JP2018099713A - Method for bonding metallic component and resin member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for bonding a metallic component and a resin member.SOLUTION: A method for joining a metallic component and a resin member includes: a process in which a metallic component at a prescribed position of which a dowel is formed and a resin member in which an open hole having a shape at a portion corresponding to the dowel is formed are prepared; a first process in which the resin member and the metallic component are overlapped so that the dowel of the metallic component is engaged with the open hole of the resin member; a second process in which a first electrode tip is brought into contact with a tip of the dowel of the metallic component, and at the same time, a second electrode tip is brought into contact with a recess formed on a face on a side opposite to the tip of the dowel of the metallic component, electricity is conducted between the first and second electrode tips thereby causing the metallic component to generate heat and to soften, and further, heat is transferred to the resin member by softening or melting the resin member; and a third process in which application of a pressurizing force between the first and second electrode tips, the tip of the dowel is collapsed and is simultaneously expanded radially outward, and engaging parts of the metallic component and the resin member are deformed and are tightly adhered to each other, whereby the metallic component and the resin member are bonded.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of superposing and joining a metal member and a resin member.

  Conventionally, as a method of joining the overlapped metal member and the resin member, a method of fastening using a rivet, a bolt, a nut or the like (Patent Document 1) is known, and these joining methods are used. High bonding strength can be obtained. However, the above-described joining method has a problem that the degree of freedom in design is reduced and the cost and weight are increased due to auxiliary materials such as rivets, bolts and nuts.

As another joining method, there is known a method (Patent Document 2) in which a dowel is formed in one member, a through hole is formed in the other member, and the dowel is fitted into the through hole and caulked and joined. According to this joining method, since rivets, bolts and nuts are not required, the number of parts to be used can be reduced.

JP 2007-064386 JP 61-123430 A

However, in order to obtain a desired bonding strength, the above-described bonding method requires a considerable pressing force when caulking, resulting in a problem that the apparatus becomes large and energy required for processing increases. Moreover, when the applied pressure is increased in order to ensure mutual restraining force, there is a problem that the resin member is cracked.

The present invention has been made to solve such a problem, and it is possible to ensure the bonding strength without using additional parts and with a low pressure using mass production equipment (such as a servo gun for spot welding). An object of the present invention is to provide a method for joining a metal member and a resin member that can prevent cracking of the resin member due to the applied pressure during joining.

The invention according to claim 1 is a method of joining a metal member and a resin member, the step of preparing a metal member having a dowel formed at a predetermined position, and a through-hole having a shape corresponding to a portion corresponding to the dowel A first step of superimposing the resin member and the metal member so that the dowels of the metal member are engaged with the through holes of the resin member, The first electrode chip is brought into contact with the tip of the dowel of the metal member engaged with the through hole of the resin member, and at the same time, the recess formed on the surface opposite to the tip of the dowel of the metal member. The resin member is softened or melted by bringing the second electrode tip into contact and energizing between the first and second electrode tips to generate heat and soften the metal member and further transfer heat to the resin member. A second step of performing the first and first steps By applying a pressure force between the two electrode tips, the tip of the dowel is crushed and simultaneously spread outward in the radial direction, and the engaging portion of the metal member and the resin member is deformed and brought into close contact with the metal member. And a third step of joining the resin member.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, a pressure applied between the first and second electrode chips is 1.4 to 4.0 kN.

According to a third aspect of the invention, in addition to the configuration of the first or second aspect, a second step of energizing the workpiece and a third portion of applying pressure between the first and second electrode tips. This step is performed by a normal servo gun for spot welding.

According to a fourth aspect of the invention, in addition to the configuration of the second or third aspect, the metal member is an alloyed hot-dip galvanized steel sheet, and a current value to be passed between the first and second electrode tips is It is characterized by 1.7 to 3.5 kA.

According to a fifth aspect of the present invention, in addition to the configuration of the second or third aspect, the metal member is an aluminum alloy, and a current value applied between the first and second electrode tips is from 4.9. It is characterized by 10.0 kA.

According to a sixth aspect of the present invention, in addition to the configurations of the first to third aspects, a metal washer is provided on the upper portion of the resin member engaged with the dowel between the first step and the second step. The method further includes the step of further engaging.

According to the first aspect of the present invention, the metal member is heated and softened by contacting the energized resin member and the metal member with the first and second electrodes and energized, and further the heat is transferred to the resin member. As a result, the resin member is softened or melted. Then, by applying a pressure force between the first and second electrode tips, the tip of the dowel is crushed and simultaneously spread outward in the radial direction, and the engagement portion between the metal member and the resin member is deformed and adhered. And join. Therefore, the shape of the softened or melted resin member is deformed so as to be compatible with the abutting metal member, and the two members can be joined in a closely contacted state. Further, since the metal member is heated and softened and the resin member is softened or melted and then pressed and joined, it can be firmly joined with a small applied pressure.

