KR20070038916A - Exhaust valve bushing - Google Patents

Abstract

A bushing assembly for an exhaust system includes at least one first bushing component and at least one second bushing component, the at least one first bushing component receiving a rotating exhaust component rotating relative to the non-rotating exhaust component, the one The first first bushing part is made from a first material that provides a low friction surface for the rotating exhaust part, the at least one second bushing part is made of a second material different from the first material, and the second material is It provides noise reduction when the rotating exhaust component rotates with respect to the non-rotating exhaust component. As the shaft rotates, the first and second bushing parts cooperate to provide a good bearing surface that reduces noise while the valve is operating.

Description

Exhaust Valve Bushing {EXHAUST VALVE BUSHING}

1 is an illustration of an exhaust system having a bushing assembly according to the present invention.

2 is a cross-sectional view taken along plane 2-2 in FIG.

3 illustrates another embodiment of an exhaust valve having a bushing assembly according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: exhaust system

12: exhaust parts

14: noise damping valve

18: shaft

20: axis

24: housing

26: linkage assembly

28: Actuator

30: Internal parts

32: external parts

The present invention relates to a bushing assembly for an exhaust valve, using one type of material for providing a low friction surface and various types of material for providing a noise reduction function.

Often noise damping valves are used in vehicle exhaust systems to reduce noise generated while the vehicle is operating. In general, the noise damping valve is mounted on a shaft that pivots the flapper valve in an inlet tube formed inside an exhaust component, such as a muffler, for example. The flapper valve has a disk-shaped body that rotates inside the inlet tube to deform the exhaust flow region. The shaft is supported on a bushing that provides a bearing surface as the shaft rotates with respect to the housing. The shaft is coupled to an actuator that controls the movement of the shaft by a linkage assembly. As the shaft rotates, the flapper valve deforms the area of exhaust gas flow required to dampen the noise.

One problem with the conventional form is that the components and actuators in the noise damping valve generate operating noise. This type of noise is squeaking noise, which is caused by the motion between the shaft or the housing and the bearing surface. The other type of noise is known as impact noise. Impact noise is generated by a bushing against the housing or a collision of the shaft against the bushing at the maximum limit of movement of the actuator.

Conventionally, two different types of bushings have been used. One known bushing consists of a wire mesh material. Wire mesh bushings provide good noise damping properties against impact noise but have a high level of friction on the bearing surface, which causes squeaking noises. In addition, wire mesh bushings have relatively low wear characteristics, ie they wear quickly and deteriorate.

In other known shapes, ceramic bushings are used. Solid ceramic bushings have a low friction level that minimizes squeaking noises at the bearing surface. However, due to the solid configuration of the ceramic bushing, all impact noise is transmitted through the ceramic bushing.

Another problem with solid ceramic bushings is their thermal expansion. Ceramic materials have lower thermal expansion than the steel used to make the housing. Due to this difference in thermal expansion, the impact noise is formed relatively large when the exhaust component is cooled, and the bushing can be formed in a loose state inside the housing when the exhaust component is heated.

It is therefore desirable to provide a bushing assembly for an exhaust valve that provides a good bearing surface and reduces working noise.

The present invention provides a bushing assembly for an exhaust valve supported on a shaft. The bushing assembly causes the shaft to rotate the exhaust valve relative to the non-rotating exhaust component. The bushing assembly includes a first bushing component that provides a low friction bearing surface and a second bushing component that provides improved noise attenuation characteristics. The first bushing part is a solid part formed from a material such as a ceramic or sintered metal material, and the second bushing part is a non-solid part made of, for example, a wire mesh material.

In one exemplary embodiment, the second bushing component substantially surrounds the first bushing component. The first bushing part receives the shaft and the second bushing part is located between the first bushing part and the non-rotating exhaust part. In another exemplary embodiment, the first bushing part surrounds a first portion of the shaft and the second bushing part surrounds a second portion of the shaft axially spaced from the first portion.

In this configuration, the material of the first bushing part provides a low friction bearing surface that reduces squeaking noise, and the material of the second bushing part provides good noise damping properties against impact noise. The material of the second bushing part also accommodates the difference in thermal expansion between the steel material and the first material used to produce the non-rotating exhaust part.

