JP2016068130A - Method of joining metal member with resin member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for jointing a resin member containing an electric conductive material with a metal member capable of achieving a junction with a sufficient strength, as well as sufficiently preventing corrosion of the metal member.SOLUTION: A method for jointing a metal member with a resin member is a thermal pressing type jointing method comprising: providing a metal member 11 and a resin member 12 containing an electric conductive material; overlapping at least an end part of one of the members on a surface of the other member; applying heat and pressure to soften and melt the resin member. The method for jointing a metal member with a resin member comprises forming a molten solidified portion 51 by providing a thermoplastic resin sheet 50 between the metal member and the resin member, and by applying heat and pressure to extrude a part of the thermoplastic resin sheet in a molten state from between at least an end part of one of the members and a surface of the other member onto the surface of the other member.SELECTED DRAWING: Figure 4

Description

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

  Conventionally, weight reduction has been demanded in the fields of automobiles, railway vehicles, aircraft, and the like. For example, in the field of automobiles, the use of high-tensile materials has made it possible to reduce the thickness of steel sheets, or aluminum alloy materials have been used as substitutes for steel materials, and the use of resin materials has also advanced. In such a field, development of a joining technique between a metal member and a resin member is important not only from the viewpoint of weight reduction, but also from the viewpoint of realizing an increase in strength, rigidity, and productivity of the joining member. So far, a so-called friction stir welding (FSW) method has been proposed as a method for joining a metal member and a resin member. As shown in FIG. 14, the friction stir welding method directly superimposes the metal member 211 and the resin member 212 and rotates the rotary tool 216 while pressing the metal member 211 to generate frictional heat. In this method, the metal member 211 and the resin member 212 are joined by melting and softening the resin member 212 with this frictional heat (Patent Document 1).

  However, in the conventional friction stir welding method, from the viewpoint of improving the strength of the resin member itself, when a reinforcing fiber is contained in the resin member, the resin member is melted and softened on the joint surface with the metal member at the time of joining. It is hard for flow to occur sufficiently. Specifically, even if melting / softening occurs in the region immediately below the rotary tool in the resin member, the bonding strength may decrease because the reinforcing fibers inhibit the flow of the molten resin.

JP 2010-158885 A

  Therefore, from the viewpoint of improving the bonding strength, as shown in FIG. 15, a thermoplastic resin sheet 250 is interposed between the metal member 211 and the resin member 212, and heat and pressure are applied from the metal member side by the pressing member 216. The inventors of the present invention have attempted to join the metal member 211 and the resin member 212 by melting the sheet by applying. At this time, as shown in FIG. 16, the thermoplastic resin sheet 250 that is softened and melted by frictional heat is pushed away immediately below the pressing member, and between the metal member 211 and the resin member 212, the circumferential direction (in the drawing, the arrow Direction), and a joint between them is achieved. On the other hand, the metal member 211 and the resin member 212 come into direct contact immediately below the pressing member. In such an attempt, the thermoplastic resin sheet 250 is used to improve the bonding strength, and in order to avoid poor appearance of the bonded portion of the bonded body, which is often a problem from the past, as shown in FIG. In addition, the molten thermoplastic resin sheet 250 did not protrude from between the metal member 211 and the resin member 212.

  However, in the trial as described above, the end surface 211A of the end portion of the metal member 211 disposed on the surface of the resin member 212 and the unfilled portion of the thermoplastic resin sheet 250 in the joining portion of the metal member 211 and the resin member 212 In addition, there is a new problem that the region 211B adjacent to the contact region with the thermoplastic resin sheet 250 on the resin member side surface of the metal member 211 corrodes relatively early.

As a result of intensive investigations on the corrosion of such metal members, the inventors of the present invention have found that the corrosion occurs based on the following mechanism due to carbamic corrosion, and have made the present invention. For example, in the end surface 211A of the end portion of the metal member 211 arranged on the surface of the resin member 212, as shown in FIG. 17, the metal member 211 and the resin member 212 are located immediately below the workpiece mark 251 by the pressing member. Due to the direct contact, the metal member 211 is directed from the metal member 211 toward the resin member 212 due to the difference in ionization tendency between the metal constituting the metal member 211 and the reinforcing fiber (for example, carbon fiber) contained in the resin member 212. As a result, electrons (e ⁻ ) try to flow. Therefore, when the water 252 containing a chlorine component (Cl ⁻ ) stays in contact with the surface 212A of the resin member 212 and the end surface 211A of the end of the metal member 211, the water 252 is formed when the metal member 211 is made of, for example, Al. Al coming into contact with the substrate emits electrons to become Al ³⁺ and is eluted in water 252. The emitted electrons reach the interface between the water 252 and the resin member 212 via the interface between the metal member 211 and the resin member 212 immediately below the workpiece mark 251 and react with the water 252 to generate OH ⁻ . . This OH ⁻ reacts with Al ³⁺ eluted in the water 252 to generate rust. Such a series of reactions forms an electron / ion loop (see FIG. 17), so that it is considered that corrosion occurs relatively early. FIG. 17 is an enlarged schematic view of the vicinity of the end of the metal member in FIG. Moreover, also in the area | region 211B adjacent to the contact area with the thermoplastic resin sheet 250 in the resin member side surface of the metal member 211 as shown in FIG. 16, corrosion arises by the mechanism similar to the above.

  The present invention provides a method of joining a metal member and a resin member, which can join a resin member containing a conductive material to the metal member with sufficient strength and can sufficiently prevent corrosion of the metal member. The purpose is to do.

