JP3463671B2 - Joining method and apparatus using friction stirring - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining method and apparatus for melting and agitating metal members such as castings and plate materials by friction.

[0002]

2. Description of the Related Art In the conventional joining technique, a plate material and a metal member which has been press-formed into a three-dimensional shape are superposed and joined by electric resistance welding, arc welding, adhesive, bolt fastening, rivet or the like.

When the metal member has a complicated three-dimensional shape, spot welding is used which can locally join a plurality of jointed portions.

As another joining technique, a joining method of friction stirring in a non-melted state is disclosed in Japanese Patent No. 2712838. In this joining technique, a protrusion called a probe is inserted and translated on a joint surface where two members are butted against each other while rotating, and a metal structure near the joint surface is plasticized by frictional heat to be joined.

Further, Japanese Unexamined Patent Publication Nos. 10-183316 and 2000-15426 disclose a rotary tool having a protrusion at a tip shoulder portion in surface treatment of a casting such as a mating surface of a cylinder head with a cylinder block. A surface treatment method is disclosed in which the material is press-fitted while rotating and stirred by heat in a non-molten state.

[0006]

In the friction stir welding in the non-melted state, if the tool rotation speed, the tool pushing amount, the tool advancing speed, etc. are excessively increased, the welding may be incomplete, or the welded portion may not be welded. Melts. Therefore, there is a limit to the reduction of processing time.

The present invention has been made in view of the above problems, and an object thereof is to provide a welding method and apparatus using friction stirrer, which can reduce the welding time by eliminating the need for the electric current required for welding as compared with the conventional welding. It is to be.

[0008]

In order to solve the above-mentioned problems and to achieve the object, a joining method using friction stirrer according to the present invention has a first tool part and an area smaller than the first tool part. And rotating a rotating tool including a second tool portion protruding from the tip end portion of the first tool portion, and locally agitating and joining the joining portion where the first member and the second member are overlapped to each other. In the joining method using the friction stirrer described above,
Placed facing the rotating tool so that it is sandwiched between
And the first tool is attached to the tip portion facing the rotary tool.
Tool with a receiving surface smaller than the cross-sectional area of the section
Is set so that the separation distance from the rotary tool is variable.
First, the first and second overlapping parts on the receiving surface of the fixing tool.
And a second member, the rotary tool is pressed against the first member and the second member from the second tool portion while the rotary tool is rotated, and the rotary tool is press-fitted. by rotating in the inside member, said cutting members surrounding the rotary tool, Rutotomoni melted and stirred by friction within the member by the cutting by said member first tool portion and second tool portion , The melting
The first part and the second member are joined together by plastically flowing the peripheral part of the region to be made , and after the joining is completed, the rotary tool is retracted from the member in a rotated state. Also good
More preferably, the receiving surface of the fixed tool is the rotary tool.
The second tool portion is formed to have substantially the same area as the tip portion.

[0009]

Further , the joining method using the friction stirring of the present invention
Is the area smaller than the first tool part and this first tool part
And the second tool protruding from the tip of the first tool part
And rotating the rotary tool including the first portion and the second member.
The joint portion where the members are overlapped is locally agitated by friction.
In a joining method using friction stirring to stir and join,
The overlapping first and second members with the rotating tool
It is placed facing the rotary tool so that it is sandwiched between
At the tip facing the rotary tool, disconnect the first tool part.
Has a receiving surface smaller than the area, and
The taper shape that the cross-sectional area increases toward the counter-rotating tool side
The fixed tool with the enlarged diameter part formed on the
And the fixed tool
The receiving surface of the base for receiving the first and second members
In the state where the rotary tool is rotated, the first member
And the rotating tool with respect to the second member, the second tool
Portion, press-fitted, and the rotary tool was press-fitted
By rotating inside the member, the circumference of the rotating tool
The first tool part and the second tool part
The first member and the second member are joined by stirring by friction
Then, after the joining is completed, the rotating tool is rotated.
To retract from the member. Also, preferably, the solid
The area of the receiving surface of the constant tool is the first tool of the rotary tool.
The cross-section area is approximately equal to or less than
It

