JPH0229220Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an improvement in the exhaust structure of an engine.

(Prior Art) When an engine exhaust structure has two cylinder groups, such as a V-type engine or a horizontally opposed engine, it is necessary to provide an exhaust manifold for each cylinder group.

In this way, for an engine with two exhaust manifolds, it is extremely disadvantageous in terms of cost, installation space, etc. to provide separate exhaust pipes. As shown in the publication, both exhaust manifolds are connected near the engine body, and the exhaust pipe is connected to only one exhaust manifold.

In this way, when connecting two exhaust manifolds, the connection is made via a connecting member such as a steel pipe, but this connection is usually made by connecting a flange on the exhaust manifold and a flange on the connecting member. are butted against each other, and the butted flanges are fastened with a plurality of bolts that pass through the flanges and are spaced apart in the circumferential direction, and nuts that are screwed into the bolts. was.

However, as mentioned above, if multiple bolts and nuts are used to fasten the flanges between the connecting member and each exhaust manifold, the radial width of the flanges inevitably increases due to the bolts passing through them. In addition, in order to secure space for tightening bolts and nuts located between the engine body and the connecting member or exhaust manifold, the connecting member must be located at a considerable distance from the engine body. This was a disadvantage in making the engine as a whole more compact. Also, multiple bolts,
Another drawback was that tightening the nuts required a considerable amount of effort. In addition, the engine body and the exhaust manifold undergo thermal expansion, and assembly errors are likely to occur, so some kind of countermeasure is desired in this regard.

(Purpose of the invention) The present invention was developed in consideration of the above circumstances, and it is possible to make the engine as a whole more compact by bringing the connecting member that connects the exhaust manifolds together as close as possible to the engine body. In addition, this connection work can be done quickly,
Moreover, it is an object of the present invention to provide an exhaust structure for an engine, particularly an exhaust structure for a V-type engine, which can effectively absorb differences in thermal expansion between the engine body and the exhaust manifold and errors in assembly.

(Structure of the invention) In order to achieve the above-mentioned object, in the present invention, a V cylinder equipped with a first cylinder group and a second cylinder group is provided.
In a type engine, a first exhaust manifold and a second exhaust manifold, which are connected to each cylinder group, extend near the engine body in the same direction and approximately parallel to the engine crankshaft, and their tips are connected to both cylinders. An exhaust structure for a V-type engine that is located at a portion corresponding to the valley of the group and connected via a flexible tube, wherein the exhaust manifold and the flexible tube have their flange portions butted against each other. The abutted flange portions are connected to each other by a coupling ring, and the abutted flange portions have a substantially V-shaped cross section that gradually becomes narrower toward the outside in the radial direction. The coupling ring includes a main body that expands and contracts when the open end is opened and closed by rotatably connecting a plurality of arc-shaped covering members each having a substantially V-shaped cross section; a fixture that connects the open ends to reduce the diameter of the main body, and the open ends are connected to each other with the outer peripheral edge of the abutted flange portion wrapped around the coupling ring by the main body. The structure is such that it is fastened by the fixing device.

That is, in a V-type engine equipped with a first cylinder group and a second cylinder group, the first exhaust manifold and the second exhaust manifold connected to each cylinder group are substantially parallel to the engine crankshaft, and The exhaust manifolds extend in the same direction near the engine body, and their tips are positioned at locations corresponding to the valleys of both cylinder groups, so that the tips of these exhaust manifolds are connected via flexible tubes. Therefore, differences in thermal expansion between the engine body and the exhaust manifold and errors in assembly can be effectively absorbed. Here, it is sufficient that the flexible tube has a length that can absorb at least the above-mentioned difference in thermal expansion.

In addition, since this flexible tube is arranged at a position corresponding to the valley of each cylinder group of a V-type engine, that is, it is arranged corresponding to one end of the V-bank central space, this flexible tube is Even if the flexible tube is placed close to the main body, the workability of fastening the flexible tube and the exhaust manifold will not be impaired.

Furthermore, since the above-mentioned coupling is used as a fastener between the flexible tube and the exhaust manifold, this fastening procedure can be facilitated. That is, the main body of the coupling ring rotatably connects a plurality of arc-shaped covering members each having a substantially V-shaped cross section, so that the main body can be expanded or contracted by opening or closing the open end. The fixing tool is said to reduce the diameter of the main body by fastening the open ends together, so the fastening work generally involves tightening at least one fastening tool to one coupling. That's all you need to do.

