JP6102806B2 - Dissimilar member joining method - Google Patents

Description

  The present invention relates to different types of different members, and more particularly, to a method for joining a metal member and a resin member.

  Conventionally, automobiles, railway vehicles, aircraft, home appliances, and the like have been required to be lighter. For example, in automobiles, the use of high-tensile materials has led to thin steel sheets, or aluminum alloy materials have been used as substitutes for steel materials, and the use of resin materials has also advanced. The joining technology of these different materials is not only a light weight, but can realize an increase in strength and rigidity of the vehicle body, and is also important as a vehicle body manufacturing technology from the viewpoint of improving productivity. Until now, as a joining method of steel material and aluminum alloy material, in place of welding method, friction stir welding (FSW: friction stir welding) is useful, and many techniques have been shown as patent documents.

  That is, there is a technique disclosed in Patent Document 1 as a technique for joining a metal member made of, for example, an aluminum material and a resin member made of, for example, polypropylene (PP), which are different from each other. This technique uses friction stir welding (FSW), and forms a coating film made of a thermoplastic resin that is compatible with the thermoplastic resin of the resin member on one surface of the metal member. The metal member on which the coating film is formed faces the resin member, the metal member and the resin member are overlapped, and then the friction is generated by pressing while rotating the rotating tool from the metal member side. Heat is generated, the interface between the coating film and the resin member is heated to make them compatible, and then cooled to integrate the two to join the metal member and the resin member. .

  Patent Document 2 also discloses a method of joining a resin member and a metal member using friction stir welding. According to this, when a resin member made of PET (polyethylene terephthalate) and a metal member made of aluminum alloy are overlapped, and both members are joined by friction stirring with a rotary tool from the metal member side, From the viewpoint of achieving tensile strength and preventing overloading of the friction stir welding apparatus, the amount of pushing of the rotary tool should be set to 5% to 20% of the plate thickness of the metal member, or the outer diameter of the rotary tool Is set to be not less than 2 times and not more than 5 times the plate thickness of the metal member.

JP 2009-279858 A (paragraph 0007) JP 2010-158885 A (paragraphs 0059-0071)

  In the technique disclosed in Patent Document 1, before the friction stir welding, a coating film made of a thermoplastic resin having good compatibility with the thermoplastic resin of the resin member is formed on the surface of the metal member in advance. There is a disadvantage that the number of processes increases and costs increase. In addition, there is a need to overcome new problems such as controlling the thickness of the coating film.

  In the technique disclosed in Patent Document 2, when a resin member made of polypropylene, which is a typical general-purpose resin, is used as the resin member, the bonding strength with the metal member may be insufficient. The reason is that polypropylene is a resin having a saturated hydrocarbon skeleton consisting only of carbon (C) and hydrogen (H), and has no functional group in the molecular structure and lacks reactivity. This is because it is a difficult resin. Also, since polypropylene has a lower thermal conductivity than other resins (0.125 W / m · K), it takes time to soften and melt, and from this point, it is also a resin with low bondability to metal materials. is there.

  In contrast, the PET resin has a carbonyl group (C═O) as a functional group in the molecular structure and has a relatively high thermal conductivity (0.31 W / m · K). According to the technology, it is considered that a resin member made of PET and a metal member made of an aluminum alloy are joined without forming a resin coating film as in Patent Document 1.

  Therefore, it is considered that the resin member made of a resin having a functional group in the molecular structure can be friction stir welded to the metal member without increasing the steps such as the formation of a coating film. However, in the technique disclosed in Patent Document 2, the pressing amount of the rotary tool is set to 20% or less of the plate thickness of the metal member, so that the frictional heat is generated on the surface portion of the metal member relatively separated from the resin member. Occur. Therefore, even if it is a resin member having a functional group, it takes time to soften and melt the resin member, or the frictional heat is not sufficiently transmitted to the resin member. The strength may be insufficient.

  In order to cope with this problem, it is conceivable to increase the pressure of the rotating tool and push the rotating tool deeply into the metal member. However, when the rotary tool is pushed too deeply, the rotary tool penetrates the metal member, and a hole through which the rotary tool has passed is opened, which may cause poor bonding.

  The present invention has been made in view of the circumstances as described above, and is a bonding method for dissimilar members capable of bonding a resin member having a functional group and a metal member with high strength without making them open. The purpose is to provide.

In order to solve the above problems, the present invention provides a first step of superimposing a metal member and a resin member having a functional group, and a resin member side from the metal member side while rotating the rotary tool. the pressed to generate frictional heat, the resin member is softened by the frictional heat and a second step of joining the metal member and the resin member to a joining method of including different member, the rotating As a tool, a tool having a shoulder part formed of a tip of a cylindrical body and a cylindrical pin part protruding from the shoulder part and having an outer diameter smaller than that of the shoulder part is prepared, and the second step includes the rotation a preheating step of only pin portion and shoulder portion of the tool to rotate the rotary tool in a state in contact with the surface portion of the metal member, after the preheating step, the metallic member is pushed the rotating tool to a metal member Pushing and stirring step for approaching and approaching to a depth that does not reach the joint boundary surface with the resin member, and stirring and maintaining step for continuing the rotational operation of the rotary tool at a position that enters and approaches the depth that does not reach the joint boundary surface look including the door, in the above preheating step is rotated only between a first pressurization while pressing the rotating tool in a first pressing force, the rotating tool first larger than the above first pressing force in the pushing stirring step While rotating with a pressing force of 2, the rotating tool is rotated for a second pressing time shorter than the first pressing time, and in the stirring maintaining step, the rotating tool is rotated with a third pressing force smaller than the first pressing force. The dissimilar member joining method is characterized in that it is rotated for a third pressurizing time longer than the first pressurizing time while pressing (claim 1).

