JP4446895B2 - Exhaust control valve - Google Patents

Description

  The present invention relates to an exhaust pressure-sensitive exhaust control valve that is provided at an end portion of an exhaust pipe disposed in a muffler, a communicating hole formed in a partition plate (baffle plate), and the like, and opens and closes by exhaust pressure. .

  This type of conventional exhaust control valve has a silencing effect by opening and closing an exhaust passage that is arranged so that small chambers inside the muffler body communicate with each other in an arbitrary combination in response to fluctuations in exhaust pressure flowing from the engine side. In order to prevent the engine output from being reduced due to exhaust pressure loss, it is built into the muffler.

  As such an exhaust control valve, for example, as shown in FIG. 9, it can be opened / closed via a support shaft 104 with respect to an annular seat surface 103 of a valve seat 102 provided at an end of an exhaust pipe 101 in the muffler body. And a coil spring 106 for engaging the valve body 105 with the seat surface 103 of the valve seat 102 and urging the control valve in a closing direction. When the engine rotates at a low speed, the exhaust pipe 101 is closed by the urging force of the coil spring 106 so that the small chamber is used as a resonance chamber to give priority to the silencing effect, and the engine rotates at a high speed. Sometimes, when the exhaust pressure becomes greater than the biasing force of the coil spring 106, the exhaust pipe 101 is opened by pushing and opening the valve body 105, and the small chamber is expanded. · Conventional example 1 adapted to prioritize preventing deterioration in engine output due to the low profile pressurization of high speeds as (e.g., see Patent Document 1).

  However, the exhaust control valve of the conventional example 1 opens and closes the exhaust passage in response to the pressure fluctuation of the exhaust flowing from the engine side, thereby improving the silencing effect and preventing the engine output from decreasing. However, in the conventional exhaust control valve, as described above, the urging force of the coil spring 106 becomes larger as the opening degree becomes larger than when the valve body 105 is initially opened. Since the structure acts so as to increase, there is a problem that the back pressure cannot be sufficiently reduced during high-speed rotation of the engine.

  In this case, by setting the urging force of the coil spring 106 to be weak, it is possible to sufficiently reduce the back pressure at the time of high-speed rotation of the engine and reduce exhaust pressure loss. Since the valve body 105 starts to open from the time of rotation, there is a problem that a request for noise reduction at the time of low-speed rotation of the engine is not satisfied.

  Thus, in the conventional structure, there is a trade-off between the noise reduction measures at the time of engine low speed rotation and the low back pressure measures at the time of engine high speed rotation, and there is a problem that both requests cannot be achieved simultaneously. .

  Therefore, as a prior application for solving the above-described problems, as shown in FIG. 10, the seat surface 202 that defines the exhaust pressure receiving surface of the valve body 203 is formed downstream of the seat surface 202 in the valve seat 201 portion. A cylindrical portion 204 having an inner diameter larger than the inner diameter is extended. On the valve body 203 side, the valve body 203 abuts against the seat surface 202 and the control valve is closed to a predetermined valve opening position. There is a structure in which a plug body part 205 is provided in the cylinder part 204 so as to close the upper end opening of the cylinder part 204. .. Conventional example 2 (see, for example, Patent Document 2).

  That is, in this conventional example 2, the exhaust pressure receiving surface that acts on the valve body 203 when the valve body 203 is initially opened is a range defined by the inner diameter of the seat surface 202. By setting the urging force of the urging means to be strong enough that the engine speed is not opened in a predetermined low speed range, the area required for The noise reduction requirement 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 203 is pushed open from the seat surface 202, then the predetermined valve opening state is reached. Up to the position of the angle, the tube portion 204 extends downstream from the seat surface 202 and has an inner diameter larger than the inner diameter of the seat surface 202 and closes the upper end opening of the tube portion 204. Since the plug body portion 205 constitutes the exhaust pressure receiving surface, the exhaust pressure receiving area is larger than that at the time of initial valve opening, and the valve opening force due to the exhaust pressure is relatively strong. Once the valve body 203 is separated from the valve 202, the valve body can be pushed open at a lower exhaust pressure than at the time of initial valve opening, so that the demand for lower back pressure during high-speed engine rotation is satisfied. Can do.
Accordingly, it is possible to simultaneously achieve a request for reducing noise required when the engine rotates at a low speed and a request for reducing back pressure required when rotating at a high speed.

