JP3644831B2 - Resistance welding apparatus and welding method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a resistance welding apparatus suitable for resistance welding two objects to be welded, particularly indirect welding of a rotor and a shaft of an automobile engine.
[0002]
[Prior art]
As an example describing a resistance welding electrode structure for indirect welding of a rotor and a shaft, there is JP-A-3-57570. This is characterized by the fact that the welding electrode has a die-set structure in order to increase the coaxiality of the rotor with respect to the shaft. It can be made very small, so that the coaxiality between the shaft and the rotor supported on each of the welding electrodes can be increased.
[0003]
[Problems to be solved by the invention]
However, in a resistance welding apparatus having a die-set structure welding electrode by the indirect welding method, a mechanism for applying pressure from both above and below is required during welding. In order for the mechanism that applies the pressing force from below to stably receive the pressing force from above, it is necessary to be a mechanism that applies approximately twice the pressing force from above. For example, if the applied pressure from above during welding is about 3 tons, the applied pressure from below must be about 6 tons, which requires a very large pressurizing mechanism and increases the size of the device. Not only does this have the disadvantage of being expensive.
[0004]
Therefore, the main object of the present invention is to provide a resistance welding apparatus and method for performing welding without applying a pressing force from below while maintaining the coaxial accuracy of the workpieces without forming the welding electrode in a die set structure. To do.
[0005]
[Means for solving problems]
In order to solve the problems as described above, in the first invention, in a resistance welding apparatus that performs resistance welding of a rod-shaped first workpiece to be welded and a second workpiece to be welded, which is longer than the diameter , A base mechanism having mechanical strength capable of withstanding the applied pressure, an X and Y direction drive mechanism capable of moving the second workpiece in the X and Y directions, and the second workpiece. And a support mechanism coupled to a part of the X and Y direction drive mechanism through a linear guide mechanism, and a pressure between the X and Y direction drive mechanism and the support mechanism. In the state where the bearing is not applied, the support mechanism is lifted from the base mechanism, the spring mechanism enabling the support mechanism to move up and down, the first welding electrode capable of supporting the first work piece, and the first The first welding object and the front work together with the welding electrode of A second welding electrode capable of causing a welding current to flow on a joint surface with the second workpiece, and gripping the first workpiece in the middle of the longitudinal direction of the first welding electrode. There is provided a resistance welding apparatus including a positioning mechanism for performing positioning, the positioning mechanism being provided to move together with the first welding electrode .
[0006]
In order to solve the above-described problems, in the second invention, in the first invention, the welding current substantially equals the pressure applied to the workpiece by at least the first welding electrode when the welding current is passed. Tempering by passing a single pulse current when the temperature of the welded portion of the first and second workpieces decreases to about the transformation point. After being performed, the resistance welding apparatus is characterized in that the pressure applied to the first welding electrode is released .
[000 7 ]
In order to solve the above-described problems, in the third invention, resistance welding is performed by passing a welding current between the rod-shaped first workpiece to be welded and the second workpiece to be welded that are longer than the diameter. In a resistance welding apparatus having a first welding electrode and a second welding electrode, a positioning mechanism is provided in the middle of the longitudinal direction of the first welding electrode for gripping and positioning the first workpiece. The positioning mechanism is provided in the middle of the first positioning member extending from the opening in the middle of the first welding electrode to the set position in the longitudinal cavity and the longitudinal wall of the first welding electrode. And a second positioning member that positions by moving forward and backward through the opening and selectively gripping the rod-shaped first workpiece in cooperation with the first positioning member. A resistance welding apparatus is provided.
[000 8 ]
In order to solve the above-described problems, in the fourth invention, resistance welding is performed by passing a welding current between the rod-shaped first workpiece to be welded and the second workpiece to be welded which is longer than the diameter. In a resistance welding method having a first welding electrode and a second welding electrode , a positioning mechanism is provided for gripping and positioning the first workpiece in the middle of the longitudinal direction of the first welding electrode. The positioning mechanism grips the first workpiece and descends together with the first welding electrode while maintaining the positioning state, and freely moves the second workpiece in the X and Y directions. X, Y that can be moved to A direction drive mechanism drives the first work piece and the second work piece so as to coincide with each other. Provided is a resistance welding method in which a first pulsed welding current is passed to weld the first workpiece and the second workpiece.
