JPH0444812Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an exhaust manifold attachment device for attaching an exhaust manifold with a plurality of branches to a cylinder head of an engine.

(Prior art) The exhaust manifold 11 of the conventional internal combustion engine has the fourth and fifth exhaust manifolds.
As shown in the figure, it is attached to the cylinder head 18 by inserting bolts (not shown) into attachment holes 16 provided in the attachment flange 12. Further, the mounting flange 12 is provided with a slit 17,
This slit 17 absorbs thermal strain between the branches 13, 14, and 15.

In such a conventional exhaust manifold 11, the mounting flange 12 and the exhaust branches 13 to 15 are integrated, so the mounting flange 12 and the exhaust branches 1
If a thermal expansion/contraction difference occurs due to the temperature difference between the mounting flange 12 and the exhaust branches 13 to 15,
A crack appears between them. Also exhaust branch 13,1
4 and 15 is directly transmitted to the mounting flange 12, so that the mounting flange 12 curves. Incidentally, prior art documents related to the present application include Japanese Utility Model Application No. 55-39352 and Japanese Utility Model Application Publication No. 57-164209.

(Problems to be Solved by the Invention) The technical problem of this invention is to manufacture the mounting flange 12 and the exhaust manifold 11 separately, and to attach the cylinder head while the exhaust manifold 11 is held down by the mounting flange 12. 18, even if the amount of thermal expansion and contraction between the mounting flange 12 and the exhaust manifold 11 is different, unreasonable force is not applied between them.

(Means for solving the problem) The above problem is solved by an exhaust manifold mounting device having the following structure. That is, the exhaust manifold attachment device according to the present invention is an exhaust manifold attachment device for attaching an exhaust manifold having a plurality of branches to a cylinder head of an engine, in which a flange-like flange formed at the end of each branch of the exhaust manifold is provided. a seat, an opening through which the branch is inserted, and a recess surrounding the opening to accommodate the flange-like seat, and the cylinder head is fixed to the cylinder head with the seat accommodated in the recess. It has a port flange.

When the port flange is fixed to the cylinder head, the outer peripheral surface of the seat and the inner wall surface of the recess of the port flange, and the outer surface of the branch and the inner wall surface of the opening of the port flange are connected. A gap is formed between them in the circumferential direction.

(Function) According to the present invention, the exhaust manifold has a flange-shaped seat formed at the end of the branch, which is pressed by the port flange.
Attached to the engine cylinder head. Furthermore, when the exhaust manifold is attached to the cylinder head, the outer peripheral surface of the seat of the branch and the inner wall surface of the recess of the port flange, and the outer surface of the branch and the inner wall surface of the opening of the port flange are connected. A gap is formed between them in the circumferential direction.

Therefore, even if the exhaust manifold expands or contracts due to heat, the branches and seats of the exhaust manifold can move relative to the port flange. Furthermore, since the gap is formed in the circumferential direction, even if the branches are deformed in different directions due to expansion and contraction of the exhaust manifold, the deformation is reliably absorbed by the gap. Therefore, no excessive force is applied to the connecting portion between the branch of the exhaust manifold and the port flange.

In addition, in a structure in which the port flange is fixed to the cylinder head with bolts, the tightening force from the bolts is not directly applied to the flange-shaped seat, but is evenly distributed by the recess of the port flange. Participate in the same state. Therefore, even if the tightening torque of the bolt is sufficiently large, it is possible to slide the flange-shaped seat portion with respect to the port flange. Furthermore, since the entire periphery of the flange-shaped seat is pressed by the recess of the port flange, a reliable sealing function can be ensured.

