JP4988993B2 - Heat insulator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure for increasing the rigidity of a heat insulator .
[0002]
[Prior art]
For example, as shown in FIG. 11, an automotive heat insulator 101 is formed by bending an aluminum plate or a steel plate into a mountain shape, and this is mainly for the purpose of blocking heat from a catalytic converter or the like installed under the floor of the automobile. used. A bead 104 is formed on the plate surface of the heat insulator 101 so as to protrude along a mountain shape in order to increase rigidity.
[0003]
However, since the heat insulator 101 is installed in the gap between the underfloor and the catalytic converter, the shape and number of the beads 104 are insufficient to ensure the required rigidity for the heat insulator 101.
[0004]
Therefore, as shown in FIG. 12, in order to ensure sufficient rigidity without increasing the plate thickness, a metal plate on which a large number of circular convex portions 201a are formed in advance by embossing is formed by a mold having a mold gap. In addition, a heat insulator 201 and a manufacturing method thereof have been proposed (see Japanese Patent Laid-Open No. 2000-136720).
[0005]
[Problems to be solved by the invention]
However, in the heat insulator 101 in which the beads 104 as shown in FIG. 11 are formed, in order to secure the size and number of the beads 104 in order to ensure sufficient rigidity, in order to attract the material during the molding. There is a problem that the line length of the cross section increases, resulting in an increase in the size of the material used.
[0006]
Further, in the heat insulator 201 shown in FIG. 12, since it is necessary to form the circular convex portion 201a on the metal plate in advance by embossing, there is a problem that the number of processing steps increases and cost increase cannot be avoided. Since the formation of the circular convex portion 201a by embossing is intended to increase the rigidity in all directions, in the case of a part having a different rigidity to be strengthened depending on the direction, such as a heat insulator, any direction is the same. There was also a problem that the rigidity could be increased only at a ratio and the efficiency was poor.
[0007]
The present invention has been made in view of the above problems, and a purpose of the process is to provide a heat insulator that can efficiently increase the rigidity in the required direction without incurring an increase in cost, thereby achieving reduction in thickness and weight. It is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is a heat insulator in which an aluminum plate or a steel plate is formed with a cross-section in the width direction curved in a chevron shape, and protrudes along the width direction. And a plurality of beads arranged at a predetermined interval in the length direction orthogonal to the width direction, and the beads arranged continuously between these adjacent beads, extending along the width direction. while being provided with a plurality of irregularities width of the longitudinal direction smaller than the bead, the bead surface is smoothly formed, the cross-sectional shape along said length direction of said irregularities, It is formed in the trapezoid wave shape shape which connected the some linear part continuously .
[0009]
According to a second aspect of the present invention, in the first aspect of the present invention, the bead and the unevenness are formed in the same forming step .
[0010]
Therefore, according to the first aspect of the present invention, by forming an uneven corrugated shape heat insulator, said the rigidity of the heat insulator irregularities extending direction is increased, the required direction of stiffness without increasing the cost The heat insulator can be made thinner and lighter.
[0011]
According to invention of Claim 2, the increase in cost accompanying the increase in a process and the change of a material dimension can be avoided.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0013]
1 is a perspective view of a heat insulator for an automobile having a highly rigid structure according to the present invention, FIG. 2 is a side view of the heat insulator, FIG. 3 is a plan view of the heat insulator, and FIG. 4 is a line AA in FIG. Sectional drawing and FIG. 5 are enlarged sectional views showing the sectional shape of corrugated irregularities.
[0014]
As shown in FIG. 1, an automotive heat insulator (heat shield plate) 1 according to the present embodiment covers a catalytic converter 2 installed under the floor of an automobile from above, and heat (catalyst and catalyst) from the catalytic converter 2 is covered. The transmission of heat (reaction heat with exhaust gas) to the vehicle body is interrupted, and this is obtained by press forming a steel plate or an aluminum plate. In other words, the heat insulator 1 is bent into a mountain shape (substantially arcuate in cross section) along the outer shape of the cylindrical catalytic converter 2, and both edges 1a in the width direction (Y direction in the drawing) are curled in a U shape. Molded (see FIG. 4).
[0015]
In addition, mounting bosses 1b are integrally projected at three positions, both ends and an intermediate portion in the length direction (X direction in the drawing) of the upper surface of the heat insulator 1, and bolt insertion holes are provided at the center of each mounting boss 1b. 1c is perforated.
