JP4388558B2 - Heat insulator - Google Patents

Description

  The present invention relates to a heat insulator formed with a plurality of embossed projections, and more particularly to a heat insulator that can be suitably used for heat insulation of automobile catalytic converters and mufflers.

Since this type of heat insulator is often installed in an empty space below the vehicle floor of an automobile, the bead cannot be sufficiently protruded to avoid interference with a fuel tube or the like, or the bead is placed over the entire plate surface. In some cases, it is not possible to form, so that the rigidity is generally secured by increasing the thickness of the heat insulator. It is also known to form irregularities in order to increase rigidity (see Patent Document 1).
Japanese Patent Laid-Open No. 2002-60878

  However, increasing the plate thickness of the heat insulator inevitably increases the weight and increases the cost, and when forming irregularities, it is difficult to arrange the flat plate portions to remain linearly between the concave grooves. Is not enough.

  Therefore, the present invention solves such problems, and an object of the present invention is to provide a heat insulator that can ensure sufficient rigidity without increasing the plate thickness.

For this reason, the present invention is a heat insulator formed with a plurality of embossed convex portions, wherein the convex portions have a hexagonal shape in plan view, and a longitudinal section passing through a vertex forming a diagonal has an arc shape, The flat plate portions are arranged so as not to remain in a straight line between the convex portions, and the convex portions are formed so that the height H of the convex portions / the width W1 of the convex portions are not less than 12% and not more than 20%. The width W1 of the protrusions is 10 mm to 16 mm and the distance C between the protrusions is 75% or less of the base width W2 which is the sum of the distance C / 2 and the width W1 of the protrusions. It is characterized by.

  The present invention can provide a heat insulator that can ensure sufficient rigidity without increasing the plate thickness.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the heat insulator 1 before forming the convex portion 2, FIG. 2 is a partial perspective view of the heat insulator 1 after forming the convex portion 2, and FIG. 3 is a heat insulator after forming the convex portion 2. 1 is a partial plan view of FIG.

  The heat insulator 1 is formed by forming a rectangular aluminum plate into a mountain shape downward, and a plurality of beads 3 having a predetermined width are provided on the plate surface at intervals in the longitudinal direction so as to cross the plate. Protrusions are formed. Except for the side edge portions 4 and 5 formed along both sides of the heat insulator 1, a large number of convex portions 2 are formed on most of the plate surface of the heat insulator 1. The heat insulator 1 is attached to the vehicle body by inserting a bolt into a mounting hole 5B formed in the vertical piece 5A of the one side edge 5.

  Next, the manufacturing method of the heat insulator 1 will be described. First, an array is formed so that a large number of convex portions 2 are not left in a straight line between the convex portions 2 by embossing on an aluminum flat plate. Form in state. The convex portions 2 are formed at equal intervals, but the plan view has a regular hexagonal shape, and the longitudinal section passing through the apex forming the diagonal has an arc shape.

  And the flat plate in which the said convex part 2 was formed is inserted and shape | molded in the up-and-down press type | mold (not shown) which has the predetermined | prescribed type | mold space | gap which followed the final shape of the heat insulator. At this time, most of the flat plate is formed into a desired shape without causing the convex portions 2 of the plate surface to be crushed because the upper and lower mold surfaces have a predetermined gap.

  In the process of manufacturing as described above, the following 23 cases were manufactured. First, as shown in FIG. 4, the thickness of the aluminum plate is 0.3 mm, the width W1 of the convex portion 2 is 8 mm, the base width W2 is 10 mm, and the planar dimension (C / 2) is 1 mm. The performance improvement rate was investigated from the maximum displacement amount of 23 cases manufactured by changing the height H of the portion 2 every 0.1 mm between 0.8 mm and 3.0 mm.

  According to FIG. 4, the height H / width W1 of the first example is about 10.0%, the maximum displacement is 0.845, and the height H / width W1 of the second example is about 11.3%, the maximum displacement is 0.779, the performance improvement rate (845/779) is about 108%, the height H / width W1 of the third example is 12.5%, the maximum displacement Is 0.725, the performance improvement rate (779/725) is about 107%, the performance improvement rate of the fourth example (725/677) is about 107%, and so on. The rate (396/390) is about 101%, and the performance improvement rate (2800/2712) of the 23rd example is about 103%. In addition, description is abbreviate | omitted here about the actual length of the circular arc part of the convex part 2, and the elongation rate of material.

  Therefore, the optimum value of the convex portion height H / the convex portion width W1 is the sixth example of about 16.3% immediately before the start of the slowdown of the performance improvement rate, but the satisfactory performance improvement rate is 105% or more. It is conceivable that the convex height H / convex width W1 is 12% to 20.0% within a suitable range.