  According to the present invention, in a method of joining a metal member and a resin member using friction stir welding, a certain degree of reaction is obtained as a resin member, for example, compared to a resin member made of only a saturated hydrocarbon skeleton. A resin member having a functional group having a property or an interaction property is used. Therefore, it becomes possible to join the metal member and the resin member without increasing the steps such as the formation of the coating film.

  In addition, the rotating tool is inserted and approached to a depth that does not reach the joint boundary surface between the metal member and the resin member in the indentation stirring step, and then the depth that does not reach the joint boundary surface in the stirring maintenance step. The rotation operation is continued at a position approached and approached (this is referred to as “reference position”). For this reason, when the rotary tool is pushed deeply into the metal member, it is prevented that the rotary tool penetrates the metal member and the hole through which the rotary tool passes is opened. Then, frictional heat is generated at a reference position close to the resin member, and the generation of the frictional heat is continued. Therefore, a large amount of frictional heat is generated, and most of the generated frictional heat is transferred to the resin member. . Therefore, the softening and melting of the resin member is promoted, and the resin member is sufficiently softened and melted in a wide range so that the metal member and the resin member are joined with high strength in a wide range. Is obtained. As described above, there is provided a joining method for dissimilar members, which can join a resin member having a functional group and a metal member with high strength without making them open.

Further, in the preheating step before the indentation stirring step, only the pin portion and the shoulder portion of the rotating tool are brought into contact with the surface portion of the metal member, so that the frictional heat generated on the surface portion of the metal member is made of the metal member. The metal member is preheated. Thereby, the rotary tool can be easily pushed into the metal member in the next pushing and stirring step.

On the other hand, in the indentation stirring step, the rotary tool can be deeply pushed into the metal member by increasing the applied pressure compared to the preheating step. In that case, in the indentation stirring step, the pressurization time is shortened compared to the preheating step, so that the rotating tool passes through the metal member through the joint interface between the metal member and the resin member. Can be prevented.

Furthermore , in the stirring maintaining step, by reducing the applied pressure as compared with the preheating step, it is possible to prevent the rotating tool from passing through the metal member by passing over the joining boundary surface between the metal member and the resin member. it can. In that case, in the stirring maintaining step, a large amount of frictional heat can be generated at the reference position close to the resin member by making the pressurization time longer than in the preheating step.

In the present invention, preferably, the first pressurizing force is a value of 700 N or more and less than 1200 N, the first pressurizing time is a value of 0.5 second or more and less than 2.0 seconds, and the second pressurizing time is The applied pressure is a value of 1200 N or more and less than 1800 N, the second pressurizing time is a value of 0.1 to 0.5 seconds, and the third applied pressure is a value of 100 N or more and less than 700 N. The third pressurization time is a value of not less than 1.0 seconds and less than 10 seconds ( Claim 2 ).

  According to this configuration, for example, from the viewpoint of productivity (balance between time reduction and yield) when joining a metal member having a thickness of 1 mm to 2 mm and a resin member having a thickness of 2 mm to 4 mm, Preferable specific numerical values of each pressing force and each pressurizing time in the preheating step, the indentation stirring step, and the stirring maintaining step are shown.

In the present invention, preferably, in the second step, after the stirring maintaining step, the rotation of the rotary tool is stopped, and in this state, the rotary tool is held for a predetermined pressurizing time with a predetermined pressing force. A process ( claim 3 ).

  According to this configuration, in the holding step after the stirring maintaining step, the rotating tool whose rotation is stopped clamps the joint portion between the metal member and the resin member with a predetermined pressure, so that after the friction stir welding is completed The adhesion force between the metal member and the resin member during the cooling period is increased, and the bonding strength after the cooling is completed is increased.

In the present invention, it is preferable that the functional group contains at least one element of N, O, F, Si, S, Cl, Br, and I ( Claim 4 ).

  If it does in this way, interaction with a resin-made member and a metal member can be accelerated | stimulated more reliably, and the joining property of a resin-made member and a metal member can be improved more reliably.

Here, among the above elements, a functional group containing O, S, and Cl has both availability and an effect of improving the bonding property due to high electronegativity, and therefore, those containing these elements as the above functional group. If used, the bondability between the resin member and the metal member can be further increased at a relatively low cost ( Claim 5 ).

In the present invention, preferably, the resin of the resin member is a polyamide resin, polyethylene terephthalate, or polylactic acid ( Claim 6 ).

  According to this configuration, a joined body of different types of members having particularly high joining strength can be obtained.

  As described above, the present invention provides a technique for joining a resin member and a metal member with high strength, so that the industry in the technical fields such as automobiles, railway vehicles, aircrafts, and home appliances that are required to be reduced in weight. Contribute to the development and improvement of

It is a figure which shows typically an example of the friction stir welding apparatus suitable for the joining method of the dissimilar member concerning embodiment of this invention. It is an enlarged view of the front-end | tip part of the rotary tool of the said friction stir welding apparatus. It is a process chart of the joining method of the said dissimilar member. It is sectional drawing for demonstrating the preheating process of the joining method of the said dissimilar member. It is sectional drawing for demonstrating the pushing stirring process of the said dissimilar member joining method, the stirring maintenance process, and a holding process. It is sectional drawing of the conjugate | zygote obtained by the joining method of the said dissimilar member. In the said embodiment, it is a graph which shows joining strength with a metal member about various resin members. In the said embodiment, the result of having investigated the relationship between each process and joining strength is shown.

  Embodiments of the present invention will be described below with reference to the drawings.

(1) Joining apparatus First, a friction stir welding apparatus used for carrying out the joining method for different members according to the present embodiment will be schematically described.

  FIG. 1 is a diagram schematically showing an example of the friction stir welding apparatus. A friction stir welding apparatus 1 shown in FIG. 1 is an apparatus for friction stir welding a metal member 11 and a resin member 12.

