JP4030003B2 - Hollow panel structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hollow panel structure in which distortion of a hollow panel configured by overlapping two metal plates is suppressed to ensure high planar accuracy.
[0002]
[Prior art]
As one of structural members such as a plasma display and various OA devices, for example, a hollow panel 101 having a predetermined thickness as shown in FIG. 7 is often used as a strength member or a planar accuracy holding member (Japanese Patent Laid-Open No. 2002-16384). reference).
[0003]
That is, FIG. 7 is a partial side sectional view of the hollow panel 101. The illustrated hollow panel 101 has a relatively thin flat plate shape on the protrusion 103a of the metal plate 103 in which a plurality of protrusions 103a are provided in a scattered manner. The metal plate 102 is placed on top of each other, the metal plates 102 and 103 are overlapped, and the contact portion between the projection 103a of one metal plate 103 and the other metal plate 102 is joined by welding, caulking or the like to form a hollow shape. However, by using such a hollow panel 101, it is possible to reduce the weight while ensuring the required strength and rigidity.
[0004]
[Problems to be solved by the invention]
However, the conventional hollow panel 101 is warped due to distortion due to welding heat generated when the two metal plates 102 and 103 are joined together and residual stress due to caulking, and the required plane accuracy cannot be ensured. was there.
[0005]
Therefore, conventionally, in order to ensure a predetermined flat accuracy for the hollow panel, the method of correcting the hollow panel itself after joining, or joining the hollow panel in a state in which the hollow panel is warped in the direction opposite to the direction of strain generated during joining, etc. However, in any case, in order to obtain stable quality, it must be said that the production method is extremely difficult.
[0006]
The present invention has been made in view of the above problems, and the intended process is to produce a high-planar-precision hollow panel without requiring correction or the like regardless of the thickness, material, size, and joining method of the metal plate. An object of the present invention is to provide a hollow panel structure that can be obtained with good performance.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, the tip surfaces of two metal plates having thicknesses t ₁ and t _{2 formed} by projecting a plurality of protrusions in a scattered manner are brought into contact with each other. In this way, a hollow panel having a thickness B is formed by joining the contact portions between the protrusions of the two metal plates, and the center of distortion generated by the connection between the protrusions of the two metal plates is the two metals. The heights h ₁ and h ₂ of the protrusions of both metal plates are set as follows so as to coincide with the neutral axis of the cross section of the plate :
h ₁ = (Bt ₂ -t ₂ ² -t ₁ · t ₂ ) / (t ₁ + t ₂ )
h ₂ = (Bt ₁ −t ₁ ² −t ₁ · t ₂ ) / (t ₁ + t ₂ )
It is characterized in that it is set to a value obtained by .
[0008]
According to a second aspect of the present invention, in the first aspect of the present invention, the thicknesses t ₁ and t ₂ of the _two metal plates are different from each other.
[0009]
The invention according to claim 3 is the invention according to claim 1 or 2, wherein the projections of the two metal plates are joined to each other by welding, and the center of distortion caused by the joining of the projections is set at the joint of both projections. The center height position of the thickness (t ₁ + t ₂ ) is used.
[0010]
The invention according to claim 4 is the invention according to claim 3, wherein the welding is laser welding.
[0011]
The invention according to claim 5 is the invention according to claim 1 or 2, wherein the projections of the two metal plates are joined to each other by caulking or rivet joining, and the center of distortion caused by the joining of the projections is set to the center of both projections. It is characterized by the position of the joint surface.
[0012]
Therefore, according to the first aspect of the present invention, the center of strain generated by joining the protrusions of both metal plates to the neutral axis (centroid: no stress line) of the cross section of the hollow panel constituted by two metal plates. Therefore, the distortion caused by the joining of the two metal plates is concentrated on the neutral axis. As a result, the entire hollow panel is not distorted (warped) or bent. And since this is true regardless of the plate thickness, material, size and joining method (welding, caulking, rivet joining) of the metal plate, even if it is a large hollow panel, it is easy to ensure high planar accuracy. Therefore, a hollow panel having a stable quality can be obtained with high productivity without requiring correction or the like.
