JP2020049532A - Friction agitation joining apparatus and friction agitation joining method - Google Patents

Abstract

To provide a friction agitation joining apparatus and a friction agitation joining method which can perform position setting of a joining tool in a Z-axis direction (a vertical direction) with high accuracy.SOLUTION: The friction agitation joining apparatus comprises: a joining tool that is inserted into members to be joined and moves forward while rotating so as to join the members; a joining head for holding the joining tool; an apparatus main body that holds the joining head, rotates the joining tool and makes the joining tool move forward; and distance measuring means that measures a distance between a first reference point, a predetermined position of the joining head and a second reference point opposing in the vertical direction to the first reference point on a placement pedestal on which the members to be joined are placed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a friction stir welding apparatus and a friction stir welding method for joining members to be joined by friction stir welding, and is particularly applied to joining of members to be joined which require high quality (high accuracy) joining. Regarding effective technology.

  Friction Stir Welding (FSW), in which the materials to be welded are softened by the frictional heat generated by rotating a cylindrical welding tool and the parts are agitated to join the materials to be welded, is a material other than the material. Since no material is used, the material has high fatigue strength, and since the material does not melt, bonding with less welding deformation (strain) is possible, and applications in a wide range of fields such as aircraft and automobile bodies are expected.

  As a background art in the present technical field, for example, there is a technique as described in Patent Document 1. Patent Literature 1 states that “joining conditions (position of the joining head in the Z-axis direction, rotational speed, and advancing speed) are set before the joining tool is inserted into the member to be joined, and the joining tool is inserted into the member to be joined. After starting the friction stir welding, a technique for controlling the rotation speed and / or the progress speed so as to keep the welding temperature near the welding portion substantially constant is disclosed.

Japanese Patent No. 5883978

  When a thin plate such as an automobile member is friction stir welded using a friction stir welding device (FSW device), a change in the Z-axis direction (vertical direction) of a mounting table on which a member to be welded is placed during friction stir welding. As a result, the quality of the members to be joined (joining) is reduced.

  Factors that cause the position of the mounting table in the Z-axis direction (vertical direction) to fluctuate include heat input from the members to be joined during friction stir welding and an increase in the temperature around the mounting table.

  Regarding the variation of the mounting table in the Z-axis direction (vertical direction), focusing on the distance between the tip end position of the welding tool and the mounting table, the position of the mounting table in the Z-axis direction (vertical direction) fluctuates after joining, and thus the The distance between the tip end position of the welding tool and the mounting table is smaller than that of the welding tool. That is, it is agreed that the tip position of the welding tool has changed in the Z-axis downward direction.

  The members to be joined these days tend to be thinner, and the variation of the tip position of the joining tool in the Z-axis downward direction cannot be ignored. In particular, it is remarkable in the automobile field where weight reduction is required. is there.

  In Patent Literature 1, in order to keep the welding temperature substantially constant, the rotation speed and the advance speed are controlled in real time after the friction stir welding is started. No consideration is given to stretching by heat.

  Therefore, an object of the present invention is to provide a friction stir welding apparatus capable of accurately setting an initial position of a welding tool in a Z-axis direction (vertical direction) in a welding condition setting stage which is a stage before inserting the welding tool into a member to be welded. And a friction stir welding method.

  In order to solve the above-described problems, the present invention provides a joining tool that is inserted into a member to be joined, advances while rotating, and joins the member to be joined, a joining head that holds the joining tool, and the joining head. Holding and rotating the welding tool, the device body for moving the welding tool, a first reference point that is a predetermined position of the welding head, and a mounting table on which the member to be welded is mounted. Distance measuring means for measuring a distance between the first reference point and a second reference point vertically opposed to the first reference point.