According to a second aspect of the present invention, the pressure applied between the first and second electrode chips is 1.4 to 4.0 kN. When caulking is performed without energization, a pressing force of about 10 kN is required. However, the construction of the present invention combined with energization enables processing with a much lower pressing force and mass production equipment such as a servo gun for spot welding. Can be diverted.
When the applied pressure is 1.4 kN or less, the applied pressure is too small to sufficiently deform the dowel, resulting in insufficient bonding strength. When the applied pressure is 4.0 kN or more, the applied pressure is large. For this reason, the dowels are deformed excessively, and on the contrary, the bonding force may be reduced, and the resin member may be deformed or cracked. By carrying out the method of the present invention under the conditions described in claim 2, high bonding strength can be reliably obtained.

According to the third aspect of the present invention, the second step of energizing the workpiece and the third step of pressurization between the first and second electrode tips are usually performed for spot welding. Servo guns can be used, and mass production equipment such as spot welding servo guns can be used.

According to the fourth aspect of the present invention, it is preferable that the metal member is an alloyed hot-dip galvanized steel sheet and the current value applied between the first and second electrode tips is 1.7 to 3.5 kA. It is. By carrying out the method of the present invention under such conditions, a high bonding strength can be reliably obtained.

  According to the fifth aspect of the present invention, it is preferable that the metal member is an aluminum alloy, and a current value to be passed between the first and second electrode tips is 4.9 to 10.0 kA. By carrying out the method of the present invention under such conditions, a high bonding strength can be reliably obtained.

  According to the sixth aspect of the present invention, it is possible to reliably obtain a higher bonding strength while minimizing the weight increase due to the addition of the washer.

It is typical sectional drawing which shows the joining method of 1st, 2nd Example. It is sectional drawing which shows the junction part of 1st, 2nd Example. It is a graph which shows the relationship between the umbrella size and height of the junction part of 1st Example. It is a table | surface which shows the tensile shear strength of the junction part in each case where the applied pressure and the electricity supply cycle were made constant and the current value was changed in the first example. It is a table | surface which shows the cross peel strength of the junction part in each case which changed the electric current value by making the pressurization force and the electricity supply cycle constant in 1st Example. It is a graph which shows the umbrella size and height relationship of the junction part of 2nd Example. It is a table | surface which shows the tensile shear strength of the junction part in each case where the applied pressure and the energization cycle were made constant and the current value was changed in the second example. It is a table | surface which shows the cross peeling strength of the junction part in each case where the applied pressure and the energization cycle were made constant and the current value was changed in the second example. It is sectional drawing which shows the junction part of 3rd Example. It is a table | surface which shows the tensile shear strength of a junction part when a pressurizing force, an energization cycle, and an electric current value are fixed in 3rd Example, and a washer is used. It is a table | surface which shows the cross peel strength of a junction part when a pressurizing force, an energization cycle, and an electric current value are fixed in 3rd Example, and a washer is used. It is the image which observed the cross section of the junction part by SEM. It is the table | surface which computed the applied pressure in the case of changing the plate | board thickness of a galvannealed steel plate. It is the table | surface which computed the applied pressure when changing the plate | board thickness of an aluminum alloy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following description of the embodiment is merely an exemplification, and is not intended to limit the present invention, its application, or its use.

  First, a metal member 1 and a resin member 2 to be joined are prepared. The metal member 1 is a plate-like member and has a dowel 1a as shown in FIG. The tab 1a is formed with a height of about 10 times the thickness of the metal member 1, and a recess 1b is formed on the surface opposite to the tip of the dowel 1a. Dowels can be formed by, for example, press molding using a well-known method. However, it is necessary to perform optimal mold design and process design depending on the size, height, thickness, and material of the dowel. It is manufactured in the process.

  The resin member 2 is also a plate-like member, and has a through hole 2a as shown in FIG. The through hole can be processed by a known method such as punching or drilling. Then, as shown in FIG. 1A, the dowel 1a of the metal member 1 is engaged with the through hole 2a of the resin member 2, and the dowel 1a passes through the through hole and protrudes above the resin member 2. The resin member 2 and the metal member 1 are overlapped.