JP 2002-235536 A (page (3) of the specification, FIG. 1) Japanese Patent Application No. 2002-331256

However, in the exhaust control valve of the conventional example 2, when the valve body starts to open, as shown in FIGS. 10 (B) and 10 (C), the seat surface 202 of the valve seat is supported on the support shaft side that supports the valve body 203. A gap h is formed between the extended portion 204b and the extended portion 205b of the valve body 203, and exhaust gas leaks from the gap h. Therefore, the cylindrical portion 204 and the extended portion 204b, the plug body portion 205, and the extended portion are provided. There is a problem that the effect of reducing the back pressure during high-speed rotation of the engine due to the expansion of the exhaust pressure receiving area formed by the portion 205b cannot be sufficiently expected.
Further, the high temperature exhaust gas leaking from the gap h on the support shaft side supporting the valve body 203 is directed toward the urging means such as a coil spring mounted on the support shaft. There was also a problem of worsening the nature.

  Further, at the initial valve opening time when the valve body 203 is pushed open from the seat surface 202, the exhaust pressure receiving area in the valve body 203 rapidly increases, so that the opening degree of the valve body 203 is greatly hunted in the increasing / decreasing direction, There was a problem of causing an unstable phenomenon of pressure amplitude.

  The problem to be solved by the present invention is that it is possible to simultaneously and sufficiently achieve a low noise requirement required during low-speed rotation of an engine and a low back pressure requirement required during high-speed rotation, An additional object is to provide an exhaust control valve that can improve the sag resistance of the urging means, and to suppress an unstable phenomenon of pressure amplitude due to a sudden increase in exhaust pressure receiving area. .

  In order to solve the above-mentioned problems, in the invention according to claim 1, 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 an urging means for urging the control valve in a closing direction by contacting the seat surface of the valve seat, the outer shape of the seat surface of the valve seat with which the main body portion of the valve body abuts is The valve body is formed in a rectangular shape having sides parallel to the axial direction of the support shaft, and the main body of the valve body is formed in a rectangular shape along the outer shape of the seat surface, and the seat surface of the valve seat Side walls extending in parallel with each other toward the downstream side, which is the valve opening direction of the valve body, extend in parallel with each other on both sides adjacent to the side parallel to the support shaft, and the base end of the main body portion of the valve body on the support shaft side A shield wall having an outer surface substantially extending along the rotation trajectory of the base end centered on the support shaft extends on the side Is configured so that the base end side of the seat surface and the base end side of the main body are in contact with each other with a minute gap, and the support shaft on the seat surface of the valve seat A distal end outer wall having an inner surface substantially along the rotation trajectory of the distal end edge of the main body portion with the support shaft as the center is directed to the distal end side facing the proximal end side of the support shaft side parallel to By being extended, the valve body is configured to open when the valve body exceeds the predetermined rotation range from the state in which the main body portion of the valve body abuts on the seat surface by the front outer wall and the both side walls and the control valve is closed. It was set as the means characterized by.

  According to a second aspect of the present invention, in the first aspect of the present invention, a flange portion extending in a direction away from the support shaft is extended at an upper end edge portion of a distal end outer wall of the valve seat, and a main body portion of the valve body is extended. A distal end inner wall that extends at least to an upper end edge of the outer wall of the distal end of the valve seat and a plug body that extends from the upper end edge of the inner wall of the distal end in a direction away from the support shaft are provided at the distal end edge. A second outer end wall having an inner surface substantially along the rotation trajectory of the distal end edge of the plug body with the support shaft as a center is extended toward the downstream side at the distal end edge of the portion. The second tip outer wall and the both side walls are configured to open the valve body when the valve body is in contact with the seat surface and the control valve is closed to exceed a predetermined rotation range. It was set as the characteristic feature.

  According to a third aspect of the present invention, in the second aspect of the present invention, a third flange portion and a third distal end further extending in a direction away from the support shaft at an upper end edge portion of the second distal end outer wall of the valve seat. One or more outer walls are provided, and a second tip inner wall extending to at least a top edge of a third tip outer wall of the valve seat and a second tip inner wall at the tip edge of the plug body in the valve body When the second plug body portion extending in a direction away from the support shaft from the upper end edge of the valve is extended by one or more stages, the main body portion of the valve body is formed on the seat surface by the third distal end outer wall and the both side walls. The control valve is configured to open when it exceeds a predetermined rotation range from a state in which the control valve is closed.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the valve seat is configured by a baffle plate that partitions the inside of the muffler main body, and the both side walls and the front outer wall are the baffle plate. It is set as the means characterized by being fixed to the seat surface of the valve seat comprised by these.