  The friction stir welding apparatus 1 includes a cylindrical rotating tool 16. The rotary tool 16 rotates around the central axis X (see FIG. 2) as indicated by an arrow A1, and the joint P of the workpiece 10 is overlapped so that the metal member 11 is on top and the resin member 12 is on the bottom. It is pressed against (scheduled joint location). At this time, the rotary tool 16 is pressed downward from the metal member 11 side toward the resin member 12 side as indicated by an arrow A2. By the pressing of the rotary tool 16, frictional heat is generated at least at the joint P. Upon receiving this frictional heat, the resin member 12 is softened and melted, whereby the metal member 11 and the resin member 12 are joined.

  FIG. 2 is an enlarged view of the distal end portion of the rotary tool 16. In FIG. 2, the right half shows the appearance of the rotary tool 16, and the left half shows a cross section. As shown in FIG. 2, the columnar rotary tool 16 has a pin portion 16 a and a shoulder portion 16 b at the distal end portion (lower end portion in FIG. 2). The shoulder portion 16 b is a portion at the tip of the rotary tool 16 including the circular tip surface of the rotary tool 16. The pin portion 16a is a cylindrical portion having a smaller diameter than the shoulder portion 16b, which projects outwardly (downward in FIG. 2) from the circular tip surface of the rotary tool 16 on the central axis X of the rotary tool 16. is there. The pin portion 16a is for positioning the rotating tool 16 when the rotating tool 16 that is rotating is brought into contact with the workpiece 10 and pressed.

  The material of the rotary tool 16 and the dimensions of each part are mainly set according to the metal type of the metal member 11 pressed by the rotary tool 16. For example, when the metal member 11 is made of an aluminum alloy, the rotary tool 16 is made of tool steel (for example, SKD61), the diameter D1 of the shoulder portion 16b is 10 mm, the diameter D2 of the pin portion 16a is 2 mm, and the pin portion 16a The protrusion length h is set to 0.5 mm. For example, when the metal member 11 is made of steel, the rotary tool 16 is made of silicon nitride, PCBN (cubic boron nitride sintered body), etc., the diameter D1 of the shoulder portion 16b is 10 mm, and the diameter of the pin portion 16a. D2 is set to 3 mm, and the protruding length h of the pin portion 16a is set to 0.5 mm. Needless to say, these are merely examples, and the present invention is not limited thereto.

  Returning to FIG. 1, below the rotary tool 16, a cylindrical receiving member 17 having the same diameter as the rotary tool 16 or a larger diameter than the rotary tool 16 is disposed coaxially with the rotary tool 16. The receiving member 17 is moved upward toward the workpiece 10 as indicated by an arrow A3 by a driving source (not shown). The receiving member 17 is moved to a position where the upper end surface thereof abuts on the lower surface of the workpiece 10 (more specifically, the lower surface of the resin member 12) before the rotary tool 16 starts pressing the workpiece 10 at the latest. The holder 17 holds the workpiece 10 between the rotary tool 16 and the workpiece against the pressing force of the rotary tool 16 during the period when the rotary tool 16 presses the joint P, that is, during friction stir welding. 10 is supported from below.

  Note that the receiving tool 17 does not necessarily have to be moved in the direction of the arrow A3, and a method of moving the rotary tool 16 in the direction of the arrow A2 after placing the workpiece 10 on the receiving tool 17 can also be adopted.

  The friction stir welding apparatus 1 including the rotating tool 16 and the receiving member 17 is attached to a drive control device (not shown) composed of an articulated robot or the like. The coordinate positions of the rotary tool 16 and the receiving tool 17, the rotational speed (rpm) of the rotary tool 16, the pressure (N), the pressurization time (second), and the like are appropriately controlled by the drive control device.

  Although not shown in FIG. 1, the friction stir welding apparatus 1 fixes a workpiece 10 in advance and a spacer, a clamp, and the like for preventing the metal member 11 from being lifted when the rotary tool 16 is pressed. The jig is equipped.

(2) Joining method Next, the specific content of the joining method (friction stir welding) of the dissimilar members concerning this embodiment implemented using the said friction stir welding apparatus 1 is demonstrated.

  In the present embodiment, a resin member having a functional group is used as the resin member 12. The functional group has a certain degree of reactivity or interaction compared to, for example, a saturated hydrocarbon skeleton. Therefore, if the resin member 12 having a functional group is used, the friction stir welding with the metal member 11 can be performed without increasing the steps such as the formation of a coating film.

  That is, the interaction between the resin that is the material of the resin member 12 and the metal member 11 is promoted via the functional group, and the bondability between the resin member 12 and the metal member 11 is improved.

  Specifically, a region having an oxide layer (for example, an aluminum oxide or iron oxide layer) on the surface of the metal member 11 (more specifically, the contact surface with the resin member 12) (for example, FIG. 5 described later). In the region indicated by the circle β), the functional group interacts with this oxide layer. More specifically, the functional group interacts with oxygen, hydroxy group (—OH), etc. present in the metal oxide layer. Further, in a region where there is no oxide layer (for example, a region indicated by a circle α in FIG. 5 described later), it interacts with a new surface (for example, aluminum alloy (Al) or iron) of the metal member 11. By this interaction, the resin member 12 and the metal member 11 are easily joined.