In the present invention, a metal member and a resin member containing a conductive material are superposed, heat and pressure are applied so that at least a part of one member is disposed on the surface of the other member. It is a joining method between a metal member and a resin member by a hot-pressure joining method that softens and melts the resin member,
By applying a heat and pressure by interposing a thermoplastic resin sheet between the metal member and the resin member, heat is generated from between the end of at least a part of the one member and the surface of the other member. The present invention relates to a method for joining a metal member and a resin member, characterized in that a part of a plastic resin sheet is protruded on the surface of the other member in a molten state.

The present invention also provides
In the above bonding method, the hot-pressure bonding method is a friction stir welding method,
The friction stir welding method relates to a joining method including the following steps:
A first step of superimposing the metal member and the resin member; and while rotating the rotating tool, the metal member is pressed against the metal member to generate frictional heat, and the thermoplastic resin sheet and the resin member are softened and melted by the frictional heat. Then, a second step of solidifying and joining the metal member and the resin member.

According to the joining method of the present invention, a part of the thermoplastic resin sheet is caused to protrude from the surface of the other member in a molten state from between the end of at least a part of the one member and the surface of the other member. Solidify. The melted and solidified product 51 of the thermoplastic resin sheet that protrudes in this way inhibits the retention of water between the end of one member and the surface of the other member. Even if water stays between the end of one member and the surface of the other member, due to the presence of the molten solidified product 51, the water will end up at the end surface of the one member and the surface of the other member. And simultaneous contact with both are avoided. As a result, the formation of electron / ion loops in the occurrence mechanism of carbamic corrosion is inhibited, and corrosion is sufficiently prevented.
According to the joining method of the present invention, since the resin member and the metal member are joined via the thermoplastic resin sheet, the resin member and the metal member can be joined with sufficient strength.

It is a schematic diagram which shows an example of a part of friction stir welding apparatus suitable for the joining method of the metal member and resin member concerning this invention. It is an enlarged view of the front-end | tip part of an example of the rotary tool used for the joining method of this invention. It is a schematic sectional drawing when the ZZ section in Drawing 1 is seen in the direction of an arrow, and is a schematic sectional view for explaining an example of the preheating process in the joining method of the present invention. It is a schematic sectional drawing for demonstrating the indentation stirring process, stirring maintenance process, and holding process in the joining method of this invention performed after the preheating process in FIG. It is a schematic sectional drawing for demonstrating an example of the preheating process in another embodiment of this invention. It is a schematic sectional drawing for demonstrating the indentation stirring process, stirring maintenance process, and holding process in the joining method of this invention performed after the preheating process in FIG. It is a schematic sectional drawing for demonstrating an example of the preheating process in another embodiment of this invention. It is a schematic sectional drawing for demonstrating the indentation stirring process, stirring maintenance process, and holding process in the joining method of this invention performed after the preheating process in FIG. It is a schematic sectional drawing for demonstrating an example of the preheating process in another embodiment of this invention. It is a schematic sectional drawing for demonstrating the indentation stirring process, stirring maintenance process, and holding process in the joining method of this invention performed after the preheating process in FIG. It is a schematic sectional drawing for demonstrating an example of the preheating process in another embodiment of this invention. It is a schematic sectional drawing for demonstrating the indentation stirring process, stirring maintenance process, and holding | maintenance process in the joining method of this invention performed after the preheating process in FIG. It is the schematic for demonstrating the measuring method of the joint strength in an Example. It is this schematic sketch for demonstrating the joining method of the metal member and resin member in a prior art. It is a schematic sectional drawing for demonstrating an example of the preheating process in a prior art. It is a schematic sectional drawing for demonstrating an indentation stirring process, a stirring maintenance process, and a holding process performed after the preheating process in FIG. It is a schematic sectional drawing for demonstrating the generation | occurrence | production mechanism of the corrosion which occurs in a prior art.

  In the joining method of the present invention, the metal member and the resin member are overlapped and heat and pressure are applied, preferably by applying locally from the metal member side, so that the resin member is softened and the metal member and the resin are applied. This is a hot-pressure joining method for joining members. The joining method employed in the joining method of the present invention is not particularly limited as long as it is a method of heating while applying pressure. For example, a friction stir welding method, a laser heating joining method, a resistance heating joining method (electric heating) Bonding method), induction heating bonding method, ultrasonic heating bonding method and the like. Among these, the friction stir welding method is preferably employed.

As will be described in detail later, the friction stir welding method refers to frictional heat generated by pressing against a metal member while rotating the rotary tool in a state where the metal member and the resin member are overlapped and restrained. It is the method of joining using.
The laser heating bonding method is a method of bonding using heat generated by irradiating a metal member with a laser in a state where the metal member and the resin member are superposed and restrained. As the laser, a YAG laser, a fiber laser, a semiconductor laser, or the like is used.
The resistance heating bonding method is a method of bonding using heat generated by flowing a current directly through a metal member in a state where the metal member and the resin member are superposed and restrained.
The induction heating bonding method is a method in which an induction current is generated in a metal member by an electromagnetic induction action in a state where the metal member and the resin member are superposed and restrained, and bonding is performed using heat generated by the current.
The ultrasonic heating bonding method is a method in which a metal member and a resin member are superposed on each other and restrained by applying pressure from the metal member side while causing ultrasonic vibration to occur between the metal member and the resin member. It is the method of joining using the frictional heat of.