  Further, the present invention is a friction stir welding method for joining members to be joined by friction stir welding, in which a power source is turned on to the apparatus main body, and in a pre-joining stage before joining the members to be joined, a predetermined welding head is joined. A reference distance for measuring a reference distance between a first reference point that is a position and a second reference point that is vertically opposed to the first reference point on a mounting table on which the member to be joined is mounted. Measuring the current distance between the first reference point and the second reference point after performing the measurement step and the reference distance measurement step, and after friction stir welding the workpiece to be joined with a welding tool. A current distance measuring step, and a position for correcting a vertical position of the joining head so that the deviation becomes smaller than the predetermined threshold when a deviation between the reference distance and the current distance reaches a predetermined threshold. Correction step , Characterized by having a.

  According to the present invention, a friction stir welding apparatus and a friction stir welding apparatus capable of accurately setting an initial position of a welding tool in a Z-axis direction (vertical direction) in a welding condition setting stage which is a stage before inserting a welding tool into a member to be welded. A stir welding method can be realized.

  Accordingly, the position of the welding tool in the Z-axis direction (vertical direction) can be set with high accuracy, and high-quality (high accuracy) friction stir welding can be performed.

  Problems, configurations, and effects other than those described above will be apparent from the following description of the embodiments.

It is a figure showing the whole outline of the friction stir welding device concerning one embodiment of the present invention. It is a figure which shows notionally the operation | movement (operation) of the friction stir welding apparatus which concerns on one Embodiment of this invention. 3 is a flowchart illustrating a friction stir welding method according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description of overlapping portions will be omitted.

  First Embodiment A friction stir welding apparatus and a friction stir welding method according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing the general outline of the friction stir welding apparatus 1 of the present embodiment, and FIG. 2 is a diagram conceptually showing the operation (action). FIG. 3 is a flowchart showing a typical friction stir welding method (control method) according to the present embodiment.

  As shown in FIG. 1, the friction stir welding apparatus 1 of the present embodiment has, as main components, a holder (joining head) holding the apparatus main body 2 and a holder (joining head) connected to the apparatus main body 2 via a vertical drive mechanism 3. The holder 4 includes a holder (joining head) 5 connected (held) to the holder (joining head) holder 4, and a joining tool 6 held by the holder (joining head) 5. For example, a ball screw or the like is used for the up-down movement driving mechanism 3, as illustrated in FIG. The joining tool section 6 includes a shoulder section 7 and a probe section (joining pin) 8, and the probe section (joining pin) 8 is held by the holder section (joining head) 5 via the shoulder section 7. The apparatus body 2 holds the holder (joining head) 5 and rotates the joining tool 6, and moves the joining tool 6 in the X-axis direction, the Y-axis direction, and the Z-axis direction in FIG.

  The probe portion (joining pin) 8 is inserted into a butt portion (not shown) of a plurality of members to be joined placed on the mounting table 9, and rotates at a high speed. Friction heat is generated between the members to be joined, and the frictional heat causes a plastic flow in the members to be joined, so that the joint is agitated. When the probe portion (joining pin) 8 moves, the stirring portion (joining portion) is cooled, and the members to be joined are joined.

  FIG. 1 shows a configuration in which the holder unit 5 and the joining tool unit 6 are connected (held) to the apparatus main body 2 via the holder unit holding unit 4 and the vertical movement driving mechanism unit 3, but the invention is not limited to this. For example, a configuration connected (held) to the apparatus main body 2 via only the vertical drive mechanism 3, a configuration connected (held) to the apparatus main body 2 via other movable means, A configuration in which the holder unit 5 and the joining tool unit 6 are directly connected (held) to the apparatus main body 2 or a configuration in which a C-shaped frame is further provided between the holder unit 5 and the apparatus main body 2 in addition to the configuration in FIG. The configuration connected (held) to the apparatus main body 2 having the robot arm is also included in the scope of the present embodiment.

  The holder section (joining head) 5 is provided with a distance measurement sensor 10. The distance measuring sensor 10 is disposed on the side opposite to the traveling direction (joining direction) of the holder portion (joining head) 5 at the time of joining, and the predetermined distance of the holder portion (joining head) 5 (distance measuring sensor 10) is determined. Is measured between the position (referred to as a first reference point) and a predetermined position (referred to as a second reference point) of the mounting table 9 on which the members to be joined are placed. The first reference point and the second reference point are arranged (set) at positions facing each other in the vertical direction.

