JPH08200052A - Overhead engine exhaust system - Google Patents

Abstract

PURPOSE: To form the whole of an engine in a compact size, and suppress vibration of a muffler effectively. CONSTITUTION: One side 1a of an exhaust pipe 1 approaches a supporting flange 3 by inclining it in an inclining shape so as to face a bolt inserting port to the inside of an exhaust passage 8, a bolt inserting pipe 10 is penetrated from the other side 1b of the exhaust pipe 1 toward the bolt inserting port to which one side 1a of the exhaust pipe 1 is faced, and a fastening bolt 5 is inserted from the other side 1b of the exhaust pipe 1 toward the bolt inserting pipe 10. Since the exhaust pipe 1 approaches the supporting flange 3 by inclining in the inclining shape, a muffler 7 approaches an engine main body side so as to form the whole of the engine in a compact size. Since the strength of the exhaust pipe 1 is reinforced by the bolt inserting pipe 10 effectively, vibration of the muffler 7 is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for an overhead valve engine, and provides an exhaust system in which the exhaust pipe is inclined with respect to a support flange so that the engine as a whole can be made compact and vibration of a muffler can be suppressed. .

[0002]

BACKGROUND OF THE INVENTION The basic structure of an exhaust system for an overhead valve engine, which is the subject of the present invention, has a support flange 3 formed at a base end portion 2 of an exhaust pipe 1, as shown in FIG. 1 or 4. 3, a plurality of bolt insertion openings 6 are opened, and the fastening means 5 is inserted into the bolt insertion openings 6, so that the support flange 3 is attached to the cylinder head 11 of the overhead valve engine E by the fastening means 5.
The exhaust end 1 of the exhaust pipe 1 into the muffler 7,
The exhaust gas of the engine E is of a type configured to be guided from the exhaust pipe 1 to the muffler 7.

[0003]

2. Description of the Related Art As a conventional technique of this type, as shown in FIGS. 4 and 5, an L-shaped exhaust pipe 1 in a plan view is provided at an exhaust port 13 of a cylinder head 11 of a vertical overhead valve engine E. In some cases, a pair of bolt insertion openings 6 are opened in the support flange 3 while being arranged, and the support flange 3 is fixed to the cylinder head 11 with fastening bolts 5.

[0004]

In the above-mentioned prior art, since the L-shaped exhaust pipe 1 is led out from the cylinder head 11, the muffler 7 protrudes from the engine body, and the size of the entire engine increases. In order to reduce the protrusion of the exhaust pipe 1, it is conceivable to extend the exhaust pipe 1 obliquely laterally from the support flange 3 and fix the muffler to the free end of the exhaust pipe 1. Exhaust pipe 1 in space 50
Since the fastening bolt (not shown) interferes with the exhaust pipe and cannot be inserted into the support flange 3 or the insertion operation becomes extremely difficult, the interference space 50 is removed and the fastening bolt 5 is inserted into the cylinder head. 11 must be screwed.

Therefore, the fastening strength of the support flange 3 to the cylinder head 11 may remain insufficient, and the muffler 7
May be easily vibrated or the exhaust pipe 1 may be damaged. In order to reduce the protrusion of the exhaust pipe 1, the present invention extends the exhaust pipe 1 obliquely laterally from the support flange 3,
A technical problem is to fix the muffler to the free end of the exhaust pipe 1 to make the entire engine compact and to effectively suppress the vibration of the muffler.

[0006]

Means for achieving the above object will be described below with reference to FIGS. 1 to 3 showing an embodiment. That is, according to the present invention, in the exhaust device for an overhead valve engine having the basic structure, one side 1a of the exhaust pipe 1 is inclined to the support flange 3 so that the bolt insertion port 6 faces the exhaust passage 8. The bolt insertion tube 10 is penetrated from the other side 1b of the exhaust pipe 1 to the bolt insertion opening 6 facing the one side 1a of the exhaust pipe 1, and the fastening means 5 is provided from the other side 1b of the exhaust pipe 1. It is characterized in that it is configured to be inserted into the bolt insertion tube 10 and the bolt insertion port 6.