As said resin member 12, what consists of the following resin materials, for example can be employ | adopted. Below, the functional group which each resin material has is written together. In addition, it cannot be overemphasized that the following resin material and functional group are only illustrations to the last.
Polyamide resin (PA (PA6, PA66, PA11, PA12, PA6T, PA9T, MXD6, etc.)): Amide bond (—CONH—)
・ Polyethylene terephthalate (PET): Carbonyl group (C = O)
-Polylactic acid (PLA): carbonyl group (C = O), hydroxy group (-OH)
Polymethyl methacrylate resin (PMMA): carbonyl group (C = O)
Polycarbonate (PC): carbonate group (-O, CO, O-)
-Polybutylene terephthalate (PBT): carbonyl group (C = O)
Polytrimethylene terephthalate (PTT): carbonyl group (C = O)
Liquid crystal polymer (LCP): carbonyl group (C = O)
・ Urethane resin: Urethane bond (-NH, CO, O-)
・ Fluorine resin: Fluorine (-F)
・ Polyphenylene ether (PPE): Ether bond (-O-)
・ Polyacetal (POM): Ether bond (-O-)
Polyphenylene sulfide (PPS): thioether bond (-S-)
However, as a result of investigating the influence on the bondability between the resin member and the metal member for a plurality of functional groups, the present inventors use a functional group having an element having a high electronegativity as the resin member. The bonding strength between the metal member 12 and the metal member 12 can be increased by introducing Si (for example, a silane coupling agent) into the resin member 11 having no functional group. I found it to improve. Therefore, the functional group introduced into the resin member is at least one of N, O, F, S, Si, Cl, Br, and I, which are elements having high electronegativity (elements having an electronegativity of 2.5 or more). It is preferable to use one containing one element. Here, among these elements, the functional group containing O, S, and Cl achieves both high availability and higher electronegativity. Therefore, if a functional group containing O, S, and Cl is introduced into the carbon fiber as a resin member, the bondability between the resin member and the metal member can be further increased at a relatively low cost.

  Also, as the resin member 12 having the above functional group, a functional group is incorporated in the resin member 12 by including a carbon fiber having a functional group introduced into a matrix resin having no functional group. May be used. For example, a resin member 12 in which a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is used as a matrix resin and carbon fibers having a functional group introduced therein are mixed may be used.

  In addition to the carbon fiber as described above, the resin member 12 may contain various additives in order to improve the performance of the resin member alone. For example, a filler such as talc, glass fiber, or the like may be included as an additive for increasing rigidity. Further, a specific method for molding the resin member 12 into a predetermined shape is not particularly limited, and an injection molding method, a press molding method, an extrusion molding method, a pultrusion molding method, an autoclave molding method, and the like are appropriately used. It ’s fine.

  Below, the case where the said metal member 11 and the resin member 12 each have plate shape is demonstrated.

  In this embodiment, the friction stir welding apparatus 1 moves from the metal member 11 side to the resin member 12 side while rotating the rotary tool 16 with respect to the workpiece 10 in which the metal member 11 and the resin member 12 are overlapped. The frictional heat is generated by pressing, and the resin member 12 is softened and melted by the frictional heat to join the metal member 11 and the resin member 12 together. That is, the friction stir welding apparatus 1 includes a first step of superimposing the metal member 11 and the resin member 12 having a functional group, and the metal member 11 side to the resin member 12 side while rotating the rotary tool 16. To generate frictional heat, and the second step of softening and melting the resin member 12 with the frictional heat to join the metal member 11 and the resin member 12 is performed. In the second step of pressing the rotary tool 16 against the workpiece 10, the four steps shown in FIG. 3 (preheating step C1, indentation stirring step C2, stirring maintaining step C3, holding step C4) are further performed.

  Details of each step of the second step will be described next.

In the first preheating step C1, the rotary tool 16 and the receiving member 17 are brought close to each other. Then, as shown in FIG. 4, the rotating tool 16 is in a state where only the front end portions (the pin portion 16 a and the shoulder portion 16 b) of the rotating tool 16 are in contact with the surface portion (upper surface portion in the illustrated example ) of the metal member 11. Rotate.

  In the preheating step C1, the rotary tool 16 is rotated at a predetermined number of revolutions for the first pressurizing time with the first applied pressure.

  In the preheating step C <b> 1, frictional heat is generated on the surface portion (upper surface portion in the illustrated example) of the metal member 11 by pressing of the rotary tool 16. This frictional heat is transmitted to the inside of the metal member 11 and preheats the range of the joint P of the metal member 11 and the range in the vicinity of the joint P. By preheating the metal member 11 in this way, it becomes easy to push the rotary tool 16 into the metal member 11 in the next indentation stirring step C2.

  Further, the frictional heat is also transmitted to the resin member 12 through the joint boundary surface between the metal member 11 and the resin member 12. The frictional heat is transmitted to the inside of the resin member 12, and preheats the range of the joint portion P of the resin member 12 and the vicinity of the joint portion P. By preheating the resin member 12 in this manner, the resin member 12 is easily softened and melted in the next indentation stirring step C2.

  The first pressurizing force and the first pressurizing time in the preheating step C1 are set from the viewpoints of ease of pushing the rotary tool 16 and the ease of softening and melting of the resin member 12. For example, each value is set according to the number of rotations of the rotary tool 16 and the type of material of the metal member 11 and the resin member 12. In the example shown in FIG. 3, the first pressure is 900 N, the first pressurization time is 1.00 seconds, and the predetermined rotational speed is 3000 rpm.

  In the pushing and stirring step C2 next to the preheating step C1, the rotating tool 16 and the receiving member 17 are further brought closer to each other, and the rotating tool 16 is pushed into the metal member 11. Specifically, in this indentation stirring step C2, the pressing force of the rotary tool 16 is set to a second pressing force that is higher than the first pressing force. Then, the rotary tool 16 is rotated at a predetermined number of revolutions for a second pressurization time shorter than the first pressurization time by the second pressurizing force.

  As the applied pressure becomes larger than the applied pressure in the preheating step C1, the rotary tool 16 is pushed into the metal member 11 as shown in FIG. That is, the rotary tool 16 enters deep inside the metal member 11. By pressing the rotary tool 16, the joining boundary surface between the metal member 11 and the resin member 12 moves to the receiving member 17 side (lower side in the illustrated example).

  Here, if the rotary tool 16 is further pushed in (that is, if the applied pressure is too high and / or the pressurizing time is too long), the shoulder portion 16b of the rotary tool 16 is moved between the metal member 11 and the resin member 12. The rotating tool 16 passes through the metal member 11 and contacts the resin member 12 beyond the bonding boundary surface with the metal member 11, and the hole in which the rotating tool 16 has passed through the metal member 11 is opened. Defects occur.