  As shown in FIG. 1, in a state where the joining tool unit 6 is at the origin position (a position before the operation for inserting the joining tool into the member to be joined, that is, a position before joining), the distance measurement sensor 10 A reference distance (L0), which is a distance between the first reference point and the second reference point, is measured. The reference distance (L0) is the origin position in the Z-axis direction (vertical direction) of the holder (joining head) 5 when the power is turned on to the apparatus main body 2.

  As the distance measurement sensor 10, for example, a non-contact type displacement sensor such as a laser displacement sensor using a laser is used. Alternatively, if the distance measurement and the friction stir welding process are not affected, a contact-type displacement sensor such as a linear gauge may be used. When a laser displacement sensor is used, the first reference point is a point where the distance measurement signal of the distance measurement sensor 10 is irradiated as shown in FIG. 1, and the second reference point is a point where the distance measurement signal of the distance measurement sensor 10 is received. Becomes

  A control unit (control device) 11 that controls the operation of the friction stir welding apparatus 1 is installed in the apparatus main body 2. The control unit (control device) 11 includes a joining condition signal for determining joining conditions by the joining tool unit 6 and a holding position (a position of the joining pin 8) of the joining tool unit 6 in the height direction (Z direction) by the vertical movement driving mechanism unit 3. A storage unit (not shown) is provided for storing welding parameters (FSW welding conditions) such as a holding position determination signal for determining the insertion amount) and a change position signal of the welding head 5 (welding tool unit 6).

  The apparatus main body 2 is provided with a linear drive mechanism section 12 that can be driven in the X-axis direction and a linear drive mechanism section 14 that can be driven in the Y-axis direction. The holder portion (joining head) 5 is moved along the rail 13 of the provided linear guide and the rail 15 of the linear guide provided in the Y-axis direction, thereby moving the holder portion (joining head) 5 in the X-axis direction (joining direction) and the Y-axis direction ( (A direction orthogonal to the X-axis direction).

  As described above, the friction stir welding apparatus 1 of the present embodiment is inserted into a member to be welded, advances while rotating and joins the member to be welded, and a holder that holds the tool 6 to be welded. (Joining head) 5, holding the holder (joining head) 5, rotating the joining tool 6 and moving the joining tool 6, and a predetermined position of the holder (joining head) 5. And a distance measuring sensor 10 for measuring a distance between the first reference point and a second reference point vertically opposed to the first reference point on the mounting table 9 on which the member to be joined is mounted. I have. Further, a control unit (control device) 11 for controlling the operation of the joining tool unit 6 is provided.

  A typical friction stir welding method (control method) using the distance measurement sensor 10 described above will be described with reference to FIGS.

  First, in response to a command from the control unit (control device) 11, in a stage before the friction stir welding (in a state where the mounting table 9 is not fluctuated by heat), the holder unit (welding head) 5 (the distance measurement sensor 10) is used by the distance measurement sensor 10. ) Is measured between a predetermined position (first reference point) and a predetermined position (second reference point) of the mounting table 9 on which the member to be joined is mounted, The position (reference position: Z0) of the welding head 5 (welding tool unit 6) on the Z axis at that time is stored in the storage unit of the control unit (control device) 11. (Step S1) Here, a step of acquiring a reference distance (L0), which is a distance between the first reference point and the second reference point, from the distance measurement sensor 10 before the start of joining (before joining). The operation is referred to as a “reference distance measurement mode”.

  As described above, the reference position (Z0) on the Z axis is the position of the device on the Z axis when the reference distance (L0) is measured in the pre-joining stage, and is within the Z axis movable range of the device. Is position information for specifying the position of the device. For example, it is preferable that positioning is automatically performed by PLC control (Programmable Logic Controller), and the repetition accuracy is controlled to about ± 0.01 mm.

