JPH0526251Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a heat shield plate for an exhaust manifold provided in an internal combustion engine.

(Prior art) In the case of internal combustion engines for automobiles, a heat shield plate is attached to cover the exhaust manifold, and the ignition system, fuel system, and various auxiliary equipment are protected from the thermal influence of the exhaust manifold, which becomes hot due to exhaust heat. (See Utility Model Application Publication No. 59-215943).

Conventionally, as shown in FIGS. 3 and 4, for example, the heat shield plate 1 is formed by pressing a metal plate having a predetermined thickness, and bolt holes 5 (not shown) are formed in several places to pass through the heat shield plate 1. It is attached to the exhaust manifold with a predetermined gap via bolts and spacers.

(Problem that the invention aims to solve) However, since engine vibrations and vehicle vibrations propagate from the exhaust manifold to the heat shield plate 1, which is made of a single metal plate, the heat shield plate 1 has a unique film. There was a problem in that it caused vibration and increased noise.

Conventional countermeasures have been to apply damping material to the surface of the heat shield, or to stack two metal plates with damping material in between, but these methods have not provided sufficient noise prevention effects. This also led to an increase in production costs.

The present invention aims to solve the above problems.

(Means for solving the problem) The present invention provides a heat shield plate that is attached to the exhaust manifold of an internal combustion engine with a predetermined gap.
The heat shield plate is formed by overlapping two metal plates with different wall thicknesses in the same shape so that the metal plate with the smaller wall thickness faces the exhaust manifold, and with a small surface pressure on each other. Both metal plates were joined by welding at multiple locations so that they were in contact with each other, and were attached to the exhaust manifold with a predetermined gap through bolts inserted into bolt holes formed at positions different from these welding locations.

(Function) By joining two metal plates at several points,
Metal plates with different wall thicknesses come into contact with each other with small surface pressure, and the resonance points for the vibrations propagating from the exhaust manifold are different, so the metal plates suppress each other's vibrations to obtain a damping effect, and the heat shield This can effectively prevent noise from being generated. It has been confirmed through experiments that this vibration damping effect is more effective when a thin metal plate is placed facing the exhaust manifold.

In addition, while two metal plates are welded together at multiple points, installation to the exhaust manifold is
Since these welds are performed using bolts at different positions, the two metal plates can be joined to each other at any position depending on the shape of the heat shield so that the vibration damping effect of the two metal plates can be most effectively exerted. , the noise reduction effect due to vibration damping of the heat shield plate can be significantly enhanced.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

As shown in FIGS. 1 and 2, the heat shield 1 includes an inner 2 made of a metal plate with a thickness of, for example, 0.4 mm,
It is formed by overlapping the outer 3 made of a 0.8 mm metal plate.

The heat shield plate 1 is attached to the exhaust manifold with a predetermined gap through bolts and spacers that pass through bolt holes 5, with the thinner inner 2 facing the exhaust manifold and the thicker outer 3 facing the outside. It is arranged so that

The manufacturing process of this heat shield plate 1 consists of pressing a flat plate, cutting the outer shape, drilling bolt holes 5, and spot welding the inner 2 and outer 3.

In the press working, the inner 2 and outer 3 are simultaneously molded by overlapping two flat plates with different thicknesses, so that the inner 2 and the outer 3 have similar shapes to each other.

Joints 4 between the inner 2 and outer 3 by spot welding are formed at several locations at predetermined intervals so that the inner 2 and outer 3 are brought into contact with each other with an appropriately small surface pressure.

It is constructed as described above, and its operation will be explained next.

By covering the exhaust manifold with a predetermined gap, the heat shield plate 1 protects the ignition system, combustion system, and various auxiliary equipment from the thermal influence of the exhaust manifold, which becomes high in temperature due to exhaust heat.

In the heat shield plate 1, the inner 2 and outer 3, which have different plate thicknesses, resonate at different frequencies with respect to engine vibrations and vehicle vibrations propagated from the exhaust manifold. Because the inner 2 and outer 3 are fixed to each other only at a few points, one metal plate that causes resonance will not move in the amplitude direction even if it makes strong partial contact with the other metal plate depending on the vibration waveform. Deformation is suppressed, so the metal plates rub against each other in the plane direction,
The vibrational energy is consumed by the friction between the metal plates in the plane direction, thereby providing a damping effect. As a result, it is possible to prevent the noise generated from the heat shield plate 1 from increasing in a specific rotation speed range.

It has been confirmed through experiments that by arranging the inner 2 with a smaller thickness on the side closer to the vibration source (exhaust manifold), the vibration damping effect can be enhanced.

In addition, by stacking two metal plates and pressing them at the same time, the processing accuracy of the inner 2 and outer 3, which have similar shapes to each other, is ensured, and the surface pressure acting between them is adjusted to an appropriate value by spot welding. It becomes possible to set the above-mentioned vibration damping effect effectively.

Further, since the larger the thickness of the metal plate, the less wrinkles, dents, etc. that occur on the surface during press working, it is aesthetically preferable to arrange the outer 3 having a larger thickness on the outside.

(Effects of the invention) As described above, the present invention provides a heat shield plate that is attached to the exhaust manifold of an internal combustion engine with a predetermined gap. The small metal plates are formed so as to face the exhaust manifold so that they overlap each other in the same shape, and the two metal plates are joined by welding at multiple locations so that they contact each other with a small surface pressure. Since it is attached to the exhaust manifold with a predetermined gap through bolts inserted into bolt holes formed at positions different from these welding points, the vibration of the heat shield plate is suppressed by the vibration damping effect of the two metal plates. At this time, while the two metal plates are welded to each other at multiple points, the attachment to the exhaust manifold is done with bolts at positions different from these welding points. In order to maximize the vibration damping effect of the metal plates, it is possible to connect them to each other at any position depending on the shape of the heat shield plate, effectively suppressing the vibration of the heat shield plate. Noise can be significantly reduced, and due to the relatively simple structure, it is easy to implement without significantly increasing the number of man-hours during manufacturing.

[Brief explanation of the drawing]

Figure 1 is a front view showing one embodiment of the present invention;
The figure is a sectional view taken along line A-A in the same figure. FIG. 3 is a front view showing a conventional example, and FIG. 4 is a side view of the same. 1...Heat shield plate, 2...Inner, 3...Outer.

Claims (1)

[Scope of utility model registration request] In a heat shield plate that is attached to an exhaust manifold of an internal combustion engine with a predetermined gap, the heat shield plate is made of two metal plates with different wall thicknesses, such that the metal plate with the smaller wall thickness faces the exhaust manifold, In addition to forming them in a polymerized manner in the same shape,
Both metal plates are welded together at multiple locations so that they contact each other with small surface pressure, and a predetermined gap is connected to the exhaust manifold through bolts inserted into bolt holes formed at different locations from these welded locations. A heat shield plate for an exhaust manifold, which is characterized by being attached with a side.