JP5224384B2 - Conductor welding method and welding apparatus therefor - Google Patents

Description

  The present invention relates to a welding method and a welding apparatus for welding conductors, and more particularly, to a welding method and a welding apparatus for a copper foil and a connection terminal, such as those used in a steering roll connector for an automobile.

  Conventionally, there are various welding methods for welding conductors, and welding is performed by a welding method suitable for a welding target. A plurality of methods have also been proposed for determining the quality of welding at a weld location.

  For example, in a resistance welding method for studs, a method has been proposed in which an electrical resistance value of a welded portion is calculated based on a welding voltage and a welding current, and the quality of welding is determined based on the calculated electrical resistance value (Patent Document 1). reference).

  The determination method proposed in Patent Document 1 compares a preset reference value of an electric resistance value with an electric resistance value calculated during or after welding, and if the calculated electric resistance value is lower than the reference value, welding is performed. It is determined to be defective.

  However, in the determination method of Patent Document 1, since the electric resistance value of the welded portion is calculated based on the welding voltage and the welding current, the resistance of the welding object and the electrode itself, and the electric resistance such as the contact resistance of each of them are calculated. There are many factors that affect the value, and it is difficult to accurately determine the welding state based on the calculated electrical resistance value.

  Specifically, in order to compare the resistance value calculated during welding with the reference value, when the material variation, the electrical resistance value of the electrode, etc., and the contact resistance value change over time, the welding voltage and welding current change, and the electrical resistance value Therefore, it is difficult to accurately determine the welding state.

JP-A-7-323376

  It is an object of the present invention to provide a conductor welding method and a welding apparatus for the conductor that can accurately measure the electrical resistance value of the welded portion between the conductors and accurately determine the quality of the welded state.

The present invention provides a first welded portion that presses the welded portion of the superimposed first conductor and second conductor against the welded portion from the outside, and a second welded portion that presses against the second conductor. A conductor welding method for welding to be energized by a pair of welding means comprising: a pre-welding resistance value measuring step for measuring an electric resistance value before welding; a welding step for welding the welding portion; A resistance value measuring step of energizing the resistance value measuring means to measure the electric resistance value of the welded portion, the electric resistance value measured in the resistance value measuring step, and the pre-welding measured in the pre-welding resistance value measuring step and the resistance value change amount detecting step of detecting an electrical resistance value variation amount indicating the change in electrical resistance based on the resistance value, and the measured the electric resistance value change amount, a change in electrical resistance based on excellent welding And having a comparison step of comparing a reference resistance value variation amount indicating and the discrimination step of discriminating the quality of the weld based on the comparison result.

Further, as an aspect of the present invention, the electric resistance value measuring means can be constituted by a four terminal method electric resistance value measuring means for measuring an electric resistance value by a four terminal method.
As an aspect of the present invention, the first conductor can be made of copper foil, and the second conductor can be made of a terminal.

Further, according to the present invention, a first welded portion that presses the welded portion of the superimposed first conductor and second conductor against the first conductor from the outside with respect to the welded portion, and a second that presses against the second conductor. A welding apparatus for a conductor that is welded so as to be energized by a pair of welding means constituted by a welded portion, and that detects a change in resistance value that indicates a change in electrical resistance value from an electrical resistance value before welding. and amount detecting means, and the electric resistance value measuring means for measuring a first conductor and the electric resistance of the welded portions by energizing the second conductor superimposed, the measurement results of the electrical resistance measuring means, good welding Bei example comparing means for comparing a reference resistance value of the reference resistance value variation amount indicating the change in the reference resistance value based on, and discriminating means for discriminating the quality of the weld on the basis of a comparison result of the comparison means, the comparison Means for changing the electric resistance value Characterized by a configuration of comparing the reference resistance value variation.

Further, as an aspect of the present invention, the electric resistance value measuring means can be constituted by a four terminal method electric resistance value measuring means for measuring an electric resistance value by a four terminal method.
As an aspect of the present invention, the first conductor can be made of copper foil, and the second conductor can be made of a terminal.