[000 9 ]
BEST MODE FOR CARRYING OUT THE INVENTION
First, an embodiment of a resistance welding apparatus according to the present invention will be described with reference to FIGS. 1 and 2, a first welding electrode 1 has a longitudinal cavity 1a that can be received except for a tip portion of a first workpiece 3 such as a shaft, and supplies a welding current. A lower pressurizing force is applied during welding by a pressurizing mechanism not shown.
[00 10 ]
A positioning mechanism 2 is disposed midway in the longitudinal direction of the first welding electrode 1. The positioning mechanism 2 is provided so as to move together with the first welding electrode 1. The positioning mechanism 2 is fixed in the middle of the first welding electrode 1 and extends into the longitudinal cavity 1a. A movable positioning member that moves forward and backward through an opening 1b provided in the middle of the longitudinal wall of the electrode 1 to selectively position the rod-shaped first workpiece 1 in cooperation with the fixed positioning member 2a. 2b.
[00 11 ]
The distal end portion of the fixed positioning member 2a has a V-shaped groove 2a1 so as to come into contact with the rod-shaped first workpiece 3 to be inserted into the longitudinal cavity 1a of the first welding electrode 1 at two points. The movable positioning member 2b is, for example, a cylinder device, and a cylindrical member 2b3 having a diameter larger than that of the rod is attached to the distal end side of the cylinder rod 2b2 that extends from the cylinder body 2b1 and moves forward and backward. The rod-shaped first workpiece 3 can be gripped by the flat end surface of 2b3 and the V-shaped groove 2a1 of the fixed positioning member 2a.
[00 12 ]
The first workpiece 3 is, for example, a turbine shaft of an automobile engine, and the tip thereof is a large-diameter portion 3a having a diameter larger than that of the longitudinal cavity 1a of the first welding electrode 1, The large-diameter portion is inserted into the longitudinal cavity 1a of the first welding electrode 1 until the upper end surface of the large-diameter portion contacts the flat lower end surface of the first welding electrode 1.
[00 13 ]
A second workpiece 4 such as a rotor to be welded with the first workpiece 3 has a welding surface 4a larger than the welding surface of the first workpiece 3, and the welding surface has a projection. An annular protrusion 4b is formed that acts as: The second workpiece 4 is selectively gripped and released by the collet chuck mechanism 6 on the support base 5. The collet chuck mechanism 6 is a normal one, and the second work piece is subjected to an expansion / contraction diameter operation by moving in an oblique direction (arrow direction) within a range of an angle with respect to the central stationary member 6a. Collet chuck claw 6b for selectively gripping and releasing 4; and
The collet chuck claw 6b includes a tightening / opening member 6c that moves the collet chuck claw 6b in this manner.
[00 14 ]
The second welding electrode 7 includes two electrode portions 7a and 7b, and can be moved in the left-right direction and the up-down direction, or in an oblique direction by a driving device (not shown). During welding, the lower flat surfaces of the two electrode portions 7a and 7b apply pressure to the welding surface 4a of the second work piece 4, and the tip surfaces 7a1 and 7b1 face each other with a slight gap therebetween. An imaginary hole having a diameter somewhat larger than the diameter of the large diameter portion 3a is defined so as not to contact the large diameter portion 3a of the one work piece 3.
[00 15 ]
Normally, since the base member 6a of the collet chuck mechanism 6 is made of a metal material, it is placed on the support base 9 via an insulating plate 8 made of an electrically insulating material, and a part of the welding current flows through the collet chuck mechanism 6. It comes to prevent. The support base 9 is supported by a columnar column member 10, and an inner ring (not shown) of a linear motion bearing member 11 is fixed to the outer surface of the column member 10 as a linear motion guide mechanism. Eleven outer rings (not shown) are fixed to a part of the X and Y direction drive mechanism 12.
