JP2007192185A - Exhaust gas control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas control valve capable of simultaneously satisfying a demand for reducing noise required when an engine rotates at low speed while satisfying a demand for reducing back pressure required when the engine rotates at high speed, reducing a space in the direction of a valve element opening for assembling, and reducing the number of parts to reduce cost and weight. <P>SOLUTION: This exhaust gas control valve is constituted in such a way that a recessed part 21 is formed on a baffle plate 14 partitioning the inside of a muffler body 1, a valve element 23 for opening and closing an opening of the recessed part 21 by turning along a short side internal wall face 21c on one side and both long side internal wall faces 21b, 21d constituting the square cylindrical internal wall face of the recessed part 21 centered on a supporting shaft 22 in the recessed part 21 is provided, an exhaust gas circulation hole 27 having a seat face 26a having a smaller opening area than that of the recessed part 21 is formed on the internal bottom face 21e of the recessed part 21, and a coil spring 28 for energizing the valve element 23 in the direction for closing the exhaust gas circulation hole 27 by letting the valve element 23 abut on the seat face 26a is provided in a supporting shaft 22 part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an exhaust pressure sensitive exhaust control valve that is provided in a portion of a communication hole formed in a partition plate that partitions the inside of a muffler and opens by exhaust pressure.

  Conventionally, a valve body that is openable and closable via a support shaft with respect to a valve seat provided in the middle of the exhaust flow passage in the muffler body, and the control valve is brought into contact with the seat surface of the valve seat. In an exhaust control valve provided with an urging means for urging in the closing direction, the diameter of the valve seat portion on the downstream side of the seat surface is larger than the inner diameter of the seat surface that defines the exhaust pressure receiving surface of the valve body. A plurality of tube portions formed on the inner diameter of the tube portion are respectively extended through outward flange portions, and a plurality of plug body portions that respectively close the opening portions of the plurality of extended tube portions are extended on the valve body side. The valve body is in contact with the seat surface and the control valve is closed. An exhaust control valve characterized in that the exhaust control valve is configured to be opened to an open position is disclosed (example: If, see Patent Document 1.).

According to this conventional example, there is an advantage that it is possible to simultaneously achieve a low noise requirement required at the time of low-speed rotation of the engine and a low back pressure requirement required at the time of high-speed rotation.
JP 2005-207382 A

  However, in the exhaust control valve of the conventional example, the upper end of the plurality of cylindrical portions by the plurality of plug bodies according to the rotation angle of the valve body from the state where the valve body abuts on the seat surface and the control valve is closed. In order to configure the opening to be opened step by step from the one with the smaller diameter, the valve body constituting the plug body is enlarged in the height direction, resulting in high material cost and weight. In addition, the rotation angle of the valve body also increases, which makes it difficult to assemble the valve body in a portion that is restricted in the height direction.

  The problem to be solved by the present invention is that it is possible to simultaneously achieve a low noise requirement required at the time of low-speed rotation of an engine and a low back pressure requirement required at the time of high-speed rotation. An object of the present invention is to provide an exhaust control valve that can be assembled even if the space in the valve direction is small and can be reduced in cost and weight by reducing the number of parts.

  In order to solve the above-mentioned problem, in the exhaust control valve according to claim 1, a recessed portion is formed in a partition plate that partitions the inside of the muffler body, and along the cylindrical inner wall surface of the recessed portion around the support shaft in the recessed portion. A valve body that opens and closes the opening of the recess by rotating is provided, and an exhaust circulation hole having a seat surface with a smaller opening area than the recess is formed on the inner bottom surface of the recess, and the support shaft The part is provided with urging means for urging the valve body in contact with the seat surface in a direction to close the exhaust circulation hole.

  The exhaust control valve according to the present invention is configured as described above, and the exhaust pressure receiving surface that acts on the valve body when the valve body is initially opened is a range defined by the inner diameter of the seat surface. By setting the urging force of the urging means to be strong enough to prevent the valve from opening when the engine speed is within the specified low speed range, the engine's low speed rotation The noise reduction requirement that is sometimes required can be satisfied.

  In addition, when the engine speed exceeds a predetermined low speed rotation range and the exhaust pressure exceeds the urging force of the urging means and the valve body is pushed open from the seat surface, an initial valve open state is established. Since the opening area of the recess constitutes the exhaust pressure receiving surface, the exhaust pressure receiving area becomes larger than the initial valve opening, and the valve opening force due to the exhaust pressure becomes relatively strong. Once the valve body is separated from the valve, the valve body can be easily pushed open with lower exhaust pressure than at the time of initial valve opening. Can do.

