JP6564511B1 - Friction stir welding apparatus and friction stir welding method - Google Patents

Abstract

A friction stir welding apparatus and a friction stir welding method capable of high-quality (high accuracy) joining of members to be joined even on a production line with a short required tact time. A welding tool comprising a shoulder part and a probe part, inserted into a member to be joined, and rotated, a joining head holding the joining tool, and holding the joining head, and joining the joining tool. A device main body 2 that rotates the tool and moves the welding tool, a control device 12 that controls the operation of the welding tool, a first reference point that is a predetermined position of the welding head, and the mounting table 10 It is characterized by comprising a distance measuring means 11 for measuring a distance from a second reference point which is a predetermined position on the placed member to be joined. [Selection] 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 in particular, applied to joining of members to be joined that require high quality (high accuracy) joining. It relates to effective technology.

  Friction Stir Welding (FSW) that softens the material to be welded by friction heat generated by rotating a cylindrical joining tool and stirs the part to join the materials to be joined. Since no material is used, fatigue strength is high, and since the material does not melt, joining 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 this technical field, for example, there is a technique such as Patent Document 1. In Patent Document 1, “the joining conditions (position of the joining head in the Z-axis direction, rotational speed, traveling speed) are set before the joining tool is inserted into the member to be joined, After the friction stir welding is started, a technique for controlling the rotational speed and / or the traveling speed so as to keep the joining temperature in the vicinity of the joining portion substantially constant is disclosed.

Japanese Patent No. 5883978

  In Patent Document 1, the rotational speed and the traveling speed are controlled in real time after the friction stir welding is started in order to keep the bonding temperature substantially constant. There is no control over the position of the direction.

  However, as a result of diligent research, the inventors of the present application have found that the position of the bonding head in the Z-axis direction is also determined during bonding depending on the bonding conditions, in order to achieve higher quality (high accuracy) bonding. I found out that I needed to make corrections.

  Moreover, in the conventional friction stir welding apparatus (FSW apparatus) like patent document 1, one joining process (A joining tool is inserted in a to-be-joined member, and friction stir welding is carried out to the termination | terminus of a to-be-joined member, and a joining tool is an origin position. Each step), the bending in the Z-axis direction (upward direction) is predicted in advance, and a correction value for eliminating the value is incorporated to set the position of the bonding head in the Z-axis direction. This corresponds to the bending in the Z-axis direction (upward direction) of the joining head that occurs in FIG.

  However, such a conventional method can cope with a long required tact time of the production line, but cannot sufficiently cope with a short required tact time.

  Therefore, an object of the present invention is to provide a friction stir welding apparatus and a friction stir welding method capable of high-quality (high accuracy) joining between members to be joined even in a production line with a short required tact time. is there.

In order to solve the above-described problems, the present invention comprises a shoulder tool and a probe part, a joining tool that is inserted into a member to be joined and rotates, a joining head that holds the joining tool, and a holder that holds the joining head. An apparatus main body for rotating the joining tool and moving the joining tool, a control device for controlling the operation of the joining tool, a first reference point which is a predetermined position of the joining head, and a mounting table. A distance measuring unit that measures a distance between the second reference point, which is a predetermined position on the mounted member to be mounted, and the control device includes the bonding tool inserted into the bonded member; In the previous stage, the position of the tip of the welding tool is lowered to the position in the Z-axis direction at the time of joining, alignment is performed, and the first reference point and the second reference are not joined without joining the members to be joined. Distance between points Characterized in that it has a measurement mode for obtaining a reference distance is from said distance measuring means.

  Further, the present invention is a friction stir welding method for joining the members to be joined by friction stir welding, and (a) in the stage before the joining tool is inserted into the members to be joined, The first reference point, which is a predetermined position of the bonding head, and a position facing the first reference point, and a predetermined position on the member to be bonded. A step of measuring a reference distance, which is a distance between the second reference point as a position, at the joining start position; and (b) after the step (a), the joining tool is inserted into the member to be joined. The step of transitioning to the joining stage for joining the members to be joined, and (c) after the step (b), in the joining stage, at the distance between the first reference point and the second reference point Measuring a current distance; and (d) the current distance The deviation between the distance and the reference distance is calculated, and when the calculated deviation exceeds a predetermined value, the magnitude of the deviation is corrected in a direction opposite to the direction in which the deviation occurs in the Z-axis direction of the welding tool. The position of the bonding head is set, or the bonding head is moved a predetermined distance per unit time until the deviation reaches the predetermined value in the direction opposite to the direction in which the deviation occurs in the Z-axis direction. And continuously controlling the position of the joining head so as to move.

