JP4505855B2 - Rotating tool for friction welding equipment - Google Patents

Description

  The present invention relates to a rotary tool used in a friction welding apparatus that joins a plurality of metal plates.

2. Description of the Related Art Conventionally, there is known a friction welding apparatus that joins a plurality of stacked materials to be joined by rotation of a rotary tool (see Patent Document 1).
JP 2003-48082 A

  However, the conventional friction welding apparatus is effective when joining light metals having substantially the same melting point such as aluminum, but for joining metals having different melting points such as aluminum and steel, the friction joining method is used. If it was adopted as it was, there was a problem.

  That is, when joining light metals with almost the same melting point, such as aluminum, there is no problem even if the tip part of the rotary tool reaches the second layer metal material, but for example, metals with different melting points such as aluminum material and steel material. In the joining, there is a problem that when the tip of the rotary tool reaches the steel material and the steel material comes into contact with water or the like, the corrosion resistance is remarkably lowered due to a potential difference. However, in the past, sufficient consideration has not been given to the relationship between the tip shape of the rotary tool and the shape of the material to be coupled, and the tip shape of the rotary tool has not necessarily been the optimum shape.

  The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a rotary tool capable of stably joining different kinds of metal plates.

In order to achieve the above object, in the present invention, the first metal plate and the second metal plate having a melting point higher than that of the first metal plate are overlapped, and the friction for spot joining from the first metal plate side is achieved. the rotary tool used in the bonding apparatus, a substantially cylindrical body portion, provided on the distal end surface center of the body portion, and a substantially cylindrical pin portion of smaller diameter than the main body portion, front Stories body portion An annular mortar-shaped recess for filling the material of the first metal plate at the time of joining is formed on the front end surface of the pin portion, and the pin portion protruding in the axial direction of the rotary tool from the outer edge of the main body portion. The length is A, the outer diameter of the outer edge of the tip of the main body is B, the outer diameter of the pin is C, the inclination angle of the recess of the tip is α, and the thickness of the first metal plate is T In this case, 0.2 ≦ A ≦ T − ((BC) × tan α) /2−0.2 (the unit is mm) And wherein the determining the respective dimensions so that.

Thereby, since the length of the pin portion is set shorter than the thickness of the first metal plate, the tip of the pin portion is filled with the material of the first metal plate in the recess without contacting the second metal plate. Can be made. As a result, the first metal plate and the second metal plate can be spot-bonded without exposing the second metal plate to the surface after bonding, and stable bonding quality is ensured while preventing a decrease in corrosion resistance due to a potential difference. can do. Moreover, the generation | occurrence | production of the burr | flash at the time of joining can be suppressed, and turning of a rotary tool can be stabilized.

  The friction welding apparatus softens the first metal plate with frictional heat generated by rotation of the rotary tool and plastically flows the solid metal to join the mating surfaces of the first metal plate and the second metal plate. It is characterized by. According to this, it becomes possible to join dissimilar metal plates with sufficient strength.

  The first metal plate is an aluminum alloy material, and the second metal plate is a steel material. According to this, it becomes possible to join the aluminum alloy material and the steel material, which has been difficult in the past, with sufficient strength.

  ADVANTAGE OF THE INVENTION According to this invention, the rotary tool which can perform the joining of dissimilar metal plates stably can be provided.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the constituent elements described in this embodiment are merely examples, and are not intended to limit the scope of the present invention only to them.

  FIG. 1 is a diagram showing an overall configuration of a friction welding apparatus according to an embodiment of the present invention. This friction welding apparatus 100 is used for spot joining a plurality of materials to be joined used in an automobile body or the like. If this friction welding apparatus is used, for example, an aluminum alloy plate and a steel plate can be joined as materials to be joined. The friction joining apparatus 100 includes a joining gun 1, a robot 2 that moves the joining gun 1 to a desired position and angle, and a control unit 3 that controls the joining gun 1 and the robot 2. As the robot 2, for example, a general-purpose 6-axis vertical articulated robot is used.

  The joining gun 1 includes a rotating tool 4 and a receiving tool 5 as joining tools. The rotary tool 4 is moved up and down for pressurization by a pressure shaft motor (not shown) as a pressing means, and is rotated by a rotation shaft motor (not shown) as a rotation drive means. An induction motor or a servo motor can be used as the rotary shaft motor, and a servo motor can be used as the pressure shaft motor. The receiver 5 is disposed at the tip of the L-shaped arm so as to face the rotary tool 4. The rotating tool 4 and the receiving tool 5 are configured to be detachable from the joining gun 1.

  The control unit 3 is configured to be able to control the six axes of the robot 2 and the rotational speed and pressing force of the rotary tool 4 in the welding gun 1. That is, the control unit 3 controls the pressure shaft motor and the rotary shaft motor.

