JP6693599B2 - Structure of joining part for panel parts and joining method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a technique for adhering and bonding a back surface of a metal panel component such as an automobile panel component to a reinforcing component with a mastic adhesive. In particular, a technique for more easily avoiding a surface sink mark (local out-of-plane deformation of a panel component due to shrinkage of the mastic adhesive), which is one of the poor appearances when the panel components are joined with the mastic adhesive. Regarding

The panel parts are, for example, an outer plate part called an outer panel of an automobile, an inner plate part such as a floor or a dash lower. Such a panel component is a component group having a wide projected area. Further, the panel component contributes significantly to the weight reduction by reducing the plate thickness as compared with other skeletal components.
Such a panel component has, for example, a plate shape having a loose and wide curved surface, and tends to have relatively low rigidity in the out-of-plane direction. For this reason, a reinforcing component that reinforces the panel component may be arranged on the back side. At this time, a mastic adhesive is interposed in the gap between the back surface of the panel component and the reinforcing component, and the panel component and the reinforcing component are joined by the mastic adhesive, and the panel component is reinforced by the joining. Be bound by.

  Here, the mastic adhesive is a semi-solidified substance. When this mastic adhesive is subjected to heat treatment such as baking heat of panel coating, it foams (expands) by the heat and hardens (shrinks) by subsequent cooling, and finally has a rubber-like property. have. When the panel component receives an external force, the provided mastic adhesive has an important role such that the position where the mastic is arranged becomes a support point for the external force and the vibration of the panel component is suppressed.

  In addition, when the panel component is an outer panel component that is exposed to the eyes of the user, a high level of surface appearance quality is often required. However, the thinner the panel component is made to reduce the weight of the product, the lower the surface rigidity of the panel component, which is called the tensile rigidity. Then, the surface of the panel component may be out-of-plane deformed due to the contracting force of the mastic adhesive generated in the cooling process after coating. The deformed portion has a steep surface change as compared with the surrounding gentle curved surface, and is therefore easily noticeable to humans. Such poor appearance due to out-of-plane deformation is generally called surface sink mark, and is one of the problems in thinning outer panel components.

  Regarding the surface sink mark generated in such a panel component, Patent Literature 1 discloses a method of arranging two adhesives having different shrinkage rates in parallel to alleviate the shrinkage of the panel component on the surface. Further, Patent Document 2 discloses a method in which hollow particles made of a resin are contained in a mastic adhesive, and the hollow particles absorb shrinkage of the mastic itself to suppress surface sink marks. Further, Patent Document 3 discloses a method capable of adjusting a strain generated by heat in a paint baking process by providing a structure capable of adjusting a distance between an outer panel and a reinforcing component.

Japanese Patent Laid-Open No. 6-73342 Japanese Patent No. 5707077 JP, 2008-62696, A

However, in the method described in Patent Document 1, it is necessary to separately prepare and arrange different types of mastic adhesives, which may result in cost and lead time.
Further, in the method described in Patent Document 2, it is necessary to prepare resin spheres separately from the material of the mastic adhesive and mix them with the mastic adhesive. Therefore, the method described in Patent Document 2 leads to an increase in material cost. Further, in the method described in Patent Document 2, when the material balance of the mastic adhesive and the physical property balance of the resin forming the sphere are changed, a stable effect cannot be obtained, which may make it difficult to adjust the mixing.

Further, the method described in Patent Document 3 complicates the structure of internal parts, and requires design of parts for countermeasures whenever the shape of panel parts to be adopted or the relationship between panel parts and reinforcing parts changes. Therefore, the versatility is low as a countermeasure.
The present invention has been made in view of the above points, and it is an object of the present invention to easily suppress the occurrence of surface sink marks caused by adhering panel components with a mastic adhesive.

In order to solve the problem, one embodiment of the present invention relates to a mastic adhesive that intervenes when a reinforcing component and a back surface of a metal panel component that are opposed to each other with a gap are bonded to each other with respect to the mastic adhesive. The outer peripheral contour shape of the adhesive surface to the back surface of is formed by continuous arcs, and a cavity is formed at the central position of the mastic adhesive.
Here, the contour shape formed by continuous arcs refers to a contour shape such as a circular shape or an elliptical shape in which there is no portion having a sharp curvature such as a corner.

