JP2002235536A - Valve structure of engine exhaust system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the vibration caused by resonance of a valve element of an engine exhaust system valve. SOLUTION: A support member 10 having a tubular part 11 is joined with an end part of a muffler pipe 1 and forms a flange 12 as a valve seat and a support bracket 14. The valve element 20 is turnably supported on the support bracket 14 through a hinge shaft 15. The valve element 20 is constituted such that a ringlike outer peripheral part 23 is used as a contact face with the valve seat and a weight 30 is welded to a bead part 24 whose inner side more than the contact face swells on a rear surface. One end 18 of a spring 16 wound around the hinge shaft is locked on a rear surface of a valve wall 21 of the valve element, and the other end 19 thereof is locked in the support bracket. Since resonance frequency is reduced by the weight, the generation of whine noise in the number of revolutions in a normal use region of an engine is prevented, and since welding of the weight is done in the bead part, distortion does not occur in the outer peripheral part 23 which is the contact face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a valve installed in an engine exhaust system.

[0002]

2. Description of the Related Art As a conventional valve of this type, a structure in which a valve is installed in a pipe passage in a muffler of a vehicle is known. This is to open and close the exhaust passage in response to pressure fluctuations of the exhaust gas flowing from the engine side, thereby improving the silencing effect and preventing a decrease in engine output. In such an exhaust pressure sensitive valve, a spring for urging the valve body in the closing direction is provided, and is opened when an exhaust pressure large enough to overcome the urging force of the spring is applied.

[0003] In an environment where high-temperature exhaust gas flows, the fitting of the hinge portion supporting the valve element cannot be made precise in consideration of expansion and contraction due to thermal expansion, and the accuracy of the rotation axis is relatively high. It has to be rough.
For this reason, if the contact surface between the valve element and the valve seat is inclined, for example, in a conical shape, there is a problem that the center of the two is deviated and a gap is actually formed even though the valve is closed.

Accordingly, as shown in FIG. 3, the contact surface between the valve element and the valve seat is generally flat. In the valve structure shown in the figure, a support member 10 extending from the muffler pipe 1 has a flange 12 to form a valve seat. Support member 1
The valve body 40 supported on the hinge shaft 15 by the 0 support bracket 14 has a smooth surface facing the flange 12 of the support member, and has a flange 41 on the periphery thereof. The spring 16 is wound around the hinge shaft 15 to urge the valve body 40 against the flange 12 which is a valve seat.

[0005]

Here, the valve element 40 repeatedly opens and closes when the exhaust pressure increases, and closes when the exhaust pressure decreases. In the case of a valve element manufactured from a thin plate by press molding or the like, The resonance frequency increases due to the combination with the attached spring 16, and the valve body 4 at 2000 to 3000 rpm, which is the rotation speed of the engine in a normal range.
There is a problem that a vibration of 0 is generated, thereby generating a beat sound and deteriorating the quality of the vehicle.

In order to suppress the vibration of the valve element, the valve element 40
It is conceivable to increase the urging force of the spring 16 that urges the valve in the closing direction. However, if the spring force is increased, the valve will not open until the exhaust pressure becomes considerably high, and the original purpose is achieved. I can't. On the other hand, if the spring frequency is reduced to lower the resonance frequency, the valve opening pressure for opening the valve is reduced, and the valve body 40 itself is lightened in addition to the small exhaust pressure fluctuation. Will be lost.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and provides a valve structure of an engine exhaust system that does not generate vibration due to resonance of the valve body even when a lightweight valve body formed of a thin plate is used. The purpose is to do.

[0008]

According to the first aspect of the present invention, a valve element installed in an exhaust passage and urged in a closing direction by a spring is supported on a rotating shaft to respond to exhaust pressure. In the valve that opens and closes, the valve body has a bead portion formed in a portion of the valve wall other than a contact surface with a valve seat, and a weight is fixed to the bead portion. By fixing the weight to the valve wall, the resonance frequency of the valve body can be changed while maintaining the spring at a predetermined characteristic.