  The first conductor and the second conductor can be composed of different members such as copper foil and connection terminals, or the same member such as copper foils, and the conductors are copper foil, connection terminals, and rectangular conductors. It can comprise with electroconductive members, such as.

  The pair of welding means constituted by the first welded portion and the second welded portion is resistance welding for welding by energizing between the first welded portion and the second welded portion via a welded portion where conductors are overlapped with each other. Or it can be set as the ultrasonic welding which gives a parallel vibration and welds, applying a pressure to a welding location.

  The electrical resistance value measuring means can be a measuring circuit and measuring means using a DC resistance measuring method, and more specifically, a measuring circuit and measuring means using a four-terminal measuring method and a two-terminal measuring method.

  According to the present invention, it is possible to provide a conductor welding method and its welding apparatus capable of accurately measuring the electrical resistance value of the welded portion between the conductors and accurately determining the quality of the welded state.

The block diagram of a resistance welding apparatus. The flowchart of a welding process. Explanatory drawing about resistance value change in resistance welding.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a configuration diagram of a resistance welding apparatus 1, FIG. 2 shows a flowchart of a welding process, and FIG. 3 shows an explanatory diagram of a resistance value change in resistance welding.

  The resistance welding apparatus 1 includes a first electrode 20 that presses the welded portion H between the overlapped copper foil 100 and the connection terminal 200 against the copper foil 100 from above, and a second electrode 30 that presses against the connection terminal 200 from below. It is an apparatus which welds so that electricity supply is possible by a pair of resistance welding mechanisms 10 which comprise.

The resistance welding apparatus 1 includes an electrical resistance value measuring mechanism 40 and a control terminal 50 that functions as a comparison unit and a determination unit.
The electric resistance value measuring mechanism 40 is configured to measure the electric resistance value R of the welded portion H by energizing the overlapped copper foil 100 and the connection terminal 200.

The control terminal 50 functioning as a comparison unit is configured to compare the electric resistance value R measured by the electric resistance value measuring mechanism 40 with a reference value.
The control terminal 50 functioning as a determination unit is configured to determine whether the welding is good or not based on the comparison result between the electric resistance value R and the reference value.

  Specifically, the control terminal 50 is caused to function as a resistance value change amount detecting means, and an electric resistance value change amount V indicating a change in the electric resistance value R from the pre-welding electric resistance value Rb measured before welding is detected.

And the control terminal 50 which functions as a comparison means is the structure which compares the reference resistance value variation | change_quantity Vg (refer FIG. 3) which shows the change of the reference value based on favorable welding, and the electrical resistance value variation | change_quantity V. FIG.
The electric resistance value measuring mechanism 40 includes a voltage amplification circuit 41 and a constant current generation circuit 42, and measures the electric resistance value R by a four-terminal method.

  The above-described configuration will be described in detail. The resistance welding apparatus 1 includes a resistance welding mechanism 10, an electric resistance measurement mechanism 40, a control terminal 50, and a welding circuit 60. It is a device that conducts resistance and conducts resistance welding.

The resistance welding mechanism 10 includes a first electrode 20 that is pressed downward against the copper foil 100 and a second electrode 30 that is pressed upward against the connection terminal 200 from the lower side.
In the present embodiment, the copper foil 100 uses a foil having a thickness of about 35 to 150 μm, but is not limited to this.

The first electrode 20 includes a substantially Y-shaped electrode main body 21 in front view and an electrode holder 22 disposed on the electrode main body 21.
The electrode body 21 is formed in a substantially Y shape in front view by an upper bifurcated portion 21a and a lower electrode contact portion 21b. A measuring circuit side bifurcated portion 21aa (on the right side in FIG. 1) of the bifurcated portion 21a is provided with a fixing jig 21c for connecting and fixing a measuring electrode 44a of a voltage amplification circuit 41 described later. Moreover, it is the structure contact | abutted to the copper foil 100 by contact surface 21ba comprised by the bottom face part of the electrode contact part 21b.
In the present embodiment, the contact surface 21ba has a size of several hundred μm, but is not limited to this.