  Next, the optimum value of the above-described convex portion height H / convex portion width W1 is that the performance improvement rate of the sixth example in FIG. 4 is about 16.3%, but this convex portion height H / convex portion. If the optimum value of the width W1 is determined, there should be an optimum width W1 of the convex portion 2, and even if this width W1 is too small, the absolute height will be insufficient and the strength will not be. Even if it is too large, it is thought that the planar element becomes stronger with respect to the plate thickness and the strength is lowered. Therefore, as shown in FIG. 5, the plate thickness of the aluminum plate is set to 0.35 mm and the convex portion The performance difference with respect to the base was investigated from the maximum displacement amount of six cases manufactured by changing the width W1 of 2 every 2 mm between 6 mm and 20 mm.

  In the first example shown in FIG. 5, the convex portion width W1 is 6 mm, the convex portion height H is 0.975, the convex portion height H / the convex portion width W1 is about 16.3%, and the base width W2 is 7.5 mm. The planar dimension (C / 2) is 0.75 mm, the convex width W1 of the second example is 8 mm, the convex height H is 1.300, and the convex height H / convex width W1 is about 16.2. 3%, the base width W2 is 10.0 mm, the plane dimension (C / 2) is 1.0 mm, the maximum displacement is 0.427, and the performance difference (413/427) with respect to the base is about 97%. In three examples, the protrusion width W1 is 10 mm, the protrusion height H is 1.625, the protrusion height H / the protrusion width W1 is about 16.3%, the base width W2 is 12.5 mm, and the plane dimension (C / 2) is 1.25 mm, the maximum displacement is 0.323, and the performance difference (413/323) with respect to the base is about 128%. The width W1 is 20 mm, the convex height H is 3.250, the convex height H / the convex width W1 is about 16.3%, the base width W2 is 25.0 mm, and the planar dimension (C / 2) is 2. At 50 mm, the maximum displacement is 0.163, and the performance difference (413/163) with respect to the base is about 254%. In addition, description is abbreviate | omitted about the displacement amount when the plate | board thickness of aluminum plate body is 0.3 mm, or 0.5 mm.

  From the above, when the convex portion width W1 is changed, there is a place where the ratio of the amount of displacement decreasing with a certain width W1 decreases, and the convex portion width W1 that can be expected to improve performance is 12 mm in the fourth example, which is satisfactory. The convex portion width W1 is considered to be within a suitable range of 10 mm to 16 mm.

  Finally, the density of the protrusions 2 will be described. If the distance between the protrusions 2 is increased, the proportion of the material to be extended by the embossing is reduced, and the formability in the subsequent process is advantageous, but the rigidity is reduced. Therefore, verification is made by paying attention to rigidity (small displacement). That is, the thickness of the aluminum plate is 0.3 mm, the convex width W1 is 8.0 mm, the convex height H is 0.8 mm, and the convex height H / the convex width W1 is 10.0%. The performance improvement rate was investigated from the maximum displacement amount of 7 cases for each 1 mm of the base width W2 between 10 mm and 16 mm.

  The base width W2 of the first example shown in FIG. 6 is 10.0 mm, the plane dimension (C / 2) is 1.0 mm, the maximum displacement is 0.738, the material elongation is 102.1%, The base width W2 of the example is 11.0 mm, the plane dimension (C / 2) is 1.5 mm, the maximum displacement is 0.772, the performance improvement rate (738/772) is about 96%, and the material elongation rate is 101. The base width W2 of the third example is 12.0 mm, the plane dimension (C / 2) is 2.0 mm, the maximum displacement is 0.786, and the performance improvement rate (772/786) is about 98%. The material elongation is 101.8%, the base width W2 of the fourth example is 13.0 mm, the planar dimension (C / 2) is 2.5 mm, the maximum displacement is 0.883, and the performance improvement rate (786/883) ) Is about 89%, the material elongation is 101.6%, and the base width W2 of the fifth example is 14.0 mm. The plane dimension (C / 2) is 3.0 mm, the maximum displacement is 0.915, the performance improvement rate (883/915) is about 97%, the material elongation is 101.5%, and the base width of the sixth example W2 is 15.0 mm, the plane dimension (C / 2) is 3.5 mm, the maximum displacement is 1.008, the performance improvement rate (915/1008) is about 91%, and the material elongation is 101.4%. The base width W2 of the last seventh example is 16.0 mm, the plane dimension (C / 2) is 4.0 mm, the maximum displacement is 0.951, the performance improvement rate (1008/951) is about 106%, and the material elongation rate Is 101.3%. In addition, description is abbreviate | omitted here about the actual length of the circular arc part of the convex part 2, and the elongation rate of material.