[0007]

According to the present invention, in order to reduce the protrusion of the exhaust pipe 1, the exhaust pipe 1 is extended obliquely laterally from the support flange 3, and the muffler is fixed to the free end of the exhaust pipe 1 to secure the entire engine. Make it compact. That is, one side 1 of the exhaust pipe 1
Since "a" is inclined to approach the support flange 3 to approach,
The muffler 7 arranged at the free end 1b of the exhaust pipe 1 can be arranged close to the engine body side.

Further, a bolt insertion pipe 10 is provided so as to extend from the other side 1b of the exhaust pipe 1 to the bolt insertion port 6, and the fastening means 5 is provided.
Is penetrated from the other side 1b of the exhaust pipe 1 into the exhaust passage 8 and is inserted into the bolt insertion pipe 10 and the bolt insertion port 6, so that the exhaust pipe 1 is strong by the bolt insertion pipe 10 and the fastening means 5 inserted therethrough. It can be reinforced to increase its strength.

[0009]

【The invention's effect】

(1) The muffler can be brought closer to the engine body by tilting one side of the exhaust pipe toward the support flange in an inclined manner, so that the entire engine can be compacted and the appearance can be made smart.

(2) Since the strength of the exhaust pipe can be effectively reinforced by the bolt insertion pipe and the fastening means, the vibration of the muffler is suppressed,
It is possible to prevent damage to the exhaust pipe.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side view of a main part of an exhaust system of a vertical overhead valve gasoline engine, FIG. 2 is an enlarged cross-sectional plan view of a main part of a base end side of an exhaust pipe of the exhaust system, and FIG. 3 is an exhaust pipe of the exhaust system. It is a principal-part cross-sectional top view of a muffler.

As shown in FIG. 1, an exhaust port 13 is opened in a cylinder head 11 of a vertical overhead valve gasoline engine E, and a cylindrical exhaust pipe 1 and a substantially hexagonal muffler 7 are fixed to the exhaust port 13 in order. The exhaust of the engine E is guided from the exhaust pipe 1 to the muffler 7.

That is, as shown in FIG. 1, a substantially rhombic support flange 3 is formed at the base end portion 2 of the exhaust pipe 1, and two bolt insertion openings 6 are formed at the pair of rhombus top portions of the support flange 3. And the fastening bolt 5 is inserted into the bolt insertion opening 6 to detachably fix the support flange 3 to the cylinder head 11 of the overhead valve engine E. Further, the muffler 7 is formed in a double case structure, and the exhaust pipe 1
A part of the free end portion 4 of the
The muffler 7 into the retainer 1
6 through the muffler cover 17 and the muffler cover 17
The bottom 17a of the engine is fixed to the crankcase 21 of the engine E by the fastening bolts 19 by the muffler support stay 18.

As shown in FIG. 2, one side 1a of the exhaust pipe 1 is inclined to the support flange 3 so that one of the bolt insertion openings 6 opened in the support flange 3 faces the exhaust passage 8. Then, a cylindrical bolt insertion pipe 10 is provided in the exhaust passage 8 from the other side 1b of the exhaust pipe 1 to the bolt insertion port 6 so as to approach. That is, the base end portion 22 of the bolt insertion pipe 10 is engaged with the step portion 24 provided on the support flange 3, and the free end portion 23 of the bolt insertion pipe 10 is projected to the outside from the other side 1b of the exhaust pipe 1. The outer periphery of the protruding portion of the bolt insertion pipe 10 and the exhaust pipe 1 are welded. As described above, the base end portion 22 of the bolt insertion tube 10 is connected to the step portion 2 of the support flange 3.
When engaged with 4, exhaust pipe 1 due to the labyrinth effect
Since it is possible to prevent exhaust leakage from the base end portion 2 side of the above, welding of the joint portion becomes unnecessary, which contributes to cost reduction.