  In the electrode holder 22, an insulator 23 is arranged at the center in the width direction, and the upper bifurcated portion 21 a of the electrode body 21 is fixed in such a manner as to sandwich the insulator 23. A constant current generating circuit 42 and a welding circuit 60 are connected to a welding circuit side holder 22b (left side in FIG. 1) to which the other side of the bifurcated portion 21a is fixed.

The second electrode 30 includes a substantially inverted Y-shaped electrode body 31 as viewed from the front, and an electrode holder 32 disposed below the electrode body 31.
The electrode main body 31 is formed in a substantially inverted Y shape in front view by a lower bifurcated portion 31a and an upper electrode contact portion 31b. In addition, the measuring circuit side bifurcated portion 31aa (on the right side in FIG. 1) of the bifurcated portion 31a is provided with a fixing jig 31c for connecting and fixing a measuring electrode 44b of the electric resistance measuring mechanism 40 described later. . Further, the contact surface 31ba formed by the upper surface portion of the electrode contact portion 31b is in contact with the connection terminal 200.
In the present embodiment, the contact surface 31ba is assumed to have a size of several hundred μm, but is not limited to this.

  In the electrode holder 32, an insulator 33 is arranged at the center in the width direction, and the lower forked portion 31 a of the electrode main body 31 is fixed in such a manner as to sandwich the insulator 33. A constant current generating circuit 42 and a welding circuit 60 are connected to a welding circuit side holder 32b (left side in FIG. 1) to which the other side of the bifurcated portion 31a is fixed.

The first electrode 20 and the second electrode 30 are moved relative to each other in a vertical direction with respect to the welded portion H where the copper foil 100 and the connection terminal 200 overlap by an elevating means (not shown), and the copper foil 100 and the connection terminal 200 are moved. It is the structure inserted | pinched, pressing from the up-down direction.
In the present embodiment, the pressing force for sandwiching the copper foil 100 and the connection terminal 200 from the vertical direction is set to a strength of about 1.0 to 4.0 kgf, but is not limited thereto. .

The electric resistance value measuring mechanism 40 constitutes a measuring circuit for measuring the electric resistance value R of the welded portion H by a direct current four-terminal measuring method, and comprises a voltage amplification circuit 41 and a constant current generating circuit 42. Yes.

  The voltage amplification circuit 41 is connected to the measurement electrode 44a attached to the measurement circuit side bifurcated portion 21aa and the measurement electrode 44b attached to the measurement circuit side bifurcated portion 31aa, and amplifies the voltage with an amplification factor β. The voltage is measured with a voltmeter (not shown), and the measurement result is transmitted to the control terminal 50.

  Further, the resistance value passing through the voltage amplification circuit 41, the measurement electrode 44a, the measurement circuit side bifurcated portion 21aa, the electrode contact portion 21b, the welding location H, the electrode contact portion 31b, the measurement circuit side bifurcated portion 31aa, and the measurement electrode 44b. A voltage measurement route 41a for measurement is formed.

  The constant current generation circuit 42 is connected to the welding circuit side holder 22b and the welding circuit side holder 32b, and includes an ON / OFF switch 43, and is configured to energize the constant current I by a signal from the control terminal 50 described later. It is.

  Further, the constant current generating circuit 42, the welding circuit side holder 22b, the welding circuit side bifurcated portion 21ab, the electrode contact portion 21b, the welding location H, the electrode contact portion 31b, the welding circuit side bifurcated portion 31ab, the welding circuit side holder 32b, and A resistance measurement current route 42 a passing through the ON / OFF switch 43 is formed.

The welding circuit 60 is connected to the welding circuit side holder 22b and the welding circuit side holder 32b, and the welding current Iw supplied from the welding power source 61 is applied to the electrode contact portion 21b and the electrode contact via the welding location H. It is the structure which supplies with electricity to the part 31b.
In this embodiment, the welding current Iw is set to a current amount of about 350 to 550 A, but is not limited to this.

