JP7066106B2 - Manufacturing method of resin-metal composite member - Google Patents

Description

The present invention relates to a method for manufacturing a resin-metal composite member, and more particularly to a method for manufacturing a resin-metal composite member having a metal flange that can be welded to another metal member or the like.

In automobile parts, the weight of the vehicle is reduced by using a composite of a resin material and a metal material. In Japanese Patent Application Laid-Open No. 2010-149511 of Patent Document 1, a thermoplastic resin to which a flow aid is added is applied to an aluminum base material by an injection molding method, compression molding, or the like, and the thermoplastic resin and the aluminum base material are combined. A method for manufacturing a lightweight member having a hybrid design to be joined is described.

Japanese Unexamined Patent Publication No. 2010-149511

However, when molding by the injection molding method, the thermoplastic resin is filled in the cavity by the injection pressure. Therefore, when the thermoplastic resin contains reinforcing fibers or forms a thin wall portion, a high injection pressure is required and the cavity is formed. It is difficult to spread the thermoplastic resin throughout.

If an injection press molding method is used instead of the injection molding method or the compression molding method, it is possible to apply a molten thermoplastic resin having high fluidity to the entire cavity and firmly bond the thermoplastic resin and the metal sheet. ..

However, in the injection press molding method, since the mold is closed and pressed after the thermoplastic resin is injected into the mold, it is necessary to inject the thermoplastic resin with the mold open by the amount of the press margin. The metal sheet placed in the mold cannot be fixed.

Therefore, the metal sheet is easily pushed and moved by the injected thermoplastic resin in the mold, it is difficult to apply the thermoplastic resin to a desired position of the metal sheet, and the thermoplastic resin leaks to the welded region. Will end up.

The present invention has been made in view of the problems of the prior art, and an object thereof is a resin-metal that can surely secure a welded region without leakage of a thermoplastic resin in an injection press method. The present invention is to provide a method for manufacturing a composite member.

As a result of diligent studies to achieve the above object, the present inventor has found that the above object can be achieved by damming the thermoplastic resin injected by the pre-bent metal sheet, and completes the present invention. I arrived.

That is, the method for manufacturing a resin-metal composite member of the present invention is a method for manufacturing a resin-metal composite member having a metal flange on at least a part of the peripheral edge portion.
Then, a setting process of setting a metal sheet in a mold having at least a movable mold and a fixed mold,
The first mold closing step of bringing the movable mold into contact with the metal sheet, and
An injection process in which a thermoplastic resin is injected between the fixed mold and the metal sheet,
A second mold closing step of closing the mold is provided.
The metal sheet has a bent portion bent toward the fixed mold at least a part of the peripheral portion thereof.
The second mold closing step is characterized by including a process of further bending and plastically deforming the bent portion.

According to the present invention, since the metal sheet is bent in advance to dam the injected thermoplastic resin, it is possible to provide a method for manufacturing a resin-metal composite member that can secure a welded region without leakage of the thermoplastic resin. ..

It is a figure which shows the manufacturing process of this invention. It is sectional drawing which shows an example of a metal plate. It is sectional drawing which shows the other example of a metal plate. It is a partially enlarged view explaining the inclination of a leg part. It is a partially enlarged view explaining the state which the leg part is bent in the middle. It is a partially enlarged view explaining the fixed type which has a bending groove. It is a partially enlarged view explaining the fixed type which has a discharge groove. It is sectional drawing which shows the state which welded the resin-metal composite member.

The method for manufacturing the resin-metal composite member of the present invention will be described in detail.
In the above manufacturing method, a metal flange is provided at least a part of the peripheral portion, the metal is not covered with the resin, the metal is exposed, and the metal flange can be joined to other metal members by welding. It is a method of manufacturing a member.

In the above manufacturing method, the composite member is manufactured by an injection press method using a mold having at least a movable mold and a fixed mold.
Specifically, as shown in FIG. 1, a setting step a for setting a metal sheet in a mold, a first mold closing step b for bringing the movable mold into contact with the metal sheet, and the fixed mold. It is provided with an injection step c in which a thermoplastic resin is injected between the metal sheet and a second mold closing step d in which the mold is closed and the bent portion of the metal sheet is further bent and plastically deformed. ..

<Metal sheet>
First, a metal sheet used in the method for manufacturing a resin-metal composite member of the present invention will be described.
The metal sheet 1 has a bent portion 12 at least a part of the peripheral portion, and the leg portion 13 is formed by the bent portion. Then, the thermoplastic resin 2 is dammed by the leg portion 13 to prevent the thermoplastic resin 2 from adhering to the metal flange 11.
The thermoplastic resin 2 may contain reinforcing fibers such as carbon fibers and glass fibers.

