JP7156086B2 - METHOD AND APPARATUS FOR JOINING METAL MEMBER AND RESIN MEMBER - Google Patents

Description

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

Conventionally, there has been a demand for weight reduction 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 led to the use of thinner steel sheets, the use of aluminum alloy materials as substitutes for steel materials, and the use of resin materials. In these fields, the development of technology for joining metal members and resin members is important not only for reducing the weight of automobile bodies, but also for increasing the strength and rigidity of joining members and improving productivity. be. 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. In the friction stir welding method, a metal member and a resin member are superimposed, and while a rotating tool is rotated, the metal member is pressed against the metal member to generate frictional heat. It is a method of joining a metal member and a resin member by pressing.

Until now, as a method of joining a metal member and a resin member, in addition to the friction stir welding method, a resistance heating joining method (electrical heating joining method), an induction heating joining method, an ultrasonic heating joining method, etc. A thermocompression bonding method that involves heating is known.

On the other hand, the Zn-Fe alloy plated steel plate and the aluminum alloy plate are superimposed with an adhesive layer interposed therebetween, and the outer side of the joint (for example, the outer peripheral side) is reduced in viscosity by rotating and pressing the rotating tool. ) is known (Patent Document 1).

JP 2009-113077 A

The inventors of the present invention have found that when a metal member and a resin member are joined by a conventional thermocompression joining method, if a third component such as an adhesive is interposed between the two, the joint strength is higher than that in the case where the third component is not interposed. It has been found that there is a problem that a decrease in

For example, in the friction stir welding method, as shown in FIG. 9A, a metal member 211 and a resin member 212 are superimposed with an adhesive layer 203 interposed therebetween, and a rotating tool 216 is pushed into the metal member 211 . Then, as shown in FIG. 9B, the rotary tool 216 is further pushed in to continue its rotary motion. As a result, the joint strength was greatly reduced compared to the case where the adhesive was not interposed. It is considered that the adhesive from the adhesive layer 203 remains between the metal member 211 and the resin member 212 and interferes with the bonding between the two, resulting in a large decrease in bonding strength.

In other thermo-compression joining methods other than the friction stir joining method, if a metal member and a resin member are overlapped and an adhesive is interposed between the two, the joint strength is increased compared to the case where no adhesive is interposed. dropped significantly.

Therefore, when joining a metal member and a resin member with an adhesive interposed between them by a conventional hot-pressure joining method, the method of joining a Zn-Fe alloy plated steel plate and an aluminum alloy plate of Patent Document 1 Even if the technique of extruding the adhesive layer to the outside of the joint was applied, the joint strength was greatly reduced compared to the case where the adhesive was not interposed.

The present invention provides a method and apparatus for joining a metal member and a resin member, which can sufficiently prevent a decrease in joining strength even when an adhesive is interposed between the metal member and the resin member. intended to provide

The present invention
A metal member and a resin member are superimposed with an adhesive interposed therebetween, and pressure and heat are applied from the metal member side by a pressing member to melt the resin member, thereby joining the metal member and the resin member. A method for joining a metal member and a resin member by a thermocompression joining method for joining the
The metal member, wherein the pressure promotes the movement of the adhesive from a region of the metal member-side surface directly below the pressing member toward the outside in a plan view while the metal member-side surface of the resin member is in a non-melted state. and a method for joining resin members.

INDUSTRIAL APPLICABILITY According to the bonding method of the present invention, even when an adhesive is interposed between a metal member and a resin member in any thermocompression bonding method, it is possible to sufficiently prevent a decrease in bonding strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of a part of a friction stir welding apparatus suitable for the method of joining a metal member and a resin member according to the present invention; FIG. 4 is an enlarged view of the tip of an example of a rotary tool as a pressing member used in the joining method of the present invention; It is a schematic sectional view for demonstrating an example of the superimposition process in 1st step of this invention. FIG. 10 is a schematic cross-sectional view for explaining an example of an adhesive transfer promotion step in the second step of the present invention; It is a schematic sectional drawing for demonstrating an example of the pushing stirring process of this invention, and a stirring maintenance process. It is a schematic sectional drawing for demonstrating an example of the pushing stirring process of this invention, and a stirring maintenance process. It is a schematic diagram for explaining a method of measuring bonding strength in an example. 2 is a photograph of the surface of a resin member when the metal member is forcibly separated from the joined body obtained by the joining method of the present invention, and the surface of the resin member on the metal member side is observed. 10 is a photograph of the surface of the resin member when the metal member is forcibly separated from the joined body obtained by the conventional joining method, and the surface of the resin member on the metal member side is observed. It is a schematic sectional view for demonstrating an example of the superimposition process in the 1st step of a prior art. FIG. 3 is a schematic cross-sectional view for explaining an example of a conventional pushing-stirring process and a stirring-maintaining process.

In the joining method of the present invention, a metal member and a resin member are superimposed with an adhesive interposed therebetween, and pressure is applied to the resin member by pressing from the metal member side with a pressing member, and heat is applied. This is a thermocompression bonding method in which the resin member is softened and melted by heating, and then solidified to join the metal member and the resin member. Heat and pressure are preferably applied locally. The thermocompression bonding method of the present invention is a method of applying heat by a pressing member or another means while applying pressure by a pressing member. The thermocompression bonding method is not particularly limited as long as it is a method that can bond a metal member and a resin member by applying pressure and heat. method, laser heating bonding method, resistance heating bonding method, induction heating bonding method, or the like. A method of locally applying pressure and heat from the metal member side by a pressing member is preferred, and a friction stir welding method is more preferably employed.

As will be described in detail later, the friction stir welding method involves superimposing a metal member and a resin member and pressing the metal member while rotating a rotating tool as a pressing member to generate frictional heat. In this method, the resin member is softened and melted by heat and then solidified to join the metal member and the resin member.

The ultrasonic heating bonding method is a method in which a metal member and a resin member are superimposed, and while the metal member is pressed by the pressing member, the pressing member and the metal member are subjected to ultrasonic vibration by ultrasonic waves (heat imparting means). In this method, the resin member is softened and melted by the heat of friction between the resin member and the metal member caused by vibration, and then solidified to join the metal member and the resin member.

In the laser heating bonding method, a metal member and a resin member are superimposed, and in a state in which they are constrained by pressure with a pressing member, heat is generated by irradiating the metal member with a laser (heat imparting means). In this method, the resin member is softened and melted by heat and then solidified to join the metal member and the resin member. A YAG laser, a fiber laser, a semiconductor laser, or the like is used as the laser.

In the resistance heating bonding method, a metal member and a resin member are superimposed, and in a state in which they are constrained by pressure from a pressing member, heat generated by directly applying an electric current (heat imparting means) to the metal member is utilized. In this method, the metal member and the resin member are joined by softening and melting the resin member and then solidifying the resin member.

The induction heating bonding method is a method in which a metal member and a resin member are superimposed on each other, and in a state in which they are constrained by pressure from a pressing member, an induced current (heat imparting means) is generated in the metal member by an electromagnetic induction action, and the In this method, heat generated by an electric current is used to soften and melt a resin member, which is then solidified to join the metal member and the resin member.

Hereinafter, the joining method of the present invention employing the friction stir welding method will be described in detail with reference to the drawings. It is clear that the effect of the present invention can be obtained even if the method is used. It should be noted that the various elements shown in the drawings are only schematically shown for understanding of the present invention, and that their dimensional ratios, appearances, etc. may differ from the actual ones. The term "vertical direction" used directly or indirectly in this specification corresponds to the vertical direction in the drawings. Also, unless otherwise specified, common reference numerals in these figures indicate the same members, parts, dimensions, or areas.