  Further, a welding power source 61, a welding circuit 60, a welding circuit side holder 22b, a welding circuit side bifurcated portion 21ab, an electrode contact portion 21b, a welding location H, an electrode contact portion 31b, a welding circuit side bifurcated portion 31ab, a welding circuit. A welding energization route 60a passing through the side holder 32b is formed.

  The control terminal 50 is connected to the voltage amplification circuit 41, the ON / OFF switch 43 and the welding power source 61. The voltage value measured by the voltage amplifier circuit 41 is received. In addition, a switching signal for switching ON / OFF to the ON / OFF switch 43 is transmitted. In addition, a signal for switching ON / OFF of energization of the welding current Iw is transmitted to the welding power source 61.

  Specifically, the control terminal 50 is a so-called personal computer, a display unit configured with a CRT, a liquid crystal display, or the like, an input unit configured with a mouse or the like as a keyboard, a connected voltage amplification circuit 41, an ON / OFF switch 43, and A communication unit 51 that communicates with the welding power source 61, a control unit 52 configured by a CPU or the like, and a storage unit 53 configured by a hard disk or the like are provided.

The storage unit 53 stores various data such as various programs and a reference resistance value change amount Vg that serves as a reference for determining the quality of welding.
The various programs stored in the storage unit 53 are, for example, a control program, a communication program, a calculation program, a determination program, and other programs necessary for the resistance welding apparatus 1 to operate.

  The control program is a program for controlling the constant current generating circuit 42 and the welding circuit 60, and the communication program is a program for communicating with the voltage amplification circuit 41, the ON / OFF switch 43 and the welding power source 61 via the communication unit 51. . The calculation program is a program for calculating the electric resistance value R and the electric resistance value change amount V indicating the change amount of the electric resistance value R from the received voltage value, and the discrimination program is the electric resistance value change amount V and the reference resistance value change. This is a program for comparing the amount Vg to determine the quality of welding.

  The control unit 52 is configured to control the voltage amplification circuit 41, the ON / OFF switch 43, and the welding power source 61 connected via the communication unit 51 using the various programs.

Next, the welding process of the copper foil 100 and the connection terminal 200 using the resistance welding apparatus 1 configured as described above will be described.
First, as preparation for the welding process between the copper foil 100 and the connection terminal 200, the copper foil 100 and the connection terminal 200 are set in the resistance welding apparatus 1. Specifically, the first electrode 20 and the second electrode 30 are moved in the separation direction by lifting means (not shown).

  In this state, the copper foil 100 and the connection terminal 200 overlapped at the welding location H are disposed between the electrode contact portion 21b and the electrode contact portion 31b, and the first electrode 20 and the second electrode 30 are disposed. It moves by the said raising / lowering means, and the welding location H is pinched and gripped by the contact surface 21ba and the contact surface 31ba. In this state, preparation for the welding process between the copper foil 100 and the connection terminal 200 is completed, and then the welding process between the copper foil 100 and the connection terminal 200 is started.

The welding process between the copper foil 100 and the connection terminal 200 is a process of performing the pre-weld resistance value measurement step S1, the welding step S2, the post-weld resistance value measurement step S3, and the discrimination step S4.
In addition, the resistance value measuring step S1 before welding is a step of measuring the electric resistance value R of the welded portion H before welding, and the post-welding resistance value measuring step S3 is an electric resistance value R of the welded portion H after welding. It is a process of measuring and a process of performing the same process.

  The welding step S2 is a step of welding the welding location H by energizing the first electrode 20 and the second electrode 30 through the welding location H with the welding current Iw. The discrimination step S4 is a step of discriminating the quality of welding based on the resistance values measured in the pre-weld resistance value measurement step S1 and the post-weld resistance value measurement step S3.

Each step will be described in detail. First, the pre-welding resistance measurement step S1 performed after the preparation for the welding process is completed will be described.
In the resistance value measurement step S1 before welding, the voltage amplification circuit 41 is controlled by the control terminal 50 to start voltage measurement of the voltage amplification circuit 41 for measuring the electric resistance value Rb before welding (step t1). Then, with the voltage measurement of the voltage amplifier circuit 41 started, the control terminal 50 controls the ON / OFF switch 43 of the constant current generation circuit 42 to be ON (step t2).