[00 16 ]
A spring member 13 is disposed so as to surround the outer wall of the linear guide mechanism 11 or the column member 10, and the spring member 13 is located between the lower surface of the support base 9 and a part of the X and Y direction drive mechanism 12, The to-be-welded object 4, the collet chuck mechanism 6, the column member 10, etc. have an elastic force that overcomes the sum of weights. Therefore, the cradle 14 fixed to the lower end of the column member 10 is configured to float from the upper surface of the base mechanism 15 when no pressure is applied. The linear motion guide mechanism 11 serves to help the vertical movement of the column member 10 smoothly.
[00 17 ]
The X and Y direction driving mechanism 12 includes an X direction driving member 12A installed on the upper surface of the base mechanism 15, a receiving member 12B provided on the base mechanism 15 and moving together with the X direction driving member 12A, and a receiving member 12B. The Y direction drive member 12C is installed on the plane and moves in the Y direction perpendicular to the X direction on the plane, and the operation / drive mechanism 12D that manually or automatically drives these drive members. The X-direction drive member 12A includes an X-direction rail 12A1 laid on the upper surface of the base mechanism 15, and an X-direction slider member 12A2 that slides on the X-direction rail 12A1. Similarly, the Y-direction drive member 12C includes a Y-direction rail 12C1 extending in the Y-direction and a Y-direction slider member 12C2 sliding on the Y-direction rail 12C1.
[00 18 ]
Accordingly, as described above, when the pressure member is not subjected to pressure, the column member 10 and the cradle 14 below the base member 15 are lifted from the upper surface of the base mechanism 15, and the lower surface of the support base 9 is also separated from the upper surface of the Y-direction slider member 12C2. Since they are separated from each other, the column member 10 and the second workpiece 4 supported by the column member 10 can be easily moved in the X direction or the Y direction by the X and Y direction drive mechanism 12.
[00 19 ]
In the case of manual operation, the operation / drive mechanism 12D is a normal one that drives the X-direction drive member 12A and the Y-direction drive member 12C by turning the handles (not shown) in the X direction and the Y direction. Further, when driving automatically, in an image processing apparatus (not shown), optically equidistant points on the circumference of the second workpiece 4 are, for example, 12 points (30 ° intervals). Alternatively, a virtual average center point is obtained by detection at 18 points (20 ° intervals), and the servo motor is driven so that the center point of the first workpiece 3 matches the average center point. Automatic alignment of accuracy can be performed.
[00 20 ]
Fig. 3 shows a simple welding circuit of this resistance welding equipment, and Re is a power control type rectifier circuit that converts AC power from the AC power source PS into controlled DC power, which is generally a circuit combining a thyristor and a diode. Consists of components. A plurality of capacitors C are connected in parallel depending on the required capacity, and are charged with DC power from the rectifier circuit Re. Most of the energy charged in the capacitor C is discharged through the welding transformer T in a very short time by closing the discharge control switch SW, and the first energy is passed through the first and second workpieces W1 and W2. A large current flows between the first and second welding electrodes E1, E2. Here, the first and second workpieces W1 and W2 are respectively connected to the workpieces 3 and 4 in FIGS. 1 and 2, and the first and second welding electrodes E1 and E2 are respectively connected to the welding electrodes 1 and 7. Correspond.
[00 21 ]
Next, the operation during welding will be described. First, the first welding electrode 1 is raised to the upper limit, and the two electrode portions 7a and 7b of the second welding electrode 7 are moved to the set position and moved to the right and left, respectively, and are stationary. Furthermore, the collet chuck claw 6b is also in an open state, that is, in an expanded diameter state.
[00 22 ]
In such a stationary state, the first workpiece 3 is inserted into the longitudinal cavity 1a of the first welding electrode 1, and the upper end surface of the large-diameter portion 3a contacts the lower end surface of the first welding electrode 1. At the time of contact, the positioning mechanism 2 is operated to move the movable positioning member 2b forward, and as shown in the drawing, the first workpiece 3 is gripped in cooperation with the fixed positioning member 2a, and the positioning state is maintained. At this time, if the fixed positioning member 2a is in the way and the first welding electrode 1 cannot be inserted smoothly, the lower surface of the fixed positioning member 2a may be an inclined surface. On the other hand, the second workpiece 4 is placed on the support 5 and the collet chuck mechanism 6 is operated to hold the second workpiece 4 to the collet claw 6b as shown in the figure.