[0013]
According to the invention of claim 2, when the thicknesses of the two metal plates are different from each other, the neutral shaft is offset from the center position of the thickness of the hollow plate. The above-mentioned effect of the present invention can be obtained by setting the height of the projections appropriately and making the center of distortion generated by joining the projections of both metal plates substantially coincide with the neutral axis.
[0014]
According to the third aspect of the present invention, when the projections of the two metal plates are joined by welding, the center of distortion caused by the joining of the projections is the center height of the thickness of the joint portion of both projections. Therefore, the effect of the present invention can be obtained by making this position substantially coincide with the neutral axis.
[0015]
According to the fourth aspect of the present invention, since the projections of the two metal plates are joined by laser welding with a small amount of heat input, the effect of distortion due to welding heat is kept small, and the flatness accuracy of the hollow panel is further increased. Can do.
[0016]
According to the fifth aspect of the present invention, when the protrusions of the two metal plates are joined together by caulking or rivet joining, the center of distortion caused by the joining of the protrusions is the position of the joining surface of both protrusions. Therefore, the effect of the present invention can be obtained by making this position substantially coincide with the neutral axis.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0018]
<Embodiment 1>
1 is a side sectional view of a plasma display having a hollow panel, FIG. 2 is a partial perspective view of the hollow panel, and FIG. 3 is a side sectional view showing a hollow panel structure according to the present invention (cross sectional view taken along line AA in FIG. 2). It is.
[0019]
First, a schematic configuration of the plasma display 11 will be described with reference to FIG.
[0020]
In FIG. 1, reference numeral 12 denotes a PDP (plasma display panel) made of a rectangular glass plate, and the back surface of the PDP 12 is supported by a rectangular hollow panel 1. The periphery of the PDP 12 and the hollow panel 1 is covered with a rectangular frame-shaped front cover (bezel) 13.
[0021]
A plurality of electronic circuit boards 14 are supported by spacers 15 on the back surface of the hollow panel 1, and these are covered by a rear cover 16.
[0022]
Here, the detail of the structure of the said hollow panel 1 which concerns on this invention is demonstrated based on FIG.2 and FIG.3.
[0023]
The hollow panel 1 according to the present embodiment includes two aluminum metal plates 2 and 3 each having a plurality of frustoconical protrusions 2a and 3a protruding in a scattered manner by press molding. The front end surfaces of 3a are overlapped so that they are in contact with each other, and the contact portions of the protrusions 2a and 3a of both metal plates 2 and 3 are joined by laser welding.
[0024]
Here, the thicknesses t ₁ and t ₂ of the metal plates 2 and 3 constituting the hollow panel 1 are different from each other, and the thickness t ₁ (= 1.0 mm) of one metal plate 2 is the other metal plate. 3 is set to be larger than the thickness t ₂ (= 0.8 mm) (t ₁ > t ₂ ).
[0025]
By the way, in the hollow panel 1 according to the present embodiment, since the projections 2a and 3a of the two metal plates 2 and 3 are joined by laser welding, the projections 2a and 3a are fused and integrated, and the projections 2a and 3a are integrated. The center O of distortion caused by the joining of 3a is the center height position of the thickness (t ₁ + t ₂ ) of the joint part of both protrusions 2a and 3a.
[0026]
Thus, in the present embodiment, as shown in FIG. 3, the center O of distortion caused by the joining of the protrusions 2a and 3a is substantially coincident with the neutral axis N of the cross section of the two metal plates 2 and 3. Further, the heights h ₁ and h ₂ of the protrusions 2a and 3a of the metal plates 2 and 3 are set.
[0027]
Here, the heights h ₁ and h ₂ of the protrusions 2a and 3a are obtained as follows.
[0028]
As shown in FIG. 3, when the thickness of the hollow panel 1 is B, the distance to the neutral axis N is C, and the portions of the protrusions 2a and 3a are omitted, the interval between B, C, t ₁ and t ₂ is as follows. The formula holds.
[0029]
_{t 1 · (B-C-} t 1/2) = t 2 · (C-t 2/2) ... (1)
From the above equation (1), the distance C to the neutral axis N is obtained by the following equation.