  When the ON / OFF switch 43 is ON-controlled, the constant current I is supplied to the resistance value measurement current route 42a of the constant current generation circuit 42 (step t3), and the control terminal 50 that has received the voltage value measured at this time. To calculate the electric resistance value R of the welded portion H (step t4). Specifically, the resistance value R (Ω) when the voltage amplification factor in the voltage amplification circuit 41 is β and the voltage V is measured when the constant current I is passed is calculated by R = V / (βI). can do.

  Then, the control terminal 50 controls the ON / OFF switch 43 to be OFF (step t5), and the voltage measurement of the voltage amplification circuit 41 is ended (step t6). When the pre-welding resistance value measurement step S1 is completed, the control terminal 50 stores the calculated electric resistance value R in the storage unit 53 as the pre-welding electric resistance value Rb, and proceeds to the next welding step S2.

  When a welding start signal is transmitted to the welding power source 61 by the control terminal 50 that has completed the measurement of the electrical resistance value Rb before welding in the resistance value measuring step S1 before welding (step u1), the welding power source 61 is connected to the welding energization route 60a. The welding current Iw is energized.

  By applying the welding current Iw by the welding power source 61, the welded portion H of the copper foil 100 and the connection terminal 200 is welded between the electrode contact portion 21b and the electrode contact portion 31b (step u2). When the welding current Iw is energized for a predetermined time, the control terminal 50 transmits an energization stop signal to the welding power source 61 to stop the energization of welding (step u3), and ends the welding process S2.

  After the welding step S2, the process proceeds to a post-welding resistance value measuring step S3 for measuring the electric resistance value R of the welded portion H after welding. In addition, as above-mentioned, resistance value measurement process S3 after welding is the process of performing the same process as resistance value measurement process S1 before welding, and measuring the electrical resistance value R of the welding location H part after welding.

  Specifically, in the post-welding resistance value measurement step S3, the voltage amplification circuit 41 for controlling the voltage amplification circuit 41 by the control terminal 50 and measuring the electrical resistance value R of the welded portion H after welding is started. (Step v1). Then, with the voltage measurement of the voltage amplification circuit 41 started, the control terminal 50 controls the ON / OFF switch 43 of the constant current generation circuit 42 to be ON (Step v2).

  When the ON / OFF switch 43 is ON-controlled, the constant current I is supplied to the resistance value measuring current route 42a of the constant current generating circuit 42 (step v3), and the control terminal 50 that has received the measured voltage value at this time. To calculate the electric resistance value R of the welded portion H (step v4).

  Thereafter, the control terminal 50 controls the ON / OFF switch 43 to be OFF (Step v5), and ends the voltage measurement of the voltage amplifier circuit 41 (Step v6). When the post-welding resistance value measurement step S3 is completed, the control terminal 50 stores the calculated electrical resistance value R in the storage unit 53, and proceeds to the next determination step S4.

  In a discrimination step S4 for discriminating whether or not the welding portion H is welded, an electrical resistance value change amount V is calculated from the pre-welding electrical resistance value Rb and the electrical resistance value R stored in the storage unit 53 (step w1).

  Then, the control terminal 50 compares the reference resistance value change amount Vg stored in the storage unit 53 with the electrical resistance value change amount V, and determines whether or not the welding portion H is welded (step w2).

  The welding quality determination will be described in detail. As shown in FIG. 3, the resistance value of the welded portion in the case of good welding greatly decreases after the start of welding, and then converges gently to an appropriate resistance value (the solid line in FIG. 3). The favorable welding resistance value change curve Lg shown in FIG.

On the other hand, for example, in the case of insufficient welding due to a small welding current or a weak pressure applied to the first electrode 20 and the second electrode 30, the resistance value gradually decreases after starting welding, and the appropriate resistance (See the welding underresistance value change curve Lb1 shown by a two-dot chain line in FIG. 3).
In the case of such a resistance value change, since the resistance of the welded portion is too large and sufficient conduction performance cannot be ensured, it is determined that the welding is defective.