2 and 3 show schematic cross-sectional views of the metal sheet.
In the metal sheet 1 shown in FIG. 2, leg portions 13 are formed in the diagonally inward direction from the bent portion 12 inside the metal flange 11 toward the fixed mold. As shown in FIG. 2, when the metal sheet 1 has a shape in which the metal flange 11 is formed in advance, it is not always necessary to fold back the bent portion 12 in the second mold closing step described later. The leg portion 13 or the metal flange 1 can be formed by welding or the like.

Further, the metal sheet 1 shown in FIG. 3 has a bent portion 12 bent toward the fixed mold at the end of the metal flange 11, and the leg portion 13 is obliquely inward from the bent portion 12 toward the fixed mold. It is formed.
When the metal sheet 1 shown in FIG. 3 is used, it is folded back 180 ° from the bent portion 12 in the second mold closing step described later, and the leg portion 13 is brought into close contact with the main body portion 14 to form the metal flange 11.

In FIGS. 2 and 3, the internal angle of the bent portion 12 indicated by α is preferably less than 90 °, although it depends on the shape of the metal sheet 1.
As shown in FIG. 4, if the leg portion 13 is inclined with respect to the pressing direction indicated by the arrow, the bent portion 12 can be bent from the bent portion 12 even if the internal angle of the bent portion 12 is 90 ° or more. When the internal angle of the 12 is less than 90 °, the leg portion 13 and the main body portion 14 can be brought into close contact with each other by folding back 180 ° from the bent portion 12.

The thickness of the metal sheet 1 is not particularly limited as long as it can be plastically deformed and folded back at a press pressure of injection press molding, for example, 10 MPa to 30 MPa, and is 0.3 mm or more depending on the hardness of the metal sheet 1 and the like. It is preferably 3 mm or less.

If it is less than 0.3 mm, it cannot withstand the injection pressure, and as shown in FIG. 5, it may bend from the middle of the leg portion 13 without bending from the bent portion 12, and if it exceeds 3 mm, it is a high press for bending the metal sheet 1. Pressure is required, and the mold at the point where it comes into contact with the metal sheet is easily worn.

The length of the metal flange 11, that is, the length from the end of the metal sheet 1 to the portion to which the thermoplastic resin is applied is preferably 10 mm or more.

If the length of the metal flange 11 is less than 10 mm, not only the welding margin is small and welding is difficult, but also the thermoplastic resin is thermally decomposed by the heat of welding and easily peeled off from the metal sheet. Bond strength decreases. Further, when an external force is applied, stress is concentrated on the boundary between the place where the thermoplastic resin is applied and the metal flange, and the thermoplastic resin is easily peeled off.

The length of the legs is preferably 30 mm or less. If the length of the leg portion 13 is too long, as shown in FIG. 5, the leg portion 13 does not bend from the bent portion 12 but bends from the middle of the leg portion 13 due to the injection pressure, and the thermoplastic resin 2 accumulates inside the bent portion 12 to collect the leg. The part 13 may not be folded back.

It is preferable that at least the end portion of the metal sheet 1 in contact with the fixed mold is chamfered. Since one end of the metal sheet is chamfered and rounded, the aggression against the mold is reduced, the mold can be prevented from being worn, and the mold can be easily bent.

It is preferable that the metal sheet 1 has at least irregularities on the surface on the fixed mold side. By having the surface unevenness on the surface on the fixed mold side, the bonding area with the thermoplastic resin 2 becomes large, and it is possible to bond firmly.

As the metal sheet, a steel metal sheet can be used in addition to aluminum and aluminum alloy.

<First mold closing process>
The first mold closing step includes a process of closing the mold halfway and bringing the movable mold 3 into contact with the metal sheet 1. By bringing the movable mold 3 into contact with the metal sheet 1, the metal sheet 1 can be sandwiched between the movable mold 3 and the fixed mold 4 and fixed in the mold.

Therefore, in the injection process described later, the metal sheet 1 is prevented from being pushed by the injected thermoplastic resin 2 and moving in the mold, and the thermoplastic resin 2 is prevented from moving in the mold together with the leg portion 13 of the metal sheet 1. Can prevent leakage.

It is preferable that the first mold closing step includes a process of elastically deforming the metal sheet 1. By pressing the metal sheet 1 against the fixed mold 4 with the movable mold 3 and elastically deforming the metal sheet 1 in a state where the metal sheet 1 is not completely folded back, the contact force between the metal sheet 1 and the mold is increased, and the injection pressure is high. Also, the leakage of the thermoplastic resin 2 can be prevented.