  In the first aspect of the invention, the exhaust pressure receiving surface acting on the valve body is configured as described above, and the valve body is in contact with the seat surface and the control valve is closed. Since the range is defined by the inner diameter, the urging force of the urging means is set 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 closed state. By setting a high value, it is possible to satisfy the demand for noise reduction required when the engine rotates at a low speed.

Further, the inner surface of the seat surface of the valve seat, which faces the base end side on the side of the support shaft parallel to the support shaft, has an inner surface substantially along the rotation trajectory of the front end edge of the main body centered on the support shaft. When the outer wall of the leading end extends toward the downstream side, the valve body is brought into contact with the seat surface by the outer wall of the leading end and both side walls, and the control valve is closed. When the engine speed exceeds a predetermined low speed rotation range and the exhaust pressure overcomes the urging force of the urging means and the valve body is pushed open from the seat surface, From then on, until the predetermined rotation range, the outer shape of the main body of the valve body formed in a rectangular shape along the outer shape of the seat surface constitutes the exhaust pressure receiving surface. The pressure receiving area increases and the valve opening force due to the exhaust pressure becomes relatively strong. As a result, the valve body can be pushed open with a lower exhaust pressure than when the valve is closed once the valve body is separated from the seat surface, thus satisfying the demand for lower back pressure during high-speed engine rotation. Can be made.
Accordingly, it is possible to simultaneously achieve a request for reducing noise required when the engine rotates at a low speed and a request for reducing back pressure required when rotating at a high speed.

Further, the base surface of the valve body on the support shaft side of the main body portion is provided with a shielding wall having an outer surface extending substantially along the rotation trajectory of the base end centered on the support shaft. Since the base end side of the main body and the base end side of the main body portion are configured to be kept in contact with a minute gap, exhaust gas does not leak from the support shaft side. The effect of reducing the back pressure at the time of high-speed rotation of the engine due to the expansion of the exhaust pressure receiving area received by the valve body can be sufficiently exhibited.
Furthermore, since the hot exhaust gas does not go in the direction of the urging means such as a coil spring attached to the support shaft, the sag resistance of the urging means can be improved.

In the invention of claim 2, as described above, a flange portion extending in a direction away from the support shaft is extended at the upper end edge of the outer wall of the front end of the valve seat, and at the front end edge of the main body of the valve body, A distal end inner wall extending to at least the upper end edge of the distal end outer wall of the valve seat and a plug body portion extending from the upper end edge of the distal end inner wall in a direction away from the support shaft are extended, and is supported on the distal end edge of the flange portion of the valve seat. A second tip outer wall having an inner surface substantially along the rotation trajectory of the tip edge portion of the plug body portion centering on the shaft extends toward the downstream side, whereby the second tip outer wall and both side walls Since the valve body is configured to open when the valve body exceeds a predetermined rotation range from the state in which the main body portion of the valve body abuts on the seat surface and the control valve is closed, the valve body further rotates and the tip of the main body portion The edge is separated downstream from the upper edge of the outer wall of the tip of the valve seat. This time, the tip end edge of the plug body portion constitutes the exhaust pressure receiving area. As a result, the exhaust pressure receiving area becomes larger than the time when the valve body is separated from the seat surface, and the exhaust pressure receiving area is relatively increased. As a result, the valve opening force is further increased, so that the valve body can be pushed open with a lower exhaust pressure.
That is, before the control valve opens, the exhaust pressure receiving area expands in two stages, thereby suppressing the unstable phenomenon of pressure amplitude due to a sudden increase in the exhaust pressure receiving area. become able to.

  According to the third aspect of the present invention, as described above, the upper end edge portion of the second tip outer wall of the valve seat has the third flange portion and the third tip outer wall further extending in the direction away from the support shaft. The distal end edge of the plug body portion of the valve body extends from at least the second distal end inner wall extending to at least the upper end edge of the third distal end outer wall of the valve seat and the upper end edge of the second distal end inner wall. Since the second plug body portion extending in a direction away from the shaft extends one or more stages, the main body portion of the valve body abuts against the seat surface by the third tip outer wall and both side walls and the control valve is closed. By configuring the valve to open when it exceeds a predetermined rotation range, the exhaust pressure receiving area is expanded in three or more stages until the control valve opens. Further suppression of pressure amplitude instability due to sudden increase in pressure receiving area So that it is able to.

