JP6596394B2 - Silencer - Google Patents

Description

  The present invention relates to a silencer.

  2. Description of the Related Art Conventionally, in a silencer for an internal combustion engine, an inlet pipe and an outlet pipe are provided in the silencer, and a first valve that opens and closes according to an exhaust gas flow rate is provided at an upstream end of the outlet pipe. It is known that a downstream side is connected to an outlet pipe and a second valve is provided at an upstream end of the bypass pipe.

  The first valve is opened when the internal combustion engine is rotating at a high speed, and the second valve is set so as to start opening at a lower exhaust gas flow rate than the first valve. Accordingly, as the exhaust gas flow rate increases, the second valve starts to open before the first valve, so that the pressure fluctuation is reduced and chattering of the first valve is suppressed (see Patent Document 1).

Japanese Patent No. 4451728

  The conventional silencer requires a step of providing a first valve on the outlet pipe, a step of providing a second valve on the bypass pipe connected to the outlet pipe, and a step of attaching the bypass pipe to the outlet pipe. There is a problem that it takes time and effort.

  Therefore, an object of the present invention is to propose a silencer that is easier to assemble than the silencer.

In order to solve the above problems, the present invention provides a housing, an inlet pipe for introducing exhaust gas discharged from an internal combustion engine into the housing, and an outlet pipe for leading exhaust gas to the outside of the housing. In the silencer provided,
A plurality of sound deadening chambers are defined in the housing,
The outlet pipe is provided with a bypass hole communicating any one of the muffler chamber and the outlet pipe, and a first flow rate that can restrict the flow rate of the exhaust gas flowing into the outlet pipe by a valve opening operation. A valve body and a second valve body are provided,
The first valve body and the second valve body are provided on the upstream side of the outlet pipe and in the same silencing chamber,
The second valve body is used to open and close an opening hole formed in the first valve body .

  Further, the second valve body is configured by a leaf spring so that the second valve body starts to open with a smaller exhaust gas flow rate than the first valve body, and the second valve body is biased in the closing direction. Also good.

  A first opening hole is formed at an upstream end of the outlet pipe so as to be inclined with respect to an axis of the outlet pipe, the first opening hole is opened and closed by the first valve body, and the first valve In a state where the body is closed, a portion of the first valve body that contacts the valve seat provided in the first opening hole may be inclined with respect to the outlet pipe axis.

  A bypass pipe may be connected to the bypass hole.

  In the silencer of the present invention, a bypass hole and a first valve body and a second valve body capable of limiting a flow rate of exhaust gas flowing into the outlet pipe by a valve opening operation are provided in the outlet pipe. Since the second valve body is provided in the same silencing chamber, the assembling work is facilitated as compared with the prior art.

1 is a partial cross-sectional view of a silencer according to Embodiment 1 of the present invention. The AA line expanded sectional view of FIG. The principal part longitudinal cross-sectional view of the outlet pipe used for Example 1 of this invention. FIG. 4 is a longitudinal sectional view of a main part of the outlet pipe in a state where the rotational speed of the internal combustion engine is increased from the state of FIG. 3. The principal part longitudinal cross-sectional view of the outlet pipe of the state which raised the rotation speed of the internal combustion engine further from the state of FIG. The principal part longitudinal cross-sectional view of the outlet pipe of the state decelerated from the state of FIG. Sectional drawing equivalent to FIG. 2 which concerns on Example 2 of this invention. The partial cross section figure of the silencer which concerns on Example 3 of this invention. The partial cross section figure of the silencer which concerns on Example 4 of this invention. An example of sectional drawing equivalent to FIG. 2 which concerns on Example 5 of this invention. The other example of sectional drawing equivalent to FIG. 2 which concerns on Example 5 of this invention. The other example of sectional drawing equivalent to FIG. 2 which concerns on Example 5 of this invention. The principal part longitudinal cross-sectional view of the outlet pipe used for Example 6 of this invention. The partial cross section figure of the silencer which concerns on Example 7 of this invention.