  From the above, the displacement amount tends to decrease as the density of the convex portions 2 increases, that is, as the planar dimension decreases. However, when the base width W2 is 15 mm (a little less than twice the convex portion width W1), the performance improvement rate is reversed, and this area is considered the upper limit. Accordingly, it is considered appropriate that the interval (6.0 mm) between the convex portions 2 that is twice the plane dimension (C / 2) is 75% or less of the base width W2 (8.0 mm).

  In addition, regarding the material elongation when changing the density, the absolute amount is extremely small in the range of the convex portion to be implemented, there is no significant effect on the moldability, and if only the rigidity is considered, the spacing between the convex portions It is desirable to make the value small and zero. In this case, the regular hexagon is also an efficient shape that can narrow this interval as much as possible. However, a plane portion is necessary for actual production processing. In addition, since the flat portions are arranged so as not to remain linearly between the convex portions 2 (see FIG. 3), the dynamic directionality is lost, and the rigidity can be greatly improved.

  In addition, based on FIG. 7 which is a partial perspective view of the heat insulator 1 after forming the convex portion 20, and FIG. 8 which is a partial plan view of the heat insulator 1 after forming the convex portion 20, the second embodiment. Will be described. The convex portions 20 formed on the heat insulator 1 are formed in an arrayed state so that the flat plate portions do not remain linearly between the convex portions 20, and the convex portions 20 have a circular shape in plan view and an arc-shaped longitudinal section. It is the shape which comprises some spheres.

  However, in the second embodiment, similarly to the first embodiment, the convex portion height / the convex portion width W3 is 12% to 20.0%, and the convex portion width W3 is 10 mm to 16 mm. The interval between the convex portions 20 that is twice the plane dimension (C / 2) is 75% or less of the base width W4.

  When the convex portions 2 and 20 are formed as in the first and second embodiments, a 0.4 mm thick aluminum plate can exhibit the same or higher rigidity as a 0.5 mm thick aluminum plate. . Therefore, even when the bead cannot be sufficiently protruded or when the bead cannot be formed on the entire plate surface, the necessary rigidity can be secured without increasing the thickness of the heat insulator by forming the convex portion. And increase in weight and cost can be avoided. In particular, if the flat plate portion is not left in a straight line between the convex portions, the dynamic directionality is lost, and the rigidity can be greatly improved.

  Although the embodiments of the present invention have been described above, various alternatives, modifications, and variations can be made by those skilled in the art based on the above description, and the present invention is not limited to the various alternatives described above without departing from the spirit of the present invention. It includes modifications or variations.

It is a perspective view of the heat insulator before forming a convex part. It is a fragmentary perspective view of the heat insulator after forming the convex part of a 1st embodiment. It is a fragmentary top view of the heat insulator after forming the convex part of a 1st embodiment. Performance improvement from the maximum displacement amount of 23 cases manufactured by fixing the plate thickness etc. of aluminum plate and changing the height H of the convex part every 0.1 mm between 0.8 mm and 3.0 mm It is the investigation table which investigated the rate. In the investigation table which investigated the performance difference with respect to the base from the maximum displacement amount of 6 cases manufactured by fixing the plate thickness of the aluminum plate and changing the width W1 of the convex portion every 2 mm between 6 mm and 20 mm. is there. In a survey table investigating the performance improvement rate for the base from the maximum displacement amount of 6 cases manufactured by fixing the plate thickness etc. of the aluminum plate and changing the base width W2 every 1 mm between 10 mm and 16 mm is there. It is a fragmentary perspective view of the heat insulator after forming the convex part of a 2nd embodiment. It is a fragmentary top view of the heat insulator after forming the convex part of a 2nd embodiment.

Explanation of symbols

1 Heat insulator 2, 20 Convex part

Claims (1)

In the heat insulator formed by forming a plurality of convex portions by embossing, the convex portion has a hexagonal shape in plan view, and a longitudinal section passing through the apex forming the diagonal has an arc shape, and the convex portions are between the convex portions. The flat plate portions are arranged so as not to remain linear, and the convex portions are formed such that the height H of the convex portions / the width W1 of the convex portions are within a range of 12% to 20%, and the width of the convex portions. W1 is 10 mm or more and within 16 mm, and the interval C between the convex portions is formed to be 75% or less of the base width W2 which is the sum of the interval C / 2 and the width W1 of the convex portions. .

Images