In the present invention, a 1 mm-thick galvannealed steel sheet (abbreviated as GA in the figure) and an aluminum alloy (abbreviated as AL in the figure) having a dowel 1a having a diameter of 6 mm and a height of 10 mm as the metal member 1 are used. Prepared. In addition, a polyamide having a thickness of 2 mm (abbreviated as PA in the drawing) and a carbon fiber reinforced plastic (abbreviated as CFRP in the drawing) in which a through hole 2a having a diameter of 6.3 mm was formed as the resin member 2 was prepared.

  In the experiment of the present invention for joining the metal member 1 and the resin member 2, a normal servo gun (inverter DC transformer type, maximum current 15 kA, maximum applied pressure 3.0 kN) used in mass production is used, although not shown. It was. As the electrodes, the first and second electrode chips 3 and 4 shown in FIG. 1 were used. The first electrode tip 3 has a cylindrical shape with a diameter of 13 mm and has a flat tip. Similarly, the second electrode tip 4 has a diameter of 13 mm and the tip portion 4 a is formed to have a partial spherical shape with a radius of curvature R of 40 mm within a range of about 6 mm in diameter so as to engage with the concave portion 1 b of the dowel. Yes. The reason why the central portion of the tip portion 4a of the second electrode tip is a partial spherical shape is to restrict the movement of the metal member 1 by contacting the concave portion 1b of the dowel when contacting the metal member 1.

The first electrode chip 3 is brought into contact with the tip of the dowel 1a of the metal member 1 located in the through hole 2a of the resin member 2, and is formed on the surface opposite to the tip of the dowel 1a of the metal member 1. The second electrode tip is brought into contact with the recess 1b. Next, when the servo gun is operated and a predetermined current pulse is applied between the first and second electrode chips 3 and 4, resistance heat is generated in the metal member 1 positioned between the first and second electrode chips 3 and 4. Thus, the metal member 1 softens and transfers heat to the resin member 2 along the contact surface of the dowel 1a. Thereby, the resin member 2 around the dowel 1a is softened or melted.

Next, a predetermined pressure is applied between the first and second electrode tips 3 and 4 by operating the servo gun, so that the tip of the dowel 1a is axially moved by the first electrode tip 3 (FIG. 1 (a ) It is pressed downward) and caulking is started. Due to the softening effect of the metal member 1, the tip of the dowel 1a is crushed and the through hole of the dowel 1a as shown in FIG. In the portion protruding from 2a, a load is generated that deforms so as to expand radially outward at the peripheral edge of the opening of the through hole 2a, and the tip of the dowel 1a expands so as to be in close contact with the surface of the resin member 2. Deforms into a diameter. Further, as described above, the resin member 2 is softened and melted, so that the resin closely adheres to and joins the surrounding metal member 1, and the metal member 1 and the resin member 2 are firmly joined with a small pressure. Can do.

  In the first embodiment, an alloyed hot-dip galvanized steel sheet is used as the metal member 1, and polyamide and carbon fiber reinforced plastic are used as the resin member 2, and applied between the number of energization cycles (20 cycles / 60 Hz) and the electrode chip. Experiment to observe the shape of the joint and measure the strength of the joint when the applied pressure (2.5KN) is constant and the current applied between the electrode tips is changed from 2.0KA to 3.0KA. It was.

FIG. 2 illustrates the cross-sectional shape of the joint. In this experiment, the umbrella size and height shown in FIG. 2 were measured and evaluated. FIG. 3 is a graph showing the relationship between the umbrella size and height of the metal member 1 after bonding at each current value when an alloyed hot-dip galvanized steel sheet is used as the metal member 1 and polyamide is used as the resin member 2. . FIG. 3 shows that the higher the current, the lower the caulking height and the larger the umbrella size.

FIG. 4 is a table showing the results of the tensile shear strength under each joining condition, and the tensile shear strength was measured three times at each current value. FIG. 4 shows that the tensile shear strength increases as the current value increases in both resin members 2.

FIG. 5 is a table showing the results of the cross peel strength under each bonding condition. The peel strength was measured three times at each current value. According to FIG. 5, when polyamide is used for the resin member 2, the peel strength is reduced by 3.0 KA compared to when the current value is 2.0 KA. This is because the temperature at the time of joining becomes a high temperature exceeding the decomposition point of the polyamide and the crystallinity is lowered, so that the structural strength of the resin member 2 is considered to be lowered, and particularly the force in the peeling direction is affected. it is conceivable that. However, the tensile shear strength does not decrease when the current value is 3.0 KA. If the structure of the joint is devised to receive a load in the shear direction, there is no practical problem with a joint that has been crimped at 3.0 KA. it is conceivable that.