These and other features of the present invention will be better understood according to the following drawings, description.

1, an exhaust system 10 is shown. Exhaust system 10 includes an exhaust component 12, such as an inlet tube for a muffler to direct the flow of exhaust gas from an engine (not shown). A noise attenuation valve 14 is located inside the exhaust component 12 to reduce noise generated while the vehicle is in operation. The noise damping valve 14 may be configured as an electric or vacuum type valve.

In the example shown, the noise attenuation valve 14 includes a flapper valve body 16 mounted to the shaft 18, which shaft 18 is internal to the shaft 20 within the exhaust component 12. Pivot the flapper valve body 16 relative to. The flapper valve body 16 rotates inside the exhaust component 12 to deform the exhaust gas flow region and is generally formed as a disk shaped body.

The shaft 18 is supported on a bushing assembly 22 that provides a bearing surface as the shaft 18 rotates with respect to the housing 24. The shaft 18 is coupled to an actuator 28 that controls the movement of the shaft 18 by a linkage assembly 26. As the shaft 18 rotates, the flapper valve body 16 deforms the exhaust gas flow region needed to dampen the noise. Preferably actuator 28 is a solenoid actuator controlled by a controller, and other actuators may be used.

The bushing assembly 22 supports the shaft 18 so that the housing 24 rotates about the shaft 20. The actuator 28 generally pivots or rotates the shaft 18 by the linkage assembly 26 back and forth between the travel limit stops. In the example of the solenoid actuator, the plunger may move the linkage assembly 26 to the first maximum movement limit while extending in one direction, thereby moving the linkage assembly 26 to the second maximum movement limit while contracting in the upward direction. Can be moved to When the actuator 28 reaches this movement limit stop, impact noise is generated.

Bushing assembly 22 is configured to reduce this impact noise. As shown in FIG. 2, the bushing assembly 22 includes an inner component 30 that receives the shaft 18 and an outer component 32 that surrounds the inner component 30. The internal component 30 is formed of a solid component made of a material such as ceramic or sintered metal. The outer part 32 is formed of a non-solid part made of a material such as a wire mesh. Preferably the wire mesh is formed of a mesh mat similar to the Brillo ^™ pad shape. Any type of ceramic or sintered metal material may be used to form the inner part 30, and any type of wire mesh material may be used to form the outer part 32.

The inner part 30 comprises a central hole 34 which forms a friction bearing inner surface 36. The inner component 30 also includes an outer surface 38 that directly connects the outer component 32. The outer component 32 includes a central hole 40 forming an inner surface 42 and an outer surface 44 directly connecting the housing 24. The inner surface 42 of the outer component 32 is preferably connected with the outer surface 38 of the inner component 30 with respect to the entire circumference of the inner component 30.

The shaft 18 is in a loose-fit state such that the spacing 50 is maintained between the outer surface 38 of the inner part 30 and at least a portion of the inner surface 42 of the outer part 32. It is received inside the central hole 34 of the internal component 30. The spacing 50 is formed very small, which is provided because the shaft 18 is expanded under high temperature conditions. The spacing 50 in FIG. 2 is exaggerated for clarity.

The housing 24 includes a housing hole 52 formed by the inner surface 54. The outer component 24 is received inside the housing hole 52 in a somewhat interference-fit state. The inner surface 54 of the housing hole 52 thus connects directly with the outer surface 44 of the outer component 32.

Preferably the housing 24 and shaft 18 are made of known steel material. The inner part 30 of the bushing assembly 22 made of ceramic material or sintered metal material has a coefficient of thermal expansion smaller than the steel material used to make the housing 24 and the shaft 18. The outer component 32 of the bushing assembly 22 made of wire mesh material accepts this difference in coefficient of thermal expansion. When the housing 24 is in a high temperature state, the housing tends to increase in size, compressing the wire mesh material from its initial shape. When the housing 24 is cooled, the housing 24 is retracted and the wire mesh material can be expanded to form an initial shape.

The wire mesh material of the outer component 32 also reduces the effect of impact noise. Since the external parts are not made of solid, ie mesh material, the impact noise is easily dispersed.