  According to the present invention, when a friction stir welding device (FSW device) is used in a production line with a short required tact time, even if the welding tool is bent in the Z-axis direction (upward) due to a reaction force, the welding tool is accurately obtained. It is possible to correct the position in the Z-axis direction (upward).

  That is, it is possible to realize a friction stir welding apparatus and a friction stir welding method capable of high-quality (high accuracy) joining between members to be joined even in a production line with a short required tact time.

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

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole outline | summary of the friction stir welding apparatus which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole outline | summary of the friction stir welding apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the friction stir welding method which concerns on one Embodiment of this invention.

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

  The friction stir welding apparatus and the friction stir welding method of Example 1 will be described with reference to FIGS. 1 and 2 are views showing an overall outline of the friction stir welding apparatus 1 of the present embodiment. FIG. 1 shows a state before the joining tool portion 6 is inserted into the member 9 (9a, 9b) to be joined (that is, before the start of joining), and FIG. 2 shows a joining tool on the member 9 (9a, 9b) to be joined. The state in which the part 6 is inserted and the friction stir welding is performed is shown. FIG. 3 is a flowchart showing a typical friction stir welding method (control method) according to this embodiment.

  FIG. 1 shows a state in which the reference distance (L1) is measured in a “measurement mode” to be described later. Since it is often executed, the joining tool portion 6 (the shoulder portion 7 and the probe portion (joining pin) 8) is indicated by a dotted line.

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

  This probe part (joint pin) 8 is inserted into the abutting part of the joined member 9 (9a, 9b) placed on the mounting table 10 and rotated at a high speed so that the probe part (joint pin) 8 and the joined part are joined. Frictional heat is generated between the members 9 (9a, 9b), plastic flow is generated in the members 9 (9a, 9b) to be joined by the frictional heat, and 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 together.

  1 shows a configuration in which the holder unit 5 and the welding tool unit 6 are connected (held) to the apparatus main body 2 via the holder unit holding unit 4 and the vertical movement drive mechanism unit 3, but the present invention is not limited thereto. For example, a configuration that is connected (held) to the apparatus main body 2 only through the vertical movement drive mechanism unit 3 or a structure that is 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 the configuration of FIG. The configuration connected (held) to the apparatus main body 2 having a robot arm is also included in the scope of the present embodiment.

  A distance measurement sensor 11 is provided in the holder part (joining head) 5. The distance measurement sensor 11 is disposed on the traveling direction (joining direction) side of the holder part (joining head) 5 during joining, and a predetermined position (the distance measuring sensor 11) of the holder part (joining head) 5 (distance measuring sensor 11). The distance between the first reference point) and a predetermined position (called the second reference point) on the member 9 (9a, 9b) to be joined is measured. The first reference point and the second reference point are arranged (set) at positions facing each other.

  For the distance measurement sensor 11, for example, a non-contact displacement sensor such as a laser displacement sensor using a laser is used. Alternatively, a contact displacement sensor such as a linear gauge may be used as long as the distance measurement and the friction stir welding process are not affected. When the laser displacement sensor is used, the first reference point is a distance measurement signal irradiation point of the distance measurement sensor 11 as shown in FIG.

  The apparatus main body 2 is provided with a control unit (control apparatus) 12 that controls the operation of the friction stir welding apparatus 1. The control unit (control device) 12 is a welding condition signal for determining a welding condition by the welding tool unit 6, and a holding position in the height direction (Z direction) of the welding tool unit 6 by the vertical movement drive mechanism unit 3 (of the bonding pin 8. A storage unit (not shown) is provided for storing a bonding parameter (FSW bonding condition) such as a holding position determination signal for determining an insertion amount).

  Further, the apparatus main body 2 is provided with a linear drive mechanism 13 that can be driven in the X-axis direction, and the upper part of the apparatus main body 2 is moved along the rail 14 of the linear guide provided in the X-axis direction. Thus, the holder part (joining head) 5 can be moved in the X-axis direction (joining direction).

