JP2539442Y2 - Silencer for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a silencer for an internal combustion engine.

(Prior art)

Conventionally, in the above-mentioned silencer, the inside of the muffler is divided into a plurality of chambers, and these chambers are communicated with an inner pipe fixed to an image wall. Built-in open / close valve that opens and closes, for example, when the engine is running at a low speed, the closing operation is performed with emphasis on the noise reduction effect rather than the back pressure reduction. For example, Japanese Patent Laid-Open Publication No.
No. 27719.

[Problems to be solved by the present invention]

In the conventional structure, since the open / close valve is installed in the inner pipe fixed to the image wall, the assembling of the open / close valve must be performed simultaneously with the installation of the entire silencer. Mounting is troublesome and work efficiency is poor. Also, when replacing a malfunctioning open / close valve after assembling, the outer shell and inner pipe must be disassembled, and the replacement is difficult, so the entire silencer must be replaced. There is.

In view of this, the present invention provides a unitized open / close valve as described above, which can be attached to and detached from the muffler. In addition to this, the unitized opening / closing valve can be used as a clamshell type,
It is an object of the present invention to be able to easily attach to any type of silencer such as an elliptical type.

[Means for solving the problem]

In order to solve the above-mentioned problem, the present invention is configured such that an opening / closing valve unit is detachably mounted on a mounting window provided on a front wall of a muffler. An elbow-shaped ventilation pipe (14) is provided on the back side, and a base (12)
The elbow-shaped ventilation pipe is provided with an open / close valve (16) at the lower end on the base side thereof, and is fixed to the front side of the mounting board (12). Is characterized in that a valve opening / closing control means is provided, and the elbow-shaped ventilation pipe (14) and the valve mechanism are integrated with the mounting substrate (12).

〔Example〕

 Next, an embodiment of the present invention shown in the drawings will be described.

Reference numeral 1 denotes an outer shell of the silencer, and the first to third chambers
It is divided into 3,4,5. Reference numeral 6 denotes an inlet pipe, the inner end of which is open to the first chamber 3. An outlet pipe 7 has an inner end opening to the third chamber 5 and a rear end opening to the outside. 8 is a small-diameter inner pipe connecting the first chamber 3 and the second chamber 4, 9 is a small-diameter inner pipe connecting the second chamber 4 and the third chamber 5, and 10 is the first chamber 3 and the third chamber. 5 is a large-diameter inner pipe communicating with 5. Front wall 1a in outer shell 1
Is formed with a mounting window 1b of the opening / closing valve unit.
Reference numeral 11 denotes an opening / closing valve unit, and its flat mounting substrate 12 is detachably mounted to the peripheral wall of the mounting window 1b in the front wall 1a of the outer shell 1 by bolts and nuts 13.
On the inner surface of the mounting board 12, a ventilation pipe 14 formed in an elbow shape is fixed by a support plate 15 so that one end thereof is opposed to the end of the inner pipe 10 and fitted to the end. The end of one end 14a of the ventilation pipe 14 that fits with the inner pipe 10 is formed in a trumpet shape, so that the fitting with the inner pipe 10 is facilitated. An opening / closing valve 16 is rotatably provided in the other end 14b of the ventilation pipe 14 by a valve shaft 17. The base end of the valve shaft 17 is rotatably protruded through the front surface side of the mounting board 12, and a pulley 18 is fixed to the protruding portion. A wire 19 connected to a drive source driven by the rotation state of the engine, the back pressure state, the amount of exhaust gas or the temperature is wound around the pulley 18.
The opening / closing valve 16 is opened / closed by the pulling operation and the returning operation of 19. Reference numeral 20 denotes a return spring for the valve shaft.

With the above configuration, the opening / closing valve
When the valve 16 is closed, the exhaust gas flowing from the inlet pipe 6 into the first chamber 3 flows through the small-diameter inner pipe 8, the second chamber 4, and the small-diameter inner pipe 9, and flows into the third chamber 5, Further, it flows out of the outlet pipe 7.