The ceramic or sintered metal material of the inner part 30 provides a very low friction bearing surface for the shaft 18. This low friction bearing surface eliminates or reduces any squeaking noise that may be generated by motion between the bushing assembly 22 and the housing 24 or shaft 18. The bushing assembly 22 thus additionally provides excellent noise reduction properties for squeaking and impact noises and provides a low-friction bearing surface.

The bearing assembly 22 may be located at any of a variety of locations along the shaft 18. In addition only one bushing assembly 22 is shown, while an additional bushing assembly 22 can be mounted on the shaft in various positions desired.

3 shows another example of a bushing assembly 60. In the shape of such a bushing, the bushing assembly comprises a first bushing part 62 and a second bushing part 64 made of a first material, and a third bushing part 66 and a first bushing part made of a second material. 4 bushing parts 68. The first bushing part 62 and the second bushing part 64 are made of a solid part from a material such as, for example, a sintered metal or ceramic. The third bushing part 66 and the fourth bushing part 68 are made of non-solid parts from the wire mesh material as mentioned above.

The first bushing part 62, the second bushing part 64, the third bushing part 66 and the fourth bushing part 68 are all mounted to support the shaft 18 to rotate relative to the housing 24. do. The first bushing component 62, the second bushing component 64, the third bushing component 66 and the fourth bushing component 68 are axially spaced apart from each other along the axis 20. Preferably the first bushing part 62 and the third bushing part 66 are mounted along a first shaft segment 70, and the fourth bushing part 68 connects the second shaft segment 72. Are mounted accordingly.

The first shaft segment 70 and the second shaft segment 72 are separated from each other by the third shaft segment 76. The flapper valve body 16 is supported on the shaft 18 at the third shaft segment 76.

The side edges facing the interior of the first and second bushing parts 62, 64 are separated from each other by a first axial distance A1 along the axis 20, and the third and fourth bushing parts 66, 68. The side edges facing toward the inside of) are separated from each other by a second axial distance A2 along the axis 20. The second axial distance A2 is less than the first axial distance A1. The third and fourth bushing parts 66, 68 are also located towards the interior of the first and second bushing parts 62, 64.

In the example shown, the second and fourth bushing parts 64, 68 have a longer hole length than the first and third bushing parts 62, 66. Hole lengths for the first bushing component 62, the second bushing component 64, the third bushing component 66, and the fourth bushing component 68 can be varied as needed. Additionally four bushing parts are shown in FIG. 3, and additional bushing parts or relatively few bushing parts can be integrally formed with the exhaust part 12 as required. However, one or more bushing parts made of sintered metal or ceramic material must be used in combination with one or more bushing parts made of wire mesh material.

In the shape of the bushing, ie bushing assembly 22 or bushing assembly 60, the ceramic or sintered metal material provides a low friction bearing surface to eliminate squeaking noise and the wire mesh material provides good performance for impact noise. Provides noise reduction characteristics. The wire mesh material also accommodates the difference in thermal expansion between the steel material used to make the housing 24 and the ceramic and sintered metal material. In addition, the main bushing assemblies 22 and 60 are shown to be used in the noise damping valve 14 located in the inlet tube for the muffler, while the bushing assemblies 22 and 60 are used for valves located in other types of exhaust components. Can be used for

Although a preferred embodiment of the present invention is shown, those skilled in the art will appreciate that certain modifications may be made within the scope of the present invention. Accordingly, the following claims are considered to determine the true scope and content of this invention.

Claims (20)