  Next, according to a command from the control unit (control device) 11, the joining tool unit 6 is inserted into the joining portion between the plurality of members to be joined, and the movement amount (elapsed time) of the joining tool unit 6 is set to a predetermined value (position). When the time reaches (time), the welding tool part 6 is pulled out from the welding part of the member to be welded. (Step S2) Here, step S2 is referred to as "one joining process".

Subsequently, in accordance with a command from the control unit (control device) 11, the joining head 5 (joining tool unit 6) is adjusted to the position on the Z axis (reference position: Z0) stored in step S1. (Step S3)
Subsequently, in a state where the height of the mounting table 9 is fluctuating under the influence of heat due to the joining by a command from the control unit (control device) 11, the holder unit (joining head) 5 (distance measurement) is The current distance (L1) which is a distance between a predetermined position (first reference point) of the sensor 10) and a predetermined position (second reference point) of the mounting table 9 on which the member to be joined is mounted is measured. I do. (Step S4) Here, this step S4 is called "current distance measurement mode".

  Subsequently, the control unit (control device) 11 calculates a deviation (ΔL) between the current distance (L1) measured in step S4 and the reference distance (L0) measured and stored in step S1, and sets a predetermined value that is set in advance. (Threshold: Lt). (Step S5) The deviation (ΔL) is ΔL = current distance (L1) −reference distance (L0), and the mounting table 9 fluctuated by the influence of heat such as heat input during friction stir welding and rise in outside air temperature. (The amount of stretching in the Z-axis direction).

When the deviation (ΔL) between the current distance (L1) and the reference distance (L0) reaches the threshold value (Lt) (ΔL ≧ Lt), the calculated deviation (ΔL) is given by a command from the control unit (control device) 11. (A threshold value: Lt) is output to the apparatus body 2 to move the position of the welding head 5 (welding tool portion 6) in the Z-axis direction (vertical direction). The apparatus main body 2 sets the position of the welding head 5 (welding tool part 6) in the Z-axis direction (vertical direction) while controlling the position at a predetermined rate of change (moving speed). (Step S6)
Here, this step S6 is called a "control mode". In the “control mode”, the control unit (control device) 11 changes the position signal of the holder unit (joining head) 5 that corrects the deviation (ΔL) so that the deviation (ΔL) calculated in step S5 becomes small. Command signal) and outputs it to the apparatus main body 2.

  The changed position signal (command signal) moves the holder (joining head) 5 by a predetermined distance per unit time, for example, until the deviation (ΔL) becomes smaller than a predetermined value (threshold: Lt). 2 is output continuously. The apparatus main body 2 sets the position of the holder section (joining head) 5 in the Z-axis direction (vertical direction) based on a change position signal (command signal) acquired from the control section (control apparatus) 11 and sets a predetermined change rate. The holder (joining head) 5 is moved at (moving speed).

On the other hand, if the deviation (ΔL) between the current distance (L1) and the reference distance (L0) is less than a predetermined value (threshold: Lt) (ΔL <Lt), the welding tool 6 in the Z-axis direction (vertical direction) Without performing the position setting, the friction stir welding of the members to be welded is continued while maintaining the welding conditions when the current distance (L1) is measured. (Step S7)
Then, when the movement amount (elapsed time) of the welding tool part 6 reaches a predetermined value (position / time) according to a command from the control unit (control device) 11, the welding tool part 6 is moved to the welding part of the workpiece. To finish the friction stir welding process. (Step S8)
As described above, in the friction stir welding method according to the present embodiment, the power is supplied to the apparatus main body 2 and the holder (joining head) 5 is at a predetermined position before joining before joining the members to be joined. A reference distance measurement for measuring a reference distance (L0) between the first reference point and a second reference point vertically opposed to the first reference point on the mounting table 9 on which the members to be joined are mounted. Measuring the current distance (L1) between the first reference point and the second reference point after performing the step and the reference distance measuring step, and after performing friction stir welding of the workpieces by the welding tool unit 6. When the deviation (ΔL) between the reference distance (L0) and the current distance (L1) reaches a predetermined threshold (Lt), the deviation (ΔL) becomes smaller than the predetermined threshold (Lt). To correct the vertical position of the holder (joining head) 5 And a position correcting step.