Further, the joining apparatus using friction stirring of the present invention comprises a first tool portion and a second tool portion which has an area smaller than that of the first tool portion and which projects from the tip of the first tool portion. Rotate the rotating tool provided to rotate the first member and the second member.
In a welding device using friction stirring, which locally stirs and joins a joined portion where members are superposed,
An area smaller than the cross-sectional area of the first tool portion is disposed so as to face the rotary tool so as to sandwich the first and second members that are overlapped with each other with the rotary tool, and the tip end portion that faces the rotary tool. A fixed tool provided with a receiving surface of the fixed tool and having a variable separation distance from the rotary tool, and the first and second members superposed on the receiving surface of the fixed tool, the rotary tool By rotating the rotating tool against the first member and the second member from the second tool portion by press-fitting, and rotating the rotating tool in the press-fitted member, A member around the rotary tool is cut, and the cut member is agitated and melted by friction inside the member by the first tool part and the second tool part, and the peripheral part of the melted region is By sex flow, and bonding the first member and the second member, after said bonding ends, and a tool control means to retract from the member while rotating the rotary tool. Further, preferably, the receiving surface of the fixed tool is formed to have substantially the same area as the tip portion of the second tool portion of the rotary tool. Further, the welding device using friction stirring of the present invention includes a first tool part and a second tool part which has an area smaller than that of the first tool part and which projects from the tip part of the first tool part.
In a welding device using friction stirring, in which a rotating tool including a tool portion is rotated to locally stir and join a joining portion where the first member and the second member are superposed, the joining is performed. The first and second members are sandwiched between the rotary tool and are arranged so as to face the rotary tool, and a receiving surface having an area smaller than the cross-sectional area of the first tool portion is provided at the tip end facing the rotary tool. A fixed tool that has a tapered diameter-expanded portion that has a cross-sectional area that increases from the receiving surface toward the counter-rotating tool side and that has a variable separation distance from the rotating tool. When,
The second tool unit receives the rotating tool with respect to the first member and the second member in a state where the rotating tool is rotated by receiving the superimposed first and second members on the receiving surface of the fixed tool. The first tool part and the second tool part by friction to stir the members around the rotary tool by rotating the rotary tool in the press-fitted member. And a tool control unit that joins the member and the second member, and retracts the rotary tool from the member after the joining is completed. Further, preferably, the area of the receiving surface of the fixed tool is set to be substantially equal to or smaller than the cross-sectional area of the first tool portion of the rotary tool.

[0012]

As described above, according to the present invention, the first member and the second member are received while the rotating tool is rotated by receiving the first and second members which are superposed on the receiving surface of the fixed tool.
The rotary tool is pressed against the member from the second tool section and press-fitted, and the rotary tool is rotated within the press-fitted member to cut the member around the rotary tool, and the cut member is cut into the first tool section. In addition, the second tool portion stirs and melts the inside of the member by friction, and the peripheral portion of the region to be melted is plastically fluidized to join the first member and the second member. As a result, the current required for welding becomes unnecessary, and the joining time can be shortened. Particularly, according to the inventions of claims 1, 2, 5 and 6 , the receiving surface of the fixed tool is made smaller than the cross-sectional area of the first tool portion of the rotary tool, so that the heat dissipation of the joint portion is suppressed and the heat storage efficiency is improved. It can be increased to easily generate a molten state.

[0013]

According to the second and fourth aspects of the present invention, the first and second members are arranged so as to be sandwiched by the rotary tool so as to face the rotary tool, and the distance from the rotary tool is variable. Since the fixed tool is provided and the tip of the fixed tool facing the rotary tool is formed in substantially the same area as the tip of the second tool section of the rotary tool, heat dissipation at the joint is suppressed and the joint time is shortened. The joint strength can be increased.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The embodiments described below are merely examples of means for realizing the present invention, and the present invention can be applied to modifications or variations of the following embodiments without departing from the spirit of the present invention. . [Joining Method by Friction Stirring] FIG. 1 is a conceptual diagram for explaining a joining method by friction stirring according to an embodiment of the present invention.

As shown in FIG. 1, the joining method exemplified in this embodiment is applied to joining plate-shaped members such as aluminum alloys, and at least two members are superposed to form an outermost surface. The first and second members W that are superposed on each other by pressurizing and pressing the rotary tool 1 into the first member W1 while rotating (swirling) around its axis.
The member structure between 1 and W2 is melted and agitated by frictional heat to join.

The first and second members W1 and W2 are arranged so as to sandwich the rotary tool 1 so as to face the rotary tool 1, and the fixed tool 10 has a variable separation distance from the rotary tool 1. Is provided.

The rotary tool 1 is a non-wear type tool formed of a steel material (such as cemented carbide) having a hardness higher than that of the member.
The member is not limited to the aluminum alloy as long as it is softer than the rotary tool 1. The fixed tool 10 is formed of, for example, a steel material or a copper material.

More specifically, the rotary tool 1 has a first tip at its tip.
The protruding portion 3 is provided so as to protrude from the shoulder portion 2, and the rotating tool 1 is rotated at a set rotation speed so that the rotating tool 1 and the fixed tool 10 sandwich the first and second members W1 and W2. 2 with a predetermined pressing force to the first and second members W
1, W2 is press-fitted, and the protrusion 3 is rotated inside these members to cut the member structure of the peripheral portion thereof to generate heat. Further, the facet cut by the protrusion 3 is retained inside the member by both tools 1 and 10 and agitated to collide with the surrounding member tissue and the protrusion 3 to generate heat, and the first shoulder portion 2 is also heated. A unit area is maintained by holding a given pressing force and rotational speed for a certain period of time while promoting heat generation by press-fitting with a predetermined pressing force and rotating to melt the facet, and promoting plastic flow of the member structure around the facet. The pressing force per hit is increased to increase the plastic flow volume, and the rotary tool 1 is pulled out from the member while being rotated, so that the member tissues that have plastically flowed are cooled and joined.

Further, by continuously performing this joining process, the member structure adhered to the peripheral portion of the projecting portion 3 in the previous cycle is melted and supplied as a material by stirring in the next cycle.