  Therefore, in the present embodiment, in the indentation stirring step C2, the indentation of the rotation tool 16 is stopped when the shoulder portion 16b of the rotation tool 16 enters and approaches the depth not reaching the joining boundary surface. In other words, the rotary tool 16 is made to approach and approach the depth that does not reach the joining boundary surface. As a result, in the next agitation maintaining step C3, frictional heat is generated at a reference position close to the resin member 12, and a large amount of frictional heat is transmitted to the resin member 12, which promotes softening and melting of the resin member 12. .

  The second pressurizing force and the second pressurizing time in the indentation stirring step C2 are set from the viewpoint of avoiding the opening of the metal member 11 and the rotating tool 16 as close to the resin member 12 as possible. Each value is set according to, for example, the number of rotations of the rotary tool 16 and the types of materials of the metal member 11 and the resin member 12. In the example shown in FIG. 3, the second applied pressure is 1500 N, the second pressurizing time is 0.25 seconds, and the predetermined rotational speed is 3000 rpm.

  In the indentation stirring step C2, the joining boundary surface between the metal member 11 and the resin member 12 is deformed, so that, for example, in the region indicated by the circle α in FIG. The oxide layer (layer of aluminum oxide, iron oxide, etc.) of the contact surface with the product member 12 is destroyed, and a new surface of the metal member 12 (aluminum alloy, iron, etc.) appears. The resin member 12 is in contact with both the oxide layer and the new surface, and as described above, the functional group contained in the resin member 12 is an aluminum alloy oxide layer (more specifically, a metal oxide layer). The metal member 11 and the resin member 12 are joined together by interacting with both oxygen and hydroxy groups (—OH)) and the new surface.

  Moreover, in this indentation stirring process C2, in the area | region (for example, area | region shown by circle (beta) of FIG. 5) in which the joining boundary surface of the metal member 11 and the resin member 12 does not deform | transform, the surface (in detail). Is the oxide layer (more specifically, oxygen and hydroxy groups (—OH) present in the metal oxide layer) remaining on the resin member 12 and the functionality contained in the resin member 12. The base member interacts, and the metal member 11 and the resin member 12 are joined.

  In the agitation maintaining process C3 subsequent to the indentation agitation process C2, the close proximity between the rotary tool 16 and the support 17 is stopped. Then, as shown in FIG. 5, the rotation operation of the rotary tool 16 is continued at a depth position (this is referred to as “reference position”) that does not reach the joining boundary surface between the metal member 11 and the resin member 12.

  Specifically, in the stirring and maintaining step C3, the rotary tool 16 is rotated at a predetermined rotational speed for a third pressurizing time longer than the first pressurizing time with a third pressurizing force smaller than the first pressurizing force. Rotate.

  In this way, when the pressing force is smaller than that in the preheating step C1 (of course, smaller than the indentation stirring step C2), in the stirring maintaining step C3, the rotary tool 16 is maintained at the reference position.

  Then, by continuing the rotation operation of the rotary tool 16 at the reference position close to the resin member 12, a large amount of frictional heat is generated in the stirring maintaining step C3, and most of the generated frictional heat is the resin member 12. Move to. Therefore, the resin member 12 is sufficiently softened and melted in a wide range beyond the range of the joint portion P and the vicinity of the joint portion P.

  The third pressurizing force and the third pressurizing time in the stirring maintaining step C3 are set from the viewpoint of sufficient softening and melting of the resin member 12 as described above, and each value is, for example, a rotary tool. It is set according to the number of rotations of 16 and the types of materials of the metal member 11 and the resin member 12. In the example shown in FIG. 3, the third pressure is 500 N, the third pressurizing time is 5.75 seconds, and the predetermined rotational speed is 3000 rpm.

  In the last holding process C4, the rotation of the rotary tool 16 is stopped, and in this state, the rotary tool 16 is held for a predetermined time with a predetermined pressure. In the holding step C4, the rotary tool 16 is moved to a fourth pressure that is shorter than the third pressurization time but longer than the second pressurization time at a fourth pressurization force that is larger than the third pressurization force but smaller than the second pressurization force. Hold for 4 pressurization times.

  In the holding step C4, the rotation of the rotary tool 16 is stopped, whereby the generation of frictional heat is completed. That is, the substantial operation as the friction stir welding is finished, and cooling of the workpiece 10 is started. During the cooling period of the workpiece 10, as described above, the applied pressure is smaller than the indentation stirring step C2, but larger than the stirring maintenance step C3. Therefore, the joint P between the metal member 11 and the resin member 12 is clamped with an appropriate pressure by the rotating tool 16 and the receiving member 17 that are stopped from rotating, that is, a state in which the adhesion is increased. Cooled by. Thus, the bonding strength between the metal member 11 and the resin member 12 is increased by cooling in a state in which the adhesion is increased.

  The fourth pressurizing force and the fourth pressurizing time in the holding step C4 are set from the viewpoint of improving the adhesion of the joint P during the cooling period as described above, and the values are, for example, the metal member 11 and the resin. It is set according to the type of material of the member 12. In the example shown in FIG. 3, the fourth pressure is 1000 N and the fourth pressurization time is 5.00 seconds.

  Note that the pressurizing force, pressurizing time, and tool rotation speed shown in FIG. 3 are merely examples, and can be changed as appropriate. However, for example, when joining the metal member 11 having a thickness of 1 mm or more and 2 mm or less and the resin member 12 having a thickness of 2 mm or more and 4 mm or less, mainly from the viewpoint of productivity (balance between time reduction and yield), The first pressure in the preheating step C1 is preferably 700 N or more and less than 1200 N, and the first pressurizing time is preferably 0.5 seconds or more and less than 2.0 seconds. The second pressure in the indentation stirring step C2 is preferably The pressure is preferably a value of 1200 N or more and less than 1800 N, and the second pressurization time is preferably a value of 0.1 or more and less than 0.5 second, and the third pressure in the stirring and maintaining step C3 is 100 N or more and less than 700 N The value and the third pressurizing time are preferably 1.0 seconds or more and less than 10 seconds. Further, the fourth pressing force in the holding step C4 is preferably a value of 700 N or more and less than 1200 N, for example, and the fourth pressurizing time is preferably a value of 1 second or more, for example.