  According to a fourth aspect of the present invention, as described above, the valve seat is configured by a baffle plate that partitions the inside of the muffler body, and both side walls and a front outer wall are attached and fixed to a seat surface of the valve seat configured by a baffle plate. By adopting such a configuration, it is possible to omit the plate material of the seat surface portion of the valve seat, thereby making it possible to reduce cost and weight.

  An embodiment of the present invention will be described with reference to the drawings.

The exhaust control valve of the first embodiment corresponds to the invention described in claim 1.
First, the configuration of the exhaust control valve of the first embodiment will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an exhaust control valve of the first embodiment ((A) is a closed state, (B) is an initial valve opening state, (C) is a valve opening state), FIG. 2 is a plan view thereof, FIG. 3 shows an exploded perspective view of the exhaust control valve. The exhaust control valve is connected to an end of an exhaust pipe (exhaust flow passage) P in the muffler body, and is supported by the valve seat 1. A valve body 2 provided so as to be openable and closable via a shaft 3, and a coil spring (biasing means) 4 that urges the valve body 2 against the seat surface 12 of the valve seat 1 to close the control valve. And as a main component.

  More specifically, the valve seat 1 includes a pipe portion 11 connected and fixed to an end portion of an exhaust pipe (exhaust flow passage) P in the muffler body, and substantially outward from the end portion of the pipe portion 11. A rectangular seat surface 12 extending horizontally, and a base end side 12a, a tip end side 12b, and left and right sides of the seat surface 12 whose outer shape is parallel to the axial direction of the support shaft 3 that pivotally supports the valve body 2. It is formed in a rectangle having 12c and 12c.

  Further, left and right side walls 13 and 13 extend in parallel with each other toward the upper side (downstream side) of the valve body 2 in the valve opening direction on the left and right sides 12c and 12c of the seat surface 12. The side walls 13 and 13 have base ends extending from the base end side 12a to the base end side and downward (upstream side), and the support shaft 3 is attached between the extension portions 13a and 13a. .

  The main body 21 of the valve body 2 is formed in a rectangular shape along the outer shape of the seat surface 12 of the valve seat 1, and the base end side and the lower side (from the left and right end portions of the base end side 21 a of the main body portion 21 ( The left and right shaft support portions 22, 22 extending in parallel with each other to the upstream side) are rotatably supported by the support shaft 3.

  On the front end side 12 b of the seat surface 12 of the valve seat 1, which faces the base end side 12 a on the side of the support shaft parallel to the support shaft 3, the front end side (front end edge) of the main body 21 centering on the support shaft 3. The distal end outer wall 14 having an arcuate inner surface substantially along the rotation trajectory of 21b is extended upward (downstream), whereby the body of the valve body 2 is formed by the distal end outer wall 14 and the left and right side walls 13 and 13. The valve is opened when the portion 21 exceeds the predetermined rotation range from the state in which the control valve is closed by contacting the seat surface 12.

  A shielding wall 23 having an outer surface substantially extending along the rotational trajectory of the base end side 12 a centering on the support shaft 3 is extended to the base end side 12 a on the support shaft side of the main body 21 in the valve body 2. In this way, the base end side 12a of the sheet surface 12 and the base end side 21a of the main body 21 are maintained in contact with each other.

  The coil spring 4 has a coil portion 41 mounted around the support shaft 3, and both ends of the coil spring 4 are substantially at the center of the main body portion 21 of the valve body 2 and the base end side 21 a of the main body portion 21 of the valve seat 1. The annular seal surface portion 21c of the main body portion 21 of the valve body 2 is made to contact the valve seat 2 by being brought into contact with and locked to the lower end edge portion of the extending portion 17 extending longer than the shielding wall 23 along the shielding wall 23. The urging force is applied in the direction in which the control valve is closed by being brought into contact with one seat surface 12.