In the conventional caulking and joining method, a pressure of 9.8 KN is required to obtain a preferable shape and joining strength of the joining portion by joining the metal member 1 and the resin member 2 used in the present embodiment. According to the first embodiment of the present invention, any current value set as a welding condition can be appropriately applied with a low pressure of 2.5 KN (about 1/4 of the conventional value) using the normal servo gun. The shape and bonding strength of the bonded portion can be obtained. In this example, the experiment was performed under the condition that the applied pressure applied between the electrode tips was 2.5 KN. However, suitable bonding strength can be obtained even if the applied pressure is changed between 2.0 KN and 3.0 KN. Can be obtained.

  In the second embodiment, the servo gun and the electrode have the same configuration as in the first embodiment, an aluminum alloy is used as the metal member 1, and polyamide and carbon fiber reinforced plastic are used as the resin member 2. Cycle and 60 Hz) and the pressure applied between the electrode tips (2.5 KN) is constant, and the shape of the joint is observed when the current applied between the electrode tips is changed from 6.5 KA to 7.5 KA. An experiment was conducted to measure the strength of the joint.

FIG. 6 is a graph showing the relationship between the umbrella size and height of the metal member 1 after bonding at each current value when an aluminum alloy is used as the metal member 1 and polyamide is used as the resin member 2. As can be seen from FIG. 6, the higher the current, the lower the caulking height, but the umbrella size does not change much.

  Further, FIG. 12 is an image obtained by observing a cross section by SEM when caulking is performed with polyamide and an aluminum alloy. It can be seen that the resin and the metal are in close contact and bonded at a considerable portion around the dowel that has been caulked. In addition, analysis using SCANCO's μCT35 revealed that the contact ratio between the polyamide and the aluminum at the site was 41%. As a result, in addition to mechanical joining by dowel caulking, it can be confirmed that stronger joining is realized by the joining effect caused by the resin and metal closely contacting and joining around the dowel.

FIG. 7 is a table showing the results of the tensile shear strength under each joining condition, and the tensile shear strength was measured three times at each current value. According to FIG. 7, in any of the resin members 2, it is shown that the higher the current value, the higher the tensile shear strength.

FIG. 8 is a table showing the results of the cross peel strength under each joining condition. The peel strength was measured three times at each current value. According to FIG. 8, when polyamide is used for the resin member 2, the peel strength is lower at 7.5 KA than when the current value is 6.5 KA. This is similar to the case where an alloyed hot-dip galvanized steel sheet is used for the metal member 1, and the crystallinity is lowered because the temperature at the time of joining exceeds the decomposition point of the polyamide, so that the structural strength of the polyamide is lowered. In particular, it is thought to affect the force in the peeling direction. Similarly, since the tensile shear strength does not decrease even when the current value is 7.5 KA, joining at this current value is considered to have no practical problem.

According to the second embodiment, at any current value set as a welding condition, an appropriate joint shape and joint can be obtained with a low pressurization force of 2.5 KN (about 1/4 of the conventional one) using a normal servo gun. Strength can be obtained. In this example, the experiment was performed under the condition that the applied pressure applied between the electrode tips was 2.5 KN. However, suitable bonding strength can be obtained even if the applied pressure is changed between 2.0 KN and 3.0 KN. Can be obtained.

  In the third embodiment, the servo gun and the electrode have the same configuration as those of the first and second embodiments, the alloyed hot-dip galvanized steel sheet is used as the metal member 1, the polyamide and carbon fiber reinforced as the resin member 2. Using plastic, the number of energization cycles (20 cycles, 60 Hz), the pressure applied between the electrode tips (2.5 KN), and the current value (2.5 KA) energized between the electrode tips are made constant, as shown in FIG. As shown, an experiment was conducted to measure the bonding strength of the bonded portion when the metal washer 5 was placed on the resin member 2.

  FIG. 10 shows the tensile shear strength under each joining condition, and FIG. 11 shows the result of the ten-time peel strength under each joining condition. The tensile shear strength was measured three times for each resin member, and the peel strength was measured once. According to FIGS. 10 and 11, both the tensile shear strength and the cross peel strength are higher than when the washer 5 is not used. This is considered to be because the member to be joined over a wide area could be pressed by using the washer 5. The weight of the washer 5 used in this experiment is only 0.69 g, and high-strength joining is possible with almost no increase in weight.

  FIG. 13 shows an alloyed hot-dip galvanized steel sheet having a plate thickness of 1.0 mm as the metal member 1, a current applied between the electrode tips of 2.5 KA, a pressure applied between the electrode tips of 2.5 KN, and an energization cycle. It is the table | surface which computed the electric current value and the applied pressure at the time of changing when the plate | board thickness of a galvannealed steel plate was changed based on the experimental result performed in 1st Embodiment by making a number into 20 cycles and 60 Hz.