  A typical friction stir welding method (control method) using the distance measuring sensor 11 described above will be described with reference to FIGS. 2 and 3.

  First, according to a command from the control unit (control device) 12, before the start of friction stir welding (as shown in FIG. 1, the welding tool unit 6 is removed from the holder unit (joining head) 5 or the welding tool unit 6 is joined. A reference distance (L1), which is the distance between the first reference point and the second reference point, is measured by the distance measuring sensor 11 before the member 9 (before being inserted into the joint portion of 9a, 9b). (Step S1) Here, this step S1 is referred to as “measurement mode”.

  That is, the control unit (control device) 12 is configured so that the tip position of the bonding tool unit 6 (probe unit 8) is inserted before the bonding tool unit 6 (probe unit 8) is inserted into the member 9 (9a, 9b). Is a distance between the first reference point and the second reference point without joining the members to be joined 9 (9a, 9b). A “measurement mode” for acquiring the reference distance (L1) from the distance measurement sensor 11 is provided.

  In this “measurement mode”, the first reference point and the second reference point from the joining start position to the joining end position on the joined member 9 (9a, 9b) are moved by moving the holder portion (joining head) 5 in the joining direction. The reference distance is acquired continuously or at a predetermined interval (a predetermined distance interval or a predetermined time interval).

Next, the first reference point and the second reference point are detected by the distance measurement sensor 11 during friction stir welding (after a predetermined time (t) has elapsed since the start of welding) according to a command from the control unit (control device) 12. The current distance (L2), which is the distance to (Step S2)
During friction stir welding, a “burr” is generated near the boundary between the welding tool portion 6 (probe portion 8) and the member 9 (9a, 9b), so the current distance (L2) is avoided by avoiding this “burr”. It is preferable to dispose the distance measuring sensor 11 at a position where it can be measured.

  Subsequently, the control unit (control device) 12 calculates a deviation (ΔL) between the reference distance (L1) measured in step S1 and the current distance (L2) measured in step S2, and sets a predetermined value ( Threshold value: Lt). (Step S3) This deviation (ΔL) is the amount of deflection of the welding tool portion 6 during friction stir welding.

When the deviation (ΔL) between the reference distance (L1) and the current distance (L2) exceeds the threshold value (Lt) (ΔL> Lt), the deviation (ΔL) and the distance calculated according to a command from the control unit (control device) 12 The member 9 (9a, 9b) to be joined while controlling the position in the Z-axis direction (vertical direction) of the welding tool portion 6 at a predetermined change rate (moving speed) based on the time difference (ΔT) between the measurement position and the welding tool position. Friction stir welding is performed. (Step S4)
Here, this step S4 is referred to as “control mode”. In this “control mode”, the control unit (control device) 12 generates a deviation (ΔL) in the Z-axis direction when the deviation (ΔL) calculated in step S3 exceeds a predetermined value (threshold: Lt). A change position signal of the holder part (joining head) 5 that corrects the deviation (ΔL) in the direction opposite to the direction is generated and output to the apparatus main body 2.

  That is, after the joining tool part 6 is inserted in the member 9 (9a, 9b) to be joined, the control unit (control device) 12 is connected to the first reference point and the second on the member 9 (9a, 9b). When the current distance, which is the distance to the reference point, is acquired from the distance measurement sensor 11, the deviation between the acquired current distance and the corresponding reference distance is calculated, and the calculated deviation exceeds a predetermined value In addition, it has a “control mode” in which a change position signal of the holder part (joining head) 5 that corrects the deviation in the direction opposite to the direction in which the deviation occurs in the Z-axis direction is generated and output to the apparatus main body 2.

  The change position signal is generated by, for example, moving the holder unit (joining head) 5 by a predetermined distance per unit time until the current distance (L2) or deviation (ΔL) reaches a predetermined value range. Output continuously. The apparatus main body 2 sets the position of the holder part (joining head) 5 in the Z-axis direction based on the change position signal acquired from the control part (control apparatus) 12, and sets the holder part (moving speed) at a predetermined change rate (moving speed). The joining head 5 is moved.

  This “control mode” may be continuously performed during the friction stir welding, or may be controlled to be repeated intermittently at a predetermined time interval.