  Hereinafter, although the joining method of this invention which employ | adopted the friction stir welding method is demonstrated using FIGS. 1-12, at least one part edge part of one member and the other member of a metal member or a resin member are demonstrated. As long as a part of the thermoplastic resin sheet protrudes from the surface to the surface of the other member in the molten state, it is clear that the effects of the present invention can be obtained even if other bonding methods described above are used. . In these drawings, common reference numerals indicate the same members, parts, dimensions, or regions.

  First, FIG. 1 is a diagram schematically showing an example of a part of a friction stir welding apparatus suitable for carrying out the joining method of the present invention. A friction stir welding apparatus 1 shown in FIG. 1 is configured as a device that friction stir welds a metal member 11 and a resin member 12, and includes a cylindrical rotary tool 16. As shown in the figure, the rotary tool 16 is applied to the workpiece 10 with the metal member 11 on the top and the resin member 12 on the bottom, by a drive source (not shown) as indicated by an arrow A1. While rotating around the central axis X (see FIG. 2), the metal member 11 is pressed downward in the pressing area P (scheduled pressing area) as indicated by an arrow A2. Friction heat is generated by the pressing of the rotary tool 16, and this frictional heat is conducted to the resin member 12 to soften and melt the resin member 12, and as a result, the metal member 11 and the resin member 12 are joined.

  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 arranged coaxially with the rotary tool 16. The receiving member 17 is moved upward with respect to the work 10 as shown by an arrow A3 by a driving source (not shown). The upper end surface of the receiving member 17 abuts on the lower surface of the workpiece 10 (more specifically, the lower surface of the resin member 12) by the time the rotating tool 16 starts pressing the workpiece 10 at the latest. The support 17 sandwiches the workpiece 10 between the rotary tool 16 and supports the workpiece 10 from below against the pressing force during a pressing period by the rotary tool 16, that is, during friction stir welding. 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.

  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 protrudes 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 first 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 protrudes. The 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 D2 of the pin portion 16a. 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. For example, the diameter D1 of the shoulder portion 16b is usually 5 to 100, particularly 5 to 20 mm.

  The friction stir welding apparatus 1 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 uses a spacer, a clamp, or the like for fixing the work 10 in advance and preventing the metal member 11 from floating when the rotary tool 16 is pressed. A jig is provided.

(1) One embodiment of the joining method according to the present invention (friction stir welding method)
In the present invention, the metal member 11 and the resin member 12 containing a conductive material are superposed, heat and pressure are applied so that the end of one member is disposed on the surface of the other member. As a result, the resin member is softened and melted. At this time, by interposing a thermoplastic resin sheet 50 between the metal member 11 and the resin member 12 and applying heat and pressure, at least a part of the end of the one member and the other member A part of the thermoplastic resin sheet is protruded from the surface of the other member in a molten state to form the melt-solidified portion 51.

  The end of one member is disposed on the surface of the other member. In an aspect in which one member is disposed on the other member, the end surfaces of both members form a single surface. An aspect other than the aspect is meant. Specifically, as shown in FIG. 3, the first mode in which the end portion 110 of the metal member 11 is disposed on the surface 12 </ b> B of the resin member 12 and the end portion 120 of the resin member 12 are disposed on the surface of the metal member 11. It is meant to include both aspects of the second aspect. In the first aspect, since water tends to stay between the end surface 11A of the end portion 110 of the metal member 11 and the surface 12B of the resin member 12, the carbonic corrosion is likely to occur on the end surface 11A. In the second aspect, since water tends to stay between the end surface 12A of the end portion 120 of the resin member 12 and the surface of the metal member 11, the contact with the thermoplastic resin sheet 50 on the resin member side surface of the metal member 11 The carbamic corrosion is likely to occur in the region 11B adjacent to the region. However, in the present invention, as shown in FIG. 4, a part of the thermoplastic resin sheet 50 is protruded from the surface of the other member in a molten state, so that it protrudes in any aspect. The melted and solidified product 51 inhibits the retention of water. Even if water stays, the presence of the melted solid 51 prevents the water from simultaneously contacting both the end surface of the one member and the surface of the other member. As a result, the formation of electron / ion loops in the occurrence mechanism of carbamic corrosion is inhibited, and corrosion is sufficiently prevented.

  For example, in FIG. 4, a part of the thermoplastic resin sheet 50 is protruded from the surface of the other member in a molten state from the top to the bottom or from the bottom to the top in the axial direction of the rotary tool 16. The molten solidified product 51 of the thermoplastic resin sheet flowing out from between the end surface 11A of the metal member 11 and the resin member 12 or from between the end surface 12A of the resin member 12 and the metal member 11 is formed. This means that a melt is observed.

  The protrusion width of the thermoplastic resin sheet 50 is not particularly limited as long as corrosion is prevented, and is usually 0.5 mm or more, preferably 3 mm or more. For example, the protrusion width of the molten solidified material 51 from the end surface 11A of the metal member 11 that clearly protrudes from between the metal member 11 and the resin member 12 when observed in the axial direction of the rotary tool 16 in FIG. It is width.

  Hereinafter, the aspect in which the end portion 110 of the metal member 11 is disposed on the surface 12B of the resin member 12 will be described in detail. By referring to the following description, the end portion 120 of the resin member 12 is on the surface of the metal member. It can be fully understood that corrosion is also prevented in the embodiment arranged in the above. Further, in the present invention, not all the end portions of one member have to be disposed on the surface of the other member, but at least a part of the end portion of one member is on the surface of the other member. It is only necessary that the thermoplastic resin sheet 50 protrudes from the space between the end of the one member and the surface of the other member.