On the other hand, in the case of excessive welding due to, for example, the welding current being too large or the pressurizing force between the first electrode 20 and the second electrode 30 being too strong, immediately after the start of welding, the resistance value is rapidly exceeded. The resistance value decreases (see welding excessive resistance value change curve Lb2 indicated by a broken line in FIG. 3).
In the case of such a resistance value change, the copper foil at the welded portion is melted and the copper foil may be broken around the welded portion, and sufficient durability cannot be ensured. Therefore, the welding is determined to be defective.

  Note that the reference resistance value change amount Vg stored in the storage unit 53 is a resistance value before starting welding on a good welding resistance value change curve Lg indicating a change history of resistance value in good welding, and a good welding resistance value by welding. It becomes a difference to an appropriate resistance value at which the change curve Lg converges.

  Then, the control terminal 50 compares the electric resistance value change amount V calculated from the electric resistance value R with the reference resistance value change amount Vg, and if the electric resistance value change amount V is approximately the same, the welding location H It is determined that the welding of the part was good.

On the contrary, since the electrical resistance value change amount V in the case of insufficient welding as shown in the welding underresistance value change curve Lb1 in FIG. 3 is smaller than the reference resistance value variation amount Vg, the control terminal 50 is inferior. It is determined as
Similarly, since the electrical resistance value change amount V in the case of excessive welding as shown in the welding excessive resistance value change curve Lb2 in FIG. 3 becomes larger than the reference resistance value change amount Vg, the control terminal 50 is inferior to the defective welding. It is determined as

  In this way, the control terminal 50 compares the reference resistance value change amount Vg based on the good welding resistance value change curve Lg, which is the history of the reference value, with the electrical resistance value change amount V, and compares the reference resistance value change amount Vg. Whether the quality is good or not is determined, and the determination step S4 is terminated. In this way, the welding process by the resistance welding apparatus 1 configured in the pre-weld resistance value measurement step S1, the welding step S2, the post-weld resistance value measurement step S3, and the discrimination step S4 is completed.

The resistance welding in the above-described welding process includes three elements of current i, time t, and resistance r as elements that affect the welding state. In the first place, resistance welding uses Joule heat due to the resistance r of the welded portion, and the greater the resistance r, the greater the amount of heat generated expressed by the equation Q = αi ² rt (α is a constant).

  Here, among the above three elements, the current i and the time t can be controlled by the control terminal via the welding power source. However, the resistance r is difficult to control because it is the sum of the respective contact resistances in addition to the resistance of the copper foil, the connection terminal and the electrode body itself.

  Specifically, the resistance of the copper foil, the connection terminal, and the electrode body itself, and the contact resistance between the copper foil and the connection terminal do not change, but the contact resistance between the copper foil, the connection terminal, and the electrode body is It can change.

The change in the contact resistance between the copper foil or the connection terminal and the electrode body largely depends on the pressure applied between the electrode bodies. Although this pressure can be controlled by a resistance welding apparatus, it is difficult to control the pressure during the welding process. Even if the follow-up control is performed during the welding process, the follow-up is slow and the welding state may vary.
Further, since the contact resistance between the electrode and the workpiece varies, the welding state cannot be determined only by simple comparison of the electric resistance values.

  However, the welding method of the welding location H of the copper foil 100 and the connection terminal 200 using the resistance welding apparatus 1 energizes the welding resistance S and the electrical resistance value measuring mechanism 40, and welds the welding location H. A post-welding resistance value measuring step S3 for measuring the electric resistance value R of the welding location H, and a discrimination step S4 for comparing the measured electric resistance value R with a reference value and discriminating the quality of the welding based on the comparison result. Therefore, the quality of the welding of the welding location H welded by the resistance welding apparatus 1 can be determined with high accuracy.

  Specifically, based on the electrical resistance value R measured in the post-welding resistance value measuring step S3 and the pre-welding electrical resistance value Rb measured in the pre-welding resistance value measuring step S1 in step w1 of the discrimination process S4. The electrical resistance value change amount V is detected, and in step w2 of the determination step S4, the electrical resistance value change amount V and the reference resistance value change amount Vg are compared to determine the quality of the welding, so that the accuracy is higher. Discrimination can be performed.

