JP2010144639A - Exhaust gas control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas control valve achieving both a demand for reducing noise required at a low speed state of an engine, and a demand for reducing back pressure required at a high speed state of the engine rotates at the same time and improving back pressure reducing effect in a valve opening initial stage. <P>SOLUTION: The exhaust gas control device includes a valve element 2 openably and closably provided to a valve seat 1 provided in a middle of an exhaust gas flow passage in a muffler body via a support shaft 3, a coil spring 4 for biasing the control valve in the valve closing direction by abutting the valve element 2 on a seat face 12 of the valve seat 1, and a tension coil spring 5 for biasing the control valve in the valve opening direction by biasing force weaker than that of the coil spring 4. In the tension coil spring 5, a fulcrum of the tension coil spring 5 (an axis S1 of a fulcrum side support shaft 5) with respect to the rotational center of the valve element 2 (an axis S3 of the support shaft 3), and a point of action with respect to the valve element 2 (an axis S2 of a point of action side support shaft 52) are set so that biasing force does not act in the valve opening direction at least when the exhaust control valve is closed. <P>COPYRIGHT: (C)2010,JPO&INPIT

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. .

Conventionally, this type of exhaust control valve closes the exhaust pipe by the biasing force of the coil spring and prioritizes the silencing effect with the small chamber as the resonance chamber, and the exhaust pressure resists the biasing force of the coil spring during high-speed engine rotation. The exhaust pipe is opened by pushing the valve body open, and the small chamber is used as an expansion chamber, and priority is given to preventing reduction in engine output due to low back pressure at high speed (for example, see Patent Document 1).
JP 2002-235536 A

However, since the biasing force of the coil spring acts to increase as the opening degree becomes larger than when the valve element is initially opened, the back pressure cannot be sufficiently reduced during high-speed rotation of the engine. There is a problem.
In this case, by setting the urging force of the coil spring to be weak, it is possible to reduce exhaust pressure loss by sufficiently reducing the back pressure at the time of high-speed rotation of the engine. Since it starts to open, there is a problem that it is not possible to meet the demand for noise reduction during low-speed rotation of the engine.
Further, if the biasing force of the coil spring is set to be strong, there is a problem that the effect of lowering the back pressure at the initial stage of valve opening is not sufficient.
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. .

  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 engine rotation and a low back pressure requirement required at a high-speed rotation, and at the initial stage of valve opening. An object of the present invention is to provide an exhaust control valve capable of improving the pressure lowering effect.

  In order to solve the above problems, the present invention provides a valve body that can be opened and closed via a support shaft with respect to a valve seat provided in the middle of an exhaust flow passage in the muffler body, and the valve body on the seat surface of the valve seat. And an urging means for urging the control valve in a closing direction so as to close the control valve, and an exhaust control valve having an urging force for urging the control valve in an opening direction with an urging force weaker than the urging force of the urging means. The pulling spring is set such that the urging force of the pulling spring with respect to the rotation center of the valve body and the operating point with respect to the valve body are set so that the urging force does not act in the valve opening direction at least when the exhaust control valve is closed. It was set as means.

According to the first aspect of the present invention, as described above, there is provided a tension spring that biases the control valve in the opening direction with a biasing force that is weaker than the biasing force of the biasing means, and the tension spring is at least when the exhaust control valve is closed. The fulcrum of the tension spring with respect to the rotation center of the valve body and the operating point with respect to the valve body are set so that the urging force does not act in the valve opening direction.
With this configuration, when the valve is closed, a strong urging force of the urging means acts, so that a request for low noise required when the engine rotates at a low speed is achieved, and when the valve is opened, the urging force is applied. When the biasing force of the pulling spring acts in the valve opening direction with respect to the biasing force in the valve closing direction by the means, it is possible to achieve a low back pressure requirement required during high-speed rotation.
In addition, since the urging force does not act in the valve opening direction at least when the exhaust control valve is closed, the pulling spring achieves the low noise requirement required at the time of low-speed engine rotation and achieves the back pressure in the initial stage of valve opening. The reduction effect can be improved.

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

First, the exhaust control valve of Example 1 is demonstrated based on drawing.
FIG. 1 is a longitudinal sectional view showing an exhaust control valve of the first embodiment, FIG. 2 is a plan view thereof, FIG. 3 is an explanatory view of operation ((A) is a valve closing state, (B) is an initial valve opening state, (C) Is a valve open state), and FIG. 4 shows a back pressure drop characteristic diagram.
The exhaust control valve according to the first embodiment includes a valve seat 1, a valve body 2, a support shaft 3, a coil spring (biasing member) 4, and a pair of tension springs 5 and 5.