  The thermoplastic resin sheet 50 protrudes on the surface of the resin member 12 in a molten state from between the end surface 11A of the end portion 110 of the metal member 11 and the surface 12B of the resin member 12 by application of heat and pressure. . As long as the thermoplastic resin sheet 50 exhibits such behavior, the constituent material, dimensions, and shape thereof are not particularly limited.

  As the constituent material of the thermoplastic resin sheet 50, a polymer material compatible with the resin member 12 in a molten state is preferably used. Specifically, the material similar to the below-mentioned specific example of the thermoplastic polymer which comprises a resin member can be illustrated. A preferable constituent material of the thermoplastic resin sheet 50 is a modified polyolefin resin. When the resin member 12 includes a polyolefin resin, a modified polyolefin resin is particularly preferable. The modified polyolefin resin means an acid-modified product of polyolefin resin. Specific examples of the modified polyolefin resin include a copolymer obtained by copolymerization or graft polymerization of a constituent monomer of a polyolefin resin such as ethylene and propylene and a carboxyl group-containing monomer such as maleic acid and maleic anhydride.

  The molecular weight of the constituent material of the thermoplastic resin sheet 50 is not particularly limited as long as it can be softened and melted at the time of joining. Usually, a polymer having a melt flow rate (MFR) of 2 to 200, preferably 2 to 55 is used. used.

  In the present specification, MFR is a melt flow rate, and a value (g / 10 minutes) measured at 230 ° C. based on JIS K7210 is used.

  The shape of the thermoplastic resin sheet 50 may be various shapes such as a square shape and a circular shape, but a circular shape is preferable from the viewpoint of protruding the thermoplastic resin sheet 50 in a molten state. The thermoplastic resin sheet 50 is preferably disposed so that the center of the thermoplastic resin sheet 50 is positioned on the rotation axis of the rotary tool 16 when the metal member 11 and the resin member 12 are overlapped.

  The thermoplastic resin sheet 50 may be applied (precoated) in advance to the entire surface of the metal member 11 or the entire surface of the resin member 12. Such an aspect is also included in the aspect in which the thermoplastic resin sheet 50 is interposed.

The joining method according to the present invention comprises at least the following steps:
A first step of superimposing the metal member 11 and the resin member 12 via the thermoplastic resin sheet 50; and while rotating the rotary tool 16, the metal member 11 is pressed against the metal member 11 to generate frictional heat. A second step in which the metal member 11 and the resin member 12 are joined after the member 12 is softened and melted and then solidified.
The metal member 11 and the resin member 12 obtained in the first step are called “work” 10.

First step:
In the first step, as shown in FIGS. 1 and 3, the metal member 11 and the resin member 12 are superposed via a thermoplastic resin sheet 50 at a desired joining portion. Specifically, the metal member 11 and the resin member 12 are overlapped so that the surface (for example, 120) having the filler content rate gradient as described above in the resin member 12 is in contact with the metal member 11.

Second step:
In the second step, at least a push-in stirring step C <b> 2 is performed in which the rotary tool 16 is pushed into the metal member 11 to enter a depth that does not reach the joining boundary surface 130 between the metal member 11 and the resin member 12.

In the present invention, in the second step, the preheating step C1 for rotating the rotary tool 16 in a state where only the front end portion of the rotary tool 16 is in contact with the surface portion of the metal member 11 is performed before the pushing and stirring step. Is preferred, but not necessarily.
After the indentation stirring step, it is preferable to perform the stirring maintenance step C3 in which the rotation operation of the rotary tool 16 is continued at the position where the rotary tool 16 has entered to a depth that does not reach the joining boundary surface. It doesn't have to be.

  Hereinafter, each step will be described in detail.

(Preheating process C1)
In the preheating step C1, by bringing the rotary tool 16 and the receiving member 17 close to each other, as shown in FIG. 3, only the tip of the rotary tool 16 is placed on the surface portion (upper surface portion in the illustrated example) of the metal member 11. This is a step of rotating the rotary tool 16 in a contacted state. In the preheating step C1, the rotary tool 16 is rotated at a predetermined rotation speed (for example, 3000 rpm) for a first pressurizing time (for example, 1.00 seconds) with a first pressure (for example, 900 N). FIG. 3 is a schematic cross-sectional view when the ZZ cross section in FIG. 1 is viewed in the direction of the arrow, and is a schematic cross-sectional view for explaining a preheating step in the joining method of the present invention.

  Specifically, in the preheating step C <b> 1, frictional heat is generated at the surface portion (upper surface portion in the illustrated example) of the metal member 11 by pressing of the rotary tool 16. The frictional heat is transmitted to the inside of the metal member 11, and the range of the pressing region P of the metal member 11 and the range in the vicinity of the pressing region P are preheated. Thereby, it becomes easy to push the rotary tool 16 into the metal member 11 in the next pushing and stirring step C2.

  In the preheating step C1, the frictional heat is also transmitted to the thermoplastic resin sheet 50 and the resin member 12 between the metal member 11 and the resin member 12, and in the next indentation stirring step C2, the thermoplastic resin sheet 50 and the resin member 12 are transferred. Becomes easier to soften and melt.

  The first pressurizing force and the first pressurizing time in the preheating step C1 are the viewpoint of the ease of pressing the rotating tool 16 as described above and the viewpoint of the ease of softening and melting of the thermoplastic resin sheet 50 and the resin member 12. The value varies depending on, for example, the rotational speed of the rotary tool 16, the thickness of the metal member 11, the type of material, and the like. For example, when the aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less is used, the first pressure in the preheating step C1 is 700 N or more and less than 1200 N, and the first pressurizing time is 0.5 seconds or more and 2 A value of less than 0 seconds and a rotation speed of the rotary tool are preferably 500 rpm or more and 10,000 rpm or less.