  FIG. 2A is a diagram for explaining the configuration of the distal end portion of the rotary tool 4. The rotary tool 4 has a substantially cylindrical main body portion 4a having a concave front end surface and a substantially cylindrical pin portion 4b provided at the center of the front end surface of the main body portion and having a smaller diameter than the main body portion. Have. The pin portion 4b is provided in order to properly perform centering (positioning function, position shift prevention function) of the rotary tool. The tip of the pin portion 4b protrudes from the tip surface of the main body portion 4a in the direction of the rotation axis X of the rotary tool, and the axis of the pin portion 4b matches the axis of the main body portion 4a.

  This rotary tool is for joining the aluminum plate W1 and the steel plate W2 as different materials, particularly materials having different melting points (softness). Therefore, the protrusion length of the pin part 4b is set short compared with the rotary tool for joining the same kind of materials (for example, aluminum materials). This is because, when the pin portion 4b is lengthened and hits the lower steel plate W2, the plating layer 8 formed in advance on the surface of the steel plate W2 is peeled off, and the surface of the steel plate W2 comes into contact with water or the like, and corrosion easily occurs. Because.

The plating layer 8 is formed to prevent an oxide film from being generated on the surface of the steel plate W2, and is made of, for example, zinc or a zinc alloy. Specifically, for example, a galvanized steel sheet having a coating thickness of 90 g / m ^{2 and a} thickness of 1 to 1.2 mm is bonded to a 5000 series aluminum alloy plate or a 6000 series aluminum alloy plate having a thickness of 0.7 to 2.0 mm. be able to.

  In FIG. 2 (a), the tip of the pin portion 4b is formed as a flat surface. However, the present invention is not limited to this, and may have a curved surface shape or a conical shape. May be.

  On the other hand, on the front end surface of the main body portion, an annular recess for filling the material of the first metal plate at the time of joining from the shoulder portion 4c existing on the outer periphery of the front end of the main body portion 4a toward the outer peripheral surface of the pin portion 4b. 4d is formed. Since the aluminum plate W1 softened by frictional heat is filled in the recess 4d, the amount of W1 flowing outside the rotary tool 4 is reduced, and the generation of burrs can be suppressed. Further, the aluminum plate W1 filled in the recess 4d can be plastically flowed in the rotational axis X direction of the rotary tool, and the bonding strength is higher than when the recess 4d is not formed on the tip surface of the rotary tool 4. .

  In the drawing, the length A1 of the pin portion 4b protruding in the axial direction of the rotary tool from the front end surface of the main body portion 4a is set to be smaller than the thickness T of the aluminum plate W1 that is the first metal plate. Thus, if the length A1 of the pin portion 4b is set to be smaller than the thickness of the first metal plate, the first metal plate and the second metal plate are spot-joined without exposing the second metal plate to the joint surface. Therefore, stable joint quality can be ensured while preventing a decrease in corrosion resistance due to a potential difference.

  The recess 4d of the main body 4a is formed in a mortar shape as shown in the figure, but the inclination angle α of the recess 4d of the main body 4a is set according to the thickness T of the aluminum plate W1. Specifically, in order to make it difficult to discharge the softened aluminum plate W1 as burrs and to generate a sufficient pressure, the inclination angle α is set to a value larger than 0 °. Furthermore, the inclination angle α is set to be equal to or smaller than an angle at which the aluminum plate W1 pushed away by the pin portion 4b is filled in the concave portion 4d of the rotary tool 4. That is, when the inclination angle α of the recess 4a is equal to or greater than a predetermined value, a space that is not filled with the aluminum plate W1 is formed in the recess 4d when the aluminum plate W1 is pressed by the rotated rotary tool 4. This predetermined value is determined by the thickness T of the aluminum plate W1, and the inclination angle α must be smaller than such a predetermined value.

  Thus, if the inclination angle α of the mortar-shaped recess 4d is set according to the thickness T of the aluminum plate W1, the softened aluminum plate W1 can be reliably filled in the recess 4d, and the burr at the time of joining can be reduced. While suppressing the generation, plastic flow due to friction can be promoted, and a stable bonding strength can be obtained.

  Further, the length A of the pin portion 4b protruding from the shoulder portion 4c at the outer peripheral edge of the main body portion in the direction of the axis X of the rotary tool, the outer diameter B of the shoulder portion 4c, the outer diameter C of the pin portion 4b, and the inclination The dimension of the rotary tool 4 is determined so that the angle α and the thickness T of the aluminum plate W1 satisfy the following relationship.