At this time, the area of the receiving surface 11 of the fixed tool 10 is reduced to increase the pressing force, while suppressing the heat radiation to the fixed tool 10 and increasing the plastic flow volume to increase the coupling force of the members. .

The joining method of the present embodiment is a lap joint (for example, an outer panel of a rear door and a reinforcement) of an automobile steel plate or the like which is press-formed in advance into a three-dimensional shape.
Suitable for local joining of. That is, for members having a complicated three-dimensional shape formed by press molding and a plurality of spliced joints where the rotary tool 1 cannot be continuously moved,
By using the joining method of the present embodiment, it is possible to join locally, and it is possible to join even after press molding.

According to this joining method, welding current, cooling water, air, etc., which have been used in the conventional spot welding, are completely unnecessary, and energy consumption required for joining can be greatly reduced. Further, since the above-mentioned device or equipment as an energy source is unnecessary, it is possible to significantly reduce the capital investment.

Further, the conventional welding gun used for spot welding can be diverted, and it is possible to easily achieve the ability equal to or higher than the conventional one with respect to the restriction of the joining member, the joining strength and the production efficiency.

FIG. 2 is a conceptual diagram for explaining a conventional non-melting joining method by friction stirring.

In the conventional joining method shown in FIG. 2, the first and second members W1 and W2 are arranged so as to be sandwiched between the rotary tool 1 and the fixed tool 10 ', and the rotary tool is attached to the first member W1 on the outermost surface. The procedure for pressurizing and pressurizing 1 while rotating it about its axis is the same as that of the present invention, but the member structure between the superposed first and second members W1 and W2 is not melted by frictional heat. They are different in that they are agitated and joined together.

Here, the state of non-melting and stirring means that the metal structure is softened by frictional heat at a temperature lower than the lowest melting point among the components or eutectic compounds contained in the base material. Means to stir.

In the conventional joining method, since stirring is performed without melting, there is an advantage that problems such as thermal distortion generated by electric resistance welding and the like can be solved.

On the other hand, the rotational speed and the pressing force of the rotary tool 1 cannot be increased undesirably due to frictional stirring without melting, and the area of the receiving surface 11 'of the fixed tool 10' which abuts the second member W2. Is larger than the area of the projecting portion 3 projecting from the tip of the rotary tool 1, the pressing force is dispersed over the entire receiving surface 11 ′, and the frictional heat due to the rotation of the rotary tool 1 is generated on the receiving surface 11 ′. There is a demerit that it takes time (for example, 2 to 3 seconds) for joining due to heat being radiated over the entire surface.

On the other hand, according to the present invention, it is possible to increase the number of rotations and the pressing force of the rotary tool 1 for frictional stirring in the molten state, and further to rotate at least the receiving surface 11 of the fixed tool 10. It is formed to be smaller than the cross-sectional area of the projecting portion 3 of the tool 1 to suppress heat dissipation and enhance the heat storage efficiency inside the member, which promotes melting of the facets and plastic flow and the time required for joining (for example, 0. 3 to 0.5
Second) can be shortened.

In addition, the protrusion 3 of the rotary tool 1 is shown in FIG.
As shown in FIG. 4, the total thickness of the members increases as the number of superposed members increases. Therefore, it is necessary to increase the length according to the number of superposed members. For example, as shown in FIG.
When the rotary tool 1 having the protruding portion 3 having the length for two lap joining is applied to the lap joining of three sheets, if the joining time is shortened, the stirring amount of the intermediate member W2 and the lower member W3 becomes insufficient. The strength cannot be secured (see FIG. 4A). On the contrary, if the joining time is lengthened, the amount of reduction in the plate thickness of the upper member W1 becomes too large, and the strength between the upper member W1 and the intermediate member W2 cannot be secured. (See FIG. 4B) In any case, the tool used when the number of overlapping members is small cannot be used for joining a large number of members.

Therefore, in the present invention, as shown in FIGS. 5 and 6, the second tool having a small diameter from the tip of the rotary tool 1 toward the protrusion 3 is concentric and forms at least one step. By providing the third shoulder portions 4 and 5, the length of the protruding portion 3 remains as it is for superposing two sheets, and it is possible to perform superposition joining of three or more sheets or a large total plate thickness.

Considering the pressure applied from the fixed tool 10 at the time of joining, when the receiving surface 11 shown in FIG. Increase the amount of subduction. Therefore, in the present invention, as shown in FIG. 8, the receiving surface 11 of the fixed tool 10 is formed into a curved surface and the corners 12 are formed smoothly, thereby reducing stress concentration and sinking in the member W. ing. Further, by forming the receiving surface 11 into a curved surface, even if the contact angle with respect to the member W deviates to some extent, the receiving surface 11 can be configured to form a surface instead of a point or a line, thus suppressing variations in the bonding strength. It is possible to easily ensure stable joining quality. [Rotating Tool Used for Joining] FIGS. 9 and 10 are external views of a rotating tool used for friction stir welding according to an embodiment of the present invention. FIG. 11 is a front view of a fixing tool used for friction stir welding of the embodiment according to the present invention.