According to a second aspect of the present invention, the valve body of the valve body has a ring-shaped outer peripheral portion as the contact surface, the bead portion has an inner diameter portion bulging from the outer peripheral portion to the back side, and the weight is a bead on the back surface of the valve wall. It was fixed to the part. Since the weight is fixed to the back surface of the valve wall, there is no possibility of interference with the valve seat side.

According to a third aspect of the present invention, the spring is wound around the rotation shaft, one end of the spring is locked to the back surface of the valve wall, and the weight is fixed so as to avoid the locking point of one end of the spring. . Since the locking point of the spring is avoided, one end of the spring is not accidentally locked on the weight.

[0011]

Embodiments of the present invention will be described below. 1A and 1B show an embodiment in which the invention is applied to a muffler pipe inside a muffler, wherein FIG. 1A is a front view, and FIG. 1B is a cross-sectional view taken along the line AA in FIG. FIG. 2 is an enlarged view of the valve element, in which FIG. 2A is a front view, and FIG.
FIG. 3 is a sectional view taken along the line BB in FIG. A support member 10 having a tubular portion 11 is joined to an end of the muffler pipe 1, and a flange 12 is formed at a pipe end of the support member 10 as a valve seat. The mesh sheet 3 made of stainless steel is attached to the valve seat of the support member 10, that is, the flange 12 serving as a contact surface, and extends to the inner wall of the tubular portion 11. A part of the flange 12 extends downward in the drawing and is bent in a U-shape in a direction opposite to the muffler pipe 1 to form a support bracket 14.

A hinge shaft 15 as a rotation shaft is supported by the support bracket 14, and a valve body 20 is supported by the hinge shaft 15 so as to be rotatable. The valve body 20 has a valve wall 21 facing the flange 12 of the support member 10,
A flange 22 to be described later is provided on the periphery of the first member. One end 18 of the spring 16 wound around the hinge shaft 15 is locked on the back surface of the valve wall 21, and the other end 19 is supported on the support bracket 14.
It is locked to.

As is apparent from FIG. 2, the valve wall 21 has a ring-shaped outer peripheral portion 23 directly facing the flange 12 of the support member 10 and serving as a contact surface, and has a smooth flat surface. 23, that is, the supporting member 1
Bead portion 2 swelling in the direction away from zero flange 12
It is 4. A flange 22 is formed on the outer peripheral edge of the outer peripheral portion 23 in the same direction as the bulging direction of the bead portion 24, and a part of the flange 22 is extended to form a U-shaped support bracket 14.
A U-shaped hinge portion 25 is formed by a base portion 26 and bearing portions 27 rising from both ends thereof. Reference numeral 32 denotes a notch for avoiding interference with the end 19 of the spring 16 locked on the support bracket 14. A hole 28 is formed in the bearing portion 27 by piercing, and a washer 29 formed of stainless steel mesh and having an inner diameter through which the hinge shaft 15 passes is fitted.

On the back surface of the valve wall 21, a peripheral flange 22 is provided.
Inside, a rectangular block-shaped weight 30 is fixed to the bead portion 24 by fillet welding. As shown in FIG. 2A, the weight 30 is mounted with its center of gravity G offset from the center C of the valve wall 21 in the same direction as the direction of the hinge shaft 15. As shown in FIG. 1A, the coil portion 17 of the spring 16 on the hinge shaft 15 is located on the same side as the weight 30 in the axial direction, and one end 18 of the spring is formed on the back surface of the valve wall 21 by the bead portion 24. It is locked at a position avoiding the weight 30.

The embodiment is configured as described above, and the contact surface between the valve body 20 and the valve seat (flange 12) is not an inclined surface but a flat surface, and the accuracy of the rotation axis of the valve body 20 is relatively coarse. Even when the valve is closed, no gap is generated, and the valve body 20 is provided with the weight 30, so that the resonance frequency is reduced without changing the urging force of the spring 16, and the engine is operated in the normal range. The generation of beats in numbers is prevented. For example, in an exhaust system for a normal passenger car, a valve element for a muffler pipe having a diameter of 50 mm is 1.2 mm.
When made of thick steel plate, the weight is 50-1
It is selected in the range of 00 g (gram).