When the opening / closing valve 16 is opened when the engine is running at high speed, part of the exhaust gas flowing into the first chamber 3
The gas flows through the large-diameter inner pipe 10 without flowing through the chamber 4, flows into the third chamber 5 in a short-circuit manner, and flows out of the outlet pipe 7 to the outside.

Therefore, when the engine is running at a low speed, the effect of reducing the back pressure is small but the silencing effect is high. When the engine is running at a high speed, the sound reducing effect is small but the back pressure reducing effect is high.

[Effect of the invention]

As described above, according to the present invention, the unitized opening / closing valve can be independently and detachably installed after the outer shell and the inner pipe are assembled. The on-off valve is easier to assemble than the one with a built-in on-off valve, and the work efficiency is improved. Since only the opening and closing valve unit may be replaced without disassembling the outer shell and inner pipe of the vessel, the replacement is easy and the replacement of the muffler is not required, and the replacement can be performed at low cost. Further, since the open / close valve unit is installed on the front wall of the outer shell of the muffler, the mount of the open / close valve unit can be easily performed not only on the clam shell but also particularly on the elliptical shell muffler. That is, if the open / close valve unit is mounted on the outer peripheral wall of the outer shell, since the outer wall of the elliptical shell has an arcuate surface, the assemblability of the open / close valve unit becomes difficult and the assembly is difficult due to the difficulty of mounting. Although there is a problem that gas leakage easily occurs at the attachment portion, if the opening and closing valve unit is assembled to the front wall of the outer shell as in the present invention, the front wall is a flat plate for any type of silencer. Therefore, there is a feature that the mounting is easy and the mounting can be performed without causing gas leakage. Further, in the present invention, since the inner pipe (10) erected and fixed in the muffler is positioned such that the open end thereof is opposed to the elbow-shaped front end side opening of the unit because of the above configuration, The fitting of the elbow-shaped ventilation pipe and the inner pipe is naturally and securely performed at the same time as the mounting of the unit, and of course there is an advantage that the assembling work of the unit can be easily and easily performed. With the above, the following operation and effect can be expected.

That is, if the ventilation pipe is a straight pipe, the inner pipe
When connected to 10, the muffler extends in the longitudinal direction and the chamber 5 must be enlarged. This fundamentally changes the acoustic characteristics of the muffler. Even if it is housed in the chamber 5, the end of the ventilation pipe is close to the front wall, and the gas flow becomes worse and the back pressure rises (back pressure rise = reduction in engine output and therefore bother). There is no point in bypassing at high revolutions.) In addition, the acoustic characteristics of the muffler will change, but in this case, the vent pipe is connected to the inner pipe with an elbow shape, so the end of the elbow (vent pipe) is close to the front wall The valve mechanism can be accommodated without deteriorating the gas flow and the acoustic characteristics because the opening can be made in the empty space without performing the operation.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of a silencer showing an embodiment of the present invention, and FIG.
The figure is a front view of the muffler, FIG. 3 is a partially cutaway plan view of the opening / closing valve unit, and FIG. 4 is a side view thereof. 1 ... outer shell, 1a ... front wall, 1b ... mounting window, 10 ... inner pipe, 11 ... opening and closing valve unit, 12 ... mounting board,
13 bolts and nuts, 14 vent pipes, 16 opening / closing valves

Claims (1)

(57) [Scope of request for utility model registration] An opening / closing valve unit is detachably mounted on a mounting window provided on a front wall of a muffler. Trachea (14), base side of which is substrate (12)
And is fixed so that the front end side faces the opposite side to the substrate, and an open / close valve (1) is provided at the lower end on the base side of the elbow-shaped ventilation pipe.
6), a valve opening / closing control means is provided on the surface side of the mounting substrate (12), and the elbow-shaped ventilation pipe (14) and the valve mechanism are integrated with the mounting substrate (12). Silencer for internal combustion engines.