The rotary tool shown in FIG. 9 is used for joining in which the number of superposed sheets is about 2 and the total thickness is relatively small, and the cylindrical first shoulder portion 2 (corresponding to the first tool portion). And a cylindrical protruding portion 3 (corresponding to a second tool portion) having a smaller diameter (or a smaller cross-sectional area) than the first shoulder portion 2 and protruding from the tip portion 2a of the first shoulder 2 with the same axis. With.

Further, the rotary tool shown in FIG. 10 is used for joining with three or more superposed sheets and has a large total thickness, and is composed of the cylindrical first shoulder portion 2 and the first shoulder portion 2. With a small diameter (or small cross-sectional area), the first
The cylindrical protrusion 3 protruding from the tip 2a of the shoulder 2 at the same axis and the diameter gradually decreasing from the first shoulder 2 toward the protrusion 3 so as to be concentric and form a step. Cylindrical second and third shoulder portions 4 and 5 are provided.

In the rotary tool shown in FIG. 9, the diameter φ of the first shoulder portion 2 is set to about 5 to 13 mm, and the diameter φ of the protruding portion 3 is set to about 2 to 5 mm.

In the rotary tool shown in FIG. 10, the diameter φ of the first shoulder portion 2 is about 13 to 16 mm, the diameter φ of the second shoulder portion 4 is about 10 to 13 mm, and the diameter φ of the third shoulder portion 5 is 5 to 5. About 10 mm, the diameter φ of the protrusion 3 is 2
It is set to about 5 mm.

Incidentally, in order to further improve the machinability and the stirring property, a spiral or parallel groove may be formed on the outer peripheral surface of the projecting portion 3. In the case of the spiral groove, the groove may be formed in the member in the direction of pushing the member structure.

The fixed tool 10 shown in FIG.
1 is provided with a diameter-expanded portion 13 formed in a tapered shape so that the cross-sectional area increases from the counter-rotating tool side to the receiving surface 11
The (I portion) is formed in a curved surface shape with a radius of R30 to 50 mm so as to absorb the deviation of the pressure acting point from the protruding portion 2.

By constructing a rotary tool as shown in FIG. 10 above, it is possible to perform bonding of various overlapping numbers and total plate thickness without exchanging the tool, which is caused by the conventional exchanging of the tool. It is possible to reduce the loss of the joining time which has been required. Further, since the types of tools to be used are also reduced, costs such as tool purchase / processing costs and maintenance costs can be reduced.

As shown in FIG. 11, in the fixed tool 10, the diameter φ of the receiving surface 11 is about 7 to 13 mm, the diameter φ of the large diameter portion of the expanded diameter portion 13 is about 13 to 16 mm, and the diameter φ of the small diameter portion. Expands from the receiving surface 11 toward the expanded diameter portion 13 in a tapered shape in accordance with the respective dimensions.

FIG. 12 is a front view showing a rotary tool and a mounting bracket for the rotary tool.

As shown in FIG. 12, a tapered taper hole 6 is formed on the end surface of the rotary tool 1 on the side opposite to the protruding portion 2, and the taper hole 6 is surrounded at equal intervals (for example, 9 around the axis).
The anti-rotation guide groove 7 is formed every 0 °. In addition, the end surface of the mounting bracket 20 on the rotary tool 1 side is formed in a tapered taper shape, and the detent guide 2 that fits in the detent guide groove 7 around the tapered surface 21.
2 is projected.

Then, the taper hole 6 of the rotary tool 1 and the anti-rotation guide groove 7 are fixed to each other by fitting the taper surface 21 and the anti-rotation guide 22 of the mounting bracket 20, respectively, to fix the anti-rotation guide groove 7 and the anti-rotation guide groove 7. The guides 22 are fitted together so that they do not rotate relative to each other.

The mounting bracket 20 is a rotary tool 1
Is formed so as to have an approximately same diameter φ13 to 16 mm as an integral shaft in a fixed state, and its length is set to a length suitable for a member to be joined. Further, the diameter φ is 10 to 1 on the end surface of the mounting bracket 20 on the side opposite to the rotating tool.
A robot mounting unit 23 of about 3 mm is extended, and the robot mounting unit 23 is attached to a motor shaft of an articulated robot (not shown) via a holder or the like to be rotationally driven together with the rotary tool 1.

FIG. 13 is a schematic view of an articulated robot that fixes and drives a rotary tool.

As shown in FIG. 13, an articulated robot 30
Is connected to a joint 32 provided on the base 31 and swings about the y-axis, and is connected to the first arm 34 via a joint 35 and a first arm 34 that rotates about the z-axis at the joint 33. And a third arm 39 that swings about the y-axis and rotates about the x-axis at the joint 36, and a third arm 39 that is connected to the second arm 37 via the joint 38 and swings about the y-axis. Have.