  A mode for carrying out the present invention will be described based on an embodiment shown in the drawings.

[Example 1]
FIG. 1 shows a partial cross-sectional view of a silencer 1 according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the silencer 1 has a cylindrical shell 2 that is open at both ends, and an outer plate 3, 4 is joined to both ends of the shell 2 to form a housing 5.

  In the housing 5, three sound deadening chambers 10, 11, 12 partitioned by two separators 6, 7 are formed. An inlet pipe 15 into which exhaust gas discharged from the internal combustion engine is introduced penetrates and is fixed to the outer plate 3 and the separators 6 and 7, and an outlet pipe 16 penetrates the outer plate 4 and the separators 6 and 7. And fixed. The exhaust gas introduced into the muffler chambers 10, 11, 12 is led out of the housing 5 through the outlet pipe 16.

  The inlet pipe 15 is formed with a plurality of holes 15 a that connect the interior of the inlet pipe 15 and the first silencing chamber 10, and a plurality of holes 15 b that communicate the interior of the inlet pipe 15 and the second silencing chamber 11. Further, the downstream end 15 c of the inlet pipe 15 opens into the third silencing chamber 12.

  A communication hole (not shown) is formed in the separator 6 so that the first silencing chamber 10 and the second silencing chamber 11 communicate with each other.

  An upstream side portion of the outlet pipe 16 is located in the first silencing chamber 10, and a bypass hole 18 is formed in a side surface of the upstream side portion. And communicate with each other. The opening area of the bypass hole 18 is set smaller than the flow path cross-sectional area of the outlet pipe 16.

  As shown in FIG. 3, an end plate 16a orthogonal to the axis XX of the outlet pipe 16 is provided at the upstream end of the outlet pipe 16, and a first opening hole 20 is formed through the end plate 16a. Has been. At the upstream end portion of the outlet pipe 16, a first valve body 21 made of a butterfly valve that opens and closes a part of the first opening hole 20 is centered on a valve shaft 22 orthogonal to the axis XX, and the outlet pipe 16 It is provided so that it can be rotated inward. A first valve body 21 abuts on the inner side surface of the end plate 16a and the peripheral edge of the first opening hole 20, and a valve seat 25 made of a wire mesh or the like is provided. The first valve body 21 is urged in a direction to contact the valve seat 25 by an urging means 23 such as a coil spring, that is, a valve closing direction. When the exhaust gas flow rate becomes equal to or higher than the first predetermined flow rate, the first valve body 21 is urged. The first valve body 21 starts to open against the urging force of the means 23.

  A second opening hole 28 having an opening area smaller than that of the first opening hole 20 is formed in the central portion of the first valve body 21. On the inner surface of the first valve body 21, that is, on the downstream side, a plate-like second valve body 30 that opens and closes the second opening hole 28 is fixed to the first valve body 21 by welding or the like. It is provided.

  As shown in FIG. 2, the second valve body 30 is composed of a circular opening / closing portion 30a and an attachment portion 30b formed integrally with the opening / closing portion 30a. 30b is fixed to the first valve body 21 by welding or the like. The second valve body 30 is provided by its own urging force so as to urge the valve seat 31 made of a wire mesh or the like provided on the inner surface of the first valve body in a closing direction. When the gas flow rate becomes equal to or higher than the second predetermined flow rate, the second valve body 30 starts to open against the urging force of the second valve body 30 itself. The exhaust gas flow rate at which the second valve body 30 begins to open is set to be smaller than the exhaust gas flow rate at which the first valve body 21 begins to open.

  The first opening hole 20 and the second opening hole 28 are provided so as to open to the same first silencing chamber 10, and the first valve body 21 and the second valve body 30 are arranged in the same first silencing chamber 10. Has been.

  Next, the opening / closing operation | movement of the 1st valve body 21 and the 2nd valve body 30 is demonstrated.