In a bushing assembly for an exhaust system, the bushing assembly is At least one first bushing component and at least one second bushing component, the at least one first bushing component receiving a rotating exhaust component rotating relative to the non-rotating exhaust component, wherein the at least one first bushing component is rotating Made from a first material that provides a low friction surface for the exhaust component, wherein the one or more second bushing components are made of a second material different from the first material, the second material being non-rotating with the rotating exhaust component. A bushing assembly, characterized in that it provides a noise reduction function when rotating with respect to the exhaust component. The bushing assembly of claim 1, wherein the at least one first bushing component is solid and the at least one second bushing component is non-solid. 3. The bushing assembly of claim 2, wherein the at least one second bushing part encloses the at least one first bushing part. 4. The one or more first bushing parts according to claim 3, wherein the one or more first bushing parts receive the rotary exhaust part in a loose-fitting state such that a gap is provided between at least a portion of an outer surface of the rotary exhaust part and an inner surface of the one or more first bushing parts. Bushing assembly, characterized in that. 4. The at least one second bushing component of claim 3, wherein the at least one second bushing component is directly connected with an inner surface of the non-rotating exhaust component and is directly connected with an outer surface of the at least one first bushing component. And a bushing assembly received between the at least one first bushing component and the non-rotating exhaust component. 4. The bushing assembly of claim 3, wherein the rotating exhaust component comprises a shaft connected to the exhaust valve and the non-rotating exhaust component comprises a housing. 4. The bushing assembly of claim 3, wherein the first material comprises a ceramic material and the second material comprises a wire mesh material. 3. The rotational exhaust component of claim 2, wherein the one or more first bushing components surround a first portion of the rotary exhaust component, and the one or more second bushing components surround a second portion of the rotary exhaust component axially spaced from the first portion. Bushing assembly, characterized in that. 9. The method of claim 8, wherein the at least one first bushing component comprises a first bushing and a second bushing, wherein the at least one second bushing component comprises a third bushing and a fourth bushing, the first bushing and The third bushing is mounted adjacent to each other along the first segment of the rotary exhaust component, the second bushing and the fourth bushing are mounted adjacent to each other along the second segment of the rotary exhaust component, the first segment and the second segment. And the segment is separated by a valve body supported on the rotating exhaust component. The bushing assembly of claim 8, wherein the first material comprises a sintered metal material and the second material comprises a wire mesh material. In an exhaust system, the exhaust system is A shaft supporting the exhaust valve for pivotal rotational movement in the exhaust component; A bushing assembly for supporting the shaft to make rotation about the housing and An actuator coupled to the shaft for moving the exhaust valve within the exhaust component such that exhaust flow is changed, the bushing assembly comprising one or more first materials comprised of a first material that provides a low frictional surface for the shaft; An exhaust system comprising one bushing component and at least one second bushing component comprised of a second material that provides a noise reduction function during operation of the exhaust valve. 12. The exhaust system of claim 11, wherein the at least one first bushing component is solid and the at least one second bushing component is non-solid. 13. The at least one second bushing component of claim 12, wherein the at least one second bushing component is directly connected with an inner surface of the housing and is directly connected with an outer surface of the at least one first bushing component. And wherein the at least one second bushing part surrounds the at least one first bushing part as received between the at least one first bushing part and the housing. 14. The exhaust system of claim 13, wherein the first material comprises a ceramic material and the second material comprises a wire mesh material. 15. The exhaust system of claim 14, wherein the at least one first bushing part includes an aperture for receiving the shaft in a loose-fitting state. 13. The shaft of claim 12, wherein the shaft defines an axis of rotation, the at least one first bushing part enclosing a first portion of the shaft, and the at least one second bushing part is a shaft from the first part along the axis of rotation. An exhaust system surrounding a second portion of said shaft spaced apart in a direction. 13. The method of claim 12, wherein the at least one first bushing component comprises a first bushing and a second bushing, wherein the at least one second bushing component comprises a third bushing and a fourth bushing, wherein the first bushing and the And a third bushing mounted adjacent to each other along the first shaft segment, wherein the first shaft segment and the second shaft segment are separated by a third shaft segment supporting the exhaust valve. 18. The method of claim 17, wherein the first bushing and the second bushing are spaced apart from each other by a first axial distance along the axis of rotation, wherein the third bushing and the fourth bushing are at a second axial distance along the axis of rotation. Spaced apart from each other, the second axial distance being less than the first axial distance. 18. The exhaust system of claim 17 wherein the first material is comprised of a sintered metal material and the second material is comprised of a wire mesh material. 12. The method of claim 11, wherein the housing has a first coefficient of thermal expansion, the at least one first bushing component having a second coefficient of thermal expansion that is different from the first coefficient of thermal expansion, and the at least one second bushing component has a first thermal expansion coefficient. Wherein the exhaust system is elastically formed to accommodate the difference between the coefficient and the second coefficient of thermal expansion.

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