At the tip of the third arm 39, the joining gun 5
0 is attached. The rotary tool 1 is rotatably attached to the joining gun 50, and a motor 51 for rotationally driving the rotary tool 1 and a fixed tool 10 are attached so as to face the rotary tool 1. The distance between the rotary tool 1 and the fixed tool 10 is variable by an actuator 52, and is configured so that it can be applied to lap welding of three or more sheets by controlling the pressure applied to the members during welding and the tool rotation speed. There is.

Each arm of the articulated robot 30, a motor,
The operation of the actuator is taught in advance and controlled by the robot controller 60 via the power / control cable 61.

FIG. 14 is a detailed view of the joining gun shown in FIG.

As shown in FIG. 14, the joining gun 50 includes a lower end arm 5 extending laterally from a lower end portion of a gun arm 55.
The fixed tool 10 is attached to the 6 through a mounting bracket 57.

At the upper end of the gun arm 55, a drive unit 5 for rotating and vertically rotating the rotary tool 1 is installed.
8 is attached. The drive unit 58 includes a guide table 53 that is vertically guided by a ball screw mechanism 54 that uses the vertical drive motor 52 as a drive source, and the rotary drive motor 51 is fixed to the guide table 53. The rotary tool 1 is attached to the rotary shaft 51 a of the rotary drive motor 51 via a holder or the like, and is arranged so as to face the fixed tool 10.

Then, the rotary tool 1 includes the guide table 53 formed by the vertical drive motor 52 and the ball screw mechanism 54.
Is moved in the vertical direction by the movement of, and is rotationally driven by the rotational drive motor 51.

In the present embodiment, from the control parameters of the above-mentioned welding equipment (welding gun, rotary drive motor, vertical drive motor, rotary tool, etc.), welding failure caused by equipment abnormality is prevented, and the welding of the members to be welded is prevented. The amount of heat generated is calculated from the dynamic friction coefficient and the load applied to the members (pressure, rotation speed, tool contact diameter, etc.), and welding is performed from the relationship between this amount of heat and the amount of pressing of the rotating tool into the member (sheet thickness reduction amount). It is configured to judge the joint quality, and non-destructive inspection can be performed on all joints, and it is possible to judge the quality assurance in the manufacturing line (in-line). [Joining Control] Next, a joining control method by friction stirring according to the present embodiment will be described.

FIG. 15 is a flow chart for explaining the joining control method by friction stirring according to this embodiment.

As shown in FIG. 15, in step S1,
Based on the combination of the materials to be joined and the plate thickness, suitable joining conditions are calculated from a database in which the joining conditions such as the rotation speed of the rotary tool, the pressing force, and the joining time are set in advance by experiments or the like.

In step S3, rotational driving of the rotary tool is started.

In step S5, the rotation tool waits until it reaches the set number of rotations.
Proceeding to 7, the rotary tool is lowered to start pressurizing the member. The tool rotation speed is calculated from the encoder value of the rotary drive motor. Further, the pressing force is calculated from the feedback current value of the vertical drive motor. Further, the tool-to-tool distance between the rotary tool and the fixed tool is calculated from the gun arm deflection correction table and the encoder value of the vertical drive motor set in advance by experiments or the like.

In step S9, when the rotary tool reaches the set pressing force and it is detected that the protrusion of the rotary tool has been press-fitted into the member from the distance between the tools, the shoulder portion of the rotary tool comes into contact with the member. It will rotate and generate heat.

In step S11, the tool tip position (push amount) with respect to the member of the protrusion 2 is calculated, and
In step S13, the load applied to the rotary tool is calculated.

The tool tip position (pushing amount) of the rotating tool is calculated from the tool distance. The load applied to the rotary tool is calculated from the feedback current value of the rotary drive motor.

In step S15, the plate thickness reduction amount of the upper member is calculated while monitoring the distance between the tools, and when the predetermined reference value is exceeded, the joining condition (pressurizing force, rotation speed) is corrected or changed. This reduces a reduction in plate thickness that causes a bonding failure (bonding strength reduction). In addition, step S13
The welding conditions (pressurizing force, rotational speed) are corrected or changed so as to be suitable for the tool tip position of the rotary tool calculated in step 1.

In step S17, under the joining condition corrected (changed) in step S15, the joining process of steps S13 to S17 is held until the joining time set in step S1 is reached, and after this joining time elapses, joining is performed. To complete.

The above-mentioned pressing force is controlled by setting the relationship between the pressing force at the tip of the tool and the current value of the vertical drive motor required at that time in a table in advance, and calculating the pressing force correction formula from this table. Has been done. Then, the feedback current of the vertical drive motor at the time of pressurization is detected, and the pressing force can be calculated from this feedback current value and the pressing force correction formula.

As shown in FIG. 19, the tool tip position (pushing amount) of the rotary tool is the encoder value of the vertical drive motor at the reference position when the defect is confirmed, and the motor tip position at the current rotary tool position. It is calculated by comparing with the encoder value. As for the distance between tools, as shown in FIG. 19, the relationship between the pressing force and the amount of deflection of the gun arm is set in advance in a table, the deflection correction formula is obtained from this table, and the pressing force generated at the time of welding is adjusted by the vertical drive motor. The amount of deflection of the gun arm when pressure is applied by this pressing force is calculated from the deflection correction formula. Then, the inter-tool distance is calculated from the relationship between the gun arm deflection amount and the tool tip position of the rotary tool.