  According to one aspect of the present invention, the shape of the interposing mastic adhesive (joint part for panel parts) is devised to relieve the stress applied to the surface of the panel part when the mastic adhesive contracts. Can be done. As a result, according to one aspect of the present invention, it is possible to easily suppress the occurrence of surface sink due to the panel component being bonded with the mastic adhesive.

It is a figure explaining the structure of the joint part for panel components which concerns on embodiment based on this invention, (a) is sectional drawing seen from the side, (b) is the figure which looked at the joint part from above. It is a figure explaining the structure of the joint part for other panel components which concerns on embodiment based on this invention, (a) is sectional drawing seen from the side, (b) is the figure which looked at the joint part from above. .. It is a figure explaining the analysis model used in an Example. It is a figure explaining an analysis model (side view). It is a figure explaining an analysis model (mesh subdivision). It is a figure which shows the solid type mastic model as a comparative example. It is a figure which shows a hollow type mastic model, (a) is a perspective view, (b) is a XX 'sectional view of (a). It is a figure which shows a donut shape type mastic model. It is a figure in a hollow type which shows a generation state of out-of-plane deformation which made a panel board thickness and an inside diameter of a cavity into a parameter. FIG. 7 is a diagram in which the hollow type is arranged by the maximum second derivative with the void ratio as a parameter. It is a figure in a donut shape type (hollow type with which the upper and lower sides are opened) showing the generation state of the out-of-plane deformation with the panel plate thickness and the inner diameter of the cavity as parameters. It is the figure which arranged by the maximum second derivative with a void ratio as a parameter about a donut shape type.

Next, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the structure of the joint part for a panel component of the present embodiment is a structure of the joint part 3 for joining the reinforcing component 1 and the back surface 2a of the panel component 2 made of a metal plate, which are opposed to each other with a space therebetween. That is, the structure of the joint part for a panel component made of a mastic adhesive.
Here, in the present embodiment, an outer panel component called an outer panel of a vehicle (such as a door panel or a roof panel), a panel component for an automobile such as an inner panel component such as a floor or a dash lower, and a reinforcing component, This technique is suitable for joining with a mastic adhesive. However, the structure of the panel component joint portion of the present embodiment can be applied even when panel components for other applications are joined by a mastic adhesive.

Such a panel component 2 is often formed in a plate shape having a curved surface with a gentle and wide curvature, and tends to have relatively low rigidity in the out-of-plane direction. Therefore, the reinforcing component 1 for reinforcing the panel component 2 is arranged on the back side of the panel component 2 and the panel component 2 is reinforced by connecting the reinforcing member to the peripheral portion of the panel component 2.
At this time, as shown in FIG. 1, since a gap is formed between the back surface 2a of the panel component 2 and the reinforcing component 1, a mastic adhesive is partially interposed in the gap, and the mastic adhesive is used. The panel component 2 and the reinforcement component 1 are joined together. The panel component 2 is constrained to the reinforcing component 1 by the joint portion 3 made of the mastic adhesive.

Generally, the joining of the panel component and the reinforcing component with the mastic adhesive is often carried out by spotting the mastic adhesive.
On the other hand, in the present embodiment, the shape (structure) of the joint portion 3 made of the mastic adhesive interposed between the panel component 2 and the reinforcing component 1 is set to a shape that satisfies the following two requirements. To do.
(Requirement 1) The outer peripheral contour shape R1 of the bonding surface 3A to the back surface 2a of the panel component 2 is formed by continuous arcs.
(Requirement 2) A cavity 4 is formed at the central position of the joint 3 made of a mastic adhesive.
Each requirement is explained.

<About Requirement 1>
Requirement 1 is that the outer peripheral contour shape R1 of the surface (panel bonding surface 3A) that faces the back surface 2a of the panel component 2 in the joint structure made of a mastic adhesive has a sharp curvature portion as shown in FIG. 1 (b). This is achieved by setting a contour having a curved shape that does not have. For example, the contour of the panel bonding surface 3A is set to a contour shape such as a circular shape or an elliptical shape having a continuous arc shape. The steep curvature portion is a portion where the curvature suddenly changes and forms, for example, a corner.