  Specifically, in order to compare the electric resistance value change amount V and the reference resistance value change amount Vg, the dispersion of the copper foil 100 and the connection terminal 200, the electric resistance values of the electrode body 21 and the electrode body 31, and the contact at the welding location H Even if the resistance value changes with time, it is possible to reliably determine whether welding is good or bad.

  In addition, the resistance welding apparatus 1 includes an electrical resistance value measuring mechanism 40 and a control terminal 50 that functions as a comparison unit and a discrimination unit. The electrical resistance value measuring mechanism 40 is attached to the overlapped copper foil 100 and the connection terminal 200. Since it is set as the structure which electrically supplies and measures the electrical resistance value R of the said welding location H, the electrical resistance value R of the welding location H can be measured with high precision, for example.

  Specifically, an electric resistance value measuring mechanism 40 for measuring the electric resistance value R of the welding location H is provided separately from the welding circuit 60, and the electric resistance is measured at a timing when the energization route 60a of the welding circuit 60 is not energized. Since the electric resistance value R is measured using the value measuring mechanism 40, the electric resistance value R can be more accurately compared with the case where the electric resistance value R of the welding location H is calculated based on the welding voltage and the welding current. Can be measured.

  Further, in order to determine the quality of the welding by comparing with the reference value based on the electrical resistance value R measured using the electrical resistance value measuring mechanism 40, the reason why the comparison result is determined to be defective is the welding failure. Can be identified as

  Further, the electric resistance value measuring mechanism 40 is constituted by a voltage amplification circuit 41 and a constant current generating circuit 42, and a circuit for measuring the electric resistance value R of the welded portion H by a DC four-terminal measurement method is constituted. Therefore, a small resistance value at the welding location H can be accurately measured.

  Therefore, the book in which the copper foil 100 having a thickness of about 35 to 150 μm and the connection terminal 200 are pressed with a strength of about 1.0 to 4.0 kgf and welded with a welding current Iw of about 350 to 550 A. Also in the embodiment, the electric resistance value R can be calculated with high accuracy, and the quality of welding can be accurately determined.

  Specifically, for example, in the stud resistance welding method in which the thickness of the welding object is several mm, the welding current Iw is several hundred to several thousand A, and the applied pressure is several tens kgf, the welding voltage and the welding current are In the method of calculating the electrical resistance value of the welded portion based on this and determining the quality of the welding based on the calculated electrical resistance value, the welding object as in this embodiment has a slight change in the electrical resistance value R due to welding. It is impossible to accurately calculate the electric resistance value R.

  However, like the resistance welding apparatus 1 of the present embodiment, the welding current Iw and the constant current I are separated, the energization timing is shifted, and the electric resistance value measuring mechanism 40 is further divided by the voltage amplification circuit 41 and the constant current generation circuit 42. By configuring, a slight change in the electric resistance value R can be detected. Therefore, even if the object is thin like the object to be welded as in the present embodiment, it is possible to detect the change in the electric resistance value R with high accuracy and accurately determine the quality of the welding. .

  Moreover, in the welding method using the resistance welding apparatus 1 or the resistance welding apparatus 1, the quality of the welding state can be determined as it is based on the flow welded in the welding step S2 in the welding process, which is highly convenient.

  In the above-described embodiment, after welding in the welding step S2, only the quality of the welding state is determined in the determination step S4. However, when the determination result in the determination step S4 is determined as insufficient welding, The structure which returns to welding process S2 and welds again may be sufficient.

  Moreover, in the above-mentioned Example, although it was the structure which welds the copper foil 100 and the connection terminal 200, combining conductive members, such as copper foils 100, the connection terminals 200, or a flat conductor, and a connection terminal. You may weld. Moreover, it can also be applied to a welding method for forming a nugget.

  Further, in the above-described embodiment, the welding current Iw is applied to the electrode main body 21 and the electrode main body 31 via the welding location H and resistance welding is performed. However, the welding location H is ultrasonically vibrated and welded. You may carry out by ultrasonic vibration welding.