As a calculation method, first, assuming Joule's law, the specific resistance is R, the current value is I, the energization time is t, and the electrode contact diameter is r, the generated Joule heat Q is Q = RI ² t / r ⁴ , The Joule heat Q when using a galvanized steel sheet having a thickness of 1.0 mm is 14034J. Moreover, the pressure (Pa) at the time of using an alloyed galvanized steel plate with a plate thickness of 1.0 mm is calculated from the pressure when not energized and the cross-sectional area of the dowel, and the pressure is 624.2 MPa. The non-energized applied pressure for each plate thickness is calculated from the pressure (624.2 MPa) and the dowel cross-sectional area of each plate thickness. The load ratio with respect to the plate thickness of 1.0 mm was determined from 9.8 KN). Under the precondition that the load ratio at the time of non-energization and bonding at the time of energization is the same, the pressurizing force necessary to join the alloyed hot-dip galvanized steel sheets of each plate thickness at Joule heat 14034J was calculated. .

  As shown in FIG. 13, the thickness of the alloyed hot-dip galvanized steel sheet is between 0.5 and 2.0 mm, and the current value applied between the first and second electrode tips is between 1.7 and 3. Even if it is changed between 5 kA, it is possible to obtain an appropriate joint shape and joint strength with a low pressure of 1.4 to 4.0 KN using a normal servo gun.

  In FIG. 14, an aluminum alloy having a plate thickness of 1.0 mm is used as the metal member 1, the current applied between the electrode tips is 7.0 KA, the applied pressure between the electrode tips is 2.5 KN, and the number of energization cycles is 20 cycles. -It is the table | surface which computed the electric current value and pressurizing force at the time of changing the plate | board thickness of an aluminum alloy based on the experimental result performed in 2nd Embodiment as 60Hz.

With the same calculation method as described above, the pressurizing force required to join the aluminum alloys having different thicknesses during energization was calculated.

  As shown in FIG. 14, the thickness of the aluminum alloy is between 0.5 and 2.0 mm, and the current value applied between the first and second electrode tips is between 4.9 and 10.0 kA. Even if it is changed, it is possible to obtain an appropriate joint shape and joint strength with a low pressure of 1.4 to 4.0 KN using a normal servo gun.

In said embodiment, although the case where an alloyed hot-dip galvanized steel plate and an aluminum alloy were used was illustrated as the metal member 1, it is not limited to this, This invention is a steel plate etc. which have not performed aluminum or a zinc plating process, etc. It is also applicable to.

DESCRIPTION OF SYMBOLS 1 Metal member 1a Dowel 2 Resin member 2a Through-hole 3 1st electrode chip 4 2nd electrode chip

Claims (6)

A method of joining a metal member and a resin member,
Preparing a metal member having a dowel formed in a predetermined position;
Preparing a resin member having a through-hole having a shape corresponding to a portion corresponding to the dowel;
A first step of overlapping the resin member and the metal member so that the dowels of the metal member are engaged with the through holes of the resin member;
A recess formed on the surface of the metal member opposite to the tip of the dowel at the same time as the first electrode tip is brought into contact with the tip of the dowel of the metal member engaged with the through hole of the resin member The second electrode tip is brought into contact with the first and second electrode tips to generate heat and soften the metal member, and further heat transfer to the resin member softens the resin member. A second step of melting;
By applying a pressure force between the first and second electrode tips, the tip of the dowel is crushed and simultaneously spread outward in the radial direction, and the engagement portion between the metal member and the resin member is deformed. A method for joining a metal member and a resin member, comprising: a third step of bonding the metal member and the resin member together.   2. The method of joining a metal member and a resin member according to claim 1, wherein the pressure applied between the first and second electrode chips is 1.4 to 4.0 kN. The second step of energizing the workpiece and the third step of applying pressure between the first and second electrode tips are performed by a normal servo gun for spot welding.
The joining method of the metal member of Claim 1 or Claim 2, and a resin member. The metal member is an alloyed hot-dip galvanized steel sheet, and a current value applied between the first and second electrode tips is 1.7 to 3.5 kA. 3. A method for joining the metal member and the resin member according to 3. The metal member is an aluminum alloy, and a current value applied between the first and second electrode tips is 4.9 to 10.0 kA,
The joining method of the metal member and resin member of Claim 2 or Claim 3. Between the first step and the second step, the method further comprises a step of further engaging a metal washer on an upper portion of the resin member engaged with the dowel.
The joining method of the metal member and resin member of Claim 1 thru | or 3.

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