Next, functions and effects of the first embodiment will be described.
The exhaust control valve of the first embodiment is configured as described above, and as shown in FIG. 1 (a), the main body portion 21 of the valve body 2 is in contact with the seat surface 12 and the control valve is closed. Since the exhaust pressure receiving surface acting on the valve body 2 is a range defined by the inner diameter d of the seat surface 12, the engine speed is set to a predetermined value based on the area of the exhaust pressure receiving surface in the closed state. By setting the biasing force of the coil spring 4 so as not to open in the low speed range, the exhaust pressure flowing through the muffler is small when the engine is running at low speed. The force is higher and the control valve is kept closed.
Accordingly, it is possible to satisfy the demand for noise reduction required when the engine rotates at a low speed.

Further, when the engine speed exceeds a predetermined low-speed rotation range, the exhaust pressure flowing in the muffler increases, so that the fluid force overcomes the urging force of the coil spring 4 and the main body 21 of the valve body 2 is seated. In the initial rotation state pushed open from 12, the front outer wall 14 and the left and right side walls 13 in the valve seat 1 are shown in FIG. 1 (b) until the first predetermined rotation angle θ1 position. , 13 and the entire rectangular seat surface 12 surrounded by the shielding wall 23 of the valve body 2 constitutes an exhaust pressure receiving surface, so that the exhaust pressure receiving area becomes larger than when the valve is closed and is relatively dependent on the exhaust pressure. Since the valve opening force becomes stronger, the valve body 2 can be pushed open with a lower exhaust pressure than at the time of initial rotation after the valve body 2 is once separated from the seat surface 12. Low at high engine speed It can be satisfied pressurization requirements.
Therefore, it is possible to achieve an effect that it is possible to simultaneously achieve a request for low noise required at the time of low-speed rotation of the engine and a request for low back pressure required at the time of high-speed rotation.

  Further, a shielding wall 23 having an arcuate outer surface substantially along the rotation trajectory of the base end side 21 a centering on the support shaft 3 is formed on the base end side 21 a on the support shaft side of the main body 21 in the valve body 2. By being extended, the base end side 12a of the seat surface 12 and the base end side 21a of the main body 21 are maintained in contact with each other. Therefore, the effect of lowering the back pressure at the time of high-speed rotation of the engine due to the expansion of the exhaust pressure receiving area received by the valve body 2 can be sufficiently obtained.

  Furthermore, since the hot exhaust gas does not go in the direction of the coil spring 4 attached to the support shaft 3, the effect that the sag resistance of the coil spring 4 can be improved is also obtained.

  Next, another embodiment of the present invention will be described. In the description of the other embodiments, the same components as those in the above embodiment are denoted by the same reference numerals, the description thereof is omitted, and only the differences will be described.

The exhaust control valve of the second embodiment corresponds to the invention described in claims 1 and 2.
First, the configuration of the exhaust control valve of the second embodiment will be described with reference to the drawings.
FIG. 4 is a longitudinal sectional view showing the exhaust control valve of the second embodiment ((A) is a closed state, (B) is a first stage (initial) valve opened state, (C) is a second stage valve opened state, FIG. 5 is a plan view of the same, and FIG. 6 is an exploded perspective view of the same.

  That is, in the exhaust control valve of the second embodiment, a flange portion 15 extending in a direction away from the support shaft 3 is further extended at the upper end edge portion of the distal end outer wall 14 in the valve seat 1. A distal end inner wall 24 extending at least to the upper end edge of the distal outer wall 14 in the valve seat 1 and a plug body 25 extending in a direction away from the support shaft 3 from the upper end edge of the distal inner wall 24 are provided on the distal end side 12 b of the main body 21. A second tip that is further extended and has an arcuate inner surface substantially along the trajectory of the tip edge of the plug body 25 around the support shaft 3 at the tip edge of the flange portion 15 in the valve seat 1. By further extending the outer wall 16 toward the downstream side, the main body portion 21 of the valve body 2 is seated on the seat surface 12 by the second tip outer wall 16, the left and right side walls 13, 13 and the shielding wall 23 of the valve body 2. From the state where the control valve is in contact with the The up rotation angle θ2 (> θ1) position that it is configured not to open is that different from the first embodiment.