  In the present embodiment, the resin member 12 is finally softened by the frictional heat generated by the rotation and pressing of the rotary tool 16 as shown in FIG. 6 through the steps C1, C2, C3, and C4 as described above. -The dissimilar member joined body 20 is obtained by melting and joining the metal member 11 and the resin member 12 with high strength over a wide range.

(3) Joining Test In this embodiment, in order to examine the joining strength between the resin member 12 having a functional group and the metal member 11, a joining test according to JIS Z 3136 was performed. Here, the bonding strength of each of the various resin members 12 was examined. Further, as Comparative Example 1, the bonding strength between a resin member having no functional group and a metal member was examined.

[Test conditions]
Metal member: A plate member (thickness 1.2 mm) made of a 6000 series aluminum alloy was used.
-Resin member: made of polyamide resin (PA6, nylon 6) (Example 1), made of polyamide resin (PA66, nylon 66) (Example 2), made of polyethylene terephthalate (PET) (Example 3), and poly A plate member (thickness: 3.0 mm) made of lactic acid (PLA) (Example 4) was used.
-Resin member of Comparative Example 1: A plate member (thickness: 3.0 mm) made of polypropylene (PP) was used.
-Rotating tool: The tool made from the tool steel whose dimension of each part of FIG. 2 is D1 = 10mm, D2 = 2mm, h = 0.5mm was used.

[Pressing conditions]
Preheating step C1: The pressure was 900 N, the pressurization time was 1.00 seconds, and the tool rotation speed was 3000 rpm.
Indentation stirring step C2: Pressurizing force 1500 N, pressurizing time 0.25 seconds, tool rotation speed 3000 rpm.
Stirring maintenance step C3: The pressure was 500 N, the pressurization time was 5.75 seconds, and the tool rotation speed was 3000 rpm.
-Holding process C4: The applied pressure was 1000 N and the pressurizing time was 5.00 seconds.

[Joint strength]
By a method prescribed in JIS Z 3136, the joined body in which the metal member and the resin member were joined was pulled in the directions indicated by arrows Y and Y in FIG. The results are shown in FIG.

  In Comparative Example 1 in which the resin member did not have a functional group, that is, made of polypropylene (PP), the metal member and the resin member were not satisfactorily bonded, and the bonding strength was extremely low. And in this comparative example 1, destruction occurred in the junction part P of FIG.

  On the other hand, in Examples 1-4 in which the resin member has a functional group, that is, made of polyamide resin (PA6), polyamide resin (PA66), polyethylene terephthalate (PET), and polylactic acid (PLA) The bonding strength was dramatically increased, and the fracture did not occur at the joint P but occurred with the resin member. That is, the bonding strength is equivalent to the breaking strength of the polyamide resin (PA6) itself, the breaking strength of the polyamide resin (PA66) itself, the breaking strength of the polyethylene terephthalate (PET) itself, and the breaking strength of the polylactic acid (PLA) itself. It was a level. Especially, when the resin member was made of polyethylene terephthalate, the bonding strength was the highest. Although not shown in FIG. 7, even when polypropylene (PP) containing 40% by weight of carbon fibers having chloro groups introduced is used as the resin member 12, high shear strength can be obtained. The test results were obtained.

(4) Action, etc. As described above, in the present embodiment, in the method of joining the metal member 11 and the resin member 12 using friction stir welding, as the resin member 12, for example, only from a saturated hydrocarbon skeleton. Compared to a resin member such as polypropylene (PP), etc., since a resin member having a functional group having a certain degree of reactivity or interaction is used, without increasing the steps such as the formation of a coating film, It becomes possible to join the metal member 11 and the resin member 12 with high strength.

  In particular, in the present embodiment, the preheating step C1 in which the rotary tool 16 is rotated in a state where only the tip portion of the rotary tool 16 is in contact with the surface portion of the metal member 11, and the rotary tool 16 is made of the metal member 11 and the resin member. Intrusion stirring step C2 for entering to a depth that does not reach the joint boundary surface with 12 and a stirring maintenance step C3 for continuously rotating the rotary tool 16 at a depth position (reference position) that does not reach the joint boundary surface, and the rotary tool 16 In this state, the holding step C4 for holding the rotary tool 16 for a predetermined period is sequentially performed, so that the resin member 12 and the metal member 11 are bonded with high strength without being opened. can do.

  That is, in this embodiment, after the rotary tool 16 is approached and approached to a depth that does not reach the joining boundary surface between the metal member 11 and the resin member 12 in the indentation stirring step C2, in the stirring maintaining step C3, The rotation operation is continued at a reference position that is approached and approached to a depth that does not reach the joint boundary surface. Therefore, when the rotary tool 16 is pushed deeply into the metal member 11, the rotary tool 16 penetrates the metal member 11, and the hole through which the rotary tool 16 passes is opened in the metal member 11. Can be prevented. Further, since frictional heat is generated at a reference position close to the resin member 12 and the generation of the frictional heat is continued, a large amount of frictional heat is generated and most of the generated frictional heat is generated by the resin member 12. The resin member 12 is promoted to be softened and melted, and the resin member 12 is sufficiently softened and melted in a wide range to make the metal member 11 and the resin member 12 wide in a wide range. Can be joined to strength.

  Furthermore, in this embodiment, before the indentation stirring step C2, a preheating step of rotating the rotary tool 16 in a state where only the tip portion of the rotary tool 16 is in contact with the surface portion of the metal member 11 is performed. Yes.