(Indentation stirring step C2)
The pushing and stirring step C2 is a step of pushing the rotating tool 16 into the metal member 11 by bringing the rotating tool 16 and the receiving member 17 close to each other as shown in FIG. When the indentation stirring step C2 is performed after the preheating step C1, the rotary tool 16 and the receiving member 17 are brought closer to each other, thereby pushing the rotary tool 16 into the metal member 11 as shown in FIG. As a result, the rotary tool 16 is advanced to a depth that does not reach the joint boundary surface 130 between the metal member 11 and the resin member 12, and the portion immediately below the rotary tool of the metal member 11 is protruded and deformed toward the resin member 12. As a result, the thermoplastic resin sheet 50 melted in the region immediately below and the outer peripheral region of the rotary tool is further flowed to the outer peripheral direction. As a result, the end surface 11A of the end 110 of the metal member 11 and the surface 12B of the resin member 12 are obtained. It protrudes on the surface of the resin member 12 from between.

  Specifically, in the indentation stirring step C2, the rotary tool 16 is moved at a second pressurizing time (for example, 1500 N) that is larger than the first pressurizing time and shorter than the first pressurizing time (for example, Rotate at a predetermined rotation speed (for example, 3000 rpm) for 0.25 seconds.

  In the indentation stirring step C2, the rotating tool 16 is pushed into the metal member 11 when the applied pressure is larger than that in the preheating step C1. That is, the rotary tool 16 enters deep inside the metal member 11. Due to the pressing of the rotary tool 16, the joint boundary surface 130 between the metal member 11 and the resin member 12 moves to the receiving member 17 side (lower side in the illustrated example) immediately below the rotary tool of the metal member 11. Projecting toward the resin member 12 side. Thereby, the thermoplastic resin sheet 50 moves in the outer peripheral direction in a molten state, and protrudes from between the metal member 11 and the resin member 12 onto the surface of the resin member 12.

  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 exceeds the joining boundary surface. That is, the rotary tool 16 penetrates the metal member 11 and contacts the resin member 12. Then, the metal member 11 is in a holed state in which the hole through which the rotary tool 16 has passed is opened, resulting in poor bonding.

  Therefore, in the present invention, 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 a depth that does not reach the joining boundary surface. In other words, the rotary tool 16 is advanced to a depth that does not reach the joint interface. 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 thermoplastic resin sheet 50 and the resin member 12, so that the thermoplastic resin sheet 50 and the resin member are transmitted. 12 softening / melting and flow are promoted.

  The second pressing 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 as described above and the rotating tool 16 as close to the resin member 12 as possible. The value varies depending on, for example, the number of rotations of the rotary tool 16, the thickness of the metal member 11, the type of material, and the like. For example, when the aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less is used, the second pressing force in the indentation stirring step C2 is a value of 1200 N or more and less than 1800 N, and the second pressurizing time is 0.1 second or more. The value of less than 0.5 seconds and the rotation speed of the rotary tool are preferably 500 rpm or more and 10,000 rpm or less.

(Stirring maintenance step C3)
The agitation maintaining step C3 stops the mutual approach between the rotary tool 16 and the receiving member 17 and, as shown in FIG. This is a step of continuing the rotation operation of the rotary tool 16 at the “position”). In the stirring maintaining step C3, the rotary tool 16 is moved to a third pressurizing time (for example, 5.75) longer than the first pressurizing time with a third pressurizing force (for example, 500 N) smaller than the first pressurizing force. Seconds) at a predetermined rotation speed (for example, 3000 rpm).

  In the stirring maintaining step C3, the rotating tool 16 is maintained at the reference position by the applied pressure being smaller than that of the preheating step C1 (of course, being smaller than that of the pushing stirring step C2). Since the rotation operation of the rotary tool 16 is continued at the reference position close to the resin member 12, a large amount of frictional heat is generated, and most of the generated frictional heat is transferred to the thermoplastic resin sheet 50 and the resin member 12.

  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 the values thereof are, for example, the rotary tool 16. Depending on the number of rotations, the thickness of the metal member 11, the type of material, and the like. For example, when the aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less is used, the third pressing force in the stirring and maintaining step C3 is preferably a value of 100 N or more and less than 700 N, particularly a value of 100 N or more and 600 N or less. The third pressurizing time is preferably 1.0 to less than 10 seconds, and the rotation speed of the rotary tool is preferably 500 to 10000 rpm.

(Holding process C4)
After the indentation stirring step C2 or the stirring maintaining step C3, a holding step C4 is performed in which the rotation of the rotary tool 16 is stopped and the rotary tool 16 is held at a predetermined pressure for a predetermined pressurizing time. Also good.
As shown in FIG. 4, the holding step C4 is a step in which the rotation of the rotary tool 16 is stopped and the rotary tool 16 is held for a predetermined time with a predetermined pressure in that state. In the holding step C4, the rotary tool 16 is moved at a fourth pressure force (for example, 1000 N) that is larger than the third pressure force but smaller than the second pressure force and shorter than the third pressurization time but the second pressure force. Hold for a fourth pressurization time (for example, 5.00 seconds) longer than the pressure time.