In the correspondence between the configuration of the present invention and the above embodiment,
The first conductor of the present invention corresponds to the copper foil 100,
Similarly,
The second conductor corresponds to the connection terminal 200,
The first weld corresponds to the first electrode 20,
The second weld corresponds to the second electrode 30,
The pair of welding means corresponds to the resistance welding mechanism 10,
The welding device corresponds to the resistance welding device 1,
The electrical resistance value measuring means corresponds to the electrical resistance value measuring mechanism 40,
The four-terminal method electric resistance value measuring means corresponds to an electric resistance value measuring mechanism 40 composed of a voltage amplifier circuit 41 and a constant current generating circuit 42,
The comparison unit and the determination unit correspond to the control unit 52 that executes Step S4.
The resistance value change amount detection means corresponds to the control unit 52 that executes Step w1,
The resistance value measurement step before welding corresponds to the resistance value measurement step S1 before welding,
The welding step corresponds to the welding step S2,
The resistance value measuring step corresponds to the resistance value measuring step S3 after welding,
The comparison step and the determination step correspond to the determination step S4,
The resistance value change detection step corresponds to step w1 in the determination step S4.
The present invention is not limited only to the configuration of the above-described embodiment, but can be applied based on the technical idea shown in the claims, and many embodiments can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Resistance welding apparatus 10 ... Resistance welding mechanism 20 ... 1st electrode 30 ... 2nd electrode 40 ... Electrical resistance value measurement mechanism 41 ... Voltage amplification circuit 42 ... Constant current generation circuit 52 ... Control part 100 ... Copper foil 200 ... Connection terminal H ... Welded part Vg ... Reference resistance value change amount

Claims (6)

The welded portion of the overlapped first conductor and second conductor is composed of a first welded portion that presses against the welded portion from the outside against the first conductor and a second welded portion that presses against the second conductor. A method of welding a conductor that is welded to be energized by a pair of welding means,
A resistance measurement step before welding for measuring an electrical resistance value before welding;
A welding step of welding the weld location;
A resistance value measuring step of energizing the electrical resistance value measuring means and measuring the electrical resistance value of the weld location;
Resistance value change for detecting an electrical resistance value change amount indicating a change in electrical resistance value based on the electrical resistance value measured in the resistance value measuring step and the pre-welding electrical resistance value measured in the pre-welding resistance value measuring step A quantity detection step;
A comparison step of comparing the measured electrical resistance value change amount with a reference resistance value change amount indicating a change in electrical resistance value based on good welding ;
And a determination step of determining whether or not the welding is good based on the comparison result. The electrical resistance value measuring means,
Welding method according to claim 1 configured by the 4-terminal method the electric resistance measuring means for measuring the electrical resistance by the four terminal method. The welding method according to claim 1 or 2, wherein the first conductor is made of copper foil and the second conductor is made of a terminal. The welded portion of the overlapped first conductor and second conductor is composed of a first welded portion that presses against the welded portion from the outside against the first conductor and a second welded portion that presses against the second conductor. A conductor welding device for welding to be energized by a pair of welding means,
Resistance value change amount detecting means for detecting an electric resistance value change amount indicating a change in electric resistance value from an electric resistance value before welding;
Electrical resistance value measuring means for energizing the superimposed first conductor and second conductor to measure the electrical resistance value of the welded portion;
Comparison means for comparing the measurement result by the electric resistance value measurement means with a reference resistance value as a reference resistance value change amount indicating a change in the reference resistance value based on good welding ;
E Bei and discriminating means for discriminating the quality of the weld on the basis of a comparison result of the comparison means,
The comparing means;
The welding apparatus configured to compare the electric resistance value change amount and the reference resistance value change amount . The electrical resistance value measuring means,
The welding apparatus according to claim 4 , comprising a four-terminal method electric resistance value measuring means for measuring an electric resistance value by a four-terminal method. The welding apparatus according to claim 4 or 5, wherein the first conductor is made of copper foil and the second conductor is made of a terminal.

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