[Method of Joining Metal Member and Resin Member by Friction Stir Welding Method]
The welding method (friction stir welding method) of the present invention will be specifically described with reference to FIGS. 1 to 6. FIG.

(1) Welding Apparatus First, FIG. 1 is a diagram schematically showing an example of a part of a friction stir welding apparatus suitable for carrying out the welding method of the present invention. A friction stir welding apparatus 1 shown in FIG. 1 is configured as an apparatus for friction stir welding a metal member 11 and a resin member 12, and includes a cylindrical rotating tool 16 as a pressing member.

As shown in the figure, the rotating tool 16 is applied to the work 10, which is superimposed with the metal member 11 on top and the resin member 12 on the bottom, as indicated by an arrow A1 by a driving source (not shown). While rotating about the central axis X (see FIG. 2), it moves downward as indicated by arrow A2. At this time, the rotary tool 16 applies pressure to a pressing region P (to-be-pressed region) on the surface of the metal member 11 . Frictional heat is generated by the pressing of the rotary tool 16, and this frictional heat is transferred to the resin member 12 to soften and melt the resin member 12, and then solidify the molten resin. As a result, the metal member 11 and the resin member 12 are joined together.

FIG. 2 is an enlarged view of the tip of an example of the rotary tool 16. As shown in FIG. In FIG. 2, the right half shows the appearance of the rotating tool 16, and the left half shows a cross section. As shown in FIG. 2, the cylindrical rotary tool 16 has a pin portion 16a at the tip portion (lower end portion in FIG. 2) that contacts the metal member and a shoulder portion 16b that supports the pin portion. The shoulder portion 16b is the tip portion of the rotary tool 16 that includes the circular tip surface of the rotary tool 16 . The pin portion 16a is a columnar portion having a smaller diameter than the shoulder portion 16b and protruding outward (downward in FIG. 2) from the circular tip surface of the rotary tool 16 on the center axis X of the rotary tool 16. be. The pin portion 16a is for positioning the rotating tool 16 when the rotating tool 16 is first brought into contact with the workpiece 10 and pressed.

The material and dimensions of each part of the rotary tool 16 are mainly set according to the type of metal of the metal member 11 to be 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 0.3-0.5 mm. Further, for example, when the metal member 11 is made of steel, the rotating tool 16 is made of silicon nitride, PCBN (cubic boron nitride sintered body) or the like, the diameter D1 of the shoulder portion 16b is 10 mm, and the diameter D2 of the pin portion 16a is 10 mm. is set to 3 mm, and the protruding length h of the pin portion 16a is set to 0.3 to 0.5 mm. However, these are only examples, and needless to say, the present invention is not limited to these.

The rotary tool 16 does not necessarily have to have the pin portion 16a. In the present invention, further promotion of adhesive migration and thereby further reduction of the adhesive present in the melted and solidified regions 60 and 61 (especially the melted and solidified region 60 in the region immediately below the rotating tool), and reduction in bonding strength From the viewpoint of more sufficient prevention, it is preferable that the rotating tool does not have the pin portion 16a. A rotary tool without a pin portion 16a (also called a "flat tool") is, for example, a rotary tool similar to the rotary tool 16 of FIG. 2, except that it has dimensions D2=0 mm and h=0 mm.

Below the rotating tool 16 , a cylindrical receiver 17 having the same diameter as the rotating tool 16 or a larger diameter than the rotating tool 16 is arranged coaxially with the rotating tool 16 . The receiver 17 is moved upward as indicated by an arrow A3 with respect to the workpiece 10 by a drive source (not shown). The upper end surface of the receiver 17 contacts the lower surface of the workpiece 10 (more specifically, the lower surface of the resin member 12) by the time the rotary tool 16 starts pressing the workpiece 10 at the latest. The receiver 17 holds the work 10 between itself and the rotating tool 16, and supports the work 10 from below against the pressing force during the pressing period of the rotating tool 16, that is, during friction stir welding. Note that it is not always necessary to move the receiving tool 17 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 be adopted.

In the friction stir welding apparatus 1, when the metal member side surface of the resin member is in a non-melted state, pressure is applied to the metal member side surface from the region immediately below the pressing member toward the outside (for example, the outer peripheral direction) in plan view. a drive control device (not shown) for controlling the drive, in particular the push drive and/or the rotation drive, preferably the push drive and the rotation drive, of the rotary tool as the push member, so as to facilitate the movement of the . In this specification, the term “planar view” refers to a state when the metal member 11 and the resin member 12 are viewed from above or below along the thickness direction based on the overlapping direction of the metal member 11 and the resin member 12 (upper surface). or bottom view).

The drive control device may adopt a position control method that controls the coordinate position (for example, the amount of entry) of the rotary tool, the speed of movement to that coordinate position, and the number of revolutions, as will be described in detail later, or A pressure control system may be employed that controls the pressure applied to the metal member by the rotary tool, the time for which the pressure is applied, and the number of revolutions.

Although not shown in FIG. 1, the friction stir welding apparatus 1 has a workpiece 10 fixed in advance and a spacer, a clamp, or the like for preventing the metal member 11 from floating when the rotating tool 16 is pressed. Equipped with fixtures.

(2) Joining method According to the joining method of the present invention, the melted and solidified regions 60 and 61 (see FIG. 6; A meshed region 61) is formed, and the melted and solidified regions 60 and 61 contribute to bonding between the metal member 11 and the resin member 12. FIG. A melted and solidified region 60 (hatched region) is a region where the molten resin 120 on the surface of the resin member melted in the region directly below the rotating tool on the joint boundary surface 13 solidifies in the region directly below. The melted and solidified region 61 (dotted line region) is an outer peripheral region (that is, an outer region thereof) of the molten resin 120 on the surface of the resin member that has been melted in the region directly below the rotary tool at the joint boundary surface 13. ) and solidified. In the present invention, bonding is performed such that the amount of adhesive present in such melted and solidified regions 60 and 61 (especially melted and solidified region 60 in the region immediately below the rotating tool) is reduced. Specifically, when the metal member-side surface 121 of the resin member 12 is in a non-melted state, the adhesive is applied from the area 120 directly below the pressing member of the metal member-side surface 121 toward the outside (for example, the outer peripheral direction) in a plan view by pressure. Joining is performed so as to promote the movement of As a result, it is possible to sufficiently prevent a decrease in bonding strength between the resin member and the metal member. In a state where the metal member side surface 121 of the resin member 12 (particularly, the region directly under the pressing member 120) is melted, the pressure causes the metal member side surface 121 of the metal member side surface 121 to move outward from the region directly under the pressing member 120 (for example, in the outer peripheral direction) in a plan view. Even if the bonding is performed so as to promote the movement of the adhesive toward the , it may not be possible to sufficiently prevent the decrease in bonding strength. This is because the adhesive in the melt-solidified regions 60 and 61 (especially the melt-solidified region 60 in the region immediately below the rotary tool) is not sufficiently reduced.

In the present invention, the movement of the adhesive may be promoted only by pressure as described above, but in a more preferred embodiment, the movement of the adhesive is promoted by not only pressure but also a combination of pressure and frictional heat. Further, it can be sufficiently promoted. Frictional heat is the frictional heat that causes the adhesive to be in a particular temperature state when promoting the transfer of the adhesive. Specifically, it is more preferable that the adhesive is at a temperature lower than the melting point of the resin member and higher than the softening point of the adhesive when promoting the movement of the adhesive. Thereby, the movement of the adhesive can be further sufficiently promoted.

Specifically, the method for joining a metal member and a resin member by the friction stir welding method according to the present invention includes at least the following steps:
a first step of overlapping the metal member 11 and the resin member 12; A second step of bonding the metal member 11 and the resin member 12 by softening and melting the resin member 12 with heat:
includes.