[0016]
Thus, in the heat insulator 1 according to the present embodiment, a large number of irregularities 3 having a corrugated shape are integrally formed over the entire width direction (Y direction in the drawing) along the mountain shape, A plurality of beads 4 having a predetermined width are formed along the width direction.
[0017]
By the way, the gap between the catalytic converter 2 where the heat insulator 1 is installed and the under floor of the automobile is narrow, and it is difficult to satisfy the rigidity required for the heat insulator 1 with the shape and number of the beads 4.
[0018]
Therefore, in the present embodiment, a necessary number of the irregularities 3 having a corrugated shape having a small size (height, width, pitch, etc.) with respect to the shape of the bead 4 are formed in a direction satisfying the required rigidity. I tried to do it.
[0019]
The heat insulator 1 having the above configuration is integrally formed by press forming of a steel plate or an aluminum plate, but the dimensions of the corrugations 3 forming the corrugated shape formed on the heat insulator 1 can be formed without drawing materials. It is set to a valid value.
[0020]
Therefore, it is not necessary to add a new process to the forming process of the corrugations 3 having a corrugated shape, and the unevenness 3 can be formed within the existing process (for example, simultaneous processing with the forming of the beads 4). Therefore, it is possible to avoid an increase in cost due to an increase in the number of processes and a change in material dimensions.
[0021]
Thus, the heat insulator 1 integrally formed by press forming of a steel plate or an aluminum plate is attached to the lower surface of the vehicle body by a bolt (not shown) inserted from below into a bolt insertion hole 1c formed in the mounting boss 1b. As described above, the catalytic converter 2 is covered from above and functions to block the transfer of heat from the catalytic converter 2 to the vehicle body.
[0022]
By the way, the rigidity of a product is generally expressed by the following equation.
[0023]
I × E (4)
Where I: secondary moment of inertia (value determined by product shape)
E: Young's modulus (coefficient determined by material properties)
Conventionally employed beads to increase the rigidity of a product aim to increase the value of the moment of inertia by changing the shape of the product.
[0024]
On the other hand, a convex portion by embossing (hereinafter referred to as “embossed shape”) and a corrugated unevenness according to the present invention (hereinafter referred to as “corrugated shape”) are sufficiently smaller than the bead. When set, since the effect of increasing the rigidity can be obtained without greatly changing the shape of the product, it can be considered that the value of the Young's modulus E is artificially increased.
[0025]
Therefore, when the shape and number of beads cannot be secured sufficiently due to restrictions such as mounting space, and when it is desired to avoid an increase in the plate thickness of the material, which increases costs, the embossed shape and the corrugated shape according to the present invention are rigid. This is an effective way to increase
[0026]
However, there is a great difference in the directionality of the stiffness value between the embossed shape and the corrugated shape. Here, the rigidity values in the two orthogonal directions (X and Y directions) for the embossed shape and the corrugated shape with respect to the metal flat plate are shown in FIGS. 6A and 6B, where the rigidity value of the flat plate is 1. FIG.
[0027]
As shown to Fig.6 (a), in an embossed shape, a rigidity value does not show directionality but shows the same value (1.6) over all directions. The rigidity value is represented by the ratio of the flat plate as 1. On the other hand, in the corrugated shape, as shown in FIG. 6B, the rigidity value is very high (12) in the direction parallel to the wave (Y direction), but the direction orthogonal to the direction (X (Direction) shows a low stiffness value (0.85).
[0028]
Therefore, many chevron shapes are adopted as the shape of the heat insulator, and the rigidity value of the heat insulator having such a shape varies greatly depending on the direction.
[0029]
Here, the rigidity values in two orthogonal directions (X and Y directions) of the heat insulator as a flat plate, the heat insulator having an embossed shape, and the heat insulator having a corrugated shape are set to 1 as the rigidity value of the flat plate as shown in FIG. They are shown in a), (b), and (c), respectively.
[0030]
In the flat plate heat insulator shown in FIG. 7A, the rigidity value in the length direction (X direction) shows a high value (104), while the rigidity value in the width direction (Y direction) shows a very low value (2 ).
[0031]
In the heat insulator having the embossed shape shown in FIG. 7B, the rigidity values in the length direction (X direction) and the width direction (Y direction) are the rigidity values of the flat plate heat insulator shown in FIG. The stiffness value in the length direction (X direction) shows a high value (166), whereas the stiffness value in the width direction (Y direction) shows a very low value (3). In the same manner as the flat plate heat insulator shown in FIG.