  As described above, according to the friction stir welding apparatus and the friction stir welding method of the present embodiment, the reference distance that is the distance between the first reference point and the second reference point before the start of welding (before welding). (L0) is measured, and after the friction stir welding, the current distance (L1) which is the distance between the first reference point and the second reference point in a state where the height of the mounting table 9 fluctuates due to the influence of heat due to welding. ) Is measured, and the holder portion (joining head) 5 (joining tool) is adjusted so that the deviation (ΔL) between the current distance (L1) and the reference distance (L0) is smaller than a predetermined threshold (within a predetermined range). By setting the position of the part 6) in the Z-axis direction (vertical direction), it is possible to correct the fluctuation amount (displacement amount) of the mounting table 9 that has fluctuated (displaced) due to the influence of heat.

  Accordingly, the position of the joining tool in the Z-axis direction (vertical direction) can be set with high accuracy, and the members to be joined can be joined with high quality (high accuracy).

  By repeating the “current distance measurement mode” and the “control mode” alternately, a higher quality (higher accuracy) bonding can be performed.

  In steps S2 and S8 in FIG. 3, friction stir welding is started from one end of the member to be joined, and friction stir welding is continuously performed to the other end of the member to be joined, that is, so-called “line welding” is performed. In addition, the joining quality (reliability) can be further improved.

  Further, FIGS. 1 and 2 show an example in which the distance measurement sensor 10 is disposed on the side opposite to the traveling direction (joining direction) of the holder portion (joining head) 5 at the time of joining. It may be arranged on the side of the traveling direction (joining direction) of the holder portion (joining head) 5 at the time of joining.

  Further, the initial position of the welding tool in the Z-axis direction (vertical direction) is set by the friction stir welding apparatus and the friction stir welding method of the present embodiment in the welding condition setting stage, which is a stage before the welding tool is inserted into the member to be welded. Since the present invention is applied to a multi-station type friction stir welding apparatus having a plurality of mounting tables 9, the initial position of the welding tool in the Z-axis direction (vertical direction) can be accurately set for each mounting table 9 because the setting can be performed accurately. The setting can be performed, and high-quality (high-precision) bonding can be performed on all the mounting tables 9.

  Note that the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described above. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of one embodiment can be added to the configuration of another embodiment. Also, for a part of the configuration of each embodiment, it is possible to add, delete, or replace another configuration.

  DESCRIPTION OF SYMBOLS 1 ... friction stir welding apparatus, 2 ... apparatus main body, 3 ... vertical drive mechanism part (ball screw), 4 ... holder part (welding head) holding part, 5 ... holder part (welding head), 6 ... welding tool part 7: shoulder portion, 8: probe portion (joining pin), 9: mounting table, 10: distance measurement sensor, 11: control portion (control device), 12: (X-axis direction) linear drive mechanism portion, 13: linear guide (X-axis), 14 ... (Y-axis direction) linear drive mechanism, 15 ... Rail of linear guide (Y-axis).

In order to solve the above-described problems, the present invention provides a joining tool that is inserted into a member to be joined, advances while rotating, and joins the member to be joined, a joining head that holds the joining tool, and the joining head. Holding and rotating the welding tool, the device body for moving the welding tool, a first reference point that is a predetermined position of the welding head, and a mounting table on which the member to be welded is mounted. A distance measuring unit that measures a distance between the first reference point and a second reference point that is vertically opposed to the first reference point; and a control device, wherein the control device frictionally stirs the member to be welded by the welding tool. In a pre-joining stage before joining, the reference distance measurement mode includes a reference distance measurement mode for acquiring a reference distance that is a distance between the first reference point and the second reference point from the distance measurement unit. After execution, and after the friction stir welding of the members to be welded by the welding tool, a current distance which is a distance between the first reference point and the second reference point, and is obtained from the distance measuring means. Having a measurement mode, after executing the current distance measurement mode, calculating a deviation between the reference distance and the current distance, and when the deviation reaches a predetermined threshold, the deviation becomes smaller than the predetermined threshold As described above, the apparatus has a control mode for outputting a command signal for moving a vertical position of the joining head to the apparatus main body, and the apparatus main body is configured to move the joining head in a vertical direction at a predetermined moving rate based on the command signal. Is moved .