[00 23 ]
In this state, as described above, the cradle 14 fixed to the lower surface of the column member 10 by the repulsive force of the spring member 13 is separated from the upper surface of the base mechanism 15, and the lower surface of the support base 9 is the Y-direction slider member 12C2. It is far from the top surface. In this state, the operation / drive mechanism 12D is operated, the X and Y direction drive mechanism 12 is driven to move the column member 10 in the X direction and the Y direction, and the second workpiece is moved to the center point of the first work piece 3. Match the center point of the work piece 4. The X and Y direction drive mechanism 12 is stopped at the matched position and latched so as not to move.
[00 24 ]
Thereafter, while the movable positioning member 2b and the fixed positioning member 2a cooperate to hold the state of gripping the first workpiece 3, the first welding electrode 1 is lowered and the first workpiece is welded. 3 is brought into contact with the annular protrusion 4b of the second workpiece 4. On the other hand, the two portions 7a and 7b of the second welding electrode 7 are moved forward in the horizontal direction by a drive mechanism (not shown) and brought close to each other as shown in FIG. The movement in the horizontal direction is stopped at a position slightly apart from the large-diameter portion 3a of the first workpiece 3 without being contacted with the surface. Next, the two parts 7a and 7b are lowered to bring the two parts 7a and 7b into contact with the welding surface 4a of the second work piece 4, and an appropriate pressure force is applied by a pressurizing mechanism (not shown). To reduce the contact resistance between the second welding electrode 7 and the welding surface 4a of the second workpiece 4 to be welded.
[00 25 ]
At the same time, a downward pressing force (forging pressure) larger than the pressing force applied to the second welding electrode 7 is applied to the first welding electrode 1 by a pressurizing mechanism (not shown). Along with this, the spring member 13 contracts, and these pressures are applied to the base mechanism 15 through the support member 10, the cradle 14, and the like. At this time, even if the positioning mechanism 2 is operated to move the movable positioning member 2b backward, there is no problem because the first workpiece 3 does not move.
[00 26 ]
In this state, by closing the discharge control switch SW shown in FIG. 3, the energy charged in the capacitor C is discharged all at once, and the first workpiece 3 and the second workpiece are discharged from the first welding electrode 1. A single large pulsed welding current flows to the second welding electrode 7 through the joint with the welded article 4, and the first workpiece 3 and the second workpiece 4 are welded.
[00 27 ]
In this state, the welds of the workpieces 3 and 4 are quenched, and depending on the metal material, there is a possibility that the welded portions are brittle. A current is passed through the joint between the object 3 and the second workpiece 4. This tempering is a single pulsed current that is smaller than the pulsed welding current, for example about 7-8%, and has a substantial time width of about 50 milliseconds or less, and the temperature of the weld is the transformation point. This is done by flowing when it drops to a certain extent. What is important when performing this tempering is to maintain the pressurized state of the first welding electrode 1 and the second welding electrode 7 as they are, so that the contact between the welding electrode 1 and the work piece 3 is maintained. Since the contact surface and the contact surface between the welding electrode 7 and the workpiece 4 are sufficiently familiar with each other, good tempering can be performed in a short time of about 50 milliseconds or less. Here, the substantial time width means a time during which the current value is at a level of 10% or more of the peak value.
[00 28 ]
When such welding and tempering processes are completed, the first welding electrode 1 is immediately raised, the second welding electrode 7 is also raised once and then retracted horizontally, and the collet chuck mechanism 6 Also performs the diameter expansion operation. Thereafter, the welded first workpiece 3 and second workpiece 4 are taken out, and one cycle of the welding process is completed.
[00 29 ]
In the embodiment described above, the tempering step can be omitted depending on the metal material of the workpiece, the second welding electrode 7 is omitted, the insulating plate 8 is omitted, and the current is 5, collet chuck mechanism 6
The central stationary member 6a, the support base 9, the support member 10, and the cradle 14 may flow to the base mechanism 15. Further, when the second workpiece 4 has a stable shape such as a cube, a rectangular parallelepiped or a cylinder, the collet chuck mechanism can be omitted. Furthermore, the positioning mechanism 2 may hold the first work piece 3 until one welding is completed. In the case where the position can be fixed by the stopper mechanism, the fixed positioning member 2a is movable. It is also possible to make it.