In addition, the flange portion of the exhaust manifold and the flange portion of the flexible tube, which are butted against each other, have a substantially V-shaped cross section that gradually becomes narrower toward the outside in the radial direction. With the outer peripheral edges of the abutted flanges covered by the main body of the coupling, the open ends of the main bodies are fastened together using a fixture and a diameter reducing force is applied thereto. While its positional shift in the radial direction is prevented, due to the approximately V-shaped action described above, the diameter-reducing force of the main body of the coupling is converted into a force that pinches both flanges from the axial direction. Both flanges are firmly fastened together.

(Example) An example of the present invention will be described below based on the attached drawings.

In FIGS. 1 and 2, the engine body 1 is
It has a first cylinder group 2 and a second cylinder group 3, and both cylinder groups 2 and 3 are arranged in a V-shape, and each cylinder group is a V-type 6 cylinder having three cylinders in series. It is said to be an engine.

Each branch connection part 4a of the first exhaust manifold 4 is connected to the outer surface of the first cylinder group 2 (the surface opposite to the surface facing the second cylinder group 3). Each branch connection portion 5a of the second exhaust manifold 5 is connected to the outer surface. Each of the collecting pipe portions 4b and 5b of both exhaust manifolds 4 and 5 is bent approximately 90 degrees, and the rear surface of the engine body 1 (the right side in FIG. 2, where the transmission (not shown) is disposed) Flange portions 4c and 5c formed at the ends of the flange portions 4c and 5c are arranged along the surface and are opposed to each other with a predetermined interval.

The exhaust manifolds 4 and 5 are coupled and connected by a flexible tube 6 as a coupling member using their flanges 4c and 5c.
The connecting portion between the flexible tube 6 and each exhaust manifold 4, 5 will be explained with reference to FIGS. 3 and 4.
Since the exhaust manifold 4, the flexible tube 6 and the second exhaust manifold 5 are connected in the same manner, only the connection between the flexible tube 6 and the first exhaust manifold 4 will be explained.

First, the flexible tube 6 has a flange portion 6a at its end, and this flange portion 6a has a
It abuts against the flange portion 4c of the first exhaust manifold 4. In this abutting state, the annular engagement protrusion 6b protruding from the inner peripheral side of the abutting surface of the flange portion 6a fits into the annular engaging recess 4d formed on the inner peripheral side of the abutting surface of the flange portion 4c. As a result, the radial alignment of both flange portions 6a and 4c can be performed reliably and easily. In addition, both flange portions 6a and 4c
The back surface, that is, the side surface opposite to the abutting surface, is a tapered surface 6c or 4e that is inclined so as to gradually approach the abutting surface as it goes radially outward. In this case, both the flange portions 6a and 4c have a substantially V-shaped cross-sectional shape that becomes narrower toward the outer side in the radial direction. Note that the flexible tube 6 is, for example, as shown in FIG.
A pair of pipes 6 each having a flange portion 6a
d (one pipe is not shown) are connected by a stretchable metal bellows 6e with excellent heat resistance, and the outer periphery of the metal bellows 6e is covered and protected by a plaid 6f made of woven metal wire. can be used.

7 in FIGS. 3 and 4 indicates both flange portions 6a and 4.
This coupling 7 is composed of a main body 8 and a fixture 9. The main body 8 includes two covering members 8a formed into approximately semicircular shapes by processing metal plates, and hook portions 8b formed radially outward at one end of each of the covering members 8a. and a ring 8c installed on the ring 8c.
By opening and closing the open ends 8b formed at each other end of the covering member 8a, centering on the c portion,
The main body 8 is expandable and contractable. That is, the ring 8c has the function of a connector that rotatably connects the two covering members 8a to each other, and instead of using such a ring 8c, both the covering members 8a can be connected with a pin. They may also be rotatably connected. Each of the covering members 8a has a substantially V-shaped cross section, that is, a shape that expands toward the inside in the radial direction, and each of the open ends 8d
are bent radially outward of the main body 8.

On the other hand, the fixture 9 is composed of a bolt 9a and a nut 9b screwed onto the bolt 9a. By passing the bolt 9a through each opposing open end 8d and tightening it with the nut 9b, the main body 8 can be fixed. It is becoming smaller in diameter. In addition, this bolt 9
It is preferable to fix either the nut 9b or the nut 9b to either one of the open ends 8d in advance by welding or the like.