In the first step, as shown in FIGS. 1 and 3, the metal member 11 and the resin member 12 are overlaid at a desired joining portion with the adhesive 3 interposed therebetween. FIG. 3 is a schematic cross-sectional view of the XX cross section in FIG. 1 as viewed in the direction of the arrows.

Although the adhesive 3 has fluidity and forms an adhesive layer in FIG. 3 and the like, the present invention does not prevent the fluidity of the adhesive 3 from being lost due to application and drying. In the present invention, from the viewpoint of reducing the amount of adhesive existing in the melted and solidified regions 60 and 61 (especially the melted and solidified region 60 in the region immediately below the rotating tool), when the metal member 11 and the resin member 12 are superimposed, which will be described later, WHEREIN: It is preferable to have fluidity|liquidity.

The adhesive 3 may be applied to the surface of the resin member 12 facing the metal member 11 as long as the adhesive 3 is interposed between the metal member 11 and the resin member 12 when the metal member 11 and the resin member 12 are superimposed on each other. may be applied to the surface facing the resin member 12 in . The adhesive 3 is not formed on the opposing surfaces of the metal member 11 and the resin member 12, and is interposed between the metal member 11 and the resin member 12 in the form of an adhesive sheet independently from these opposing surfaces. You may

The adhesive 3 conventionally includes all adhesives that can contribute to adhesion between the metal member 11 and the resin member 12 . Therefore, the concept of the adhesive 3 includes not only the material used as an adhesive but also the sealing material (or sealant) used for sealing between the metal member 11 and the resin member 12. . Examples of materials constituting the adhesive 3 include thermosetting resins such as epoxy resins, urethane resins, acrylic resins and mixtures thereof, synthetic rubber resins, polyvinyl chloride resins and mixtures thereof. A plastic resin is mentioned.

The softening point of the adhesive 3 is usually 40-10°C, especially 50-80°C.

The thickness k (see FIG. 3) of the adhesive (layer) is usually 0.1 to 2 mm when the metal member 11 and the resin member 12 are superimposed, and the melted and solidified regions 60 and 61 (especially directly below the rotating tool) From the viewpoint of reducing the amount of adhesive present in the melt-solidified region 60) of the region, it is preferably 0.1 to 1.0 mm, more preferably 0.1 to 0.5 mm.

In the second step, the rotary tool 16 is pressed against the metal member 11 to accelerate the movement of the adhesive while the metal member-side surface 121 of the resin member 12 (in particular, the region 120 immediately below the pressing member) is not melted. , the rotation of the rotary tool 16 generates frictional heat, and the frictional heat softens and melts the resin member 12, so that the drive of the rotary tool is controlled. In the second step, as described above, the coordinate position (for example, the amount of entry) of the rotating tool, the speed of movement to the coordinate position, and the position control method for controlling the number of rotations, or the pressing force and pressing time of the rotating tool and a pressure control system that controls the number of revolutions. Hereinafter, the second step employing the position control method will be described as the first embodiment, and the second step employing the pressure control method will be described as the second embodiment.

<First Embodiment: Position Control System>
In the second step of the present embodiment, a movement promoting step C0 for promoting the movement of the adhesive, and a push stirring step for advancing the rotating tool 16 to a depth that does not reach the joining boundary surface 13 between the metal member 11 and the resin member 12 Preferably, at least C2 is performed.

In the second step of the present embodiment, the preheating step C1 in the pressure control method described later may be performed after the movement promoting step C0 and before the pushing stirring step C2, but the position control method is adopted. Therefore, it does not have to be done.

After the pushing-in stirring step C2, a stirring maintaining step C3 is performed as necessary to continue the rotating operation of the rotating tool 16 at the position where the rotating tool 16 entered in the pushing-in stirring step.

These steps in this embodiment will be described in detail below.

(Movement promotion step C0)
In the movement promoting step C0 of this embodiment, as shown in FIG. 4, the rotary tool 16 is pressed against the metal member 11 to promote the movement of the adhesive 3. As shown in FIG. As shown in FIG. 4, the movement of the adhesive means the movement of the adhesive 3 from the region 120 directly below the pressing member on the metal member side surface 121 of the resin member 12 toward the outside thereof (in the direction of the arrow in FIG. 4). is. If the movement of the adhesive is regarded as the discharge of the adhesive from the region 120 directly below the pressing member of the metal member-side surface 121 of the resin member 12, this step can also be referred to as the discharge promotion step of the adhesive. In this embodiment, the movement of the adhesive 3 is promoted while the metal member-side surface 121 of the resin member 12 (particularly, the area 120 immediately below the pressing member) is not melted. In other words, when the metal member-side surface 121 of the resin member 12 (especially the region 120 immediately below the pressing member) is in a non-melted state, the rotary tool 16 is pressed against the metal member 11 to promote the movement of the adhesive 3. . When the metal member-side surface 121 of the resin member 12 (especially the area 120 immediately below the pressing member) is in a molten state, the rotating tool 16 is pressed against the metal member 11 to promote the movement of the adhesive 3. Since the movement is not sufficiently promoted, the amount of adhesive existing in the region 120 immediately below the pressing member is not sufficiently reduced. Therefore, it is not possible to sufficiently prevent a decrease in bonding strength.

From the viewpoint of further improving the bonding strength, it is preferable to promote the movement of the adhesive 3 when the metal member-side surface 121 of the resin member 12 (especially the region 120 immediately below the pressing member) is in a non-softened state.

That the metal member side surface 121 of the resin member 12 (especially the area 120 immediately below the pressing member) is in a non-melted state means that it is in a non-melted state, and the non-melted state is a softened state. and a state that is not even softened (that is, a non-softened state).
Specifically, when the metal member side surface 121 of the resin member 12 (particularly, the region directly below the pressing member 120) is in a non-melting or non-softening state, the surface 121 (especially the region directly below the pressing member 120) of the resin member 12 is ) is a temperature below the melting point or softening point of the resin member (especially the thermoplastic polymer forming the resin member).

Specifically, in the movement promoting step C0 of the present embodiment, the rotation speed, the amount of entry, and the entry speed of the rotating tool are set so that the surface 121 of the resin member 12 on the metal member side (especially the region 120 immediately below the pressing member) is in a non-melting state ( It is determined depending on the thickness of the metal member 11, the type of material, the melting point of the resin member 12, and the like, from the viewpoint of further promoting the movement of the adhesive while maintaining the non-softening state. For example, when using an aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less and a resin member 12 having a melting point of 150 to 190 ° C., the rotation speed, the amount of entry, and the entry speed of the rotary tool are as follows. . In the movement promotion step C0 of this embodiment, the rotary tool may not be rotated (the number of rotations is 0), or may be rotated. Preferably, the rotary tool is rotated so that the temperature of the adhesive is below the melting point of the resin member and above the softening point of the adhesive. When rotating the rotating tool, the rotation speed of the rotating tool is, for example, 4000 rpm or less (especially 10 to 4000 rpm), preferably 10 to 2000 rpm, more preferably 10, from the viewpoint of further promoting the transfer of the adhesive. ~500 rpm. In the movement promoting step C0 of the present embodiment, the amount of penetration of the rotary tool achieved is when the metal member side surface 121 of the resin member 12 (especially the region directly below the pressing member 120) is in a non-melting state (preferably a non-softening state). As long as the movement of the adhesive is accelerated, it is not particularly limited, and the amount of penetration is set to be not 0 mm, and pressure, or pressure and frictional heat within a range that does not cause resin melting, is generated. From the viewpoint of further promoting the movement of the adhesive, the amount of entry of the rotary tool is preferably 0.2×T or less (especially 0.01×T or more and 0.2×T or less), more preferably 0.1×T. or less (especially 0.01×T or more and 0.1×T or less). In this specification, the amount of penetration of the rotary tool is the amount of penetration of the rotary tool, which is the amount of movement of the rotary tool from the contact position between the tip of the rotary tool and the metal surface. The penetration amount of the rotary tool is the amount by which the tip of the pin part enters when the rotary tool has a pin part. If the rotary tool does not have a pin portion, the amount of penetration of the rotary tool is the amount that the shoulder portion 16b has penetrated. In the subsequent steps, the amount of entry of the rotary tool is the total amount of entry at that point in each process, in other words, the cumulative (or cumulative) amount of entry. In the movement promoting step C0 of the present embodiment, the entering speed when the rotating tool enters the metal member 11 is such that the metal member side surface 121 of the resin member 12 (especially the region 120 immediately below the pressing member) is in a non-melting state (preferably There is no particular limitation as long as the adhesive is promoted to move when it is in a non-softened state). The entry speed of the rotary tool is preferably 100 mm/min or less (especially 1 to 100 mm/min), more preferably 50 mm/min or less (especially 1 to 50 mm/min), from the viewpoint of further promoting the movement of the adhesive. . In this step, the number of revolutions, the amount of entry, and the entry speed may be adjusted within the above ranges.