It is preferable to include a heating step of heating the metal sheet 1 via the mold after the first mold closing step and before the injection step described later.
By warming the metal sheet 1, the temperature drop of the thermoplastic resin 2 in contact with the metal sheet 1 is reduced, the adhesion to the metal sheet 1 is improved, and when the metal sheet 1 has surface irregularities, the surface is uneven. The thermoplastic resin 2 gets inside the unevenness and the bonding strength is increased.

For example, when nylon 6 is injected at 250 ° C. to 300 ° C., the thermoplastic resin can be bonded by setting the average temperature of the mold to 80 ° C. to 150 ° C.

<Injection process>
The injection step includes a process of injecting the thermoplastic resin 2 between the fixed mold 4 and the metal sheet 1. At this time, if the metal sheet 1 is not fixed by the movable mold 3 and the fixed mold 4, the metal sheet 1 is pressed against the movable mold 3 by the injection pressure, and a gap is created between the metal sheet 1 and the fixed mold 4. As a result, two thermoplastic resins leak from the gap and cover the metal flange 11.

In the present invention, the metal sheet 1 fixed to the mold is bent to form the leg portion 13, and the thermoplastic resin 2 is leaked in order to dam the thermoplastic resin 2 ejected by the leg portion 13. Can be prevented.

In the injection step, it is preferable that the temperature of the mold 3 is higher in the peripheral portion of the movable mold 3 than in the central portion thereof and lower in the peripheral portion of the fixed mold 4 than in the central portion thereof.

Since the central portion of the fixed mold 4 is high, the injected thermoplastic resin 2 does not easily cool and maintains fluidity, so that the thermoplastic resin 2 can be easily filled in every corner of the cavity.
Further, since the temperature of the peripheral portion of the fixed mold 4 is low, the fluidity of the thermoplastic resin 2 decreases in the vicinity of the bent portion, it becomes difficult for the thermoplastic resin 2 to enter the inside of the bent portion 12, and the metal sheet 1 is folded back. It will be easier.

Further, since the temperature of the peripheral portion of the movable mold 3 that abuts on the bent portion 12 of the metal sheet 1 is higher than that of the central portion, even if the thermoplastic resin 2 enters the inside of the bent portion 12, the thermoplastic resin 2 Since the fluidity is high, the thermoplastic resin 2 is discharged from the inside of the bent portion 12 in the second mold closing step described later, and the metal sheet 1 can be easily folded back.

The injection step can be performed in parallel with the second mold closing step described later.
Specifically, in the second mold closing step, the injection pressure in the injection step is increased as the mold is closed.

By performing the injection step and the second mold closing step in parallel, the injection pressure can be increased according to the adhesion force between the metal sheet 1 and the mold, which increases as the mold is closed, and the thermoplastic resin 2 can be used. The position shift of the metal sheet 1 can be prevented against the injection pressure, and the leakage of the thermoplastic resin 2 can be prevented.

<Second mold closing process>
The second mold closing step includes a process of further bending and plastically deforming the bent portion 12 of the metal sheet 1.
By completely closing the mold and pressing the thermoplastic resin 2 together with the metal sheet 1, the thermoplastic resin 2 is filled in the entire cavity, the thermoplastic resin 2 and the metal sheet 1 are directly bonded, and the metal is formed. The bent portion 12 of the sheet 1 is bent to form a metal flange to be a welding region.

The fixed mold 4 can be provided with a bending groove 41 at a position where it comes into contact with the tip of the leg portion 13.
As shown in FIG. 6, since the bending groove 41 is formed in the fixed mold 4, the tip of the leg portion 13 in contact with the fixed mold 4 is guided inward, and the bent portion 12 of the metal sheet 1 is bent. It will be easier.

Further, the fixed mold 4 can be provided with a discharge groove 42 inside the metal flange 11 formed by folding back the bent portion 12 in the second mold closing step.
As shown in FIG. 7, by having the discharge groove 42 inside the metal flange 11, even if the thermoplastic resin 2 enters the inside of the bent portion 12, an escape route for the entered thermoplastic resin 2 is provided, and the bent portion is formed. The thermoplastic resin 2 is easily discharged from the inside of the twelve.