The coupling ring 7 as described above has its main body 8
(The covering member 8a) covers the outer peripheral edges of the abutted flanges 6a and 4c, and the open ends 8d are fastened together using the fixture 9. Ru. This more reliably prevents radial positional displacement between the flange portions 6a and 4c. In addition, the main body 8 is
As the diameter is reduced by the fastening force from the flange portions 6a and 4c, due to the substantially V-shaped action described above, this fastening force, ie, the diameter-reducing force, pinches both flange portions 6a and 4c from the axial direction. As a result, separation of the flanges 6a and 4c in the axial direction is prevented.

Here, in order to attach the coupling ring 7 as described above to both the flange parts 6a and 4c, first, the main body 8
With its open end 8d wide open, it is brought close to both flanges 6a and 4c from the wide working space side in the direction opposite to the engine main body 8, and fitted into the outer peripheral edge. Next, while reducing the diameter of the main body 8 with fingers, the open end 8d is rotated relative to the flanges 6a and 4c so that the open end 8d is located on the wide working space side opposite to the engine main body 1, and then , these open ends 8d may be fastened together using a fixture 9. Of course, the flexible tube 6 and the second exhaust manifold 5 are connected in exactly the same manner as described above.

Note that the first exhaust manifold 4 includes a collecting pipe section 4.
In part b, a common exhaust part 4f is formed to which the exhaust pipe 10 (see Fig. 1) is connected, and this allows exhaust from each cylinder group 2, 3 to the first exhaust manifold 4 or the second exhaust manifold 5. Both exhaust gases are discharged from the common exhaust section 4f to the exhaust pipe 10.
It will flow to

(Effects of the invention) As is clear from the above, the invention has the following effects:
Since the exhaust manifolds are connected to each other using a flexible tube, differences in thermal expansion between the engine body and the exhaust manifold and errors in assembly can be effectively absorbed.

Further, the first exhaust manifold and the second exhaust manifold extend near the engine body in substantially parallel to and in the same direction as the engine crankshaft, and their tips correspond to the valleys of both cylinder groups of the engine body. Because the tube is located at the same position, it is possible to shorten the length of the flexible tube, which is generally susceptible to heat loads.

Furthermore, the flexible tube is arranged at a location corresponding to the valley between the first cylinder group and the second cylinder group in the V-type engine, and in addition, the flexible tube and the exhaust manifold are connected by using one fixing member of the coupling. It is only necessary to fasten the fasteners, and since the fasteners can be fastened under a wide working space on the opposite side of the engine body, this connection work can be carried out quickly.

Furthermore, the flanges of the flexible tube and the exhaust manifold that abut each other need only be large enough to be covered by the coupling. As mentioned above, the fastening work can be carried out under a wide working space on the opposite side of the engine body, making it possible to bring this flexible tube and the exhaust manifold closer to the engine body. The overall structure can be made more compact.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the present invention. Second
The figure is a simplified plan view of FIG. 1. FIG. 3 is a cross-sectional view taken along the line shown in FIG. 4, showing the connecting portion between the flexible tube and the exhaust manifold. FIG. 4 is a sectional view taken along the line -- in FIG. 3. 1: Engine body, 2, 3: Cylinder group, 4, 5:
Exhaust manifold, 4c, 5c: Flange part, 4
e: Tapered surface, 6: Flexible tube, 6
a: flange portion, 6c: tapered surface, 7: coupling ring, 8: main body, 8a: covering member, 8c: ring (rotating connector), 8d: open end, 9: fixture, 9
a: Boruto, 9b: Natsu.

Claims (1)

[Claims for Utility Model Registration] In a V-type engine equipped with a first cylinder group and a second cylinder group, the first exhaust manifold and the second manifold connected to each cylinder group are connected to the crank of the engine. A V-type engine that extends near the engine body in the same direction and approximately parallel to the axis, and has its tips positioned at locations corresponding to the valleys of both cylinder groups, and are connected via flexible tubes. In the exhaust structure, each of the exhaust manifolds and the flexible tube have their flange portions abutted against each other, and the abutted flange portions are connected by a coupling ring, and the abutted flange portions are connected to each other by a coupling ring. , the cross section is approximately V-shaped so that the width gradually becomes narrower toward the outside in the radial direction, and the coupling ring rotatably includes a plurality of arc-shaped covering members each having a approximately V-shaped cross section. It is composed of a main body that expands and contracts as the open end of the main body is opened and closed by connecting the main body, and a fixture that connects the open end of the main body to reduce the diameter of the main body, and the main body is attached to the coupling ring. An exhaust structure for a V-type engine, characterized in that the open ends are fastened to each other by the fixing tool while the outer peripheral edge of the abutted flange portion is covered by the abutting flange.