(Preheating step C1)
The preheating step C1 may or may not be performed in this embodiment. When performing the preheating step C<b>1 in this embodiment, the preheating step C<b>1 rotates the rotating tool 16 (for example, the tip portion) while the rotating tool 16 is in contact with the metal member 11 . Thereby, frictional heat is generated between the rotating tool 16 and the metal member 11 . The frictional heat is transmitted to the inside of the metal member 11, and the range of the pressing region P (the pressing region of the rotary tool 16) of the metal member 11 and the range in the vicinity of the pressing region P are preheated. As a result, it becomes easier to push the rotary tool 16 into the metal member 11 in the next push-in agitation step C2.

Specifically, in the preheating step C1 of the present embodiment, the rotation speed, the amount of entry, and the entry speed of the rotary tool are determined from the viewpoint of ease of pushing the rotary tool 16, ease of softening/melting of the resin member 12, and productivity. is determined depending on the thickness of the metal member 11, the type of material, the melting point of the resin member 12, and the like. For example, when using an aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less and a resin member 12 having a melting point of 150 to 190 ° C., from the viewpoint of ease of pushing the rotary tool 16, the rotary tool is moved in the movement promoting step. It is preferable to hold the position of the tool at which it is advanced at a rotation speed of 1000 rpm or more and 4000 rpm or less for a holding time of 5 seconds or less (especially 0.1 to 5 seconds). In this step, the number of revolutions and the holding time may be adjusted within the ranges described above.

(Forcing stirring step C2)
In the pushing-in stirring step C2 of this embodiment, as shown in FIGS. 5 and 6, the rotating tool 16 is rotated at a predetermined number of revolutions and is advanced to a predetermined depth.

5 and 6, the rotary tool 16 is rotated and pushed into the metal member 11 to a depth that does not reach the joint interface between the metal member 11 and the resin member 12. let it enter up to When the rotating tool 16 has entered a predetermined depth, the pressing movement of the rotating tool 16 is stopped. By advancing the rotary tool 16 to the depth, the resin member surface 120 is melted in the region directly below the rotary tool, and the joint boundary surface between the metal member 11 and the resin member 12 is melted in the region 110 directly below the rotary tool of the metal member 11. It moves to the receiving tool side (lower side in the example of the figure), and the directly lower portion 110 is deformed so as to protrude toward the resin member 12 side. As a result, the melting of the molten resin 120 on the surface of the resin member is promoted in the region directly below the rotary tool at the joint boundary surface 13, and the melted resin 120 is spread outward beyond the region directly below (in the direction of the arrows in FIGS. 5 and 6). to) flow. The molten resin spreads out in a substantially circular shape centered on the area immediately below the rotating tool. At this time, the adhesive that has moved outward in the movement promoting step C0 flows further outward together with the melted resin 120 . As a result, the amount of adhesive existing in the region 120 immediately below the pressing member is sufficiently reduced, and a decrease in bonding strength can be sufficiently prevented.

If the rotary tool 16 is further pushed in (that is, if the amount of penetration of the rotary tool exceeds the thickness T of the metal member 11), the shoulder portion 16b of the rotary tool 16 exceeds the joint interface. That is, the rotating tool 16 penetrates the metal member 11 and the outer peripheral portion of the rotating tool 16 contacts the resin member 12 . As a result, the metal member 11 is in a perforated state in which the rotary tool 16 has passed through, which may result in defective joining. preferable.

Specifically, in the pushing-in stirring step C2 of the present embodiment, the rotational speed, the amount of entry, and the entry speed of the rotary tool are set so that the metal member-side surface 121 of the resin member 12 (particularly, the region 120 immediately below the pressing member) is in a molten state. From a viewpoint, it is determined depending on the thickness of the metal member 11, the type of material, the melting point of the resin member 12, and the like. For example, when using an aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less and a resin member 12 having a melting point of 150 to 190 ° C., the rotation speed, the amount of entry, and the entry speed of the rotary tool are as follows. . The rotational speed of the rotating tool is, for example, 2000 rpm or more and 4000 rpm or less. In the pushing and stirring step C2 of the present embodiment, the amount of penetration of the rotary tool achieved is the metal member from the viewpoint of melting of the metal member side surface 121 (especially the region directly below the pressing member 120) of the resin member 12 and further movement of the adhesive. When the thickness of the member is T (mm), it is preferably 0.4 × T to 0.9 × T (mm), more preferably 0.5 × T to 0.9 × T (mm), still more preferably 0.7×T to 0.9×T (mm). In the pushing-in stirring step C2 of the present embodiment, when the rotating tool enters the metal member 11, the entering speed is such that the metal member-side surface 121 of the resin member 12 (especially the region 120 immediately below the pressing member) melts and the adhesive further melts. From the viewpoint of movement, it is preferably 1 mm/min or more. The entry speed of the rotary tool is preferably 1 to 300 mm/min, more preferably 10 to 300 mm/min, and even more preferably 10 to 100 mm/min, from the viewpoint of further promoting the movement of the adhesive. In this step, the number of revolutions, the amount of entry, and the entry speed may be adjusted within the above ranges.

(Stirring maintenance step C3)
In this embodiment, the stirring maintenance step C3 may or may not be performed. When performing the stirring maintenance step C3 in this embodiment, in the stirring maintenance step C3, the rotating tool 16 is moved to the position where the rotating tool 16 was inserted in the pushing stirring step C2 without further pushing the rotating tool 1 into the metal member 11. to continue the rotating motion. As a result, a large amount of frictional heat is generated, and more of the generated frictional heat moves to the resin member 12 . Therefore, the resin member 12 is sufficiently softened and melted over a wide range beyond the range of the region immediately below the pressing region P, and further improvement in bonding strength is achieved.

Specifically, in the agitation maintenance step C3 of this embodiment, the penetration amount of the rotary tool is maintained at the penetration amount achieved in the above-described push-in agitation step C2, so the penetration speed of the rotary tool is 0 mm/sec. In the agitation maintaining step C3 of the present embodiment, the number of revolutions of the rotating tool and the holding time are determined from the viewpoint of sufficient softening and melting of the resin member 12 in a wider range, the thickness of the metal member 11, the type of raw material, and the resin member. 12 melting point, etc. For example, when using an aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less and a resin member 12 having a melting point of 150 to 190° C., the rotation speed and holding time of the rotating tool are as follows. The rotational speed of the rotating tool is, for example, 2000 rpm or more and 4000 rpm or less. In the agitation maintaining step C3 of the present embodiment, the retention time is preferably 1 second or more (especially 1 to 5 seconds) from the viewpoint of melting of the metal member side surface 121 (especially the area 120 immediately below the pressing member) of the resin member 12, More preferably, it is 2 to 5 seconds. A retention time of 0 seconds means that the agitation maintenance step C3 is not performed in this embodiment. In this step, the number of revolutions and the holding time may be adjusted within the ranges described above.