[0030]
_{C = {(B-t 1} /2) · t 1 + t 2 2/2} / (t 1 + t 2) ... (2)
Here, as described above, the center O of the distortion caused by the joint between the protrusions 2a and 3a is the center height position of the thickness (t ₁ + t ₂ ) of the joint between the protrusions 2a and 3a. Since O coincides with the neutral axis N of the cross section of the two metal plates 2 and 3, the heights h ₁ and h ₂ of the protrusions 2a and 3a are obtained by the following equations.
[0031]
h ₁ = B−C− (t ₁ + t ₂ ) / 2 (3)
h ₂ = C− (t ₁ + t ₂ ) / 2 (4)
Substituting C obtained by the expression (2) into the above expressions (3) and (4), the heights h ₁ and h ₂ of the protrusions 2a and 3a are expressed by the following expressions (3 ′) and (4 ′). expressed.
[0032]
h ₁ = (Bt ₂ −t ₂ ² −t ₁ · t ₂ ) / (t ₁ + t ₂ ) (3 ′)
h ₂ = (Bt ₁ −t ₁ ² −t ₁ · t ₂ ) / (t ₁ + t ₂ ) (4 ′)
Thus, in the present embodiment, the thickness t ₁ of one metal plate _{2 is} set to be greater than the thickness t ₂ of the other metal plate 3 (t ₁ > t ₂ ), so (3 ′ ), The height h ₁ of the protrusion 2a determined by (4 ′) is lower than the height h _{2 of the} protrusion 3a determined by equation (4 ′) (h ₁ <h ₂ ).
[0033]
By the way, in the actual production process of the hollow panel 1, a metal plate 3 formed by projecting a plurality of protrusions 3 a having a height h _{2 in} a scattered manner is installed on a surface plate (not shown) with high planar accuracy. a scattered manner the metal plate 2 formed by projecting a plurality of protrusions 2a height h ₁ thereon, as shown in FIG. 3, another of the protrusions 2a, the tip faces of 3a so as to abut against In a state where the metal plate 2 is pressed to the other metal plate 3 side (downward) with a plate (not shown) with high planar accuracy, the contact portion between the protrusions 2a and 3a is spot-laser welded. The hollow panel 1 is obtained by joining both the metal plates 2 and 3 together.
[0034]
As described above, in the hollow panel 1 obtained by laser welding the projections 2a and 3a of the two metal plates 2 and 3, the two metal plates 2 and 2 are disposed on the neutral axis (centroid) N of the cross section. Since the center O of the distortion generated by joining the three projections 2a, 3a substantially coincides with each other, the distortion caused by joining the two metal plates 2, 3 is concentrated on the neutral axis N. As a result, the hollow panel 1 No distortion (warping) or bending of the whole. This also means that the metal plates 2 and 3 have thicknesses t ₁ and t ₂ , materials (same materials and different materials), sizes, protrusion shapes (conical frustum shape, rectangular parallelepiped shape, other arbitrary shapes), and different shapes. Since it holds regardless of the bonding between the protrusions, the arrangement of the protrusions, the bonding method (welding, caulking, rivet bonding), etc., even if it is a large hollow panel 1, high planar accuracy can be easily secured to this, The hollow panel 1 with stable quality can be obtained with high productivity without requiring correction.
[0035]
In particular, in the present embodiment, the projections 2a and 3a of the two metal plates 2 and 3 are joined by laser welding with a small amount of heat input, so that the influence of distortion due to welding heat can be suppressed to a low level. The planar accuracy of the hollow panel 1 can be further increased.
[0036]
Further, the flatness accuracy of the hollow panel 1 having the above structure does not depend on the flatness of the metal plates 2 and 3 at the material stage before joining, and the hollow panel obtained by joining the metal plates 2 and 3. 1 always has high plane accuracy. Incidentally, although the size of the hollow panel 1 according to the present embodiment is 600 mm × 1000 mm, the amount of bending at the center thereof can be suppressed from 2 mm to 0.5 mm.
[0037]
By the way, in the plasma display, if the flat accuracy of the hollow panel supporting the glass-made PDP is poor, an excessive stress is applied to the PDP to cause problems such as destruction of the PDP itself or pixels or distortion of the image. In the hollow panel 1 according to the present embodiment having the structure of the present invention, since the high planar accuracy is always ensured as described above, the above-mentioned problem does not occur.