Out-of-plane deformation due to contraction of the mastic adhesive occurs on the panel component 2 side. Therefore, the outer peripheral contour shape R1 of the panel adhesive surface 3A is defined in order to suppress the contraction on the panel component 2 side, but the outer peripheral contour shape of the adhesive surface 3B of the mastic adhesive to the reinforcing component 1 is also: It is preferable to set a curved contour having no sharp curvature portion.
Here, the contour shape R1 of the panel bonding surface 3A is configured by a continuous arc shape. For example, when the contour shape R1 is a rectangular shape, the contraction of the corner becomes locally severe when contracted, and This is because it may behave differently from. As a result, the sensory confirmation by visual inspection may not match the result of the experiment.

For example, the shape of the joint portion 3 made of a mastic adhesive is set to a cylindrical shape, a hemispherical shape, a truncated cone shape, a donut shape, or the like. In the case of such a circular cross section, the above requirement 1 can be satisfied with a simple shape of the joint portion 3.
The cross-sectional shapes cut in the direction orthogonal to the line extending from the panel component 2 to the reinforcing component 1 (direction parallel to the surface of the panel component) do not necessarily have to have the same size and shape. For example, the shape of the mastic adhesive may be a donut shape as shown in FIG. 2 or may be a mountain shape whose cross section is gradually reduced. FIG. 2 is an example in which the cavity 4 is opened to the panel component 2 side.

However, it is preferable that the shape is symmetrical with respect to the surface from the panel component 2 toward the reinforcing component 1. The outer peripheral contour shape R1 of the panel bonding surface 3A in the shape of the joint portion 3 made of a mastic adhesive may be dulma-shaped. In this case, it can be considered that the joint made up of the two mastic adhesives sticks to each other to form a dharma shape.
In the following, the structure of the joining portion 3 made of the mastic adhesive to be interposed is assumed to be a structure having a substantially columnar shape (see FIG. 1) or a donut shape (see FIG. 2).

<Requirement 2>
Requirement 2 is to form a cavity 4 at the central position of the joint portion 3 made of an intervening mastic adhesive as shown in FIGS. 1 and 2. The center position may be the center position as viewed from the thickness direction of the panel component 2, that is, as viewed from the front surface side of the panel component 2.
The void ratio of the voids 4 is sure to be 5% or more of the volume of the joint portion 3 made of the mastic adhesive to be interposed and solid, as compared with the case where the mastic adhesive is solid. Demonstrates the effect of suppressing face sinking. More preferably, the porosity is 10% or more.

The volume of the mastic adhesive may change due to heating / cooling in the initial state, but the above-mentioned void ratio is the void ratio after heating / cooling.
However, if the porosity becomes larger than a predetermined value, the effect of suppressing the vibration of the panel component 2 by the intervening mastic adhesive and the effect of improving the tensile rigidity become low, so the porosity is preferably suppressed to less than 80%. More preferably, the upper limit of the void ratio is less than 60%.

The cross-sectional shape of the cavity 4 is also preferably a contour shape having a curved shape without a steep curvature portion. Further, the cross-sectional shape of the cavity 4 is preferably similar to or close to the cross-sectional shape of the joint portion 3 made of a mastic adhesive.
Further, if the void ratio is the same, it is preferable that the formation position of the cavity 4 in the height direction is close to the panel component 2 side. This is because it is easier to relieve the stress on the panel bonding surface 3A.

  Further, as shown in FIG. 2, it is preferable that the cavity 4 be opened at least on the panel component 2 side where surface sinkage is likely to occur. At this time, it is preferable that the contour shape R2 of the opening is also formed by continuous arcs (see FIG. 2). In addition to this, the reinforcing component 1 side may be opened. When the cavity 4 is open as described above, the volume of the cavity at the hollow position of the joint becomes the volume of the cavity 4.

The method for forming the joint portion 3 made of a mastic adhesive that satisfies the above two requirements is, for example, the shape of the opening of the tip portion of the filling nozzle for application, which is used when the mastic adhesive is applied to a component ( The portion where the adhesive is blown out) is applied using a ring-shaped (O-shaped) or C-shaped one. In the case of this forming method, the joining process can be performed with the same takt time as the conventional one. When the opening shape at the tip of the filling nozzle is C-shaped, the gap of C cut may be set so that the cross-section has a donut shape due to expansion in the heating step.
Further, as a method of forming the cavity 4 inside the mastic adhesive, for example, the mastic adhesive applied to a part in a predetermined amount is pierced with an injection needle and filled with air or an inert gas. To do.