As shown in FIGS. 1 and 2, the valve seat 1 includes a pipe portion 11, an annular seat surface 12, a cylindrical portion (cylindrical portion) 13, a substrate portion 14, and a pair of shaft support portions 15 and 15. It is equipped with.
The pipe portion 11 is connected and fixed to an end portion of an exhaust pipe (exhaust flow passage) P in the muffler body.
The annular seat surface 12 extends substantially horizontally from the end of the pipe portion 11 toward the outside.
The cylindrical portion (tubular portion) 13 is extended upward from an outer peripheral edge portion that further extends the seat surface 12 outward.
The substrate portion 14 extends in the horizontal direction from one end of the upper end opening edge of the cylindrical portion (tubular portion) 13 outward.
The pair of shaft support portions 15 and 15 are vertically raised by bending both side portions of the substrate portion 14 upward.
That is, the inner diameter φd2 of the cylindrical portion 13 is formed larger than the inner diameter φd1 of the seat surface 12.

The valve body 2 includes a main body portion 21, a flange portion 22, a cylindrical portion 23, a substrate portion 24, and shaft support portions 25 and 25.
The main body 21 has a width in a range in contact with the seat surface 12.
The flange portion 22 extends substantially horizontally from the outer peripheral edge portion of the cylindrical portion 22 toward the outside.
The cylindrical portion 23 extends substantially vertically from the outer peripheral edge portion of the flange portion 22 along the inner peripheral surface of the cylindrical portion 13 upward.
The substrate portion 24 extends horizontally from a part of the upper end opening of the cylindrical portion 23 toward the outside.
Both shaft support portions 25, 25 are vertically raised by bending the substrate portion 25 extending horizontally outward from one end of the upper end opening edge of the cylindrical portion 23 and both side portions thereof upward. ing.
The shaft support portions 25, 25 are located inside the shaft support portions 15, 15 of the valve seat 1, and the support shaft 3 that is horizontally mounted between the shaft support portions 15, 15 of the valve seat 1. The valve body 2 is assembled to the valve seat 1 so as to be openable and closable with the support shaft 3 as a center.
As described above, since the inner diameter φd2 of the cylindrical portion 13 is larger than the inner diameter φd1 of the seat surface 12, the outer diameter φd3 of the flange portion 22 is larger than the inner diameter φd1 of the seat surface 12. It is a diameter.

The coil spring 4 is provided with a coil portion 41 around the support shaft 3, and both ends of the coil spring 4 are brought into contact with and locked to the substantially central portion of the main body portion 21 of the valve body 2 and the base plate portion 14 of the valve seat 1. As a result, the main body portion 21 of the valve body 2 is brought into contact with the seat surface 12 of the valve seat 1 to apply a biasing force in a direction in which the control valve is closed.
That is, the flange portion 22 is in the cylindrical portion 13 of the valve seat 1 from the state in which the main body portion 21 of the valve body 2 is in contact with the seat surface 12 and the control valve is closed to the predetermined valve opening θ1 position. The upper end opening of the cylindrical portion 13 is maintained closed, and the upper end opening of the cylindrical portion 13 is opened and the control valve is opened when the valve opening exceeds θ1. Yes.

The pair of tension springs 5 and 5 serve to urge the control valve in the direction of opening the control valve with an urging force weaker than the urging force of the coil spring 4, and the tension spring 5 is at least when the exhaust control valve is closed. A fulcrum of the tension spring 5 with respect to the rotation center of the valve body 2 and an operating point with respect to the valve body 2 are set so that an urging force does not act in the valve opening direction.
That is, the valve body 2 is arranged at an intermediate portion on the straight line L connecting the axis S1 of the fulcrum side support shaft 51 serving as the fulcrum of the tension spring 5 and the axis S2 of the action point side support shaft 52 serving as the operation point with respect to the valve body 2. A rotation center (axial center S3 of the support shaft 3) is arranged.
The fulcrum side support shaft 51 is provided in a state of passing through the pair of shaft support portions 15, 15, and the action point side support shaft 52 is provided in a state of passing through the pair of shaft support portions 25, 25.