Therefore, it is possible to simultaneously achieve the low noise requirement required at the time of low speed rotation of the engine and the low back pressure requirement required at the time of high speed rotation.
In addition, since there is no part that protrudes greatly other than the valve body on the valve plate opening side of the partition plate, it can be assembled even if there is little space in the valve body valve opening direction. The degree of freedom can be increased.

  Further, since the exhaust control valve is formed simply by assembling the valve body in the recess of the partition plate by the support shaft, the cost can be reduced and the weight can be reduced by reducing the number of parts.

  Embodiments of the present invention will be described below with reference to the drawings.

First, the exhaust control valve of this embodiment will be described with reference to the drawings.
1 is a cross-sectional view showing a muffler to which the exhaust control valve of this embodiment is applied, FIG. 2 is a plan view showing the exhaust control valve of the embodiment in a closed state, and FIG. 3 is a cross section taken along line AA of FIG. 4 is a cross-sectional view taken along line BB in FIG. 2, FIG. 5 is a cross-sectional explanatory view showing an initial state of the first stage valve opening, and FIG. 6 is a cross-sectional explanatory view showing a fully opened state after the second stage valve opening. is there.

First, a muffler to which the exhaust control valve of this embodiment is applied will be described with reference to FIG.
In this muffler, the inside of the muffler body 1 in which the opening portions at both ends of the cylindrical shell 11 are closed by end plates 12 and 13 is partitioned into three chambers 1a, 1b and 1c by two baffle plates (partition plates) 14 and 15. It has been.

  Further, in the muffler body 1, an inlet pipe 16 that penetrates the end plate 12 and the baffle plate 14 and communicates with the chamber 1b constituting the expansion chamber, and the baffle plate 15 and the end plate 13 penetrate to the chamber 1b. A first outlet pipe 17 that communicates, a second outlet pipe 18 that passes through the two baffle plates 14 and 15 and the end plate 13 and communicates with the chamber 1a that constitutes the exhaust passage when the engine rotates at high speed, and the baffle plate 15 And a communication pipe 19 that communicates between the chamber 1b and the chamber 1c constituting the resonance chamber.

The exhaust control valve 2 includes the baffle plate 14 as a part of its configuration.
That is, as shown in detail in FIGS. 2 to 4, a rectangular recess 21 that is recessed toward the chamber 1 b is formed on the surface of the baffle plate 14 on the chamber 1 a side, and a rectangular cylinder in the recess 21 is formed. The other short side inner wall surface 21c and the both sides constituting the rectangular cylindrical inner wall surface of the recessed portion 21 around the support shaft 22 provided along one short side inner wall surface 21a constituting the inner wall surface. A valve body 23 that opens and closes the opening of the recess 21 by rotating along the long side inner wall surfaces 21b and 21d is provided.

  The support shaft 22 is provided with a pair of L-shaped support shaft brackets 24 and 24 fixed to the baffle plate 14 and bearings 25 and 25 inserted and supported at both ends thereof.

  And the exhaust flow hole 27 provided with the circular stainless steel mesh 26 which comprises the sheet | seat surface 26a whose opening area is narrower than the dent part 21 is formed in the inner bottom face 21e of the dent part 21. As shown in FIG.

  A coil spring (biasing means) 28 is provided on the outer periphery of the support shaft 22 to urge the valve body 23 in contact with the seat surface 26a and close the exhaust circulation hole 27.

Next, the operation and effect of this embodiment will be described.
The exhaust control valve 2 of the present invention is configured as described above, and the exhaust pressure receiving surface acting on the valve body 23 when the valve body 23 is initially opened is a range defined by the inner diameter of the seat surface 26a. By setting the urging force of the coil spring 28 to be strong so that the engine speed is not opened in a predetermined low speed range based on the area of the exhaust pressure receiving surface in the initial stage of valve opening. When the rotational speed is below a predetermined low speed rotational speed range, the exhaust control valve 2 is maintained in a closed state as shown in FIGS.

As a result, when the exhaust gas from the engine flows from the inlet pipe 16 into the chamber 1b constituting the expansion chamber, a silencing effect due to expansion is obtained, and the chamber 1b constitutes a resonance chamber via the communication pipe 19 Since it is in communication with 1c, a sound deadening effect of a specific frequency due to resonance can be obtained. Thereafter, the chamber 1b is exhausted to the atmosphere through only the first outlet pipe 17.
Accordingly, it is possible to satisfy the demand for noise reduction required when the engine rotates at a low speed.