<Action and others>
When the mastic adhesive having the shape of the present embodiment is adopted, when the heated mastic adhesive contracts by cooling, not the panel bonding surface 3A but mainly the cavity 4 is deformed. Therefore, the force of pulling in the panel component 2 generated on the panel bonding surface 3A becomes small.

Further, in the present embodiment, the outer peripheral contour shape R1 of the panel bonding surface 3A has no corner portion. Therefore, it is possible to suppress the occurrence of partial stress concentration at the time of cooling, which is generated in the outer peripheral contour shape such as when there is a corner part.
As described above, in the present embodiment, by devising the shape of the joint portion 3 made of the mastic adhesive, the surface of the panel component 2 is loaded at a low cost and easily when the mastic adhesive shrinks. Stress can be relaxed. As a result, it is possible to easily suppress the occurrence of surface sink due to the panel component 2 being bonded with the mastic adhesive.

  As will be described later in the embodiment, if the panel component 2 has the same plate thickness, the joint portion 3 made of a hollow type mastic adhesive is adopted rather than the joint portion 3 made of a solid type mastic adhesive. Therefore, the sink mark can be suppressed more. That is, in the case of designing with the same quality as the joint portion made of the solid type mastic adhesive, it becomes possible to thin the panel component 2.

  For example, when applied to automotive panel parts, by controlling the adhesive method of the mastic adhesive without changing the automobile manufacturing line, it is possible to suppress the surface sink of the panel parts and achieve stable quality production. In addition, it also leads to the solution of the problem of surface sinkage caused by thinning the panel, which can contribute to the weight reduction of the automobile body.

Next, examples based on the present invention will be described.
<Analysis conditions>
As an analysis model, as shown in FIG. 3, a panel part model a simulating an outer panel having a rectangular shape of which one side is 286 mm square in projection and a convex shape curved upward, a frame b supporting the same, and an outer plate. A model c simulating the reinforcing component 1 of the component was set. By providing the columnar mastic adhesive model d in the central portion, the panel component model a is supported in a curved shape of a semi-cylindrical shape that is curved upward.

  As shown in FIG. 4, the panel part model a is a curve of R5000, which is assumed to be a roof panel of an automobile, directed in one direction, and the surface shape in a direction orthogonal to the curve is set to be flat. The plate thickness of the panel part model a is set to 0.50 mm, 0.60 mm, 0.70 mm and 1.0 mm, and the contour diagram of the displacement distribution of the panel part 2 in the z direction (the plate thickness direction of the panel part 2) in each case. Was parsed and output.

The frame b was set to a rigid body, and the material properties of the panel part model a, the model c of the reinforcing part 1 and the model d of the mastic adhesive were input as follows.
As for the models a and c, the density of 7.8 g / cm ³ and the Young's modulus of 210 GPa were input assuming iron, and for the model d, the physical property values of the mastic adhesive were input. In this example, as a physical property value of a mastic, a thermoelastic FEM model is used, a thermal expansion coefficient at expansion is 0.850 × 10 ⁻³ / ° C. · m, a Young's modulus is 150 MPa, and a thermal expansion coefficient at contraction is 0.905 × 10 ⁻³ / ° C. · m, Young's modulus was 210 MPa.

At this time, as shown in FIG. 5, the frame b and the panel component model a were divided into meshes, and the mastic adhesive model d was divided into solid elements as shown in FIG.
The external shape of the mastic adhesive to be set was set to a cylinder having a diameter of 20 mmφ. Here, FIG. 6 is a solid type, FIG. 7 is a hollow type, and FIG. 8 is a donut-shaped type (a hollow-shaped type having an opening at the top and bottom). In the case of the hollow type and the donut shape type, the diameter of the cavity 4 was set to 5 mm, 10 mm and 15 mm.

In the case of the doughnut-shaped type as shown in FIG. 8, the cavity ratio is 6% when the inner diameter is 5 mmφ, the cavity rate is 25% when the inner diameter is 10 mmφ, and the cavity rate is 56% when the inner diameter is 15 mmφ.
In the case of the hollow type as shown in FIG. 7, the void ratio is 2% when the inner diameter is 5 mmφ, the void ratio is 8% when the inner diameter is 10 mmφ, and the void ratio is 19% when the inner diameter is 15 mmφ.
The analysis was performed using a static implicit method using LS-DYNA ver9.71 as a solver.