[00 30 ]
【The invention's effect】
As described above, the present invention provides a resistance welding apparatus and method for performing welding while maintaining the coaxial accuracy of the workpieces without applying a pressure force from below without forming the welding electrode in a die set structure. can do.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a resistance welding apparatus according to the present invention.
FIG. 2 is a view showing a part of the resistance welding apparatus shown in FIG.
FIG. 3 is a diagram for explaining an example of an electric circuit to which the present invention is applied.
[Explanation of symbols]
1 ・ ・ ・ First welding electrode 2 ・ ・ ・ Positioning mechanism
3 ... first work piece 4 ... second work piece
5 ... Bearing base 6 ... Collet chuck mechanism
7 ・ ・ ・ Second welding electrode 8 ・ ・ ・ Insulating plate
9 ・ ・ ・ Support base
10 ... Prop member
11 ... Linear guide mechanism
12 ... X and Y direction drive mechanism
13 ... spring member 14 ... cradle
15 ... Base mechanism

Claims (4)

In a resistance welding apparatus that performs resistance welding of a rod-shaped first workpiece to be welded and a second workpiece to be welded that is longer than the diameter,
A base mechanism having mechanical strength capable of withstanding the pressure applied during welding;
An X and Y direction drive mechanism capable of moving the second workpiece in the X direction and the Y direction;
A support mechanism that supports the second workpiece and is coupled to a part of the X- and Y-direction drive mechanisms via a linear motion guide mechanism;
A spring mechanism provided between the X- and Y-direction drive mechanisms and the support mechanism, which floats the support mechanism from the base mechanism in a state where no pressure is applied from the outside, and allows the support mechanism to move up and down; ,
A first welding electrode capable of supporting the first workpiece,
A second welding electrode capable of flowing a welding current to a joint surface between the first workpiece and the second workpiece in cooperation with the first welding electrode;
A positioning mechanism is provided in the middle of the longitudinal direction of the first welding electrode to grip and position the first workpiece, and the positioning mechanism is arranged to move together with the first welding electrode. The resistance welding apparatus characterized by the above-mentioned. 2. The first welding target according to claim 1, wherein a pressure applied by at least the first welding electrode to the workpiece when the welding current flows is maintained even after the welding current becomes substantially zero. When the temperature of the welded part of the workpiece and the second workpiece to be welded is lowered to about the transformation point, a single pulse current is applied to perform tempering, and then the pressure applied to the first welding electrode is released. Resistance welding equipment characterized by. Resistance welding having a first welding electrode and a second welding electrode for performing resistance welding by passing a welding current between a rod-shaped first workpiece to be welded and a second workpiece to be welded that are longer than the diameter In the device
In the middle of the longitudinal direction of the first welding electrode, provided with a positioning mechanism for gripping and positioning the first workpiece.
The positioning mechanism includes a first positioning member extending from an opening in the middle of the first welding electrode to a set position in the longitudinal cavity, and an opening provided in the middle of the longitudinal wall of the first welding electrode. And a second positioning member that positions the rod-shaped first work piece by selectively cooperating with the first positioning member and moving forward and backward through the first positioning member. Resistance welding equipment. Resistance welding having a first welding electrode and a second welding electrode for conducting resistance welding by passing a welding current between a rod-shaped first workpiece to be welded and a second workpiece to be welded that are longer than the diameter In the method
In the middle of the longitudinal direction of the first welding electrode, provided with a positioning mechanism for gripping and positioning the first workpiece.
The positioning mechanism grips the first workpiece and descends together with the first welding electrode while maintaining the positioning state,
X direction and Y X, Y that can freely move the second workpiece in the direction A direction drive mechanism drives the first work piece and the second work piece to match,
A single large pulsed welding current is passed through the joint between the first workpiece and the second workpiece, and the first workpiece is welded. And resistance welding method for welding the second workpiece.

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