  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, the rotating tool 16 whose rotation has been stopped is reduced by the metal member 11, the thermoplastic resin sheet 50, and the resin member because the applied pressure is smaller than the indentation stirring process C 2 but larger than the stirring maintenance process C 3. 12 is clamped between the receiving part 17 and the pressing area P. Thereby, the adhesive force during cooling between the metal member 11 and the resin member 12 via the thermoplastic resin sheet 50 is increased, and the bonding strength after the completion of cooling and solidification 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 strength of the pressing region P during the cooling period as described above, and the values thereof are, for example, those of the material of the metal member 11 It varies depending on the type. For example, when the aluminum alloy metal member 11 is used, the fourth pressure in the holding step C4 is preferably a value of 700 N or more and less than 1200 N, and the fourth pressurization time is preferably a value of 1 second or more, for example.

  In the present invention, at least through the above-described steps C2, preferably through the above-described steps C1 and C2, more preferably through the above-described steps C1 to C3, and most preferably through the above-described steps C1 to C4, the metal member 11 And the joined member 20 of the metal member 11 and the resin member 12 in which the resin member 12 and the resin member 12 are joined to each other through the thermoplastic resin sheet 50 in a wide range with high strength.

  After performing a predetermined process in the second step, cooling is usually performed to solidify the molten resin. The cooling method is not particularly limited, and examples thereof include a standing cooling method and air cooling.

  As described above, the case where the metal member and the resin member are joined in a point shape without moving the rotary tool in the surface direction on the contact surface of the metal member (point joining) has been described. It is clear that the effect of the present invention can be obtained even when the metal member and the resin member are joined linearly while being moved (line joining).

(2) Resin member In the present invention, the resin member 12 contains a thermoplastic polymer and a conductive filler. The conductive filler is an additive having conductivity that is added to the resin member for the purpose of reinforcement, rigidity improvement, etc. in the field of the joining method between the metal member and the resin member. It is an inorganic additive that exists independently of the plastic polymer component. Specific examples of such a conductive filler include conductive materials such as carbon fiber and talc.

The filler preferably includes a conductive material different from the metal material constituting the metal member. Galvanic corrosion occurs when the resin member includes a conductive material different from the metal material constituting the metal member. In the present invention, even if the resin member includes such a conductive material, the corrosion is not caused. This is because it can be effectively prevented. The metal material constituting the metal member is a metal material mainly constituting the metal member. That the conductive material is different from the material constituting the metal member means that the conductive material and the metal member constituting material are represented by different chemical formulas. For example, when the conductive material is represented by Al ₂ O ₃ and the material mainly constituting the metal member is represented by Al, these materials are different.

  The filler may have various shapes such as a particle shape, a fiber shape, and a fabric, but preferably has a fiber shape. Since the fibrous filler such as carbon fiber inhibits the flow of the molten resin, the bonding strength is lowered. In the present invention, even if the resin member includes such a fibrous filler, the bonding is reduced. This is because a decrease in strength can be effectively prevented.

  The resin member 12 contains a conductive filler, particularly a fibrous conductive filler, in a content of usually 5 to 50% by weight with respect to the total amount. Such a content rate can be calculated | required by dissolving the whole resin member in the solvent in which the resin component can melt | dissolve, filtering a filler, and calculating the ratio with respect to the whole quantity of this filler weight.

As the thermoplastic polymer, any polymer having thermoplasticity can be used. Of these, thermoplastic polymers used in the field of automobiles are preferably used. Specific examples of such thermoplastic polymers include, for example, the following polymers and mixtures thereof:
Polyolefin resins such as polyethylene and polypropylene, and modified products thereof;
Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polylactic acid (PLA);
Polyacrylate resins such as polymethyl methacrylate resin (PMMA);
Polyether resins such as polyether ether ketone (PEEK) and polyphenylene ether (PPE);
Polyacetal (POM);
Polyphenylene sulfide (PPS);
PA6, PA66, PA11, PA12, PA6T, PA9T, MXD6 and other polyamide-based resins (PA);
Polycarbonate resin (PC);
Polyurethane resin;
A fluoropolymer resin; and a liquid crystal polymer (LCP).

  The molecular weight of the thermoplastic polymer is not particularly limited as long as it can be softened and melted at the time of joining. Usually, a thermoplastic polymer having a melt flow rate (MFR) of 2-200, preferably 2-55 is used. .

  In the present specification, MFR is a melt flow rate, and a value (g / 10 minutes) measured at 230 ° C. based on JIS K7210 is used.

  The resin member 12 may contain other additives.

  As described above, the resin member 12 is described as having a substantially flat plate shape as a whole, but is not limited to this, and when the resin member 12 is overlapped with the metal member 11 for bonding, the portion immediately below the metal member 11 is As long as it has a substantially flat plate shape, it may have any shape.

  The thickness t of the portion immediately below the metal member 11 in the resin member 12 is usually 2 to 10 mm.

(3) Metal member Although the metal member 11 has a substantially flat plate shape as an overall shape in FIG. 1 and the like, it is not limited to this, and only a portion that overlaps the resin member 12 for bonding is provided. As long as it has at least a substantially flat plate shape, it may have any shape.

  The thickness T of the substantially flat plate-shaped portion that overlaps the resin member 12 in the metal member 11 is not particularly limited, and is usually 2 to 10 mm.

As the metal constituting the metal member 11, any metal having a melting point higher than that of the thermoplastic polymer constituting the resin member 12 can be used. Among these, the following metals and alloys used in the automotive field are preferably used:
Aluminum and aluminum alloys such as 5000 series and 6000 series;
steel;
Magnesium and its alloys;
Titanium and its alloys.

  In the present invention, in a preferred embodiment from the viewpoint of preventing corrosion, the metal member is deformed or processed so as to form a pool space in which the melt of the thermoplastic resin sheet accumulates between the end portion and the resin member. Use metal parts.