Further, as shown in FIG. 7, if the discharge groove 42 is a groove dug diagonally inward, when the thermoplastic resin 2 flows toward the leg portion 13, the thermoplastic resin 2 is the discharge groove. It is difficult to enter the 42, and when the resin is discharged from the inside of the bent portion 12 and the direction of the flow is changed, the thermoplastic resin 2 easily enters the discharge groove 42.

When the fixed mold 4 has the discharge groove 42, the volume of the thermoplastic resin 2 to be injected in the injection step is
It is expressed by the following (formula).

CV ≧ PV ＞ (CV-RV) ・ ・ ・ (Equation)

However, in the above formula, PV represents the volume of the thermoplastic resin injected in the injection step, CV represents the volume of the cavity formed after the second mold closing step, and RV represents the volume of the discharge groove.

When the discharge groove 42 is not provided, a short shot will not occur if the thermoplastic resin 2 is injected by the volume of the cavity formed after the second mold closing step.
be.

When the discharge groove 42 is provided, the volume (CV) of the cavity formed after the second mold closing step is larger by the amount of the discharge groove (RV) as compared with the case where the discharge groove 42 is not provided. It is necessary to inject more thermoplastic resin 2 than the volume of the cavity (CV-RV) when the discharge groove 42 is not provided.

Further, as shown in FIG. 7, since it is not necessary to fill all of the discharge grooves (RV) with the thermoplastic resin 2, the volume is the same as the volume (CV) of the cavity formed after the second mold closing step. It is not always necessary to inject the thermoplastic resin 2.

According to the method for manufacturing a resin-metal composite member of the present invention, the metal flange 11 is formed and can be joined to another metal member by welding.
Therefore, as shown in FIG. 8, a sandwich structure in which a thermoplastic resin is sandwiched between metal plates can be formed, and it can be used for manufacturing skeleton members such as body side panels, rear fenders, and dash panels, as well as door panels and back door panels. It is preferably applicable.

1 Metal sheet 11 Metal flange 12 Bending part 13 Leg part 14 Main body part 2 Thermoplastic resin 3 Movable type 4 Fixed type 41 Bending groove 42 Discharge groove 5 Welded part

Claims (11)

A method for manufacturing a resin-metal composite member having a metal flange on at least a part of the peripheral portion.
The setting process of setting a metal sheet in a mold having at least a movable mold and a fixed mold,
The first mold closing step of bringing the movable mold into contact with the metal sheet, and
An injection process in which a thermoplastic resin is injected between the fixed mold and the metal sheet,
A second mold closing step of closing the mold is provided.
The metal sheet has a bent portion bent toward the fixed mold at least a part of the peripheral portion thereof.
A method for manufacturing a composite member, characterized in that the second mold closing step includes a process of further bending and plastically deforming the bent portion. The method for manufacturing a composite member according to claim 1, wherein the second mold closing step includes a process of folding back the bent portion. The method for manufacturing a composite member according to claim 1 or 2, wherein the internal angle of the bent portion is less than 90 °. The method for manufacturing a composite member according to any one of claims 1 to 3, wherein the first mold closing step includes a process of elastically deforming the metal sheet. The above-mentioned injection step and the above-mentioned second mold closing step are performed in parallel,
The method for manufacturing a composite member according to any one of claims 1 to 4, wherein the injection step includes a process of increasing the injection pressure as the mold is closed. The method for manufacturing a composite member according to any one of claims 1 to 5, wherein at least the end portion of the metal sheet in contact with the fixed mold is chamfered. The method for manufacturing a composite member according to any one of claims 1 to 6, wherein the fixed mold is provided with a bending groove at a position where the metal sheet comes into contact with an end portion. After the first mold closing step and before the injection step,
The method for manufacturing a composite member according to any one of claims 1 to 7, further comprising a heating step of heating the metal sheet via the mold. Any of claims 1 to 8, wherein the temperature of the mold in the injection step is higher in the peripheral portion of the movable mold than in the central portion thereof and lower in the peripheral portion of the fixed mold than in the central portion thereof. The method for manufacturing a composite member according to one item. The fixed mold has a discharge groove inside the metal flange formed in the second mold closing step.
The method for manufacturing a composite member according to any one of claims 1 to 9, wherein the amount of the thermoplastic resin injected in the injection step satisfies the following (formula).

CV ≧ PV ＞ (CV-RV) ・ ・ ・ (Equation)

However, in the above formula, PV represents the volume of the thermoplastic resin injected in the injection step, CV represents the volume of the cavity formed after the second mold closing step, and RV represents the volume of the discharge groove . The method for manufacturing a composite member according to any one of claims 1 to 10, wherein the metal sheet has at least irregularities on the surface on the fixed mold side.

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