JPH05332135A - Exhaust manifold cover for vehicle - Google Patents

Abstract

PURPOSE:To reduce the sound pressure level of radiant sound to improve the easiness of use by forming an exhaust manifold cover in nearly fixed wall thickness and also providing a bead section on the exhaust manifold cover. CONSTITUTION:An exhaust manifold cover 12 comprises an upper cover 14 covering an exhaust manifold 4 from the upper side and a lower cover 16 covering the exhaust manifold 4 from the lower side. The exhaust manifold cover 12 has nearly fixed wall thickness. A bead section 20 is provided on the exhaust manifold cover 12 to improve the rigidity of the exhaust manifold cover 12 with the shape of at least one of recessed and projecting parts forming in the direction of an arbitrary cross section. A minimum characteristic frequency can be reduced in the frequency caused when the periphery of the exhaust manifold cover 12 is fixed. This allows to reduce the sound pressure level of radiant sound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle exhaust manifold cover, and more particularly to a vehicle exhaust manifold cover for increasing the minimum natural frequency of the exhaust manifold cover and reducing the sound pressure level of radiated sound due to resonance at high frequencies. Regarding

[0002]

2. Description of the Related Art Vehicles are equipped with an exhaust manifold cover, an exhaust pipe cover, a catalyst case cover, a muffler cover, a worm air cover, a heat shield plate, a sheet metal air cleaner case, and a blow-molded box that are molded from a plate-shaped molded member. Other than that, dash panels, floors, etc. of automobile bodies are used to secure a predetermined surface rigidity after molding the molding member.

An example of the vehicle exhaust manifold cover is disclosed in Japanese Utility Model Laid-Open No. 61-65231. The heat shield plate of the exhaust manifold disclosed in this publication is attached to the exhaust manifold of the engine and is provided with a heat shield plate for shielding the heat of the exhaust manifold. The heat shield plate includes an outer plate and an inner plate. A space is provided between the outer plate and the inner plate, and the outer plate is provided with a large number of protruding portions that project outward.

Further, there is one disclosed in Japanese Utility Model Laid-Open No. 63-154717. The heat shield device for an exhaust manifold disclosed in this publication covers the exhaust manifold multi-branch pipe and the downstream end of an exhaust conduit where this multi-branch pipe merges, respectively, to cover the exhaust manifold and to cover all of the multi-branch pipes. In a heat shield device having a heat shield plate in which a pair of press pieces each having a convex or concave bead formed around the circumference are joined to each other by a flange, a heat shield plate of a split mid-matching type is provided. It is below.

When molding the exhaust manifold cover for a vehicle, as shown in FIGS. 8 and 9 (a), (b), and (c), a relatively thin sheet metal or resin blow-molded plate is used. In the molding member 122 having a substantially constant wall thickness, the molding member 122
In order to reinforce the relatively flat portion, the bead portion 120 having an uneven shape extending in one longitudinal direction is formed on the surface to improve the rigidity after molding.

Further, as shown in FIG. 10, a molding member 222
There is also one in which a lattice-shaped bead portion 220 is formed.

[0007]

By the way, in a conventional exhaust manifold cover for a vehicle, as shown in FIG.
When the exhaust manifold cover is molded by the molding member 122, as shown in FIG. 9A, the cross-sectional shape of the molding member 122 is uneven, the second moment of area is high, and the rigidity after molding is large.

However, in FIG. 9B, the cross-sectional shape of the molding member 122 is fairly flat, the second moment of area does not increase, and in FIG. 9C, the cross-sectional shape of the molding member 122 is high. Has a substantially flat plate shape.

As a result, when the periphery of the exhaust manifold cover is fixed and vibrated, the lowest natural frequency is mainly determined by the surface bending rigidity, though it depends on the fixing method. Therefore, the lowest natural frequency with respect to the flat plate. Is difficult to expect.

Further, when the exhaust manifold cover is molded by the molding member, since the area per flat portion is wide, the resonance sound when excited at a higher frequency has a high sensitivity and a large radiated sound. Therefore, there is a disadvantage that it is disadvantageous in practical use.

[0011]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides an exhaust manifold for a vehicle, which is covered by an intake manifold cover formed by an upper cover and a lower cover. The exhaust manifold cover is provided with a bead portion in order to improve the rigidity of the exhaust manifold cover by forming the cover to have a substantially constant wall thickness and at least one of the uneven shapes in the arbitrary cross-sectional direction. Is characterized by.