When the stirring maintenance step C3 is performed in the present embodiment, solidification is usually achieved by standing to cool after performing the stirring maintenance step C3.
In the present embodiment, when the agitation maintenance step C3 is not performed, solidification is usually achieved by standing to cool after performing the push-in agitation step C2.

<Second Embodiment: Pressure Control System>
In the second step of the present embodiment, a movement promoting step C0 for promoting the movement of the adhesive, and a push stirring step for advancing the rotating tool 16 to a depth that does not reach the joining boundary surface 13 between the metal member 11 and the resin member 12 Preferably, at least C2 is performed.

In the second step of the present embodiment, a preheating step C1 of rotating the rotating tool 16 while the rotating tool 16 is in contact with the metal member 11 after the movement promoting step C0 and before the pushing stirring step C2. is preferred, but not necessarily required.

After the pushing-in stirring step C2, it is preferable to perform the stirring maintaining step C3 in which the rotating operation of the rotating tool 16 is continued at the position where the rotating tool 16 entered in the pushing-in stirring step C2, but this step must also be performed. It doesn't mean you have to.

These steps in this embodiment will be described in detail below.

(Movement promotion step C0)
The movement promotion step C0 of this embodiment is the same as the movement promotion step C0 of the first embodiment except that the pressure control method is employed as described below. In the movement promoting step C0 of this embodiment, as shown in FIG. 4, the rotary tool 16 is pressed against the metal member 11 to promote the movement of the adhesive 3. As shown in FIG. In the movement promoting step C0 of this embodiment, as in the movement promoting step C0 of the first embodiment, the movement of the adhesive 3 is promoted by the metal member side surface 121 of the resin member 12 (in particular, the region directly below the pressing member 120). It is carried out in a non-melted state, preferably in a non-softened state. When the metal member-side surface 121 of the resin member 12 (especially the area 120 immediately below the pressing member) is in a molten state, the rotating tool 16 is pressed against the metal member 11 to promote the movement of the adhesive 3. Since the movement is not sufficiently promoted, the amount of adhesive existing in the region 120 immediately below the pressing member is not sufficiently reduced. Therefore, it is not possible to sufficiently prevent a decrease in bonding strength. FIG. 4 is a schematic cross-sectional view of the XX cross section in FIG. 1 as viewed in the direction of the arrows.

In the movement promotion step C0 of this embodiment, the rotary tool 16 is pressed against the metal member 11 with a first pressure and a first rotation speed for a first pressure time. The first applied pressure and the first rotational speed in this step are usually the following conditions (1) to It is preferable to satisfy any one of the conditions (3) and to satisfy the condition (3) from the viewpoint of further promoting the transfer of the adhesive.
(1) the first applied pressure is less than the second applied pressure;
(2) the first rotational speed is less than the second rotational speed; or (3) the first applied force is less than the second applied force and the first rotational speed is less than the second rotational speed. is also small.
The first pressurization time may be equivalent to the second pressurization time of the preheating step C1 described later in this embodiment.

Specifically, in the movement promotion step C0 of this embodiment, the number of rotations of the rotating tool (that is, the first number of rotations), the first pressure, and the first pressure time are set to the metal member side of the resin member 12. From the viewpoint of further promoting the movement of the adhesive while keeping the surface 121 (especially the region 120 immediately below the pressing member) in a non-melted state (preferably in a non-softened state), the thickness and material type of the metal member 11 and the melting point of the resin member 12 are selected. etc. For example, when using an aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less and a resin member 12 having a melting point of 150 to 190° C., the first rotation speed of the rotary tool, the first pressure and the first pressure For example, the pressure time is as follows. In the movement promotion step C0 of this embodiment, the rotary tool may not be rotated (rotational speed 0 rpm), or may be rotated. Preferably, the rotary tool is rotated so that the temperature of the adhesive is below the melting point of the resin member and above the softening point of the adhesive. The first rotation speed of the rotary tool is, for example, 4000 rpm or less (including 0 rpm), preferably 10 to 2000 rpm, more preferably 10 rpm or more and less than 500 rpm, from the viewpoint of further promoting the movement of the adhesive. In the movement promoting step C0 of this embodiment, the first pressure is applied when the metal member-side surface 121 of the resin member 12 (especially the region directly below the pressing member 120) is in a non-melting state (preferably a non-softening state). For example, it is 500 N or less (especially 10 to 500 N), preferably 10 to 200 N from the viewpoint of further promoting the movement of the adhesive. In the movement promoting step C0 of this embodiment, the first pressurization time is set when the metal member side surface 121 of the resin member 12 (especially the region directly below the pressing member 120) is in a non-melting state (preferably a non-softening state). It is not particularly limited as long as the movement of the agent is promoted, and is usually 0.5 seconds or more and less than 2.0 seconds, and from the viewpoint of further promoting the movement of the adhesive, preferably 0.5 seconds or more and 1.5 seconds. seconds or less. In this step, the number of revolutions, the pressing force and the pressing time may each be adjusted within the above ranges.

(Preheating step C1)
The preheating step C1 may or may not be performed in this embodiment. When performing the preheating step C<b>1 in this embodiment, the preheating step C<b>1 rotates the rotating tool 16 (for example, the tip portion) while the rotating tool 16 is in contact with the metal member 11 . Thereby, frictional heat is generated between the rotating tool 16 and the metal member 11 . The frictional heat is transmitted to the inside of the metal member 11, and the range of the pressing region P (the pressing region of the rotary tool 16) of the metal member 11 and the range in the vicinity of the pressing region P are preheated. As a result, it becomes easier to push the rotary tool 16 into the metal member 11 in the next push-in agitation step C2.

In this embodiment, the preheating step C1 is the same as the preheating step C1 of the first embodiment, except that the pressure control system is employed as described below.

In the preheating step C1 of this embodiment, the rotary tool 16 is pressed against the metal member 11 with a second pressure and a second rotation speed for a second pressure time. The second applied pressure and the second rotational speed in this step are usually in relation to the first applied pressure and the first rotational speed in the above-described movement promoting step C0 of the present embodiment, and the condition (1) described above From the viewpoint of further promoting the transfer of the adhesive, it is preferable to satisfy any one of the conditions (3) to satisfy the above condition (3).

In the preheating step C1 of this embodiment, frictional heat is generated on the surface portion (upper surface portion in the figure) of the metal member 11 due to the adhesion of the rotary tool 16 to the metal member 11 . The frictional heat is transmitted to the inside of the metal member 11, and the range of the pressing region P (the pressing region of the rotary tool 16) of the metal member 11 and the range in the vicinity of the pressing region P are preheated. This makes it easier to push the rotary tool 16 into the metal member 11 in the next push-in agitation step C2.

Specifically, in the preheating step C1 of the present embodiment, the number of rotations of the rotary tool (that is, the second number of rotations), the second pressure, and the second pressure time are determined according to the thickness of the metal member 11 and the material. It is determined depending on the type, the melting point of the resin member 12, and the like. For example, when using the aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less and the resin member 12 having a melting point of 150 to 190° C., the second rotation speed of the rotary tool, the second pressure and the second pressure For example, the pressure time is as follows. The second rotation speed of the rotary tool is, for example, 2000 rpm or more and 4000 rpm or less, and from the viewpoint of ease of pushing the rotary tool 16, preferably 2500 rpm or more and 3500 rpm or less. In the preheating step C1 of the present embodiment, the second pressure is usually 600 N or more and less than 1300 N, and preferably 800 N or more and 1100 N or less from the viewpoint of ease of pushing the rotary tool 16 in the following push-in stirring step C2. be. In the preheating step C1 of this embodiment, the second pressurization time is usually 0.5 seconds or more and less than 2.0 seconds, and from the viewpoint of ease of pushing the rotary tool 16 in the following pushing-in stirring step C2, It is preferably 0.5 seconds or more and 1.5 seconds or less. In this step, the number of revolutions, the pressing force and the pressing time may each be adjusted within the above ranges.