  Further, the predetermined time interval for repeating the “control mode” is determined in advance based on the characteristics of the members 9 (9a, 9b) to be bonded, and the predetermined time intervals corresponding to the characteristics of the members 9 (9a, 9b) are determined. It is also possible to select a value corresponding to the characteristic of the member 9 (9a, 9b) to be joined from the stored characteristic table.

  Further, in the “control mode”, after the change position signal is output based on the deviation (ΔL), a “control stop mode” for stopping the control mode may be set to control intermittently.

  As shown in FIG. 2, since the distance measurement position (measurement position of the current distance (L2)) and the position of the welding tool portion 6 are different, the time difference (ΔT) of the difference (distance) of this position is delayed and controlled. There is a need to. Accordingly, in step S4, in addition to the deviation (ΔL) calculated in step S3, the time difference (ΔT) between the distance measurement position (measurement position of the current distance (L2)) and the position difference (distance) of the welding tool portion 6 is calculated. Take control into consideration.

  That is, the distance measurement sensor 11 and the welding tool part 6 are separated by a fixed distance (a constant distance), and the fixed distance (a constant distance) is required until the welding tool part 6 reaches the point measured by the preceding distance measurement sensor 11. Since a time difference (ΔT) by (distance) occurs, the control timing is matched with the speed and distance in the X-axis direction.

  The time difference (ΔT) is calculated by time (T) = distance (L) / speed (V). Here, the speed (V) is a speed (constant speed) number m / min at the time of joining, and the distance (L) is a distance (fixed distance) between the centers of the joining tool portion 6 and the distance measuring sensor 11.

On the other hand, when the deviation (ΔL) between the reference distance (L1) and the current distance (L2) is equal to or less than the threshold value (Lt) (ΔL ≦ Lt), the position control of the welding tool portion 6 in the Z-axis direction (vertical direction) is performed. Instead, the friction stir welding of the member 9 (9a, 9b) to be joined is continued while maintaining the joining condition when the current distance (L2) is measured. (Step S5)
Thereafter, when the movement amount (elapsed time) of the welding tool unit 6 reaches a predetermined value (position / time) according to a command from the control unit (control device) 12, the welding tool unit 6 is joined to the member 9 (9a). 9b), and the friction stir welding process is completed. (Step S6)
As described above, according to the friction stir welding apparatus and the friction stir welding method of the present embodiment, the predetermined position (first measurement) of the holder part (joining head) 5 (distance measurement sensor 11) before the start of friction stir welding is performed. The distance (reference distance: L1) between the reference point) and a predetermined position (second reference point) on the member 9 (9a, 9b) to be joined is measured, and during friction stir welding (predetermined from the start of joining) The distance (current distance: L2) between the first reference point and the second reference point is measured again after the elapse of time (t) so that the deviation ΔL (L2−L1) is within a predetermined range. By correcting the position of the welding tool part 6 in the Z-axis direction (vertical direction), it is possible to correct the bending caused by the pressing of the welding tool part 6.

  Thereby, even if it is a production line with a short required tact time, it becomes possible to join the members to be joined with high quality (high accuracy).

  In addition, in step S6 of FIG. 3, friction stir welding is started from one end of the member 9 (9a, 9b) to be joined, and friction stir welding is continuously performed to the other end of the member 9 (9a, 9b). By performing so-called “line bonding”, the quality (reliability) of bonding can be further improved.

  The present invention is not limited to the above-described embodiments, 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. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Friction stir welding apparatus, 2 ... Apparatus main body, 3 ... Vertical motion drive mechanism part (ball screw), 4 ... Holder part (joining head) holding part, 5 ... Holder part (joining head), 6 ... Joining tool part, DESCRIPTION OF SYMBOLS 7 ... Shoulder part, 8 ... Probe part (joining pin), 9, 9a, 9b ... Joined member, 10 ... Mounting stand, 11 ... Distance measuring sensor, 12 ... Control part (control apparatus), 13 ... (X-axis direction) ) Linear drive mechanism, 14 ... Rail of the linear guide (X axis).