In the above control, the welding time may be changed according to the load applied to the rotary tool.

According to the above-described embodiment, the joining state is detected from the tool tip position and the load, and the joining conditions (pressurizing force, rotation speed, joining time) suitable for this joining state are controlled to join the materials to be joined. It is possible to secure a stable joining quality by generating a plastic flow suitable for the combination and plate thickness to reduce joining defects. [Quality Assurance Method] Next, a quality assurance method in the joining method by friction stirring of the present embodiment will be described.

FIG. 16 is a flow chart for explaining the quality assurance method in the friction stir welding method of this embodiment.

As shown in FIG. 16, in step S21, the position where the protrusion 2 of the rotary tool 1 abuts on the member is calculated without interposing the member before the actual joining.

In step S23, the above step S21 is performed.
The contact position calculated in step 1 is compared with a predetermined reference position, and a defect check due to wear of the protrusion 2 of the rotary tool 1 is performed.

The reference position is a position when a new rotary tool 1 having no defect is used and the rotary tool 1 comes into contact with the fixed tool 10 to reach a predetermined pressing force. Then, when the contact position exceeds the reference position by a predetermined amount, it is determined that there is a defect.

If it is determined in step S23 that the protrusion 2 is missing, the process proceeds to step S25, and the robot operation thereafter is stopped as an abnormality.

If it is determined by the loss confirmation in step S23 that there is no loss, this program is activated in step S27 to start the joining process.

In step S29, rotational driving of the rotary tool is started.

When the rotational speed of the rotary tool reaches the set rotational speed from the encoder value of the rotary drive motor in step S33, the process proceeds to step S37, in which the rotary tool 1 is lowered to start pressing the member. If the set number of revolutions has not been reached even after the lapse of a predetermined time, step S35.
Then, as an abnormality, the subsequent robot operation is stopped.

When the rotating tool reaches the set pressing force in step S39, the shoulder portion of the rotating tool rotates while contacting the member to start heat generation.
In 43, the tool tip position (pushing amount) with respect to the member of the protrusion 2 is calculated, and in step S45, the load applied to the rotary tool is calculated. Further, if the set pressure is not reached even after the lapse of a predetermined time, it is judged as abnormal in step S41 and the subsequent robot operation is stopped.

The above-mentioned pressing force is controlled by setting the relationship between the pressing force at the tip of the tool and the current value of the vertical drive motor required at that time in advance in a table, and calculating the pressing force correction formula from this table. Has been done. Then, the feedback current of the vertical drive motor at the time of pressurization is detected, and the pressing force can be calculated from this feedback current value and the pressing force correction formula.

As shown in FIG. 19, the tool tip position (pushing amount) of the rotary tool is the encoder value of the vertical drive motor at the reference position when the defect is confirmed and the motor tip position at the current rotary tool position. It is calculated by comparing with the encoder value. As for the distance between tools, as shown in FIG. 19, the relationship between the pressing force and the amount of deflection of the gun arm is set in advance in a table, the deflection correction formula is obtained from this table, and the pressing force generated at the time of welding is adjusted by the vertical drive motor. The amount of deflection of the gun arm when pressure is applied by this pressing force is calculated from the deflection correction formula. Then, the inter-tool distance is calculated from the relationship between the gun arm deflection amount and the tool tip position of the rotary tool.

As the load applied to the rotary tool, a reference current for each rotation speed is preliminarily tabled based on the relationship between the feedback current value of the rotation drive motor in the unloaded state and the rotation speed detected by the encoder of the rotation drive motor. The reference current calculation formula is calculated from this table, and the reference current calculated from this reference current calculation formula and the following relational expression 1 of the feedback current value of the rotary drive motor at the time of joining are calculated. (Equation 1) Load during welding = feedback current value of rotary drive motor during welding-reference current In step S47, the tool tip position of the rotary tool and a welding characteristic file (see FIG. 18) stored in advance are used to apply pressure. Calculate the plate thickness reduction amount of the member.

In step S49, the amount of heat generated by friction agitation is calculated from the load or pressure, the tool rotation speed, the surface resistance (dynamic friction coefficient) of the member, and the tool contact diameter.

In step S51, the joining quality is judged while monitoring the amount of reduction in thickness and the amount of heat generation, and if it is judged that the quality cannot be guaranteed at the time of completion of joining, the operator is warned of the joining defect and repair is performed. . The reduction amount of the plate thickness becomes a factor that determines the magnitude of the bonding strength. This is because the size of the remaining plate thickness after joining greatly affects the joining strength.