(Forcing stirring step C2)
In this embodiment, the forced stirring step C2 is the same as the forced stirring step C2 of the first embodiment except that the pressure control system is employed as described below. Also in this embodiment, in the pushing-in stirring step C2, the rotating tool 16 and the receiver 17 are brought close to each other, so that the rotating tool 16 is pushed into the metal member 11 as shown in FIGS. When the forcing stirring step C2 is performed after the preheating step C1, the rotating tool 16 and the receiver 17 are brought closer to each other, so that the rotating tool 16 is attached to the metal member 11 as shown in FIGS. push in. As a result, the rotating tool 16 is advanced to a depth that does not reach the joining interface 13 between the metal member 11 and the resin member 12 . At this time, as shown in FIGS. 5 and 6, it is preferable to deform the metal member 11 directly under the rotating tool 110 so as to protrude toward the resin member 12 side. As a result, the molten resin 120 on the surface of the resin member that is melted in the region directly below the rotary tool is melted and flowed outward from the region directly below (in the direction of the arrow in FIGS. 5 and 6), The adhesive that has moved outward in the movement promoting step C0 can be made to flow further outward. As a result, the amount of adhesive existing in the region 120 immediately below the pressing member is sufficiently reduced, and a decrease in bonding strength can be sufficiently prevented.

Specifically, in the pushing-in stirring step C2 of the present embodiment, the rotating tool 16 is rotated by a predetermined pressure with a third pressure higher than the second pressure for a third pressure time shorter than the second pressure time. Rotate by number.

In this embodiment, in the push-in stirring step C2, the rotating tool 16 is pushed into the metal member 11 by applying a greater pressure than in the preheating step C1. That is, the rotating tool 16 deeply enters the inside of the metal member 11 . Preferably, the pressing of the rotary tool 16 moves the joint boundary surface 13 between the metal member 11 and the resin member 12 toward the receiver 17 (lower side in the figure) at the portion 110 immediately below the rotary tool of the metal member 11 . , the right lower portion 110 is deformed to protrude toward the resin member 12 side. By the main pushing-in stirring step C2 and the stirring maintaining step C3 preferably performed after this, the melting of the molten resin 120 on the surface of the resin member that is melted in the area directly below the rotary tool on the joint boundary surface 13 is promoted, and the area directly below is accelerated. and flows to its outer region (in the direction of the arrow in FIG. 5). The molten resin spreads in a substantially circular shape centering on the region immediately below the rotating tool, and can cause the adhesive that has moved outward in the movement promoting step C0 to flow further outward.

If the rotary tool 16 is pushed further (ie too high pressure and/or too long time), the shoulder 16b of the rotary tool 16 will exceed the joint interface. That is, the rotating tool 16 penetrates the metal member 11 and the outer peripheral portion of the rotating tool 16 contacts the resin member 12 . As a result, the metal member 11 has a hole through which the rotary tool 16 has passed, resulting in poor bonding.

Therefore, in this push-in agitation step C2, the push-in of the rotary tool 16 is stopped when the shoulder portion 16b of the rotary tool 16 has entered 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 maintenance step C3, frictional heat is generated at the reference position near the resin member 12, a large amount of frictional heat is transmitted to the resin member 12, and softening and melting of the resin member 12 are accelerated.

Specifically, in the forcing stirring step C2 of the present embodiment, the number of rotations of the rotary tool (that is, the third number of rotations), the third pressure, and the third pressure time are determined by the thickness and material of the metal member 11. and the melting point of the resin member 12 and the like. For example, when using an aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less and a resin member 12 having a melting point of 150 to 190° C., the third rotation speed of the rotary tool, the third pressure and the third pressure For example, the pressure time is as follows. The third rotation speed of the rotary tool is, for example, 2000 rpm or more and 4000 rpm or less, and preferably 2500 rpm or more and 3500 rpm or less from the viewpoint of ease of pushing the rotary tool 16 . In the pushing and stirring step C2 of this embodiment, the third pressure is usually 1300 N or more and less than 2200 N, and preferably 1400 N or more and 2000 N or less from the viewpoint of ease of pushing the rotary tool 16. In the pushing and stirring step C2 of the present embodiment, the third pressurizing time is usually 0.1 seconds or more and less than 0.5 seconds, and from the viewpoint of ease of pushing the rotary tool 16, preferably 0.1 seconds or more. 0.4 seconds or less. In this step, the number of revolutions, the pressing force and the pressing time may each be adjusted within the above ranges.

(Stirring maintenance step C3)
In this embodiment, the agitation maintenance step C3 is the same as the agitation maintenance step C3 of the first embodiment, except that the pressure control method is employed as described below. Also in the present embodiment, in the agitation maintaining step C3, the rotating tool 16 and the receiver 17 are stopped from approaching each other, so that the position (this is referred to as the "reference position") is advanced to a depth that does not reach the joint boundary surface 13. ) to continue the rotating operation of the rotating tool 16 . In the agitation maintaining step C3, the rotary tool 16 is applied with a fourth pressure lower than the second pressure (for example, less than 600 N) for a fourth pressure time longer than the second pressure time (for example, 2.0 N). 75 to 6.75 seconds) at a predetermined number of revolutions (eg, 3000 rpm).

Specifically, in the agitation maintaining step C3 of this embodiment, the rotary tool is pressed with a fourth pressure that is smaller than the second pressure and is greater than or equal to the first pressure, while the second pressure is longer than the second pressure. Rotate for the pressurization time of 4. By making the applied pressure (i.e., the fourth applied pressure) in the main stirring maintenance step C3 smaller than the applied pressure (i.e., the second applied pressure) in the preheating step C1 (of course, by making it smaller than in the push-in stirring step C2). , the rotary tool 16 is maintained substantially at the reference position. Since the rotary tool 16 continues to rotate at the reference position near the resin member 12 , a large amount of frictional heat is generated and most of the generated frictional heat is transferred to the resin member 12 . Therefore, the resin member 12 is sufficiently softened and melted over a wide range beyond the range of the region immediately below the pressing region P. In the main agitation maintaining step C3, the applied pressure (that is, the fourth applied pressure) is usually equal to or higher than the applied pressure (that is, the first applied pressure) in the movement promoting step C0.

Specifically, in the agitation maintaining step C3 of the present embodiment, the number of rotations of the rotating tool (that is, the fourth number of rotations), the fourth pressure, and the fourth pressure time are set according to the thickness and material of the metal member 11. and the melting point of the resin member 12 and the like. For example, when using the aluminum alloy metal member 11 having a thickness of 1 mm or more and 2 mm or less and the resin member 12 having a melting point of 150 to 190° C., the fourth rotation speed of the rotary tool, the fourth pressure and the fourth pressure For example, the pressure time is as follows. The fourth rotation speed of the rotary tool is, for example, 2000 rpm or more and 4000 rpm or less, and from the viewpoint of melting the resin member 12, preferably 2500 rpm or more and 3500 rpm or less. In the stirring maintaining step C3 of this embodiment, the fourth pressure is usually less than 600N (especially 100N or more and less than 600N), preferably 200N or more and 500N or less from the viewpoint of melting of the resin member 12. In the stirring maintaining step C3 of this embodiment, the fourth pressurization time is usually 2.0 seconds or more and less than 8.5 seconds, and from the viewpoint of melting the resin member 12, preferably 2.0 seconds or more8. 0 seconds or less. In this step, the number of revolutions, the pressing force and the pressing time may each be adjusted within the above ranges.