[0012]

According to the invention as described above, when the exhaust manifold cover is molded, it is formed to have a substantially constant wall thickness, and at least one bead portion having an uneven shape in an arbitrary cross-sectional direction is formed. By revealing it, the rigidity of the exhaust manifold cover is improved, the minimum natural frequency is increased, and the radiated sound due to resonance at high frequencies is reduced.

[0013]

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

1 to 7 show an embodiment of the present invention. In FIG. 2, 2 is an engine of a vehicle (not shown), and 4 is an exhaust manifold.

A catalyst 6 is mounted on the downstream side of the exhaust manifold 4, and a muffler 10 is connected to the catalyst 6 via an exhaust center pipe 8.

The exhaust manifold 4 is covered by an exhaust manifold cover 12. The exhaust manifold cover 12 covers the exhaust manifold 4 from the upper side and the exhaust manifold 4 from the lower side. It consists of the lower cover 16.

Reference numeral 18 indicates the exhaust center pipe 8
It is a thermofuse arranged inside.

When the exhaust manifold cover 12 including the upper cover 14 and the lower cover 16 is molded, the exhaust manifold cover 12 is formed so as to have a substantially constant wall thickness, and at least one of the concavo-convex shape appears in any cross-sectional direction. In order to improve the rigidity of the exhaust manifold cover 12, a bead portion 20 is provided on the exhaust manifold cover 12.

More specifically, when the upper cover 14 and the lower cover 16 are molded, as shown in FIG. 1, the cross-shaped or T-shaped bead portion 20 is closely exposed on the molding member 22, and at the same time, it is optional. At least one of the concavo-convex shape is revealed in the cross-sectional direction of.

At this time, the cross-sectional shape of the bead portion 20 is set to, for example, a substantially semicircular shape.

3 and 4 (a), (b) and (c),
It is an example when the bead portion 20 is exposed on the upper cover 14.

As shown in FIG. 3, the upper cover 14 includes
A bead portion 20-1 having a cross shape, a T shape, or another shape that is difficult to explain appears, and the resonance area between the bead portions 20-1 is small.

Further, FIGS. 5 and 6 (a), (b),
(C) is an example when the bead portion 20 is exposed on the lower cover 16.

As shown in FIG. 5, similar to the upper cover 14 described above, a bead portion 20-2 having a cross shape, a T shape, or another shape that is difficult to explain is exposed on the lower cover 16, and each bead is exposed. The resonance area between the parts 20-2 is small.

When the bead portion 20 is exposed, if the bead portion 20 is exposed to a relatively flat portion or a surface portion of the upper cover 14 or the lower cover 16, the effect of improving the rigidity is further enhanced.

In addition, regarding the frequency that occurs when the periphery of the exhaust manifold cover 12 is fixed, the lowest natural frequency is mainly determined by the surface bending rigidity, although it depends on the fixing method.

Next, the operation will be described.

When the engine 2 mounted on a vehicle (not shown) is driven, a radiated sound is generated in the exhaust manifold 4 due to resonance at a high frequency, and the radiated sound collides with the upper cover 14 and the lower cover 16.

At this time, the radiated sound having directivity is finely dispersed by the bead portion 20 formed on the upper cover 14 and the lower cover 16 to reduce the sound pressure level of the radiated sound.

As a result, the bead portion 20 can be made to have a substantially semicircular cross-sectional shape in any cross-sectional direction, the second moment of area can be increased, and the surface bending rigidity can be increased, and the exhaust manifold cover can be increased. The lowest natural frequency can be lowered in the frequency that occurs when the circumference of 12 is fixed.

Further, since the lowest natural frequency can be lowered, the sound pressure level of the radiated sound emitted to the outside of the exhaust manifold cover 12 can be reduced, the quietness can be improved, and in practical use. It is advantageous.

Further, by closely exposing the bead portion 20 on the exhaust manifold cover 12, each bead portion 2
The resonance area at a high frequency between 0 can be narrowed, there is no fear of vibration, and usability can be improved.

Furthermore, the exhaust manifold cover 12
By making the thickness substantially constant, the material cost can be reduced, the cost can be reduced, and it is economically advantageous as compared with the conventional exhaust manifold cover.