The outer peripheral portion 23 of the valve wall 21, which is a contact surface of the valve body 20 with the valve seat, is a flat surface, and the inside thereof is formed as a bead portion 24 bulging out from the outer peripheral portion 23 to the rear side. Since the weight 30 is welded to 24, the influence of heat at the time of welding does not reach the outer peripheral portion 23 and the contact surface is not distorted. Furthermore, since the weight 30 is offset, a wide space is secured on one side, and the spring 1
It is easy to lock one end 18 of 6 directly to the back surface of the valve wall 21 while avoiding the weight 30. Conversely, since the weight 30 avoids the locking point of the one end 18 of the spring, there is no possibility that the weight 30 is erroneously locked on the weight 30 and the urging force of the spring 16 fluctuates.

Further, since the mesh sheet 3 made of stainless steel is adhered to the flange 12 of the support member 10 as a valve seat, there is no generation of an impact sound when the valve body 20 is closed. And the mesh sheet 3 is the tubular portion 1 of the support member.
Since it extends to the inner wall of the first unit, a reliable attachment state is maintained.

Although the weight 30 has a rectangular block shape in the embodiment, a circle, a semicircle, or any other shape can be selected. Further, the fixing of the weight 30 to the valve wall 21 is not limited to the fillet welding alone, and a welding hole may be formed in the bead portion 24 to perform plug welding, or may be fixed by other appropriate means.

[0019]

As described above, according to the present invention, in a valve in which a valve element urged by a spring opens and closes in response to exhaust pressure, a bead portion is provided at a portion of a valve wall of the valve element other than a contact surface with a valve seat. Is formed, and the weight is fixed to the bead portion, so that the resonance frequency of the valve body can be changed while maintaining the spring at a predetermined characteristic, and the beat due to the vibration of the valve body in the normal rotation range of the engine. The generation of noise is prevented, and the quality of the vehicle is improved.

In particular, the ring-shaped outer peripheral portion of the valve wall is used as a contact surface, and the bead portion is formed by bulging an inner diameter portion from the outer peripheral portion to the back side. There is no danger of interference.

Further, one end of the spring wound around the rotation shaft is locked to the back surface of the valve wall, and the weight is fixed at a position avoiding the locking point, so that the spring is erroneously placed on the weight. Locking is prevented, and there is no possibility that the biasing force of the spring fluctuates.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is an enlarged view showing a valve body.

FIG. 3 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Muffler pipe 3 Mesh sheet 10 Support member 11 Tubular part 12 Flange 14 Support bracket 15 Hinge shaft 16 Spring 17 Coil part 20 Valve element 21 Valve wall 22 Flange 23 Outer part 24 Bead part 25 Hinge part 26 Base part 27 Bearing part 28 Hole 29 Washer 30 weight

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaomi Fukuhara 5-24-15 Minamidai, Nakano-ku, Tokyo Calso Nic Kansei Corporation (72) Inventor Sea Shiroishi 5-24-15 Minamidai, Nakano-ku, Tokyo Calso Nick Kansei Corporation F term (reference) 3G004 AA01 BA03 BA04 DA24 EA02 EA03

Claims (3)

[Claims] A spring (1) installed in an exhaust passage.
6) A valve body (20) urged in the closing direction by a rotating shaft (15) that opens and closes in response to exhaust pressure, wherein the valve body is a valve seat on a valve wall (21). (12)
A bead portion (24) is formed at a portion other than the contact surface of the valve, and a weight (30) is fixed to the bead portion. 2. The valve wall (21) of the valve element (20) has a ring-shaped outer peripheral portion (23) as the contact surface, and the bead portion (24) has an inner diameter portion bulging rearward from the outer peripheral portion. The valve structure for an engine exhaust system according to claim 1, wherein the weight (30) is fixed to the bead portion on a back surface of the valve wall. 3. The spring (16) is wound around the rotation shaft (15), one end of the spring (16) is locked on the back surface of the valve wall (21), and the weight (30) is engaged with one end of the spring. 3. The valve structure for an engine exhaust system according to claim 1, wherein the valve structure is fixed so as to avoid a stop point.