  For example, the metal member 11 shown in FIGS. 5 to 6 and FIGS. 7 to 8 is deformed so as to form a pool space 115 in which the melt of the thermoplastic resin sheet 50 is accumulated between the end portion 110 and the resin member 12. Has been. In such a metal member 11, the end portion 110 is bent to the side opposite to the resin member 12 side, and as a result, a pool space 115 is formed. FIG. 5 is a schematic cross-sectional view showing an example of a preheating step when using the metal member of one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing an indentation stirring step, stirring maintaining step, and holding step in the joining method of the present invention performed after the preheating step in FIG. FIG. 7 is a schematic cross-sectional view showing an example of a preheating step when using a metal member according to another embodiment of the present invention. FIG. 8 is a schematic cross-sectional view showing an indentation stirring step, stirring maintaining step, and holding step in the joining method of the present invention performed after the preheating step in FIG.

  Further, for example, the metal member 11 shown in FIGS. 9 to 10 and FIGS. 11 to 12 forms a pool space 115 in which the melt of the thermoplastic resin sheet 50 is accumulated between the end portion 110 and the resin member 12. Has been processed. In such a metal member 11, the end portion 110 has a cutout portion on the resin member 12 side, and as a result, a pool space 115 is formed. FIG. 9 is a schematic cross-sectional view showing an example of a preheating step when using a metal member according to another embodiment of the present invention. FIG. 10 is a schematic cross-sectional view showing an indentation stirring process, a stirring maintenance process, and a holding process in the joining method of the present invention performed after the preheating process in FIG. 9. FIG. 11 is a schematic cross-sectional view showing an example of a preheating step when using a metal member according to another embodiment of the present invention. FIG. 12 is a schematic cross-sectional view showing an indentation stirring step, stirring maintaining step, and holding step in the joining method of the present invention performed after the preheating step in FIG.

  In the present invention, when the metal member 11 as shown in FIGS. 5, 7, 9 and 11 is used, if heat and pressure are applied from the metal member side, the thermoplastic resin sheet 50 is melted. Thereafter, as shown in FIGS. 6, 8, 10, and 12, the melt is accumulated in the accumulation space 15 between the end portion 110 of the metal member 11 and the resin member 12, and a part thereof is the metal member 11. It protrudes from between the end surface 11A of the end portion 110 and the surface 12B of the resin member 12.

  When the metal member is deformed or processed as described above, even if water stays, the probability of simultaneously contacting both the end surface 11A of the end portion 110 of the metal member and the surface 12B of the resin member is significantly reduced. As a result, formation of electron / ion loops in the mechanism of occurrence of carbamic corrosion is hindered, and corrosion is further prevented sufficiently.

[Example 1]
(Resin member)
As the polymer A, a pellet obtained by blending carbon fiber with a polyamide pellet (trade name; Unitika nylon A1020, manufactured by Unitika Co., Ltd.) made only of polyamide was used. The carbon fiber content of the pellet was 40% by weight. The MFR of the polyamide was 20.

  A resin member 12 having a size of (length 100 mm × width 50 mm × thickness 3 mm) was produced by injection molding using polymer A. Specifically, 100 parts by weight of polymer A was heated to 250 ° C. to obtain a mixed melt. The mixed melt was injected and injected into a mold heated to 50 ° C. at an injection speed of 100 mm / second, and then cooled and solidified to obtain a resin member 12.

(Thermoplastic resin sheet)
A 0.2 mm thick polymer sheet (Modic P565; manufactured by Mitsubishi Chemical Corporation) made of modified polypropylene was used. The modified polypropylene was a copolymer of propylene and maleic anhydride.
The thermoplastic resin sheet 50 was a circular sheet having a diameter of 12 mm.
The area of the thermoplastic resin sheet 50 (12 mm × 12 mm × 3.14 = 452 mm ² ) is defined as X (30 mm × 30 mm = 900 mm ² ) when the metal member 11 and the resin member 12 are overlapped. Was 0.50 × X.

(Metal member)
As the metal member, a flat plate member made of a 6000 series aluminum alloy was used (length 100 mm × width 30 mm × thickness 1.2 mm).
(Rotation tool)
As the rotating tool, a tool made of tool steel having dimensions of each part in FIG. 2 of D1 = 10 mm, D2 = 2 mm, and h = 0.5 mm was used.

(Joining method)
The joined body of the metal member 11 and the resin member 12 was manufactured by the following method.
First step:
The end of the metal member 11 and the end of the resin member 12 were overlaid as shown in FIGS. Between them, the thermoplastic resin sheet 50 was arranged so that the center of the circular thermoplastic resin sheet 50 was positioned on the rotation axis of the rotary tool 16.

Second step:
As shown in FIG. 3, the rotary tool 16 was rotated in a state where only the tip of the rotary tool 16 was in contact with the surface portion of the metal member 11 (preheating step C1: pressure 900N, pressurization time 1.00 seconds). Tool rotation speed 3000 rpm).
Next, as shown in FIG. 4, the rotary tool 16 is pushed into the metal member 11 to a depth that does not reach the joining interface between the metal member 11 and the resin member 12 (pushing stirring step C2: pressure 1500N, pressure applied). Pressure time 0.25 seconds, tool rotation speed 3000 rpm).
Next, as shown in FIG. 4, the rotation operation of the rotary tool 16 was continued at a position where the rotary tool 16 was advanced to a depth that did not reach the joining boundary surface (stirring maintenance step C3: pressurizing force 500 N, pressurizing time. 5.75 seconds, tool rotation speed 3000 rpm).
Next, as shown in FIG. 4, the rotary tool 16 was extracted from the joined body 20 and left to cool.