  When the rotational speed of the internal combustion engine is extremely low (for example, 1000 rpm or less), as shown in FIG. 3, the first valve body 21 is urged by the urging means 23 and the second valve body 30 is urged by itself. The valves are closed by the force, and the exhaust gas flows from the first silencer chamber 10 through the bypass hole 18 into the outlet pipe 16 and is led out of the silencer 1. Since the opening area of the bypass hole 18 is smaller than the flow path cross-sectional area of the outlet pipe 16, a noise reduction effect can be obtained by passing exhaust gas through the bypass hole 18.

  When the rotational speed of the internal combustion engine is increased from the state of FIG. 3 and the rotational speed of the internal combustion engine becomes a low to medium rotational range (for example, 1000 to 2500 rpm), the flow rate of exhaust gas discharged from the internal combustion engine increases. As a result, as shown in FIG. 4, the second valve body 30 opens against its own urging force. However, the first valve body 21 remains in the closed state by the urging force of the urging means 23. Thus, the exhaust gas flows from the first silencing chamber 10 through the bypass hole 18 and the second opening hole 28 into the outlet pipe 16 and is led out of the silencer 1.

  At this time, the first valve body 21 may cause chattering due to exhaust pulsation. However, when the second valve body 30 is opened earlier than the first valve body 21, the exhaust pulsation is caused by the second opening hole 28. It is discharged to the outside of the silencer 1 through, and the occurrence of chattering in the first valve body 21 can be suppressed. The second valve body 30 may also cause chattering. However, since the second valve body 30 is formed smaller than the first valve body 21, chattering is unlikely to occur even if there is exhaust pulsation. Further, even if chattering occurs in the second valve body 30, since the second valve body 30 is small and light, chattering sound generated in the second valve body can be kept small.

  When the rotational speed of the internal combustion engine is increased from the state of FIG. 4 and the rotational speed of the internal combustion engine is in a medium to high rotational range (for example, 2500 rpm or more), the first valve body 21 is attached by exhaust gas as shown in FIG. The valve is opened against the urging force of the urging means 23, and the first valve body 21 and the second valve body 30 are opened. The exhaust gas flows from the first silencing chamber 10 through the bypass hole 18 and the first opening hole 20 into the outlet pipe 16 and is led out of the silencer 1. Since the exhaust gas flows into the outlet pipe 16 through the first opening hole 20 having a large diameter, an increase in back pressure can be suppressed.

  Further, when the rotational speed of the internal combustion engine shown in FIG. 5 is decelerated from the middle and high speed range, the first valve body 21 is first closed by the urging force of the urging means 23 as shown in FIG. 2, the second valve body 30 is closed by its own urging force, and the first silencing chamber 10 and the outlet pipe 16 communicate with each other only by the bypass hole 18.

  As shown in FIG. 6, after the second valve body 30 is first closed by its own urging force, the first valve body 21 is urged by the urging force of the urging means 23 as shown in FIG. The first valve body 21 and the second valve body 30 may be closed by integrating the two valve bodies 30 so that the first silencer chamber 10 and the outlet pipe 16 communicate with each other only by the bypass hole 18. You may make it close simultaneously as one.

  At the time of deceleration, as to which of the first valve body 21 and the second valve body 30 is closed first, or whether both valve bodies 21 and 30 are closed simultaneously, each valve body 21, It can be arbitrarily set by adjusting the urging force for closing the valve 30.

  Thus, in the silencer 1 of the present invention, the above-described silencing effect can be obtained, the back pressure increase can be suppressed, and the occurrence of chattering in the first valve body 30 can be suppressed. Moreover, since it is only necessary to attach the first valve body 21 having the second valve body 30 to the outlet pipe 15, the assembling work is facilitated as compared with the conventional technique.

  Moreover, by providing the 2nd valve body 30 in the 1st valve body 21, the outlet pipe 16 can be formed compactly and the space in the housing 5 can be used effectively.