The plate thickness reduction amount is obtained by subtracting the distance between tools from the total plate thickness, and becomes the total plate thickness reduction amount. The plate thickness reduction ratio (the plate member thickness reduction amount of the upper member / total (Thickness reduction amount)
By multiplying by, the plate thickness reduction amount of the upper member is calculated. Further, the plate thickness reduction amount of the lower member is calculated by subtracting the plate thickness reduction amount of the upper member from the total plate thickness reduction amount (see the following relational expressions 2 to 4). As the plate thickness reduction ratio, a ratio obtained by experiments or the like is set in advance. (Equation 2) Total thickness reduction = Total thickness-Tool distance (Equation 3) Upper member thickness reduction = Total thickness reduction x Thickness reduction ratio (Upper thickness reduction / Total thickness) Thickness reduction amount (Equation 4) Plate thickness reduction amount of lower member = Total plate thickness reduction amount-Plate thickness reduction amount of upper member FIG. 18 shows the relationship between the pressing force and the bonding strength, and the bonding conditions A, B, C are shown. It is determined that the quality assurance is possible when the bonding strength exceeds the lower limit and the quality assurance is not possible when the bonding strength is less than the lower limit. [Joining Quality Judging Method] Next, the joining quality judging method in step S51 will be described.

FIG. 17 is a flow chart for explaining the quality assurance method in the friction stir welding method of this embodiment.

As shown in FIG. 17, in step S55, the calorific value calculated in step S49 is substituted into a formula for calculating the calorific value and the joint area (or diameter, etc.) obtained in advance by experiments and the like. Calculate the area. At the same time, in step S53, it is determined whether the thickness reduction amount calculated in step S47 is within a preset reference value,
If it is within the reference value, the strength of the joint area is determined in step S57, and if it exceeds the reference value, it is determined that the quality of the joint cannot be guaranteed because it is difficult to secure the joint strength, and the operator is warned of the joint failure and the repair is performed. I do.

In the strength judgment of the joint area in step S57, it is judged from the previously stored joint characteristic file (see FIG. 18) whether the joint area is within the reference value, and if it is within the reference value, it is judged that the quality can be guaranteed. Then, the joining is completed, and if the standard value is exceeded, it is determined that the quality of the joint cannot be guaranteed because it is difficult to secure the joining strength, and the operator is warned of the joining failure and repair is performed.

As can be seen from FIG. 18, as the applied pressure is increased, the bonding strength decreases from a certain point P.
This is because the amount of reduction in plate thickness increases and affects the joining strength, and the joining conditions (pressurizing force, rotation speed) are determined with the point P at which the joining strength decreases as a reference value.

According to the above-mentioned embodiment, it is possible to detect a joining defect caused by equipment abnormality from the control parameters of the above-mentioned joining equipment (joining gun, rotary drive motor, vertical drive motor, rotary tool, etc.). Also, the amount of heat generated is calculated from the dynamic friction coefficient of the members to be joined and the load (pressure, rotation speed, tool contact diameter, etc.) applied to the members, and this amount of heat generation and the amount of pushing of the rotating tool into the member (thickness reduction amount) By determining the joining quality during joining from the relationship with, it is possible to perform non-destructive inspection for all joining, and it is possible to determine the quality assurance in the manufacturing line (in-line).

[0089]

A computer program for executing the bonding control method, the bonding guarantee method, and the bonding quality judgment method corresponding to the flowcharts shown in FIGS. 15 to 17 and a storage medium storing the program code are supplied to the computer. Then, the computer may read the program code stored in the storage medium and execute the processing of the above-described embodiment.

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating a joining method by friction stirring according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating a conventional non-melting joining method by friction stirring.

FIG. 3 is a diagram showing a state of joining with a rotary tool having three protrusions having a length for lap joining.

FIG. 4 is a view showing a state of joining when three lapped joints are performed by changing a time with a rotary tool having a protruding portion of a length for two lapped joints.

FIG. 5 is a diagram showing a state of joining when two superposed joints are performed by the rotary tool according to the embodiment of the present invention.

FIG. 6 is a diagram showing a state of joining when three superposed joints are performed by the rotary tool according to the embodiment of the present invention.

FIG. 7 is a diagram showing an influence on a member due to pressurization of a fixing tool having a flat receiving surface.

FIG. 8 is a diagram showing an influence on a member due to pressurization of a fixed tool having a curved receiving surface.

FIG. 9 is an external view of a rotary tool used for friction stir welding according to an embodiment of the present invention.

FIG. 10 is an external view of a rotary tool used for friction stir welding according to an embodiment of the present invention.

FIG. 11 is a front view of a fixing tool used for friction stir welding according to an embodiment of the present invention.

FIG. 12 is a front view showing a rotary tool and a mounting bracket for the rotary tool.

FIG. 13 is a schematic view of an articulated robot that fixes and drives a rotary tool.

FIG. 14 is a detailed view of the joining gun shown in FIG.

FIG. 15 is a flowchart illustrating a joining control method by friction stirring according to the present embodiment.

FIG. 16 is a flowchart illustrating a quality assurance method in the friction stir welding method according to the present embodiment.

FIG. 17 is a flowchart illustrating a quality assurance method in the friction stir welding method according to the present embodiment.

FIG. 18 is a diagram showing a relationship between a pressing force and a bonding strength.

FIG. 19 is a diagram illustrating the relationship between the tool tip position, the tool distance, and the gun arm deflection amount.