As a result, as shown in FIG. 4, a part of the thermoplastic resin sheet is melted between the end surface 11A of the end of the metal member 11 and the surface 12B of the resin member 12 on the surface 12B of the resin member 12. It protruded and solidified. The protrusion width was 0.5 to 5 mm.
Further, as shown in FIG. 4, a part of the thermoplastic resin sheet protrudes in a molten state from between the end surface 12 </ b> A of the end portion of the resin member 12 and the surface of the metal member 11 and solidifies. The protrusion width was 0.5 to 5 mm.

(Joint strength immediately after joining)
The joined body in which the metal member and the resin member were joined by a method defined in JIS Z 3136 was pulled in the directions indicated by arrows Y and Y in FIG. Evaluation was based on the shear strength S.
A; 3 kN ≦ S (good);
B; 2 kN ≦ S <3 kN (no problem in practical use);
C; S <2 kN (problem in practical use).

(Corrosion resistance)
The bonded body was subjected to a salt spray test for 30 days in accordance with JISZ2371. Then, it evaluated based on the presence or absence of generation | occurrence | production of corrosion.
◎; no corrosion occurred;
○: Slight corrosion occurred, but no problem in practical use;
X: Corrosion occurred.

[Example 2]
The metal member and the resin member were joined and evaluated by the same method as in Example 1 except that the end 110 of the metal member 11 was deformed as shown in FIGS. 5 and 6.

[Example 3]
The metal member and the resin member were joined and evaluated by the same method as in Example 1 except that the end 110 of the metal member 11 was processed as shown in FIGS. 9 and 10.

[Comparative Example 1]
The metal member and the resin member were joined and evaluated by the same method as in Example 1 except that the thermoplastic resin sheet 50 was not used.
In the joined body, no protrusion from between the metal member 11 and the resin member 12 occurred.

  The joining method according to the present invention is useful for joining a metal member and a resin member in the fields of automobiles, railway vehicles, aircraft, home appliances, and the like.

1: Friction stir welding apparatus 10: Workpiece 11: Metal member 12: Resin member 16: Rotating tool 17: Receiving tool 50: Thermoplastic resin sheet P: Pressing area (scheduled pressing area) by rotating tool on metal member surface

Claims (12)

Resin by superimposing a metal member and a resin member containing a conductive material, and applying heat and pressure so that at least a part of one member is disposed on the surface of the other member A method for joining a metal member and a resin member by a hot-pressure joining method for softening and melting a member,
By applying a heat and pressure by interposing a thermoplastic resin sheet between the metal member and the resin member, heat is generated from between the end of at least a part of the one member and the surface of the other member. A method for joining a metal member and a resin member, characterized in that a part of the plastic resin sheet is protruded on the surface of the other member in a molten state. At least a part of the end of the metal member is disposed on the surface of the resin member,
The method for joining the metal member and the resin member according to claim 1, wherein the melt that protrudes between the metal member and the resin member covers at least a part of the end surface of the end portion of the metal member.   The metal member and the resin according to claim 2, wherein the metal member is a metal member that is deformed or processed so as to form a pool space in which a melt of the thermoplastic resin sheet is accumulated between the end portion and the resin member. Joining method with member.   The method for joining a metal member and a resin member according to claim 3, wherein the metal member is a metal member whose end is bent to the side opposite to the resin member side.   The joining method of the metal member and resin member of Claim 3 which uses the metal member which an edge part has a notch part in the resin member side as a metal member.   By applying heat and pressure from the metal member side, the thermoplastic resin sheet is melted, and after the melt is accumulated in a storage space between the end of the metal member and the resin member, a part of the melt is applied to the metal member. The joining method of the metal member and resin member in any one of Claims 2-5 made to protrude from between the edge part of this, and the surface of a resin member. The hot-pressure bonding method is a friction stir welding method,
The joining method according to any one of claims 1 to 6, wherein the friction stir welding method includes the following steps:
A first step of superimposing the metal member and the resin member; and while rotating the rotating tool, the metal member is pressed against the metal member to generate frictional heat, and the thermoplastic resin sheet and the resin member are softened and melted by the frictional heat. Then, a second step of solidifying and joining the metal member and the resin member.   The joining method according to claim 7, wherein the second step includes a pushing agitation step of pushing the rotary tool into the metal member to enter a depth that does not reach the joining interface between the metal member and the resin member.   The said 2nd step is further equipped with the pre-heating process which rotates the said rotation tool in the state which contacted only the front-end | tip part of the rotation tool with the surface part of the metal member before an indentation stirring process. Joining method. In the preheating step, the rotary tool is rotated by a first pressurizing time while being pressed with a first pressing force,
10. The method according to claim 9, wherein, 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. Joining method. The second step further comprises an agitation maintaining step of continuing the rotating operation of the rotating tool at a position where the rotating tool has entered to a depth that does not reach the joining boundary surface,
The said stirring maintenance process WHEREIN: The said rotating tool is rotated only for 3rd pressurization time longer than the said 1st pressurization time, pressing with the 3rd pressurization force smaller than the said 1st pressurization force. Joining method.   The said 2nd step is further equipped with the holding process which stops rotation of the said rotation tool after a stirring maintenance process, and hold | maintains the said rotation tool with a predetermined pressurizing force for a predetermined pressurization time in that state. 11. The joining method according to 11.

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