[0038]
In addition, if the rigidity of the hollow panel is low, the PDP and substrate supported by the hollow panel may be destroyed by impact during mounting or transportation, or the hollow panel may be distorted due to gravity or the like during setting, and the image may be distorted, or the pixels may be destroyed. This causes a malfunction. For this reason, high rigidity is required for the hollow panel. In addition, there are models such as a wall-mounted type and a portable type for the plasma display. From the viewpoint of effective use of resources, the hollow panel is desired to be lightweight.
[0039]
Thus, since the hollow panel 1 according to the present embodiment is configured as a hollow structure formed by joining two metal plates 2 and 3, the weight can be reduced and a large second moment of section can be obtained. This ensures high bending and torsional rigidity. Since the two metal plates 2 and 3 are joined in a scattered manner by laser welding, a substantial decrease in rigidity can be minimized. Even when the thicknesses t ₁ and t ₂ of the two metal plates 2 and 3 are thin, sufficient rigidity is secured to the hollow panel 1 by adjusting the distance between the surfaces of the two metal plates 2 and 3. can do. Incidentally, rigidity (secondary moment of section) is approximately proportional to the cube of the inter-surface distance.
[0040]
Furthermore, in a plasma display, heat is generated in the PDP due to discharge, so that the heat distribution on the screen may be non-uniform depending on the image, and the local temperature rise damages the device. In fact, since heat is generated from the elements on the electronic circuit board, the hollow panel is required to have high thermal conductivity and heat dissipation.
[0041]
Thus, in the present embodiment, aluminum having high thermal conductivity is selected as the material of the two metal plates 2 and 3 constituting the hollow panel 1 to ensure high thermal conductivity and heat dissipation in the hollow panel 1. I tried to do it. Actually, the heat from the PDP 12 is conducted from one metal plate 2 of the hollow panel 1 to the other metal plate 3 through the projections 2a and 3a, but the number of the projections 2a and 3a is increased, You may make it improve the heat dissipation of the hollow panel 1 by making the cut-and-raised part formed in the plate 2 (3) contact the other metal plate 3 (2), and expanding a heat-transfer area.
[0042]
In the above embodiment, the case where the thicknesses t ₁ and t _{2 of the two} metal plates 2 and 3 constituting the hollow panel 1 are different from each other (t ₁ ≠ t ₂ ) has been described. As shown in FIG. 4, when the thicknesses t of the two metal plates 2 and 3 are equal, the distance C to the neutral axis N is expressed by the following equation by setting t ₁ = t _{2 in the} equation (2). Thus, it becomes 1/2 of the thickness B of the hollow panel 1 (that is, the center position of the width B).
[0043]
C = B / 2 (5)
The heights h ₁ and h ₂ of the protrusions 2a and 3a can be obtained by the following equation by setting t ₁ = t ₂ = t in the equations (3 ′) and (4 ′).
[0044]
h ₁ = h ₂ = B−t / 2 (6)
<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a side sectional view showing the hollow panel structure according to the present embodiment. In FIG. 5, the same elements as those shown in FIG. 3 are denoted by the same reference numerals. Omitted.
[0045]
In the present embodiment, the protrusions 2a and 3a of the two metal plates 2 and 3 constituting the hollow panel 1 are joined by caulking. In the case of joining by caulking, unlike the first embodiment in which both projections 2a and 3a are integrated by welding, slip occurs on the joining surface of both projections 2a and 3a. The center of the distortion produced by the joining is the position of the joining surface of both protrusions 2a and 3a.
[0046]
Accordingly, in the present embodiment, the position of the joint surface between the two protrusions 2a and 3a, which is the center of distortion caused by the joint between the protrusions 2a and 3a, is substantially coincident with the neutral axis N of the cross section of the two metal plates 2 and 3. It was set as the structure to make it show. With this configuration, high planar accuracy can be ensured even for the hollow panel 1 that employs caulking as the joining means, and the same effects as those of the first embodiment can be obtained.
[0047]
<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 6 is a side sectional view showing the hollow panel structure according to the present embodiment. In FIG. 6, the same elements as those shown in FIG. 3 are denoted by the same reference numerals. Omitted.