(Description of Examples) This invention will be explained below with reference to FIGS. 1 to 3 showing examples. At the end of each exhaust branch 4 of the exhaust manifold 1, a circular flange-shaped seat 5 is formed. And this part is the exhaust intake port part 7
functions as 2 and 3 are port flanges, which are manufactured separately from the exhaust manifold 1. The port flange 2 (the port flange 3 is also the same, so only the port flange 2 will be described) is provided with a circular recess 2a in which the seat 5 is accommodated.
The respective radii are set so that a gap 10 of dimension d is formed between the recess 2a and the seat 5, and the depth of the recess 2a is set larger than the wall thickness of the seat 5. . At the bottom 2c of the recess 2a of the port flange 2, an insertion hole 2b for loosely inserting the end of the exhaust branch 4 is provided concentrically with the recess 2a. 2d is a contact surface between the port flange 2 and the exhaust manifold gasket 19. Reference numeral 8 designates mounting holes for bolts (not shown) for fastening the port flanges 2, 3 to the cylinder head 18.
The bottom 2c of the recess 2a of the port flange 2 and the seat 5
A ring-shaped spacer 6 surrounding the end of the exhaust branch 4 is interposed between the exhaust branch 4 and the exhaust branch 4. The port flange 2 is fastened to the cylinder head 18 by bolts (not shown) inserted into bolt mounting holes 8 thereof. Therefore, the seat 5 is fastened to the cylinder head 18 by the port flange 2 through the spacer 6.

In the above configuration, when the exhaust manifold 1 is cooled and heated to contract and expand, the contact surface 9 between the seat portion 5 and the spacer 6 is within the gap 10 by the difference in thermal deformation between the port flange 2 and the exhaust branch 4. It slides and absorbs the thermal expansion and contraction of the exhaust branch 4. As a result, no cracks or bends occur in the exhaust branch 4.

In addition, since the expansion and contraction of the exhaust branch 4 is not transmitted to the port flanges 2 and 3, the port flanges 2 and 3
No deformation such as curvature occurs. Further, since the port flanges 2 and 3 are in contact with the exhaust branch 4 via the spacer 6, heat transfer from the exhaust branch 4 is small and temperature rise is also small. Therefore, thermal deformation of the port flanges 2, 3 and breakage of the tightening bolts fixing the port flanges 2, 3 to the cylinder head 18 are also eliminated.

(Effects of the invention) According to the invention, the exhaust manifold is attached to the cylinder head of the engine with the seat portions of its branches held down by the port flanges. Further, the seat portion is configured to be movable relative to the port flange. Therefore, even if the exhaust manifold expands and contracts due to heat, no excessive force is applied to the connecting portion between the exhaust manifold and the port flange. As a result, the durability of the exhaust manifold, port flange, etc. is improved.

Furthermore, since the entire periphery of the seat formed at the end of the branch is pressed by the recess of the port flange, a reliable sealing function is ensured.

[Brief explanation of the drawing]

FIG. 1 shows a plan view of one embodiment, FIG. 2 shows a front view, and FIG. 3 shows an enlarged detailed view of the main part of FIG. 2. FIG. 4 shows a plan view of a conventional exhaust manifold, and FIG. 5 shows a front view of the conventional exhaust manifold. DESCRIPTION OF SYMBOLS 1... Exhaust manifold, 2, 3... Port flange, 5... Seat part, 6... Spacer, 7... Exhaust intake port part, 18... Cylinder head, 19...
...Exhaust manifold gasket.

Claims (1)

[Claims for Utility Model Registration] An exhaust manifold attachment device for attaching an exhaust manifold having a plurality of branches to a cylinder head of an engine, comprising: a flange-shaped seat formed at an end of each branch of the exhaust manifold; A port flange comprising: an opening through which the branch is inserted; and a recess around the opening for storing the flange-shaped seat, and the port flange is fixed to the cylinder head with the seat stored in the recess. with the port flange fixed to the cylinder head, the outer peripheral surface of the seat, the inner wall surface of the recess of the port flange, and the outer surface of the branch and the inner wall surface of the opening of the port flange. An exhaust manifold mounting device characterized in that a gap is formed in the circumferential direction between the exhaust manifolds.