Further, the present invention is a friction stir welding method for joining members to be joined by friction stir welding, in which a power source is turned on to the apparatus main body, and in a pre-joining stage before joining the members to be joined, a predetermined welding head is joined. A reference distance for measuring a reference distance between a first reference point that is a position and a second reference point that is vertically opposed to the first reference point on a mounting table on which the member to be joined is mounted. Measuring the current distance between the first reference point and the second reference point after performing the measurement step and the reference distance measurement step, and after friction stir welding the workpiece to be joined with a welding tool. A current distance measuring step, and a position for correcting a vertical position of the joining head so that the deviation becomes smaller than the predetermined threshold when a deviation between the reference distance and the current distance reaches a predetermined threshold. Correction step , Have a, the apparatus body is in the position correction step, characterized by moving the vertical position of the bonding head at a predetermined transfer rate.

Claims (9)

A joining tool that is inserted into the member to be joined, advances while rotating, and joins the member to be joined;
A joining head for holding the joining tool;
An apparatus body that holds the joining head and rotates the joining tool, and advances the joining tool.
Measure a distance between a first reference point that is a predetermined position of the joining head and a second reference point that vertically opposes the first reference point on a mounting table on which the member to be joined is placed. Distance measuring means,
A friction stir welding apparatus comprising: The friction stir welding apparatus according to claim 1,
Further comprising a control device,
The controller is configured to measure a reference distance, which is a distance between the first reference point and the second reference point, at a pre-joining stage before performing friction stir welding of the members to be joined by the joining tool. A friction stir welding apparatus having a reference distance measurement mode acquired from a device. The friction stir welding apparatus according to claim 2, wherein
The control device is configured to execute the reference distance measurement mode, and, after performing friction stir welding of the member to be welded by the welding tool, determine a current distance between the first reference point and the second reference point. A friction stir welding apparatus having a current distance measuring mode for acquiring a distance from the distance measuring means. The friction stir welding apparatus according to claim 3, wherein
The control device, after executing the current distance measurement mode, calculates a deviation between the reference distance and the current distance,
When the deviation reaches a predetermined threshold, a control mode for outputting a command signal to move the vertical position of the joining head to the apparatus main body so that the deviation is smaller than the predetermined threshold is provided. Friction stir welding equipment. The friction stir welding apparatus according to claim 4, wherein
The friction stir welding apparatus, wherein the apparatus body moves the welding head in a vertical direction at a predetermined moving rate based on the command signal. The friction stir welding apparatus according to claim 4, wherein
The friction stir welding apparatus, wherein the control device alternately repeats the current distance measurement mode and the control mode. The friction stir welding apparatus according to claim 1,
A friction stir welding apparatus, wherein the distance measuring means is a non-contact displacement sensor. A friction stir welding method of joining members to be joined by friction stir welding,
A power is supplied to the apparatus main body, and in a pre-joining stage before joining the members to be joined, a first reference point which is a predetermined position of the joining head, and the second reference point on a mounting table for placing the members to be joined. A reference distance measurement step of measuring a reference distance between one reference point and a second reference point opposed in the vertical direction,
A current distance measurement for measuring a current distance between the first reference point and the second reference point after performing the reference distance measurement step and after friction stir welding the member to be welded with a welding tool. Steps and
When the deviation between the reference distance and the current distance reaches a predetermined threshold, a position correction step of correcting the vertical position of the joining head so that the deviation is smaller than the predetermined threshold,
A friction stir welding method comprising: The friction stir welding method according to claim 8, wherein
A friction stir welding method, wherein the current distance measuring step and the position correcting step are alternately repeated.

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