That is, in the second embodiment, because it is configured as described above, as shown in FIG. 4A, the main body portion 21 of the valve body 2 is in contact with the seat surface 12 and the control valve is closed. As shown in FIG. 4B, after turning to a predetermined turning angle θ1, the valve body 2 further turns, and as shown in FIG. If it leaves | separates downstream from the upper end edge part of the front-end | tip outer wall 14 in the valve seat 1, it will come to comprise the exhaust-pressure receiving area to the front-end | tip edge part of the plug body part 25 this time, As a result, from the seat surface 12, the valve body The exhaust pressure receiving area becomes larger than that at the time when 2 is separated, and the valve opening force due to the exhaust pressure becomes relatively stronger, so that the valve body 2 can be pushed open with a lower exhaust pressure. Become.
That is, before the control valve opens, the exhaust pressure receiving area expands in two stages, thereby suppressing the unstable phenomenon of pressure amplitude due to a sudden increase in the exhaust pressure receiving area. become able to.

  Accordingly, 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. Since the exhaust pressure receiving area in the valve body 2 gradually increases in steps, an effect that an unstable pressure amplitude phenomenon due to an increase in the exhaust pressure receiving area can be suppressed can be obtained.

The exhaust control valve of the third embodiment corresponds to the invention described in claim 4.
First, the configuration of the exhaust control valve of the third embodiment will be described with reference to the drawings.
FIG. 7 is a longitudinal sectional view showing the exhaust control valve of the third embodiment ((A) is in a closed state, (B) is in an initial valve open state, (C) is in a valve open state), and FIG. 8 is a plan view thereof. As shown, the exhaust control valve includes a baffle plate 5 in which the valve seat 1 partitions the inside of the muffler body, and a seat of the valve seat 1 in which the side walls 13 and 13 and the outer end wall 14 are formed of the baffle plate 5. The point which is attached and fixed to the surface 12 is different from the first and second embodiments.

  That is, in the third embodiment, the side walls 13 and 13 and the outer end wall 14 are integrally bent in a U-shaped cross section, and outward from the lower end edges of the side walls 13 and 13 and the outer end wall 14, respectively. A frame 6 in which the fixing plates 13b and 14a are integrally bent is formed separately, and the frame 6 is fixed by attaching the fixing plates 13b and 14a to the baffle plate 5 by spot welding or the like. Thus, the baffle plate surface in the frame 6 constitutes the seat surface 12 of the valve seat 1.

  The baffle plate 5 is formed with a protrusion 5a by pressing so as to prevent the exhaust gas from leaking by always contacting the outer surface of the shielding wall 23 when the valve body 2 is opened and closed.

  In the second embodiment, as described above, the valve seat 1 is configured by the baffle plate 5 that partitions the inside of the muffler main body, and the side surfaces 13 and 13 and the front outer wall 14 are configured by the baffle plate 5. By adopting a configuration that is fixedly attached to the seat 12, the plate material of the seat surface 12 portion of the valve seat 1 can be omitted, thereby obtaining an additional effect that the cost can be reduced and the weight can be reduced. It is done.

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 second embodiment, the example in which the exhaust pressure receiving area is expanded in two stages has been described. However, the exhaust pressure receiving area may be divided and expanded in three or more stages.

Moreover, although the case where the seat surface 12 of the valve seat 1 and the main body portion 21 of the valve body 2 are formed in a planar shape is taken as an example, the present invention can also be applied to those formed in a tapered shape.
In the embodiment, the coil portion of the coil spring 4 is mounted on the support shaft 3 on which the valve body 2 is supported. However, the coil spring 4 may be mounted on a support shaft separate from the support shaft 3.

  In the embodiment, the valve seat 1 is provided at the end of the exhaust pipe P in the muffler body. However, the valve seat 1 may be provided on a partition plate (baffle plate) in the muffler according to the inner structure of the muffler. The same effect can be obtained.

  In the embodiment, the coil spring 4 is used as the biasing means, but other known biasing means such as a plate spring can be used.