Also in this embodiment, when performing the stirring maintenance process C3, after performing the stirring maintenance process C3, solidification is normally achieved by standing-to-cool.
In the present embodiment, when the agitation maintenance step C3 is not performed, solidification is usually achieved by standing to cool after performing the push-in agitation step C2.

In this embodiment (pressure control system), the applied pressure in each step preferably has the following relationship.
1st applied pressure (movement promotion step) ≤ 4th applied pressure (stirring maintenance step) < 2nd applied pressure (preheating step) < 3rd applied pressure (push-stirring step)

(3) Metal member The metal member 11 used in the present invention has a substantially flat plate shape as an overall shape in FIG. It may have any shape as long as the portion has a substantially flat plate shape. Both surfaces of the portion of the metal member 11 that overlaps the resin member 12 are generally flat.

The thickness T (thickness before joining treatment; see FIG. 3) of the substantially flat plate-shaped portion of the metal member 11 that overlaps the resin member 12 is usually 0.5 to 4 mm, but is not limited to this.

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

Preferred metals for forming metal member 11 are aluminum and aluminum alloys.

(4) Resin Member The resin member 12 used in the present invention contains a thermoplastic polymer and may further contain reinforcing fibers.

As the thermoplastic polymer forming the resin member 12, any thermoplastic polymer can be used. Among them, 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 acid-modified products thereof;
polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and 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);
acrylonitrile-butadiene-styrene copolymer resin (ABS);
polyphenylene sulfide (PPS);
Polyamide resins (PA) such as PA6, PA66, PA11, PA12, PA6T, PA9T and MXD6;
Polycarbonate resin (PC);
polyurethane resin;
fluoropolymer resins; and liquid crystal polymers (LCPs).

As the thermoplastic polymer forming the resin member 12, a polyolefin resin, particularly polypropylene, is preferably used because it is inexpensive and has excellent mechanical properties.

The molecular weight of the thermoplastic polymer is not particularly limited. .

In this specification, the value measured by JIS K 7210 is used for the MFR of the polymer.

Although the resin member 12 has a substantially flat plate shape as an overall shape in FIG. 1 and the like, it is not limited to this. The portion may have any shape as long as it has a substantially flat plate shape. Both surfaces of the portion of the resin member 12 immediately below the metal member 11 are generally flat.

The thickness t of the portion of the resin member 12 immediately below the metal member 11 (thickness before bonding; see FIG. 3) is usually 2 to 10 mm, particularly 2 to 5 mm, but is not limited to this.

The type of reinforcing fiber that may be contained in the resin member 12 is not particularly limited, and examples thereof include carbon fiber and glass fiber. In the field of polymer-containing composite materials, reinforcing fibers are fibers that are uniformly contained and dispersed in a polymer to improve strength, and are generally divided into continuous fibers and discontinuous fibers. In , the reinforcing fiber may be any fiber.

The content of reinforcing fibers is usually 1% by weight or more, particularly 10 to 50% by weight, preferably 20 to 50% by weight, more preferably 30 to 50% by weight, based on the total weight of the resin member.

The resin member 12 may further contain additives other than reinforcing fibers, such as stabilizers, flame retardants, coloring agents, and foaming agents.

The resin member 12 can be manufactured by subjecting a mixture containing a thermoplastic polymer, reinforcing fibers, and desired additives to a molding method such as an injection molding method or a press molding method.

The melting point Tm of the resin member 12 varies depending on the type of the resin member 12, and is usually 130-350.degree. C., particularly 150-200.degree. The melting point Tm of the resin member 12 may be the melting point of the thermoplastic polymer forming the resin member 12 .
As the melting point Tm of the resin member 12, a value measured according to JIS7121 is used.

[Resin member]
A resin member 12 having dimensions of 100 mm long, 30 mm wide and 3 mm thick was manufactured by an injection molding method using polypropylene pellets (PP-CF40-11; manufactured by Daicel Polymer Ltd.) containing 40% by weight of carbon fiber. The carbon fibers in the resin member had an average fiber length of 3 mm and an average fiber diameter of 7 μm. The melting point Tm of the resin member was 170°C. The carbon fibers were randomly oriented in the resin member.

[Metal member]
As the metal member, a plate-like member (100 mm long×30 mm wide×1.2 mm thick) made of a 6000 series aluminum alloy was used.

[Rotation tool]
A rotary tool without a pin portion 16a, specifically, a rotary tool 16 (made of tool steel) having dimensions of D1=10 mm, D2=0 mm and h=0 mm in FIG. 2 was used.

[Embodiment A1] (position control method)
A joined body of the metal member 11 and the resin member 12 was manufactured by the following method.
First step:
An end portion of the metal member 11 and an end portion of the resin member 12 were overlapped with an adhesive 3 interposed therebetween as shown in FIGS. 1 and 3 . At this time, the thickness of the adhesive (layer) 3 was 0.3 mm. As the adhesive 3, an epoxy heat-curable adhesive (curing temperature: about 150° C., maximum softening point: 50° C.) was used.

Second step:
First, the metal member 11 was pressed by the rotary tool 16 to perform the movement promoting step C0 of the adhesive 3 . Specifically, as shown in FIG. 4, the metal member 11 is pressed by the rotating tool 16, and the metal member-side surface 121 of the resin member 12 is pushed outward from the region 120 immediately below the pressing member (in the direction of the arrow in FIG. 4). ) promoted the migration of the adhesive 3; The metal member side surface 121 was in a non-softened state. Movement acceleration step C0: entry amount 0.1 mm, entry speed 30 mm/sec, tool rotation speed 100 rpm.

Next, without performing the preheating step C1, as shown in FIGS. 5 and 6, the rotary tool 16 is pushed into the metal member 11 to a depth that does not reach the bonding interface 13 between the metal member 11 and the resin member 12. let me At this time, the molten resin 120 on the surface of the resin member melted in the region directly below the rotating tool flowed outward from the region 120 directly below the pressing member (in the direction of the arrow in FIGS. 5 and 6) together with the adhesive. . Push-in stirring step C2: Intrusion amount 1.8 mm, intrusion speed 30 mm/sec, tool rotation speed 3000 rpm.
After that, the rotating tool 16 was separated from the metal member 11 and left to cool, thereby obtaining a joined body.

[Examples A2 to A4 and Comparative Examples A1 to A4]
A resin member and a metal member were joined by the same method as in Example A1, except that the joining conditions were changed as shown in Table 1.

[Joint strength S]
As shown in FIG. 7, a joined body of the metal member 11 and the resin member 12 was arranged in the jig 100 . The jig 100 is constructed so that a downward force acts on the upper end portion of the resin member 12 when the jig 100 is pulled downward. By fixing the jig 100 and pulling the metal member 11 upward, a downward force acts on the upper end of the resin member 12, and shear tension is applied to the joint without being affected by the strength of the base material of the resin member 12. Strength S was measured. The bonding strength (shear tensile strength) was measured within 10 minutes after the bonding operation in each example/comparative example was completed. Although a heat-curable adhesive is used in this example/comparative example, heating during bonding does not lead to curing of the adhesive. Also, even when using a room-temperature curing adhesive, the bonding strength before curing of the adhesive can be measured by this test method. Therefore, the effect of the intervening adhesive on the joint strength is based only on its adverse effect. However, in any of the examples, the bonding strength measured after the adhesive is sufficiently hardened by additional heat or left at room temperature exhibits the bonding strength due to the adhesive discharged outside the melted and solidified region 61. The value was greater than the bond strength before curing, and as a result, the value was greater than the bond strength when no adhesive was interposed. These results demonstrate that the present invention is effective against the adverse effects of the adhesive on bonding when the adhesive is not sufficiently cured, which is a major problem when using the adhesive in combination with other bonding methods. is clear.