  Further, as shown in FIG. 5, the engine speed exceeds the predetermined low speed rotation range, and the valve body 23 is pushed open from the seat surface 26a with the exhaust pressure surpassing the urging force of the coil spring 28. Then, since the opening area of the recessed portion 21 wider than the inner diameter of the seat surface 26a constitutes the exhaust pressure receiving surface, the exhaust pressure receiving area becomes larger than that at the time of initial valve opening, and the valve opening force due to the exhaust pressure relatively. As a result, after the valve element 23 is once separated from the seat surface 26a, the valve element 23 can be easily pushed open with an exhaust pressure lower than that at the time of initial valve opening as shown in FIG. become.

  As described above, when the engine rotates at a high speed, the exhaust control valve 2 is opened as shown in FIG. 6 so that the exhaust gas is exhausted from the chamber 1b through the first outlet pipe 17 to the atmosphere. At the same time, the exhaust gas passes through the exhaust control valve 2 from the chamber 1b and is discharged from the second outlet pipe 18 to the atmosphere via the chamber 1a constituting the exhaust flow path. The pressure demand can be satisfied.

  Therefore, it is possible to simultaneously achieve the low noise requirement required at the time of low speed rotation of the engine and the low back pressure requirement required at the time of high speed rotation.

  Moreover, since there is no part which protrudes greatly except the valve body 23 in the chamber 1a side in which the valve body 23 opens in the baffle plate 14, the exhaust control valve 2 is assembled even if the space in the valve body 23 valve opening direction is small. Will be able to.

  That is, in this embodiment, the chamber 1a on the side where the valve element 23 is opened is used as an exhaust flow path, and the minimum necessary flow connecting the chamber 1b and the second outlet pipe 18 is used. Since it is sufficient to ensure the road cross-sectional area, it becomes possible to secure a large volume of the chamber 1b constituting the expansion chamber, and therefore, the silencing effect by expansion by effectively utilizing the limited space in the muffler body 1 The effect that it becomes possible to raise is acquired.

  Further, since the exhaust control valve 2 is formed simply by assembling the valve body 23 in the recessed portion 21 of the baffle plate 14 by the support shaft 22, the cost can be reduced and the weight can be reduced by reducing the number of parts. .

  Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included in the present invention.

  For example, in the embodiment, the case where the valve opening side of the exhaust control valve 2 is the exhaust passage is taken as an example, but the assembly location is arbitrary.

  In the embodiment, the L-shaped support bracket 24 is arranged so that the support shaft 22 also does not protrude from the valve opening side of the exhaust control valve 2 in the baffle plate 14, but the exhaust control valve 2 in the baffle plate 14 is opened. Even if it protrudes from the valve side, it may be lower than the valve body 23 at the time of valve opening.

Moreover, the shape of the recessed part 21 and the valve body 23 is arbitrary.
Further, as in the conventional example, the recessed portion 21 may be formed in a plurality of stages, and the recesses 21 may be sequentially opened from the small diameter.

It is sectional drawing which shows the muffler to which the exhaust control valve of an Example is applied. It is a top view of the valve closing state which shows the exhaust control valve of an Example. It is sectional drawing in the AA of FIG. It is sectional drawing in the BB line of FIG. It is a section explanatory view showing the 1st stage valve opening initial state. It is sectional explanatory drawing which shows the full open state after a 2nd stage valve opening.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Muffler main body 1a The chamber which comprises an exhaust flow path 1b The chamber which comprises an expansion chamber 1c The chamber which comprises a resonance chamber 11 Cylindrical shell 12 End plate 13 End plate 14 Baffle plate (partition plate)
15 Baffle plate (partition plate)
16 Inlet pipe 17 1st outlet pipe 18 2nd outlet pipe 19 Communication pipe 2 Exhaust control valve 21 Recessed part 21a Short side inner wall surface (tubular inner wall surface)
21b Long side inner wall surface (tubular inner wall surface)
21c Short side inner wall surface (tubular inner wall surface)
21d Long side inner wall surface (tubular inner wall surface)
21e Inner bottom surface 22 Support shaft 23 Valve body 24 L-shaped support bracket 25 Bearing 26 Circular stainless steel mesh 26a Seat surface 27 Exhaust communication hole 28 Coil spring (biasing means)

Claims (1)

A recess is formed in the partition plate that partitions the muffler body,
A valve body that opens and closes the opening of the recess by rotating along the cylindrical inner wall surface of the recess around the support shaft in the recess is provided,
An exhaust circulation hole having a seat surface with an opening area narrower than the recess is formed on the inner bottom surface of the recess,
2. An exhaust control valve according to claim 1, wherein said support shaft portion is provided with urging means for urging said valve body in contact with said seat surface in a direction to close said exhaust circulation hole.

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