0.2 ≦ A ≦ T − ((BC) × tan α) /2−0.2 (unit is mm) (1)
Here, the reason why the pin length A is made larger than 0.2 mm is to stabilize the turning center of the rotating tool 4 being joined. Further, in the above formula, 0.2 is subtracted in the right term in the pushing state in which the deepest portion of the recess 4d (the root of the pin portion 4b) is filled with the aluminum plate W1 and the steel plate W2 This is because a margin of 0.2 mm is always provided between the upper surface and the upper surface. When the above formula (1) is modified and the dimension of the rotary tool 4 and the dimension of the aluminum plate W1 are separately written, the following is obtained.

A + ((BC) × tan α) /2+0.2≦T (2)
Section where the left side is obtained by adding a 0.2mm the length from the root of the pin portion 4b, the value is set to be less than the thickness T of the aluminum plate W1.

  If the dimensions of the rotary tool are determined in this way, it is possible to prevent the corrosion resistance from being lowered due to the steel plate W2 being exposed on the surface after joining while stabilizing the turning of the rotary tool.

  Furthermore, the outer diameter B of the shoulder portion 4c and the outer diameter C of the pin portion 4b are set so as to satisfy the following expression.

0.2 × B ≦ C ≦ 0.5 × B (3)
If the dimensions of the rotary tool are determined in this manner, the pin portion 4b can be prevented from being broken when contacting the aluminum plate W1, and the frictional heat due to the rotation of the rotary tool 4 can be sufficiently generated.

In FIG. 2A, the distal end surface 4d of the body 4a has been a mortar shape, the inside and outer edge of the shoulder portion 4c of the concave portion, a plane parallel to the surface of the aluminum plate W1 may be formed.

  FIG. 3 is a diagram for explaining the control of the pressing force and the number of rotations of the rotary tool 4 by the control unit 3.

  First, the rotary tool 4 is lowered and brought into contact with the aluminum plate W1, and the rotary tool 4 is held in a state where the aluminum plate W1 and the steel plate W2 which are metal plates are gripped by the pin portion 4b of the rotary tool and the receiving member 5. Is maintained at N1 (for example, 0.98 to 3.43 kN) and the rotational speed is maintained at P1 (for example, 3000 to 3500 rpm). As a result, heat (friction heat) is generated on the surface of the aluminum plate W1 due to the rotation of the rotary tool 4. By such heating of the aluminum plate W1, the aluminum plate W1 is softened, the centering by the pin portion 4b can be performed reliably, and the turning center of the rotating root 4 is determined.

  Next, the pressing force of the rotary tool 4 is increased to N2 (for example, 2.45 to 5.88 kN) after a predetermined time from the start of rotation. By increasing the pressing force to N2, the rotary tool 4 enters the softened aluminum plate W1. However, N2 is determined so that the pin portion 4b does not contact the steel plate W2 at this time. As a result, as shown in FIG. 2B, the aluminum in a portion having a high contact pressure with the rotary tool 4 plastically flows, and accordingly, the galvanized 8 softened by heat is diffused, and the outer peripheral side of the rotary tool 4 is diffused. Is discharged. At the same time, the oxide film on the steel plate W2 side surface of the aluminum plate W1 is also destroyed, and the new surface of the aluminum plate W1 and the new surface of the steel plate W2 are in direct contact with each other, so that solid phase bonding occurs.

  At this time, if the rotational speed is high, the plastic flow of the aluminum plate W1 is performed only in a range very close to the rotary tool 4, and solid phase bonding may not be performed well. Therefore, here, the rotational speed is reduced to P2 (for example, 1500 to 2500 rpm), and a large plastic flow is generated by relatively slow rotation.

  4A to 4C are diagrams showing the relationship between the tip surface shape of the main body portion 4a and the shape of the pin portion 4b and the allowable range when the pin length A is variously changed. 4 (a) and 4 (b) show that when the shoulder diameter B is 10 mm and the pin diameter C is 2 mm, the length A is 0.3 mm, 0.5 mm, and 0.8 mm. What is the value obtained by adding 0.2 mm to the distance from the tip of the pin to the base (the entire length of the pin portion 4b) by increasing the inclination angle α of each type of rotating tool 4 by 2 ° from 1 ° to 9 °? It is the graph which showed whether it changes to. That is, a value obtained by adding 0.2 mm to the entire length of the pin portion 4b assuming a total of 15 types of rotating tools 4 is plotted.

  As shown in the above formula (2), the value obtained by adding 0.2 mm to the distance from the tip of the pin to the base (the entire length of the pin portion 4b) must be smaller than the thickness T of the aluminum plate W1. . Therefore, when the thickness T of the aluminum plate W1 is 0.8 mm, the length A of the pin portion 4b is 0.3 mm among the 15 types of assumed rotary tools 4 as shown in FIG. It can be seen that if the inclination angle α is 1 ° or 3 °, bonding can be performed without any problem. That is, in the case of thin plate bonding with a thickness of about 0.8 mm, the pin length and the inclination angle can be set only within a limited range. In particular, 3 ° having a large inclination angle α is preferable for suppressing the generation of burrs and promoting plastic flow.