In Table 1, at first glance, among the examples, there are examples in which the bonding strength is lower than that of the comparative examples. However, the example should be compared to the comparative example, which has a similar step time for the forced agitation step C2. That is, Examples A1 and A3 should be compared to Comparative Example A1, and Examples A2 and A4 should be compared to Comparative Example A2. Therefore, the bonding strengths of Examples A1 and A3 are shown as a ratio (rate of increase) to the bonding strength of Comparative Example A1. The bonding strength S of Examples A2 and A4 is shown as a ratio (rate of increase) to the bonding strength of Comparative Example A2. These rates of increase were evaluated.
◎: 140% or more (best);
○: 130% or more and less than 140% (good);
△: 110% or more and less than 130% (pass);
x: Less than 110% (failed).

FIG. 8A shows a photograph of the surface of the resin member when the metal member was forcibly separated from the joined body obtained in Example A1 and the surface of the resin member on the metal member side was observed.
FIG. 8B shows a photograph of the surface of the resin member when the metal member was forcibly separated from the joined body obtained in Comparative Example A1 and the surface of the resin member on the metal member side was observed.
In FIGS. 8A and 8B, the central white discoloration area (resin cohesion failure area) is the bonding area A, and the outer peripheral area where white discoloration does not occur in the resin melting range is where the adhesive component remains and the bonding strength is is the region B where is low. From FIGS. 8A and 8B, it can be confirmed that the range of region B is reduced and the range of region A is expanded by the bonding method of the present invention.

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

1: Friction Stir Welding Apparatus 10: Workpiece 11: Metal Member 12: Resin Member 13: Joint Boundary Surface between Metal Member and Resin Member 16: Rotating Tool 17: Receiver 100: Jig for Measuring Joint Strength 110: Immediately below the rotating tool of the metal member P: Pressing area (planned pressing area)
120: Surface layer portion of resin member directly below rotating tool 121: Metal member side surface of resin member

Claims (15)

A metal member and a resin member are superimposed with an adhesive interposed therebetween, and pressure and heat are applied from the metal member side by a pressing member to melt the resin member, thereby joining the metal member and the resin member. A method for joining a metal member and a resin member by a thermocompression joining method for joining the
The metal member, wherein the pressure promotes the movement of the adhesive from a region of the metal member-side surface directly below the pressing member toward the outside in a plan view while the metal member-side surface of the resin member is in a non-melted state. and a method of joining with a resin member. 2. The method of joining a metal member and a resin member according to claim 1, wherein the pressure promotes movement of the adhesive while the metal member-side surface of the resin member is in a non-softened state. 3. The metal member and resin according to claim 1, wherein the adhesive is at a temperature below the melting point of the resin member and above the softening point of the adhesive when promoting the movement of the adhesive. The method of joining with the member. After promoting the movement of the adhesive, the resin member is melted by the pressure and the heat, and the melted resin flows outward from the region immediately below the pressing member in plan view together with the adhesive. The method for joining a metal member and a resin member according to any one of claims 1 to 3, wherein the metal member and the resin member are joined. The thermocompression bonding method is
A first step of superimposing a metal member and a resin member with an adhesive interposed therebetween; A friction stir welding method according to any one of claims 1 to 4, comprising a second step of generating frictional heat by rotating the rotary tool, softening and melting the resin member by the frictional heat, and joining the metal member and the resin member. A method for joining a metal member and a resin member according to any one of the above. Adopting a position control method in the second step,
The second step is
a movement promoting step of pressing the rotating tool against the metal member to promote movement of the adhesive; 6. The method for joining a metal member and a resin member according to claim 5, comprising a step of pushing and stirring the metal member and the resin member to a depth not reached. In the movement promoting step, the rotating tool is pressed against the metal member with an amount of penetration of 0.2 × T or less and a rotation speed of 4000 rpm or less, where T is the thickness of the metal member;
In the pushing stirring step, the rotary tool is rotated at a speed of 2000 to 4000 rpm and 1 to 300 mm / min to an amount of penetration of 0.4 × T to 0.9 × T, where T is the thickness of the metal member. 7. The method of joining a metal member and a resin member according to claim 6, wherein the metal member is caused to enter at an approach speed. In the second step, after the movement promoting step and before the pushing stirring step,
further comprising a preheating step of rotating the rotating tool while the rotating tool is in contact with the metal member;
8. The metal member and resin according to claim 7, wherein in the preheating step, the rotating tool is held at the tool position where it was entered in the movement promoting step at a holding time of 5 seconds or less at a rotation speed of 1000 rpm or more and 4000 rpm or less. The method of joining with the member. The second step further comprises:
a stirring maintaining step of continuing the rotating operation of the rotating tool at the position where the rotating tool entered in the pushing stirring step;
including
The rotating tool according to any one of claims 6 to 8, wherein in the stirring maintaining step, the rotary tool is held at a rotation speed of 2000 to 4000 rpm at the position where it was entered in the pushing stirring step for a holding time of 1 second or more. A method of joining a metal member and a resin member. Adopting a pressure control method in the second step,
The second step is
a movement promoting step of pressing the rotating tool against the metal member to promote movement of the adhesive;
a preheating step of rotating the rotating tool while the rotating tool is in contact with the metal member;
A pushing and stirring step in which the rotating tool is pushed into the metal member and penetrates to a depth that does not reach the joint boundary surface between the metallic member and the resin member; 6. The method for joining a metal member and a resin member according to claim 5, comprising a stirring maintenance step of continuing the rotating motion. In the movement promoting step, the rotary tool is pressed against the metal member with a first pressure and a first rotation speed,
In the preheating step, the rotary tool is pressed against the metal member at a second pressure and a second rotation speed for a second pressure time,
The first applied pressure, the first rotation speed, the second applied pressure and the second rotation speed satisfy any one of the following conditions (1) to (3),
In the pushing-in stirring step, the rotary tool is pressed with a third pressure greater than the second pressure and rotated for a third pressure time shorter than the second pressure time,
In the stirring maintaining step, the rotating tool is pressed with a fourth pressure that is less than the second pressure and is greater than or equal to the first pressure, and a fourth pressure that is longer than the second pressure is applied. The method for joining a metal member and a resin member according to claim 10, wherein the rotation is for a period of time:
(1) the first applied pressure is less than the second applied pressure;
(2) the first rotational speed is less than the second rotational speed; or (3) the first applied force is less than the second applied force and the first rotational speed is less than the second rotational speed. is also small. In the movement promoting step, the first pressure is adjusted within a range of 500 N or less,
In the preheating step, the second pressure is adjusted in the range of 600 N or more and less than 1300 N,
In the pushing stirring step, the third pressure is adjusted in the range of 1300 N or more and less than 2200 N,
12. The method for joining a metal member and a resin member according to claim 11, wherein the fourth pressure is adjusted within a range of less than 600N in the stirring and maintaining step. In the movement promoting step, the rotation speed of the rotating tool is adjusted within a range of 4000 rpm or less,
Joining a metal member and a resin member according to claim 12, wherein in the preheating step, the indentation stirring step, and the stirring maintaining step, the rotation speed of the rotating tool is adjusted independently in the range of 2000 rpm or more and 4000 rpm or less. Method. The method for joining a metal member and a resin member according to any one of claims 1 to 13, wherein the metal member has a thickness T of 0.5 to 4 mm. the metal member is made of aluminum or an aluminum alloy,
The method for joining a metal member and a resin member according to any one of claims 1 to 14, wherein the resin member has a melting point Tm of 130 to 350°C.

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