As shown in FIGS. 2 and 1, the exhaust pipe 1 is
The curved heat insulating cover 20 is exposed to the external exposed portion on the base end portion 2 side of the exhaust pipe 1, and the fastening bolt 5 is inserted from the other side 1b of the exhaust pipe 1 into the bolt insertion pipe 10 and the bolt insertion port 6 to exhaust air. The pipe 1 and the heat insulating cover 20 are fastened together and fixed to the cylinder head 11, and the heat insulating cover 20 covers the exposed portions of the exhaust pipe 1 and the support flange 3. As a result, the appearance of the exhaust pipe 1 is adjusted, the worker is protected from burns, and the thermal influence on the hood of the working machine is prevented.

The function of the exhaust system for the vertical overhead valve engine of this embodiment will be described. As shown in FIG. 2, since the one side 1a of the exhaust pipe 1 is tilted and brought close to the support flange 3, the L-shaped exhaust pipe 1 is different from the prior art in which the exhaust pipe 1 is mounted in a protruding shape. The muffler 7 arranged at the free end 1b of the exhaust pipe 1 can be arranged close to the engine body side. As a result, the entire overhead valve engine E can be compactly assembled and its appearance can be made smart.

Further, a bolt insertion pipe 10 is provided so as to extend from the other side 1b of the exhaust pipe 1 to the bolt insertion port 6, and a fastening bolt 5 is passed from the other side 1b of the exhaust pipe 1 into the exhaust passage 8.
Since it is inserted into the bolt insertion tube 10 and the bolt insertion port 6,
The exhaust pipe 1 is strongly reinforced by the bolt insertion pipe 10 and the fastening bolts 5 inserted therethrough, and the strength thereof can be increased. As a result, the vibration of the muffler 7 can be suppressed and the exhaust pipe 1 can be smoothly prevented from being damaged. However, instead of inserting the headed fastening bolt 5 in the bolt insertion tube 10 and the bolt insertion port 6 as in the above-described embodiment, a headless bolt is inserted and the free end portion is fastened with a fastening nut. It does not matter if it is configured as.

The present invention can be applied not only to the gasoline engine as in the above embodiment but also to a diesel engine. Further, the present invention can be applied not only to a vertical overhead valve engine but also to a horizontal overhead valve engine.

[Brief description of drawings]

FIG. 1 is a side view of a main part of an exhaust system for a vertical overhead valve gasoline engine showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional plan view of an essential part of the exhaust device on the base end side of the exhaust pipe.

FIG. 3 is a cross-sectional plan view of main parts of an exhaust pipe and a muffler of the exhaust device.

FIG. 4 is a view equivalent to FIG. 2 showing a conventional technique.

FIG. 5 is a side view of an exhaust device for a vertical overhead valve gasoline engine showing the conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Exhaust pipe, 1a ... One side of exhaust pipe, 1b ... Other side of exhaust pipe, 2 ... Base end of exhaust pipe, 3 ... Support flange, 4 ... Free end of exhaust pipe, 5 ... Fastening means , 6 ... Bolt insertion port, 7 ...
Muffler, 8 ... Exhaust passage, 10 ... Bolt insertion tube, 11 ... Cylinder head, 13 ... Exhaust port, E ... Overhead valve engine.

Claims (1)

[Claims] 1. A support flange at the base end (2) of the exhaust pipe (1)
(3) is formed, and a plurality of bolt insertion holes are formed on the support flange (3).
By opening (6) and inserting the fastening means (5) into the bolt insertion port (6), the support flange (3) is attached to the cylinder head (11) of the overhead valve engine (E) by the fastening means (5). Fixed,
Exhaust of an overhead valve engine configured such that the free end (4) of the exhaust pipe (1) is thrust into the muffler (7) and the exhaust of the engine (E) is guided from the exhaust pipe (1) to the muffler (7). In the device, the bolt insertion port (6) faces the exhaust passage (8),
One side (1a) of the exhaust pipe (1) is tilted toward the support flange (3) to approach it, and one side (1a) of the exhaust pipe (1) from the other side (1b) of the exhaust pipe (1) 1
a) through the bolt insertion opening (6) facing the bolt insertion tube (1
0) is provided so that the fastening means (5) is inserted from the other side (1b) of the exhaust pipe (1) into the bolt insertion pipe (10) and the bolt insertion port (6). An exhaust system for an overhead valve engine.