Next, the operation of the first embodiment will be described.
<Effects to achieve low noise requirements>
Since the exhaust control valve according to the first embodiment is configured as described above, when the valve body 2 is initially opened, that is, when the main body portion 21 of the valve body 2 is separated from the seat surface 12, the valve is opened. The exhaust pressure receiving surface acting on the body 2 has an area in a range defined by the inner diameter φd1 of the seat surface 12, as shown in FIG. Therefore, by setting the urging force of the coil spring 4 to be strong enough not to open the valve in the predetermined low-speed engine speed range with reference to the area of the exhaust pressure receiving surface in the initial stage of valve opening. When the engine is running at a low speed, the exhaust pressure flowing through the muffler is small, so that the biasing force of the coil spring 4 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.

<About the achievement of low pressure reduction requirements>
Since the exhaust control valve according to the first embodiment is configured as described above, the exhaust pressure flowing through the muffler increases at medium and high speeds when the engine speed exceeds a predetermined low-speed rotation range. The fluid force overcomes the urging force of the coil spring 4 and the valve body 2 is brought into the initial valve opening state in which the main body 21 is pushed open from the seat surface 12.
Thereafter, until the predetermined valve opening θ1 position, as shown in FIG. 3B, the cylinder portion 13 has an inner diameter φd2 that is larger than the inner diameter φd1 of the seat surface 12. Since the area including the outer diameter φd3 of the flange portion 23 that closes the upper end opening portion 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 due to the exhaust pressure is relatively performed. Strength becomes stronger.
As a result, after the main body 21 of the valve body 2 is once separated from the seat surface 12, the valve body 2 is pushed at a lower exhaust pressure than that at the time of initial valve opening, as shown in FIGS. Since it is opened, it is possible to satisfy the demand for lower back pressure during high-speed rotation of the engine.
Therefore, not only the low noise requirement required at the time of low-speed rotation of the engine can be achieved, but also a low back pressure requirement required at the time of high-speed rotation can be achieved simultaneously.

<Increasing the back pressure reduction effect at the initial stage of valve opening>
By providing a pulling spring 5 that urges the control valve in the opening direction with an urging force that is weaker than the urging force of the coil spring 4 and that does not act in the opening direction at least when the exhaust control valve is closed, the engine The effect of lowering the back pressure at the initial stage of valve opening can be improved while achieving the low noise requirement required at the time of low speed rotation.
As a result, as shown in FIG. 4, in the conventional example indicated by the dotted line, the pressure drop allowance began to open at 25% of the pressure, whereas in Example 1, the pressure drop allowance began to open to 75% of the pressure. % Can be improved to more than%.

Next, the effect of the first embodiment will be described.
As described above, the exhaust control valve according to the first embodiment includes the tension spring 5 that biases the control valve in the opening direction with a biasing force that is weaker than the biasing force of the coil spring 4, and the tension spring 5 is at least closed of the exhaust control valve. In order to prevent a biasing force from acting in the valve opening direction at the time of valve operation, the fulcrum of the tension spring 5 (axis S1 of the fulcrum side support shaft 51) and the valve body with respect to the rotation center (axis S3 of the support shaft 3) 2 is set (the axis S2 of the action point side support shaft 52).
That is, the valve body 2 is arranged at an intermediate portion on the straight line L connecting the axis S1 of the fulcrum side support shaft 51 serving as the fulcrum of the tension spring 5 and the axis S2 of the action point side support shaft 52 serving as the operation point with respect to the valve body 2. A rotation center (axial center S3 of the support shaft 3) is arranged.
With this configuration, a strong urging force of the coil spring 4 acts when the valve is closed, thereby achieving a low noise requirement required when the engine rotates at a low speed, and when the valve is opened, the urging force is applied. The urging force of the pulling spring 5 acts in the valve opening direction with respect to the urging force in the valve closing direction by the means, thereby achieving a low back pressure requirement required at high speed rotation.
In addition, since the urging force does not act in the valve opening direction at least when the exhaust control valve is closed, the tension spring 5 achieves the low noise requirement required at the time of low-speed rotation of the engine and achieves the back in the initial stage of valve opening. The pressure reduction effect can be improved.

  Next, another embodiment will be described. In the description of the other embodiments, the same components as those of the first embodiment are not shown, or the same reference numerals are given and the description thereof is omitted, and only the differences are described.