The present invention is not limited to the above-mentioned embodiment, but various application modifications are possible.

For example, in the embodiment of the present invention, the bead portion is exposed on the exhaust manifold cover, but the exhaust pipe cover, the catalyst case cover, the muffler cover, the worm air cover, the heat shield plate, and the sheet metal are used. The bead portion can be exposed on members such as an air cleaner case, a blow molded box, a dash panel of a vehicle body, a floor, and the like, and the surface rigidity of a component having a substantially constant thickness can be improved.

In the embodiment of the present invention, the bead portion may have a substantially semicircular cross section, or may have a semielliptical shape other than the substantially semicircular cross section, or any other shape. is there.

[0037]

As described above in detail, according to the present invention, the exhaust manifold cover of the vehicle exhaust manifold covered with the intake manifold cover formed by the upper cover and the lower cover has a substantially constant thickness. The bead portion is provided in the exhaust manifold cover in order to improve the rigidity of the exhaust manifold cover by forming at least one of the concavo-convex shape in the arbitrary cross-sectional direction as well as forming the bead portion in the arbitrary cross-sectional direction. In, at least one of the uneven shape can be revealed, the second moment of area becomes high,
The surface bending rigidity can be increased, and the lowest natural frequency can be reduced in the frequency generated during vibration when the periphery of the exhaust manifold cover is fixed. Also, since the lowest natural frequency can be lowered, the sound pressure level of the radiated sound emitted to the outside of the exhaust manifold cover can be reduced, the quietness can be improved, and it is practically advantageous. Furthermore, if the bead portions are closely exposed on the exhaust manifold cover, the resonance area at high frequencies between the bead portions can be narrowed, there is no fear of vibration, and usability is improved. You can Furthermore, by making the thickness of the exhaust manifold cover substantially constant, the material cost can be reduced and the cost can be reduced as compared with the conventional exhaust manifold cover, which is economically advantageous.

[Brief description of drawings]

FIG. 1 is a schematic view of a bead portion formed on a plate-like member showing an embodiment of the present invention.

FIG. 2 is an assembly view of a vehicle exhaust manifold cover.

FIG. 3 is a front view of an upper cover.

FIG. 4A is a left side view of the upper cover. (B) It is a right view of an upper cover. (C) It is a top view of an upper cover.

FIG. 5 is a front view of a lower cover.

FIG. 6A is a bottom view of the lower cover. (B) It is a top view of a lower cover. (C) It is a right view of a lower cover.

FIG. 7 is an enlarged explanatory view of a main part of a bead portion.

FIG. 8 is a front view of a molded member showing a conventional technique of the present invention.

9 (a) is a sectional view taken along line AA of FIG. (B) It is sectional drawing by the BB line of FIG. (C) It is sectional drawing by the CC line of FIG.

FIG. 10 is an enlarged view of a main part of a molding member showing another conventional technique of the present invention.

[Explanation of symbols]

 2 Engine 4 Exhaust Manifold 6 Catalyst 8 Exhaust Center Pipe 10 Muffler 12 Exhaust Manifold Cover 14 Upper Cover 16 Lower Cover 20, 20-1, 20-2 Bead Part 22 Forming Member

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[Procedure amendment]

[Submission date] July 16, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

[0011]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a vehicle exhaust manifold covered with an exhaust manifold cover formed by an upper cover and a lower cover, wherein the exhaust manifold cover is omitted. The exhaust manifold cover is provided with a bead portion in order to improve the rigidity of the exhaust manifold cover by forming at least one of the irregular shapes in any cross-sectional direction while forming the exhaust manifold cover to have a constant wall thickness. To do.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

According to the invention as described above, when the exhaust manifold cover is molded, it is formed so as to have a substantially constant wall thickness, and at least one bead portion having a concavo-convex shape is formed in an arbitrary cross-sectional direction. To improve the rigidity of the exhaust manifold cover and increase the minimum natural frequency,
It also reduces the radiated sound due to resonance at high frequencies.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

[0037]