[Explanation of symbols]

1 rotation tool 3 protrusion 10 Fixed tool 30 articulated robot W1-W3 members

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23K 20/12

Claims (8)

(57) [Claims] 1. A first rotary tool comprising a first tool portion and a second tool portion having an area smaller than that of the first tool portion and protruding from a tip portion of the first tool portion.
In a joining method using friction agitation, in which a joined portion where a member and a second member are overlapped is locally agitated by friction, and the joined first and second members are sandwiched by the rotary tool. A fixed tool having a receiving surface having an area smaller than the cross-sectional area of the first tool portion at a tip end portion facing the rotary tool and having a separation distance from the rotary tool. It is provided so as to be variable, and receives the superimposed first and second members on the receiving surface of the fixed tool, and rotates the rotating tool with respect to the first member and the second member while rotating the rotating tool. The tool around the rotary tool is cut by pressing and pressing the tool from the second tool portion and rotating the rotary tool within the press-fitted member, and the cut member is the first member. The tool portion and the second tool portion frictionally stir and melt the inside of the member, and plastically flow the peripheral portion of the melted region,
A joining method using friction stirring, wherein the first member and the second member are joined, and after the joining is completed, the rotary tool is retracted from the member while being rotated. 2. The joining method using friction stirrer according to claim 1, wherein the receiving surface of the fixed tool is formed to have substantially the same area as the tip portion of the second tool portion of the rotary tool. 3. A rotating tool comprising a first tool portion and a second tool portion having an area smaller than that of the first tool portion and protruding from a tip end portion of the first tool portion is rotated to rotate the first tool portion.
In a joining method using friction agitation, in which a joined portion where a member and a second member are overlapped is locally agitated by friction, and the joined first and second members are sandwiched by the rotary tool. And has a receiving surface having a smaller area than the cross-sectional area of the first tool portion at a tip end portion that is arranged to face the rotary tool and that faces the rotary tool, A fixed tool having a taper-shaped enlarged diameter portion whose cross-sectional area expands is provided so that the separation distance from the rotary tool is variable, and the overlapping first and While receiving the second member and rotating the rotary tool, the rotary tool is pressed against the first member and the second member from the second tool portion, and the rotary tool is press-fitted. Element By rotating the member around the rotating tool by friction by the first tool portion and the second tool portion to join the first member and the second member, and after the joining is completed, A joining method using friction stirring, wherein the rotating tool is retracted from the member in a rotated state. 4. The friction stirrer according to claim 3 , wherein the area of the receiving surface of the fixed tool is set to be substantially equal to or smaller than the cross-sectional area of the first tool portion of the rotary tool. Joining method using. 5. A rotary tool comprising a first tool part and a second tool part having an area smaller than that of the first tool part and protruding from a tip end part of the first tool part is rotated to rotate the first tool part.
In a joining device using friction stirring for locally agitating and joining a joined portion where a member and a second member are superposed, the superposed first and second members are sandwiched by the rotary tool. And has a receiving surface having an area smaller than the cross-sectional area of the first tool portion at the tip end portion that is arranged so as to face the rotary tool, and the distance from the rotary tool is variable. A fixed tool provided in such a manner that the first and second members that have been superposed on the receiving surface of the fixed tool are received, and the rotating tool is rotated, with respect to the first member and the second member. By pressing the rotary tool from the second tool portion and press-fitting the rotary tool, and rotating the rotary tool in the press-fitted member, a member around the rotary tool is cut, and the cut member is The first tool part and the second tool part stir and melt the inside of the member by friction, and the peripheral part of the melted region is plastically flowed to join the first member and the second member, and the joining is performed. And a tool control means for retracting the rotating tool from the member after the completion of the welding. 6. The welding apparatus using friction stirrer according to claim 5 , wherein the receiving surface of the fixed tool is formed to have substantially the same area as the tip portion of the second tool portion of the rotary tool. 7. A rotating tool comprising a first tool part and a second tool part having an area smaller than that of the first tool part and protruding from a tip part of the first tool part is rotated to rotate the first tool part.
In a joining device using friction stirring for locally agitating and joining a joined portion where a member and a second member are superposed, the superposed first and second members are sandwiched by the rotary tool. And has a receiving surface having a smaller area than the cross-sectional area of the first tool portion at a tip end portion that is arranged to face the rotary tool and that faces the rotary tool, A fixed tool that has a taper-shaped enlarged diameter portion whose cross-sectional area expands and that is provided so that the separation distance from the rotary tool is variable; In a state where the rotary tool is rotated by receiving the first and second members, the rotary tool is pressed against the first member and the second member by pressing the rotary tool from the second tool portion, and the rotary tool is Pressed By rotating in the material, the members around the rotating tool are frictionally stirred by the first tool portion and the second tool portion to join the first member and the second member, and after the joining is completed, And a tool control means for retracting the rotary tool from the member in a rotated state, the welding apparatus using friction stirring. 8. The friction stirrer according to claim 7 , wherein the area of the receiving surface of the fixed tool is set to be substantially equal to or smaller than the cross-sectional area of the first tool portion of the rotary tool. Joining equipment using.