  Therefore, in the preheating step C1 prior to the indentation stirring step C2, the frictional heat generated on the surface portion of the metal member 11 is transmitted to the inside of the metal member 11, and the metal member 11 is preheated. The rotary tool 16 can be easily pushed into the metal member 11 in the pushing and stirring step C2.

  Specifically, in the present embodiment, in the preheating step C1, the rotary tool 16 is rotated for a first pressurizing time while being pressed with a first pressure, and in the indentation stirring step C2, the rotary tool 16 is rotated. While pressing with a second pressure greater than the first pressure, the second tool is rotated for a second pressurization time shorter than the first pressurization time, and in the stirring maintaining step C3, the rotary tool 16 is rotated with the first pressurization time. Rotating for a third pressurization time longer than the first pressurization time while pressing with a third pressurization pressure smaller than the first pressurization pressure.

  According to this, in the indentation stirring step C2, the rotary tool 16 can be pushed deeply into the metal member 11 by increasing the applied pressure compared to the preheating step C1. In that case, in the indentation stirring step C2, the pressurizing time is made shorter than that in the preheating step C1, so that the rotary tool 16 passes over the joining boundary surface between the metal member 11 and the resin member 12, and the metal member. 11 can be prevented from penetrating, that is, being in a perforated state.

  Further, in the stirring maintaining step C3, the rotating tool 16 passes over the joining boundary surface between the metal member 11 and the resin member 12 by penetrating the metal member 11 by making the pressure smaller than that in the preheating step C1. Can be prevented. In that case, in the stirring maintenance process C3, a large amount of frictional heat can be generated at the reference position close to the resin member 12 by making the pressurization time longer than that in the preheating process C1.

  In addition, in the present embodiment, after the stirring maintaining step C3, the rotation of the rotary tool 16 is stopped, and in this state, the holding step C4 for holding the rotary tool 16 with the fourth pressurizing time for the fourth pressurizing time is performed. The rotation tool 16 that has been stopped is clamped at the joint P between the metal member 11 and the resin member 12 with the fourth applied pressure. Therefore, the adhesive force during cooling between the metal member 11 and the resin member 12 can be increased, and the bonding strength after completion of cooling can be increased.

  Here, the preheating step C1 and the holding step C4 can be omitted. However, as described above, if these are performed together with the indentation stirring step C2 and the stirring maintenance step C3, the metal member 11 and the resin member 12 are more reliably avoided from being in a perforated state. Bonding can be performed with high bonding strength.

  FIG. 8 shows the results of examining the relationship between the steps to be performed and the bonding strength. In FIG. 8, Example 1 is the result when the preheating step C1, the indentation stirring step C2, and the stirring maintaining step C3 are performed while the holding step C4 is omitted. It is a result at the time of implementing holding process C4 in addition to C1-C3, and comparative example 1 and comparative example 2 are a result at the time of implementing only indentation stirring process C2. In FIG. 8, C1 to C4 represent processes C1 to C4, respectively, the time is the time of each process (the time for pressing the rotary tool 16), and the applied pressure is the force and the number of rotations for pressing the rotary tool 16 in each process. Represents the number of rotations of the rotation tool 16. The test results shown in FIG. 8 show that a 6000 series aluminum alloy plate-like member (thickness 1.2 mm) is used as the metal member 11, and 40 carbon fibers into which a chloro group is introduced are used as the resin member. Joining in which a metal member and a resin member are joined by a method defined in JIS Z 3136, using polypropylene containing wt%, using the same rotary tool 16 as that used in the above (3) test. It is the result of having pulled the body in the direction shown by arrows Y and Y in FIG.

  As shown in Comparative Example 1 of FIG. 8, when only the indentation stirring step C2 is performed and the pressing force of the rotary tool 16 is relatively high, specifically, the pressing force of 1500 N is 7. When the rotary tool 16 was pressed against the metal member 11 for 00 seconds, a hole was opened in the metal member 11, and a joined body of the metal member 11 and the resin member 12 could not be obtained. In addition, as shown in Comparative Example 2 in FIG. 8, in the case where only the pushing and stirring step C2 is performed in a state where the applied pressure is suppressed to 900 N so as to avoid the hole opening state, the hole opening state is avoided and the metal is made. Although the member 11 and the resin member 12 could be joined, the joining strength was a relatively small value of 1.55 kN.

  On the other hand, as shown in Example 1 in FIG. 8, when the preheating step C1, the indentation stirring step C2, and the stirring maintaining step C3 are performed, specifically, the rotary tool 16 is set to 1.00 at 900 N. Press the metal member 11 for 2 seconds (preheating step C1), and then press the rotary tool 16 against the metal member 11 at 1500 N for 0.25 seconds until it reaches a depth not reaching the joint interface (indentation stirring step C2). In the case where the rotary tool 16 is rotated at 500 N for 5.75 seconds at the reference position that does not reach the joining boundary surface (stirring maintenance step C3), the metal member 11 and the resin member 12 are moved while avoiding the perforated state. Further, it was possible to join at a high strength of 2.81 kN shear strength.

  Further, as shown in Example 2 of FIG. 8, when the holding step C4 is further performed in addition to the above Example 1, specifically, after the stirring maintaining step C3 in the above Example 1, the rotating tool In the case of pressing against the bonded body for 5.00 seconds with a pressure of 1000 N while stopping the rotation of 16, the shear strength of the bonded body could be increased to a value higher than Example 1 of 3.04.