  Moreover, since the 2nd valve body 30 was comprised with the leaf | plate spring, the manufacturing cost of the silencer 1 can be restrained low.

  In Japanese Patent No. 5067411, the first valve body is provided in the outlet pipe so as to be openable and closable, an opening is formed in the first valve body, and the opening is provided to be openable and closable with the second valve body. The second valve body is configured to close the opening formed in the first valve body when the exhaust gas flow rate becomes equal to or higher than the predetermined flow rate, and to open the opening portion when the exhaust gas flow rate becomes lower than the predetermined flow rate. Describes a silencer that suppresses an increase in sound pressure level due to air column resonance in the outlet pipe.

  The valve body 2 of Japanese Patent No. 5067411 prevents the increase of the back pressure by opening the internal combustion engine rotation region where the air column resonance does not occur, that is, when the exhaust gas flow rate is less than the predetermined flow rate. Is prevented. On the other hand, the second valve body 30 of the present invention opens the valve at a lower exhaust gas flow rate than the first valve body 21, thereby discharging exhaust pulsation and suppressing chattering from occurring in the first valve body 21. The structure and purpose are different.

[Example 2]
In the first embodiment, the second valve body 30 is configured by a leaf spring. However, as illustrated in FIG. 7, the second valve body 41 is configured by a butterfly valve or the like and rotates about the rotation shaft 42. The second valve body 41 may be biased in a direction in which the second valve body 41 is closed by a biasing means 43 such as a coil spring, that is, in a direction in which the second valve body 41 is in contact with the valve seat 44 provided in the first valve body.

  Since the other structure is the same as that of the first embodiment, the description thereof is omitted.

  Also in the second embodiment, the same effects as in the first embodiment are obtained.

[Example 3]
In the first and second embodiments, the first opening hole 20, the first valve body 21 and the second valve body 30 (41) are provided at the upstream end of the outlet pipe 16, and the bypass hole 18 is formed in the outlet pipe 16. Although provided on the side surface, as shown in FIG. 8, the bypass hole 18 is provided at the upstream end of the outlet pipe 16, and the first opening hole 20, the first valve body 21 and the second valve body 30 (41) are provided. You may provide in the side surface of the upstream part of the outlet pipe 16. FIG.

  Since other structures are the same as those of the first and second embodiments, description thereof is omitted.

  In the third embodiment, the same effects as in the first and second embodiments are obtained.

[Example 4]
In the first to third embodiments, the first valve body 21 is provided with the second opening hole 28 and the second valve bodies 30 and 41 are provided so as to be openable and closable with respect to the first valve body 21. As shown, the second opening hole 28 of the above embodiment is not provided in the first valve body 21A of the present embodiment, but at a position different from the first valve body 21A and at the upstream side portion of the outlet pipe 16. The second opening hole may be opened and closed by the second valve body 45 so as not to interfere with the bypass hole 18 on the side surface.

  Since other structures are the same as those in the first to third embodiments, description thereof is omitted.

  In the fourth embodiment, as in the first to third embodiments, since the first valve body 21A and the second valve body 45 are provided in the outlet pipe 16, it is easier to assemble as compared with the conventional technique. Become.

[Example 5]
In the said Example 1, 2, 4, although the bypass hole 18 was provided in the side surface of the outlet pipe 16, this bypass hole 18 can be provided in arbitrary positions.

  For example, as shown in FIG. 10, the bypass hole 47 may be provided in the end plate 16a on the upstream side of the outlet pipe 16, or the bypass hole 48 is formed in the second valve body 30 as shown in FIG. Alternatively, as shown in FIG. 12, the bypass hole 49 may be formed in the first valve body 21 where the second valve body 30 is not provided.

  Since other structures are the same as those in the first, second, and fourth embodiments, description thereof is omitted.

  In the fifth embodiment, the same effects as those of the first, second, and fourth embodiments are obtained.