The longitudinal sectional view (a) showing the exhaust control valve of the first embodiment is a valve closed state, (B) is an initial valve open state, and (C) is a valve open state)). FIG. 3 is a plan view showing an exhaust control valve according to the first embodiment. 1 is an exploded perspective view showing an exhaust control valve of Example 1. FIG. FIG. 6 is a longitudinal sectional view showing an exhaust control valve of Example 2 ((A) is in a closed state, (B) is in a first stage opened state, (C) is in a second stage opened state, and (D) is in a third stage. Open valve state)). 6 is a plan view showing an exhaust control valve of Embodiment 2. FIG. 6 is an exploded perspective view showing an exhaust control valve of Embodiment 2. FIG. A longitudinal sectional view (a) showing the exhaust control valve of the third embodiment is a valve closed state, (b) is an initial valve open state, and (c) is a valve open state)). 6 is a plan view showing an exhaust control valve of Embodiment 3. FIG. It is a longitudinal cross-sectional view which shows the exhaust control valve of the prior art example 1. It is a longitudinal cross-sectional view which shows the exhaust control valve of the prior art example 2.

Explanation of symbols

P Exhaust pipe (exhaust flow passage)
DESCRIPTION OF SYMBOLS 1 Valve seat 11 Pipe part 12 Seat surface 12a Base end side 12b Front end side 12c Side side 13 Side wall 13a Extension part 13b Fixing plate 14 End outer wall 14a Fixing plate 15 Flange part 16 End outer wall 17 Extension part 2 Valve body 21 Main body part 21a Base End side 21b Tip side (tip edge)
21c Annular seal surface part 22 Shaft support part 23 Shielding wall 24 Tip inner wall 25 Plug body part 3 Support shaft 4 Coil spring (biasing member)
41 Coil part 5 Baffle plate 5a Projection 6 Frame

Claims (4)

A valve body that can be opened and closed via a support shaft with respect to a valve seat provided in the middle of the exhaust flow passage in the muffler body;
An urging means for urging the valve body in a direction to close the control valve by abutting the seat surface of the valve seat;
In an exhaust control valve with
The outer shape of the seat surface of the valve seat with which the main body portion of the valve body abuts is formed into a rectangle having sides parallel to the axial direction of the support shaft that pivotally supports the valve body,
The valve body is formed in a rectangular shape along the outer shape of the seat surface,
On both sides adjacent to the side parallel to the support shaft on the seat surface of the valve seat, side walls extend in parallel to each other toward the downstream side which is the valve opening direction of the valve body,
The seat surface is formed by extending a shielding wall having an outer surface substantially along the rotation trajectory of the base end side around the support shaft to the base end side of the main body portion of the valve body on the support shaft side. The base end side of the main body and the base end side of the main body portion are configured to be maintained in contact with each other,
The inner surface of the seat surface of the valve seat, which is substantially along the trajectory of the distal end edge of the main body centered on the support shaft, at the front end side opposite to the base end side on the support shaft side parallel to the support shaft And a predetermined rotation range from a state in which the main body portion of the valve body abuts against the seat surface and the control valve is closed by the distal end outer wall and the both side walls. An exhaust control valve that is configured to open when exceeded. A flange portion extending in a direction away from the support shaft is extended to an upper end edge portion of a distal end outer wall of the valve seat,
A distal end inner wall extending to at least the upper end edge of the outer wall of the distal end of the valve seat and a plug body extending from the upper end edge of the inner wall of the distal end in a direction away from the support shaft extend at the distal end edge of the main body of the valve body. And
A second end outer wall having an inner surface substantially along the rotation trajectory of the front end edge of the plug body portion around the support shaft extends toward the downstream side at the front end edge of the flange portion of the valve seat. By being provided, the valve body is opened when the control valve is closed from the state in which the main body portion of the valve body abuts against the seat surface by the second outer wall and the both side walls and the control valve is closed. The exhaust control valve according to claim 1, wherein the exhaust control valve is configured. A third flange portion and a third tip outer wall that extend further in a direction away from the support shaft are provided at one or more stages on the upper edge of the second tip outer wall of the valve seat,
The distal end edge of the plug body portion of the valve body includes at least a second distal inner wall extending to the upper edge of the third distal outer wall of the valve seat and an upper edge of the second distal inner wall from the support shaft. When the second plug body portion extending in the separating direction is extended by one or more stages, the main body portion of the valve body abuts against the seat surface by the third tip outer wall and the both side walls to close the control valve. The exhaust control valve according to claim 2, wherein the exhaust control valve is configured to open when a predetermined rotation range is exceeded from a state. The valve seat is composed of a baffle plate that partitions the inside of the muffler body,
The exhaust control valve according to any one of claims 1 to 3, wherein the both side walls and the front outer wall are fixedly attached to a seat surface of a valve seat constituted by the baffle plate.

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