obtuse angle θ therebetween. It is formed in the same square shape. Then, the metal pipe 15 is arranged on the upper part of the metal pipe 17, one side 172 of the downstream end 171 is in contact with one side 162 of the downstream end 161, and one side 163,173 sandwiching an obtuse angle θ with the one side 162,172. On the two sides 152, 1 that sandwich the obtuse angle θ of the downstream end 151 of the metal pipe 15.
53 are in contact with each other, and the downstream end portions 151, 161, 171 of the respective metal pipes 15 to 17 are combined to form the metal pipes 15 to 1
7 are assembled in a substantially triangular cross section, and a metal pipe 17
It has a cantilever structure. The metal pipes 18 to 20 on the other side also have the metal pipes as shown in FIG.
By the same configuration as the 15 to 17 side, the downstream end portions 181, 19
1,201 is a cantilever structure in which metal pipes 17 are gathered in a substantially triangular cross section.

Therefore, the metal pipes 15 to 17 and the metal pipes
As shown in FIG.
1,212 are joined together and the forked assembly member 21 is welded,
Then, the exhaust pipe 12 is connected to the downstream side of the exhaust pipe 12 via the flange 22 attached to the collecting member 21.

Since the present embodiment is configured in this way, the vibration of the exhaust system is transmitted to the pipe manifold via the exhaust pipe 13.
Even when propagating to 14, the cantilever structure by the straight metal pipes 17 and 18 and the strength due to the triangular structure of the downstream end portions 151, 161, 171, and the downstream end portions 181, 191, 201 are combined, and the metal pipe 15 Prevents damage to ~ 20 assembly.

Further, each of the metal pipes 15 to 20 expands and contracts due to thermal expansion. Even if the straight metal pipes 17 and 18 expand and contract, the expansion and contraction of the metal pipes 15 and 16 and the metal pipe 19 Since it is absorbed by the bent portions of the shafts 20 and 20, the stress concentration on the connecting portion with the head flange 3 and the assembly member 21 is reduced.

As described above, according to this embodiment, the strength is improved as compared with the conventional exhaust manifold, and the metal pipes 15 to
Since the stress concentration on the head flange 3 and the assembly member 21 due to the thermal expansion of 20 is reduced, there is no fear that the pipe manifold 14 will be damaged due to long-term use.

In the above embodiment, a straight metal pipe is used.
Although the adjacent metal pipes 16 and 19 are disposed above the metal pipes 17 and 18, the metal pipes 16 and 19 may be disposed below the metal pipes 17 and 18.

[Effect of device]

INDUSTRIAL APPLICABILITY As described above, the present invention is an automobile engine in which six metal pipes, which are separately connected to respective exhaust ports of an in-line 6-cylinder engine, are assembled on the downstream side and are connected to one exhaust pipe. In the exhaust manifold described above, the two central pipes of the metal pipe are formed in a substantially straight shape, and the downstream end of the straight metal pipe and the metal for the two pipes respectively arranged outside the downstream end portion. The downstream end portions of the pipes made of metal are respectively assembled to three pipes, and the downstream end portions of the metal pipes are formed so that the cross-sectional shape of each of the gathered portions is triangular, and each gathered portion is formed into the exhaust pipe. According to the present invention, the cantilever structure with straight metal pipes and the triangular structure at the downstream end of each metal pipe are welded to each other. Combined with the strength, the strength is improved compared to the conventional exhaust manifold, and since stress concentration on the head flange and the assembly member due to thermal expansion of the metal pipe is reduced, the exhaust manifold can be used for a long time. There is no risk of damage.

[Brief description of drawings]

FIG. 1 is a perspective view of a pipe manifold according to an embodiment of the present invention. FIG. 2 is a plan view of the pipe manifold shown in FIG. FIG. 3 is a side view of the pipe manifold shown in FIG. FIG. 4 is a cross-sectional view of the collecting portion at the downstream end of the metal pipe. FIG. 5 is a side view of a conventional exhaust manifold. [Explanation of symbols of main parts] 14 …… Pipe manifold 15,16,17,18,19,20 …… Metal pipe 151,161,171,181,191,201 …… Downstream end 21 …… Aggregating member.

Claims (1)

[Scope of utility model registration request] 1. An exhaust manifold for an automobile engine in which six metal pipes, which are separately connected to respective exhaust ports of an in-line 6-cylinder engine, are assembled on the downstream side and are connected to one exhaust pipe. Then, the two central pipes of the metal pipe are formed in a substantially straight shape, and the downstream side end portion of the straight metal pipe and the downstream side of the two metal pipes respectively arranged outside thereof are provided. While assembling each of the three end portions to the respective end portions, forming the downstream end portion of each metal pipe so that each of the gathering portions has a triangular cross-section, and connecting each gathering portion to the exhaust pipe. An exhaust manifold that is welded to a mating type bifurcated assembly member.