[0032]
On the other hand, in the heat insulator according to the present invention having the corrugated shape shown in FIG. 7C, the rate of increase in the rigidity value in the width direction (Y direction) is increased to show a high value (25), The rigidity value in the length direction (X direction) is lower than that of the flat plate heat insulator shown in FIG. 7A and the heat insulator having the embossed shape shown in FIG. 7B (104, 166) (88). ).
[0033]
Thus, in the heat insulator 1 according to the present embodiment, the corrugated irregularities 3 are integrally formed by press molding along the width direction (Y direction), which has conventionally been low in rigidity, leading to an increase in cost. Therefore, the rigidity in the width direction (Y direction) can be efficiently increased, and the weight of the heat insulator 1 can be reduced by reducing the thickness of the steel plate or aluminum plate as the material by the amount of the increased rigidity. Specifically, the thickness of the steel plate or aluminum plate, which is a material, was conventionally required to be 0.5 mm, but in this embodiment, the plate thickness could be reduced to 0.35 to 0.4 mm. .
[0034]
Further, in the present embodiment, since it is not necessary to add a processing step such as embossing as in the prior art , an increase in material can be prevented, and cost reduction and weight reduction can be achieved.
[0035]
In addition, as shown in FIG. 8, if a bead 5 having a predetermined width is formed in the length direction on the top of the heat insulator 1 in which a large number of corrugated irregularities 3 are formed along the width direction, Thus, the rigidity in the length direction can be increased. Also, the rigidity can be increased by using corrugated irregularities 3 instead of the beads 5.
[0036]
Here, a form in which the present invention is applied to a floor heat insulator 11 for an automobile is shown in FIG. 9, and a form in which the present invention is applied to a silencer insulator 21 is shown in FIG. 10, but when applying the present invention, these floor heat insulators 11 are applied. In addition, the strength analysis of the silencer insulator 21 is performed in advance, the plate surface and the direction that need to be increased in rigidity are identified, and the corrugated irregularities 3 are formed along that direction .
[0037]
【Effect of the invention】
As is apparent from the above description, according to the first aspect of the present invention, when the corrugated irregularities are formed on the heat insulator , the rigidity in the direction in which the irregularities of the heat insulator extend is increased, resulting in an increase in cost. Therefore, it is possible to efficiently increase the rigidity in the necessary direction without reducing the thickness and weight of the heat insulator .
[0038]
According to the second aspect of the present invention, it effects that to be able to avoid the costs associated with changing the gain and the material dimensions of the process is obtained.
[0039]
[Brief description of the drawings]
FIG. 1 is a perspective view of an automotive heat insulator having a highly rigid structure according to the present invention.
FIG. 2 is a side view of an automotive heat insulator having a highly rigid structure according to the present invention.
FIG. 3 is a plan view of an automotive heat insulator having a highly rigid structure according to the present invention.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is an enlarged cross-sectional view showing a cross-sectional shape of corrugated irregularities.
FIG. 6 is a diagram showing rigidity values in the orthogonal directions (X and Y directions) of a flat plate having an embossed shape and a corrugated shape.
FIG. 7 is a diagram showing rigidity values in the orthogonal directions (X and Y directions) of an insulator having a flat plate and an embossed shape and a corrugated shape.
FIG. 8 is a partial perspective view of a heat insulator showing a combination example of corrugated irregularities and beads.
FIG. 9 is a perspective view showing an application example of the present invention to a floor heat insulator.
FIG. 10 is a perspective view showing an application example of the present invention to a silencer insulator.
FIG. 11 is a perspective view of a heat insulator according to Conventional Example 1.
12 is a perspective view of a heat insulator according to Conventional Example 2. FIG.
[Explanation of symbols]
1 heat insulator 1a width direction edge 1b of heat insulator 1b mounting boss 1c bolt insertion hole 2 catalytic converter 3 corrugated 4,5 bead 11 floor heat insulator 21 silence sign insulator

Claims (2)

An aluminum plate or a steel plate is a heat insulator formed by bending the cross section in the width direction into a chevron shape,
A plurality of beads that are formed to protrude along the width direction and are arranged at a predetermined interval in a length direction orthogonal to the width direction;
A plurality of concavities and convexities arranged continuously between these adjacent beads, extending along the width direction, and having a width dimension in the length direction smaller than the bead, and
The bead is formed with a smooth surface,
The cross-sectional shape along said length direction of the unevenness, the heat insulator, characterized in that it is formed in a trapezoidal wave shape obtained by connecting consecutively a plurality of straight portions.   The heat insulator according to claim 1, wherein the bead and the unevenness are formed in the same forming step.

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