[0048]
In the present embodiment, the projections 2 a and 3 a of the two metal plates 2 and 3 constituting the hollow panel 1 are joined to each other by joining with the rivet 4. Also in the case of this rivet joining, as in the caulking in the second embodiment, since the slip occurs on the joining surface of both the protrusions 2a and 3a, the center of distortion caused by the joining of the protrusions 2a and 3a is the both protrusions. It becomes a joint surface position of 2a, 3a.
[0049]
Therefore, also in the present embodiment, as in the second embodiment, the positions of the joint surfaces of the two protrusions 2a and 3a, which are the centers of distortion caused by the joint between the protrusions 2a and 3a, are set to the two metal plates 2 and 3. It was set as the structure substantially made to correspond to the neutral axis N of the cross section. With this configuration, high planar accuracy can be ensured even for the hollow panel 1 that employs rivet bonding as the bonding means, and the same effects as those of the first embodiment can be obtained.
[0050]
In the above description, the form in which the hollow panel is applied to the plasma display has been described. However, the present invention is also applicable to a hollow panel used as a strength member or flatness maintaining member of any other equipment such as various OA equipment. Of course, the same applies.
[0051]
【The invention's effect】
As is apparent from the above description, according to the present invention, two metal plates formed by projecting a plurality of protrusions in a scattered manner are overlapped so that the tip surfaces of the protrusions are in contact with each other, A hollow panel is formed by joining the contact portions between the protrusions of the two metal plates, and the center of distortion generated by the connection between the protrusions of the two metal plates substantially coincides with the neutral axis of the cross section of the two metal plates. As described above, since the heights of the protrusions of both metal plates are set, it is possible to obtain a high-planar-precision hollow panel with high productivity without requiring correction or the like regardless of the thickness, material, size and joining method of the metal plates. it can.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a plasma display having a hollow panel.
FIG. 2 is a partial perspective view of a hollow panel.
FIG. 3 is a side cross-sectional view (cross-sectional view taken along line AA in FIG. 2) showing the hollow panel structure according to Embodiment 1 of the present invention.
FIG. 4 is a side sectional view showing a special form of a hollow panel structure according to Embodiment 1 of the present invention.
FIG. 5 is a side sectional view showing a hollow panel structure according to a second embodiment of the present invention.
FIG. 6 is a sectional view showing a hollow panel structure according to a third embodiment of the present invention.
FIG. 7 is a side sectional view showing a conventional hollow panel structure.
[Explanation of symbols]
1 Hollow panel 2, 3 Metal plate 2 a, 3 a Protrusion 4 Rivet h ₁ , h ₂ Height of protrusion N Neutral axis O Center of distortion caused by joining

Claims (5)

Two metal plates having thicknesses t ₁ and t _{2 formed} by projecting a plurality of protrusions in a scattered manner are overlapped with each other so that the front end surfaces thereof are in contact with each other, and the protrusions of both metal plates are in contact with each other. The two metal plates are formed such that a hollow panel having a thickness B is formed by joining the portions, and the center of distortion caused by joining the protrusions of the two metal plates coincides with the neutral axis of the cross section of the two metal plates. the height h ₁ of the protrusions of, following equation h _2:
h ₁ = (Bt ₂ −t ₂ ² −t ₁ · t ₂ ) / (t ₁ + t ₂ )
h ₂ = (Bt ₁ −t ₁ ² −t ₁ · t ₂ ) / (t ₁ + t ₂ )
A hollow panel structure characterized by being set to a value required by The hollow panel structure according to claim ₁ , wherein thicknesses t ₁ and t ₂ of the _two metal plates are different from each other. The protrusions of the two metal plates are joined to each other by welding, and the center of distortion caused by the joining of the protrusions is set as the center height position of the thickness (t ₁ + t ₂ ) of the joints of both protrusions. The hollow panel structure according to claim 1 or 2. The hollow panel structure according to claim 3, wherein the welding is laser welding. The hollow according to claim 1 or 2, wherein the projections of the two metal plates are joined to each other by caulking or rivet joining, and the center of distortion caused by the joining of the projections is set as the joint surface position of both projections. Panel structure.

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