  At this time, assuming that the coating baking temperature of the automobile is 170 ° C. as the heating condition, the solid element of the mastic adhesive was analyzed to raise the temperature from 20 ° C. to 170 ° C. and then to 170 ° C. .. Switching from temperature increase to temperature decrease was performed by a coupled analysis that inherits the panel shape and stress distribution.

<Evaluation>
The evaluation of the surface sink mark was performed by calculating the distribution of the secondary differential value representing the change in the inclination of the surface from the Z displacement amount of the mastic adhesive adhesive portion (center of the panel) and the shape of the cross section, and using the maximum value thereof. It is said that the larger the second derivative value, the more visible it is to the human eye, and the larger the number, the larger the sink mark.

(Evaluation of hollow type)
First, FIG. 9 shows the results of the hollow type.
The increase in the plate thickness of the panel component 2 alleviates the surface sink marks at the bonded portion of the mastic adhesive. However, comparing the same plate thickness, it can be seen that the surface sink marks improve as the inner diameter increases in the examples.
Further, FIG. 10 shows the results arranged by the maximum second derivative value in the hollow type.

  As can be seen from FIG. 10, when the plate thickness 0.70 mmt is used as a reference for the joint portion 3 made of a solid type mastic adhesive, if the void ratio is 5%, the plate thickness becomes 0.60 mmt, which is equivalent to the panel component. It is recognized that even if 2 is thinned, the same level of quality as the conventional solid type can be secured. Here, in automobiles, the panel component 2 having a plate thickness of about 0.70 mmt is often applied.

(Evaluation of donut shape type)
FIG. 11 shows the result of the donut shape type (hollow type having openings at the top and bottom).
The increase in the plate thickness of the panel component 2 alleviates the surface sink marks at the bonded portion of the mastic adhesive. However, comparing the same plate thickness, it can be seen that the surface sink marks improve as the inner diameter increases in the examples.
Further, FIG. 12 shows the results arranged by the maximum second derivative value in the donut shape type.

As can be seen from FIG. 12, when the plate thickness 0.70 mmt is used as a reference for the joint portion 3 made of the solid type mastic adhesive, if the void ratio is 5%, the plate thickness becomes equal to 0.60 mmt, and the panel component It is recognized that even if 2 is thinned, the same level of quality as the conventional solid type can be secured.
As described above, according to the present invention, even if the panel thickness is thin, it is possible to suppress the sink mark more than the current solid type mastic adhesive, and it is possible to contribute to the weight reduction of the vehicle body. I understand.

As described above, the entire contents of Japanese Patent Application 2017-084629 (filed on April 21, 2017) to which the present application claims priority are made a part of the present disclosure by reference.
Although the description has been made herein with reference to a limited number of embodiments, the scope of rights is not limited thereto, and modifications of the embodiments based on the above disclosure will be obvious to those skilled in the art.

DESCRIPTION OF SYMBOLS 1 Reinforcement component 2 Panel component 2a Back surface 3 Joined portion 3A Panel bonding surface 4 Cavity R1 Outer peripheral contour shape R2 Opening contour shape

Claims (4)

A structure of a panel part joint part made of a mastic adhesive for joining a reinforcing part and a rear surface of a metal panel part, which are opposed to each other with a gap,
The outer peripheral contour shape of the bonding surface to be bonded to the back surface of the panel component is formed by a continuous arc,
Seen from the thickness direction of the panel component, a cavity is formed at the central position of the panel component joining part made of the mastic adhesive ,
The cavity formed in the panel component joint, in the panel component joint, does not open in the surface facing the reinforcing component and the panel component , the panel component joint, characterized in that Construction. The volume of the cavity is set to 5% or more of the volume of the joint part for the panel part made of the mastic adhesive when the joint part is solid, and the panel part according to claim 1 . Structure of the joint. The said panel component is a panel component for vehicles, The structure of the junction part for panel components described in any one of Claim 1 or Claim 2 characterized by the above-mentioned. A bonding method for bonding the panel component to the reinforcing component by the mastic adhesive by bonding the back surface of the metal panel component to the reinforcing component with a mastic adhesive,
The shape of the mastic adhesive to be interposed between the reinforcing component and the panel component is set so that the outer peripheral contour of the bonding surface to the back surface of the panel component is formed by continuous arcs, and the mastic bonding is performed. A joining method, wherein a cavity is formed in a central portion of the agent, and the cavity is not opened toward the reinforcing component and the panel component .

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