  As described above, if the indentation stirring step C2 and the stirring maintaining step C3 are performed, the bonding strength can be increased to some extent while avoiding the hole opening state, but the bonding strength can be further increased while avoiding the hole opening state more reliably. In order to further increase, as described above, it is preferable to perform the preheating step C1 and the holding step C4 in addition to the indentation stirring step C2 and the stirring maintaining step C3. Although not shown, when only the indentation stirring step C2 and the stirring maintaining step C3 are performed, the same shear strength as that obtained when the preheating step C1 is performed can be obtained. The metal member 11 may adhere to the rotary tool 16 depending on the temperature condition at the start of the agitation step C2 (when the temperature of the metal member 11 is low, etc.), and a high-strength bonding material is stably obtained. There is a risk that it will not be possible. Therefore, in order to obtain a bonding material with high strength more reliably, it is preferable to perform the indentation stirring step C2 after performing the preheating step C1 and preheating the metal member 11.

  In the embodiment (bonding test), as the resin when the resin itself contains a functional group, polyamide resin (PA6, nylon 6), polyamide resin (PA66, nylon 66), polyethylene terephthalate (PET), polylactic acid Although the case where (PLA) is used has been described, the type of resin is not limited thereto. However, when these are used, as described in the above “(3) Joining test”, the joined body 20 of a different member having particularly high joining strength can be obtained.

  Moreover, in the said embodiment (joining test), although the metal member made from an aluminum alloy was used as the metal member 11, the specific kind of the metal member 11 is not restricted to this, and melting | fusing point is rather than a resin member. Applicable to all high metals. Specifically, when applied to the field of automobiles, 5000 series, 6000 series aluminum alloys, steel, magnesium and alloys thereof, titanium and alloys thereof, and the like, which are frequently used in this field.

  For example, an alloyed hot-dip galvanized steel sheet is used as the metal member 11, and a polypropylene containing 40 wt% carbon fiber (with functional groups introduced) is used as the resin member 12, and the joining method according to the above embodiment (However, the pressurizing force in the indentation stirring step C2 and the pressurizing force in the stirring maintaining step C3 are values different from those in the above embodiment (pressing conditions), specifically, 2500N and 1500N, respectively). Then, it was possible to obtain a joining material that would break the resin member, that is, a joining member that would break not at the joint but at the resin member, and that the joining strength would be equivalent to the breaking strength of the carbon fiber reinforced polypropylene itself.

  Moreover, although the said embodiment demonstrated the case where the plate-shaped metal member 11 and the resin member 12 were joined, the specific shape of the metal member 11 and the resin member 12 to be joined is not restricted to this.

  Moreover, in the said embodiment, although the thing which has the pin part 16a was used as the rotation tool 16, not only this but the thing which does not have the pin part 16a can also be used.

  In the above embodiment, in “(3) Joining test”, the rotating tool 16 is made of tool steel having dimensions of each part of FIG. 2 of D1 = 15 mm, D2 = 3 mm, and h = 0.5 mm. The results were similar.

  Moreover, in the said embodiment, when the rotary tool 16 is moved only to the direction which touches / separates with respect to the overlapping part of the metal member 11 and the resin member 12, and these are point-joined, that is, Although the case where only one point of the overlapping portion is joined has been described, these may be joined together. That is, the metal member 11 and the resin member 12 may be joined linearly by moving the rotary tool 16 along the surface of the metal member 11 while pressing the rotary tool 16 against the metal member 11.

DESCRIPTION OF SYMBOLS 1 Friction stir welding apparatus 10 Workpiece | work 11 Metal member 12 Resin member 16 Rotating tool 17 Receptacle 20 Joint body P Joint part

Claims (6)

A first step of superimposing a metal member and a resin member having a functional group;
The second step of joining the metal member and the resin member by pressing the metal member side to the resin member side while rotating the rotary tool to generate frictional heat, and softening the resin member by this frictional heat. the door a method of bonding including different members,
As the rotating tool, prepare a shoulder part composed of a tip of a cylindrical body, and a cylindrical pin part protruding from the shoulder part and having an outer diameter smaller than the shoulder part,
The second step includes a preheating step of rotating the rotating tool in a state where only the pin portion and the shoulder portion of the rotating tool are in contact with the surface portion of the metal member, and after the preheating step, the rotating tool is A push-in stirring step that pushes the metal member into a depth that does not reach the joint boundary surface between the metal member and the resin member, and the rotary tool at a position that enters and approaches the depth that does not reach the joint boundary surface look containing a stirring maintaining step to continue the rotation of,
In the preheating step, the rotary tool is rotated by a first pressurizing time while being pressed with a first pressing force,
In the indentation stirring step, the rotary tool is rotated by a second pressurization time shorter than the first pressurization time while pressing the rotary tool with a second pressurization force larger than the first pressurization force,
In the stirring maintaining step, the rotary tool is rotated by a third pressurizing time longer than the first pressurizing time while pressing the rotary tool with a third pressurizing force smaller than the first pressurizing force. Member joining method. In the joining method of the dissimilar member of Claim 1 ,
The first pressing force is a value of 700 N or more and less than 1200 N, and the first pressurizing time is a value of 0.5 second or more and less than 2.0 seconds,
The second applied pressure is a value of 1200 N or more and less than 1800 N, and the second pressurizing time is a value of 0.1 second or more and less than 0.5 second,
The method of joining different types of members, wherein the third pressure is a value of 100 N or more and less than 700 N, and the third pressurizing time is a value of 1.0 second or more and less than 10 seconds. In the joining method of the dissimilar member of Claim 1 or 2 ,
The second step includes a holding step of stopping the rotation of the rotary tool after the stirring maintaining step and holding the rotary tool for a predetermined pressurizing time with a predetermined pressure in that state. To join different kinds of members. In the joining method of the dissimilar member of any one of Claim 1 to 3 ,
The functional group contains at least one element of N, O, F, Si, S, Cl, Br, and I. In the joining method of the dissimilar member of Claim 4 ,
A method for joining different types of members, wherein the functional group contains at least one element of O, S, and Cl. In the joining method of the dissimilar member of any one of Claim 1 to 5 ,
The resin for the resin member is a polyamide resin, polyethylene terephthalate, or polylactic acid.

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