The second embodiment shows a modified example of the exhaust control valve in the first embodiment. FIG. 5 is an explanatory diagram of the operation ((A) is the valve closing state, (B) is the initial valve opening state, and (C) is the valve opening state. Open state).
In the second embodiment, when the control valve is closed, the fulcrum (fulcrum side) of the tension spring 5 with respect to the rotation center of the valve body 2 (axial center S3 of the support shaft 3) so that the urging force acts in the valve closing direction. This is different from the first embodiment in that a support point S1) and an action point for the valve body 2 (action point side support shaft S2) are set.
That is, an offset in a direction approaching the seat surface 12 with respect to the straight line L at an intermediate portion of the straight line L connecting the fulcrum (fulcrum side support shaft S1) of the tension spring 5 and the action point (action point side support shaft S2) with respect to the valve body 2. The center of rotation of the valve body 2 (axis S3 of the support shaft 3) is arranged in the state h.

  Therefore, in the second embodiment, the same effects as in the first embodiment can be obtained, and when the control valve is closed, the biasing force of the coil spring 4 and the biasing force of the tension spring 5 are shown in FIG. Acts in the direction to close the control valve, so that it is possible to satisfy the requirement for low noise required during low-speed rotation of the engine while achieving the requirement for low back pressure required during high-speed rotation.

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, two tension springs are provided, but the number provided is arbitrary.
Further, in the embodiment, a cylindrical portion (tubular portion) 13 is extended upward from an outer peripheral edge portion that further extends the seat surface 12 outward, and the inner periphery of the cylindrical portion 13 is extended from the outer peripheral edge portion of the flange portion 22. Although the cylindrical portion 23 extends substantially vertically upward along the surface, the present invention can also be applied to an exhaust pressure control valve having a structure in which these portions are not provided.

1 is a longitudinal sectional view showing an exhaust control valve of Example 1. FIG. FIG. 3 is a plan view showing an exhaust control valve according to the first embodiment. FIG. 4 is an operation explanatory view showing the exhaust control valve of the first embodiment ((A) is a valve closing state, (B) is an initial valve opening state, and (C) is a valve opening state). It is a back pressure fall characteristic figure of the exhaust control valve of Example 1. FIG. FIG. 6 is an operation explanatory view showing an exhaust control valve of Embodiment 2 ((A) is a valve closing state, (B) is an initial valve opening state, and (C) is a valve opening state).

Explanation of symbols

P Exhaust pipe 1 Valve seat 11 Pipe part 12 Seat surface 13 Cylindrical part (cylinder part)
14 Substrate part 15 Shaft support part 2 Valve body 21 Main body part 22 Flange part (plug body)
23 cylindrical portion 24 substrate portion 25 shaft support portion 3 support shaft 4 coil spring (biasing member)
41 Coil part 5 Pulling spring 51 Support point side support shaft 52 Action point side support shaft

Claims (5)

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 closing direction by bringing the valve body into contact with a seat surface of the valve seat;
In an exhaust control valve with
A tension spring that biases the control valve in a direction to open the control valve with a biasing force that is weaker than the biasing force of the biasing means;
The pulling spring is set such that the fulcrum of the pulling spring with respect to the rotation center of the valve body and the operating point with respect to the valve body do not exert a biasing force in the valve opening direction at least when the exhaust control valve is closed. An exhaust control valve characterized by having The exhaust control valve according to claim 1,
An exhaust control valve characterized in that the center of rotation of the valve body is disposed at an intermediate portion on a straight line connecting a fulcrum of the tension spring and an action point for the valve body. The exhaust control valve according to claim 1,
The pulling spring is set such that the fulcrum of the pulling spring with respect to the center of rotation of the valve body and the operating point with respect to the valve body exert a biasing force in the valve closing direction when the exhaust control valve is closed. An exhaust control valve characterized by that. The exhaust control valve according to claim 3,
The center of rotation of the valve body is disposed at a position offset in the direction approaching the seat surface with respect to the straight line at an intermediate portion of a straight line connecting a fulcrum of the tension spring and an action point for the valve body. Exhaust control valve. The exhaust control valve according to any one of claims 1 to 4,
A tubular portion having an inner diameter larger than the inner diameter of the seat surface defining an exhaust pressure receiving surface of the valve body is extended downstream of the seat surface in the valve seat portion,
On the valve body side, there is a plug that is in the cylinder portion from the state in which the valve body abuts on the seat surface and closes the control valve to a predetermined valve opening position and closes the upper end opening of the cylinder portion. An exhaust control valve characterized in that a body part is extended.

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