According to the present invention as has been described [Effect Invention above in detail, substantially constant thickness the exhaust manifold cover of vehicle exhaust manifold is covered by the exhaust Ma <br/> Nihorudokaba formed by the upper cover and lower cover The exhaust manifold cover is provided with a bead portion in order to improve the rigidity of the exhaust manifold cover by forming at least one uneven shape in an arbitrary cross-sectional direction. It is possible to reveal at least one of the uneven shape in the direction,
The second moment of area can be increased, the surface bending rigidity can be increased, and the lowest natural frequency can be reduced in the frequency generated during vibration when the periphery of the exhaust manifold cover is fixed. Also, since the lowest natural frequency can be lowered, the sound pressure level of the radiated sound emitted to the outside of the exhaust manifold cover can be reduced, the quietness can be improved, and it is practically advantageous. Furthermore, if the bead portions are closely exposed on the exhaust manifold cover, the resonance area at high frequencies between the bead portions can be narrowed, there is no fear of vibration, and usability is improved. You can Furthermore, by making the thickness of the exhaust manifold cover substantially constant, the material cost can be reduced and the cost can be reduced as compared with the conventional exhaust manifold cover, which is economically advantageous.

[Procedure Amendment 6]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

[Figure 10]

[Procedure amendment]

[Submission date] April 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION This invention relates to vehicle exhaust manifold cover, in particular raising the minimum natural frequency of the exhaust manifold cover, vehicle exhaust manifold to reduce the sound pressure level of the sound radiation caused by resonance at high frequencies Regarding the cover.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

BACKGROUND OF THE INVENTION vehicle, exhaust manifold cover and the exhaust pipe cover is molded by a plate-shaped molded member, Catalyst case cover, muffler cover, warm air cover, the heat shield plate, a sheet metal air cleaner case, blow molding Boxes, other dash panels of automobile bodies, floors, and the like are used to ensure a predetermined surface rigidity after molding the molding member.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

An example of the vehicle exhaust manifold cover is disclosed in Japanese Utility Model Laid-Open No. 61-65231. Heat shield plate of the exhaust manifold disclosed in this publication, is attach to an exhaust manifold of an engine, the heat shield plate to thermally insulate the heat of the exhaust manifold provided, the heat shield plate has an outer plate and an inner A plate is provided, a space is provided between the outer plate and the inner plate, and the outer plate is provided with a large number of protruding portions that project outward.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Reference numeral 18 is a thermofuse arranged in a catalyst case (not shown).

[Procedure Amendment 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

As a result, the bead portion 20 can be made to have a substantially semicircular cross-sectional shape in any cross-sectional direction, the second moment of area can be increased, and the surface bending rigidity can be increased, and the exhaust manifold cover can be increased. Of the vibration frequencies that occur when the circumference of 12 is fixed, the lowest natural frequency is
Can be raised .

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

Further, since the lowest natural frequency can be increased, the sound pressure level of the radiated sound emitted to the outside of the exhaust manifold cover 12 can be reduced, the quietness can be improved, and in practical use. It is advantageous.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

[0037]

As described in detail above, according to the present invention, the exhaust manifold cover of the vehicle exhaust manifold covered by the exhaust manifold cover formed by the upper cover and the lower cover should have a substantially constant thickness. Since the bead portion is provided in the exhaust manifold cover in order to improve the rigidity of the exhaust manifold cover by forming at least one of the concavo-convex shape in the arbitrary cross-sectional direction, the bead portion is uneven in the arbitrary cross-sectional direction. At least one shape of can be made to appear,
The second moment of area can be increased, the surface bending rigidity can be increased , and the lowest natural frequency can be increased in the frequency generated during vibration when the periphery of the exhaust manifold cover is fixed. Further, since the lowest natural frequency can be increased, the sound pressure level of the radiated sound emitted to the outside of the exhaust manifold cover can be reduced, and the quietness can be improved, which is practically advantageous. Furthermore, if the bead portions are closely exposed on the exhaust manifold cover, the resonance area at high frequencies between the bead portions can be narrowed, there is no fear of vibration, and usability is improved. You can Furthermore, by making the thickness of the exhaust manifold cover substantially constant, the material cost can be reduced and the cost can be reduced as compared with the conventional exhaust manifold cover, which is economically advantageous.

Claims (1)

[Claims] 1. An exhaust manifold for a vehicle, which is covered by an intake manifold cover formed by an upper cover and a lower cover, wherein the exhaust manifold cover is formed to have a substantially constant wall thickness and in any cross-sectional direction. 2. An exhaust manifold cover for a vehicle, wherein a bead portion is provided on the exhaust manifold cover so as to expose at least one of the concavo-convex shape and improve the rigidity of the exhaust manifold cover.