[Example 6]
In the said Examples 1-5, although the 1st valve body 21 was formed in the state which closed the 1st valve body 21 so that it might orthogonally cross with respect to the axis | shaft XX of the outlet pipe 16, it shows in FIG. As described above, the upstream end plate 16A of the outlet pipe 16 is provided so as to be inclined with respect to the axis XX of the outlet pipe 16, the first opening hole 20 is formed in the end plate 16A, and the first valve body is formed. In a state in which the valve 21 is closed, a portion of the first valve body 21 that contacts the valve seat 25 may be provided so as to be inclined with respect to the axis XX of the outlet pipe 16.

  Since other structures are the same as those in the first to fifth embodiments, description thereof is omitted.

  In Example 6, the same effects as in Examples 1 to 5 are obtained.

  In the sixth embodiment, the first valve body 21 is generally difficult to open and close within a range of 90 °. However, as in the sixth embodiment, the end plate 16A of the outlet pipe 16 is connected to the outlet pipe. By forming it so as to be inclined with respect to the 16 axis, the first valve body 21 can be opened to a position near the position parallel to the axis XX of the outlet pipe 16 as shown by a broken line in FIG. It is possible to reduce airflow noise generated when the exhaust gas collides with the wall surface of the outlet pipe 16.

[Example 7]
As shown in FIG. 14, the seventh embodiment is an example in which a long bypass pipe 50 having a smaller diameter than the outlet pipe 16 is connected to the bypass hole 18 in the first embodiment. The upstream end 50a of the bypass pipe 50 opens into the second silencing chamber 11 as shown in FIG.

  Since other structures are the same as those in the first to sixth embodiments, description thereof is omitted.

  In Example 7, the same effects as in Examples 1 to 6 are obtained.

  In the seventh embodiment, by providing the long and small bypass pipe 50, the exhaust gas flows through the bypass pipe 50, so that a silencing effect due to the long tail effect can be exhibited.

[Other Examples]
The first valve body 21 and the second valve bodies 30, 41, and 45 are not limited to the structure of the above-described embodiment, and any structure or the like can be adopted.

  In addition, the number, shape, and the like of the sound deadening chamber in the housing 5 can be arbitrarily set.

DESCRIPTION OF SYMBOLS 1 Silencer 5 Housing 10, 11, 12 Silencer room 15 Inlet pipe 16 Outlet pipe 18, 47, 48, 49 Bypass hole 21,21A 1st valve body 28 Opening hole 30,41,45 2nd valve body 50 Bypass pipe

Claims (5)

In a silencer comprising a housing, an inlet pipe for introducing exhaust gas discharged from an internal combustion engine into the housing, and an outlet pipe for leading exhaust gas to the outside of the housing,
A plurality of sound deadening chambers are defined in the housing,
The outlet pipe is provided with a bypass hole communicating any one of the muffler chamber and the outlet pipe, and a first flow rate that can restrict the flow rate of the exhaust gas flowing into the outlet pipe by a valve opening operation. A valve body and a second valve body are provided,
The first valve body and the second valve body are provided on the upstream side of the outlet pipe and in the same silencing chamber,
A silencer, wherein the second valve body is used to open and close an opening formed in the first valve body . Muffler of claim 1, wherein than the first valve body and the second valve body, characterized in that as begins to open with less exhaust gas flow. The silencer according to claim 1 or 2, wherein the second valve body is configured by a leaf spring, and the second valve body is biased in a closing direction. A first opening hole is formed at an upstream end of the outlet pipe so as to be inclined with respect to an axis of the outlet pipe, the first opening hole is opened and closed by the first valve body, and the first valve body is opened and closed. in the closed state, any one of claims 1 to 3 wherein the first opening hole to provided a valve seat abutting portion in the first valve body and being inclined relative to the axis of the outlet pipe 1 The silencer described in the section. The silencer according to any one of claims 1 to 4 , wherein a bypass pipe is connected to the bypass hole.

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