  On the other hand, when the thickness T of the aluminum plate W1 is 1.4 mm, as shown in FIG. 4 (b), the length A of the pin portion 4b is 15 mm among the assumed 15 types of rotary tools 4. It can be seen that joining can be performed without any problems except for those having an inclination angle α of 7 ° or 9 °. That is, in the case of thick plate bonding of about 1.4 mm in thickness, both the pin length and the inclination angle can be set in a wide range. However, if the angle of inclination is small, burrs are likely to occur, resulting in a decrease in strength. Therefore, it is desirable that the angle of inclination be larger in thick plate bonding than in thin plate bonding.

  FIG. 4C shows a shoulder tool B: 10 mm, a pin diameter C: 5 mm, a pin part 4 b, a length A: 0.2 mm, a rotating tool 4, a shoulder diameter B: 10 mm, a pin diameter C: 2 mm, and a pin part 4 b. It is assumed that the rotary tool 4 has a length A of 0.5 mm, and the rotary tool 4 has a shoulder diameter B of 10 mm, a pin diameter C of 2 mm, and a pin portion 4b length A of 0.8 mm. In the case of thick plate joining with a thickness of 2.0 mm, to what extent the inclination angle α can be increased for these three types of rotary tools 4 is shown.

  As shown in FIG. 4 (c), the smaller the length of the pin portion 4b, the larger the pin diameter C, the larger the inclination angle α, the shoulder diameter B: 10 mm, the pin diameter C: 5 mm, the pin In the case of the rotating tool 4 having a length 4b of part 4b of 0.2 mm, it can be seen that even if the inclination angle is increased to about 33 °, there is no problem in the case of 2 mm thick plate joining.

  As described above, in the present embodiment, the first metal plate W1 and the second metal plate W2 having a melting point higher than that of the first metal plate are overlapped, and the friction bonding apparatus is used for point joining from the first metal plate W1 side. The rotating tool 4 used includes a substantially cylindrical main body portion 4a and a substantially cylindrical pin portion 4b provided at the center of the front end surface of the main body portion 4a and having a smaller diameter than the main body portion 4a. The length A1 of the pin portion 4b protruding from the tip surface in the axial direction of the rotary tool is set to be shorter than the plate thickness T of the first metal plate W1, and the first metal plate W1 is joined to the tip surface of the main body portion 4a at the time of joining. An annular recess 4b for filling the film was formed.

  As a result, the first metal plate W1 and the second metal plate W2 can be spot-bonded without exposing the second metal plate W2 to the surface after bonding, and stable bonding while preventing a decrease in corrosion resistance due to a potential difference. Quality can be ensured.

It is a figure which shows schematic structure of the friction welding apparatus which concerns on embodiment of this invention. It is a figure which shows schematic structure of the rotary tool which concerns on embodiment of this invention. It is a figure which shows the joining state which pushed in rotating the rotary tool which concerns on embodiment of this invention. It is a figure explaining pressing force control and rotation speed control concerning an embodiment of the present invention. It is a graph explaining the optimal shape of the rotary tool which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Friction welding apparatus 1 Joining gun 2 Robot 3 Control part 4 Rotating tool 5 Receptacle

Claims (3)

In the rotary tool used in the friction welding device for overlapping the first metal plate and the second metal plate having a higher melting point than the first metal plate, and performing point joining from the first metal plate side,
A substantially cylindrical body,
Provided in the center of the front end surface of the main body, a substantially cylindrical pin portion having a smaller diameter than the main body,
With
An annular mortar-shaped recess for filling the material of the first metal plate at the time of joining is formed on the front end surface of the main body,
The length of the pin portion protruding in the axial center direction of the rotary tool from the outer edge of the main body portion is A,
The outer diameter of the outer edge of the tip of the main body is B,
The outer diameter of the pin portion is C,
The inclination angle of the concave portion of the tip surface is α,
When the thickness of the first metal plate is T,
0.2 ≦ A ≦ T − ((BC) × tan α) /2−0.2 (unit is mm)
The rotation tool of the friction welding apparatus, wherein each dimension is determined so that   The friction welding apparatus softens the first metal plate with frictional heat generated by rotation of the rotary tool and plastically flows the solid metal to join the mating surfaces of the first metal plate and the second metal plate. The rotary tool of the friction welding apparatus according to claim 1.   The rotary tool of the friction welding apparatus according to claim 1 or 2, wherein the first metal plate is an aluminum alloy material and the second metal plate is a steel material.

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