Claims (13)

A welding tool composed of a shoulder part and a probe part, inserted into a member to be joined and rotated,
A joining head for holding the joining tool;
An apparatus main body for holding the joining head, rotating the joining tool, and moving the joining tool;
A control device for controlling the operation of the welding tool;
Distance measuring means for measuring a distance between a first reference point which is a predetermined position of the bonding head and a second reference point which is a predetermined position on the member to be bonded placed on a mounting table equipped with a,
The control device lowers the tip position of the joining tool to the Z-axis direction position during joining before the joining tool is inserted into the joined member, and joins the joined member. The friction stir welding apparatus has a measurement mode in which a reference distance, which is a distance between the first reference point and the second reference point, is acquired from the distance measuring means without performing the operation . The friction stir welding apparatus according to claim 1 ,
In the measurement mode, the control device moves the joining head in the joining direction so that the first reference point and the second reference point on the joined member from the joining start position to the joining end position To obtain the reference distance continuously or at a predetermined interval. The friction stir welding apparatus according to claim 1 or 2 ,
After the joining tool is inserted into the joined member, the control device determines a current distance, which is a distance between the first reference point and the second reference point on the joined member, as the distance. Obtained from the measuring means,
Calculate the deviation between the acquired current distance and the corresponding reference distance,
When the calculated deviation exceeds a predetermined value, a control for generating a change position signal of the joining head for correcting the deviation in a direction opposite to the direction in which the deviation has occurred in the Z-axis direction and outputting it to the apparatus main body A friction stir welding apparatus having a mode. The friction stir welding apparatus according to claim 1 or 2 ,
After the joining tool is inserted into the joined member, the control device determines a current distance, which is a distance between the first reference point and the second reference point on the joined member, as the distance. Obtained from the measuring means,
Calculate the deviation between the acquired current distance and the corresponding reference distance,
When the calculated deviation exceeds a predetermined value, a change position signal for moving the bonding head by a predetermined distance per unit time in a direction opposite to the direction in which the deviation has occurred in the Z-axis direction is generated.
A friction stir welding apparatus having a control mode in which the current distance is continuously output to the apparatus main body until the current distance reaches the range of the predetermined value. The friction stir welding apparatus according to claim 3 or 4 ,
The apparatus main body sets a position in the Z-axis direction of the bonding head based on the change position signal acquired from the control device, and moves the bonding head at a predetermined change rate. apparatus. The friction stir welding apparatus according to claim 3 or 4 ,
The control device repeats the control mode at a predetermined time interval. The friction stir welding apparatus according to claim 1 or 2 ,
In the measurement mode, the friction stir welding apparatus is characterized in that the reference distance is obtained by removing the welding tool from the welding head. The friction stir welding apparatus according to claim 1,
The friction stir welding apparatus according to claim 1, wherein the first reference point is a distance measurement signal irradiation point of the distance measuring means. The friction stir welding apparatus according to claim 1,
The distance stirrer is a displacement sensor, and is a friction stir welding apparatus. The friction stir welding apparatus according to claim 9 ,
The friction stir welding apparatus is characterized in that the displacement sensor is either a non-contact type or a contact type. The friction stir welding apparatus according to claim 1,
The friction stir welding apparatus according to claim 1, wherein the distance measuring means is installed on the joining head on the traveling direction side of the joining tool. The friction stir welding apparatus according to claim 1,
The apparatus main body starts friction stir welding from one end of the member to be joined and continuously performs friction stir welding to the other end of the member to be joined. A friction stir welding method for joining members to be joined by friction stir welding,
(A) Before inserting the joining tool into the member to be joined, the tip position of the joining tool is lowered to the position in the Z-axis direction at the time of joining, alignment is performed, and the first position which is a predetermined position of the joining head A reference distance, which is a distance between a reference point and a second reference point that is a position facing the first reference point and is a predetermined position on the member to be joined, is measured at the joining start position. Steps,
(B) After the step (a), the step of inserting the joining tool into the member to be joined and proceeding to a joining stage for joining the member to be joined;
(C) after the step (b), in a joining step, measuring a current distance that is a distance between the first reference point and the second reference point;
(D) A deviation between the current distance and the reference distance is calculated, and when the calculated deviation exceeds a predetermined value, the deviation in a direction opposite to the direction in which the deviation occurs in the Z-axis direction of the welding tool. The position of the bonding head corrected in magnitude is set, or the bonding head is moved in unit time until the deviation reaches the predetermined value in the direction opposite to the direction in which the deviation occurs in the Z-axis direction. Continuously controlling the position of the joining head to move a predetermined distance per hit;
A friction stir welding method characterized by comprising:

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