JP2003334670A - Ultrasonic welding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic welding device which can surely weld a welding workpiece with desired strength and can accurately judge a welding state of the welding workpiece. <P>SOLUTION: The ultrasonic welding device 1 is provided with an ultrasonic welding machine 4 and a laser Doppler speedometer 5, and a controller 6. The ultrasonic welding machine 4 is provided with a tip 9 and an anvil 10 to sandwich metal plates 2, 3 as the welding workpiece. The laser Doppler speedometer 5 detects the speed of the tip 9 and outputs it toward the controller 6. The controller 6 calculates a total displacement of the tip 9 and stops the ultrasonic welding machine 4 when the total displacement exceeds a prescribed value. The controller 6 judges whether the welding state of the metal plates 2, 3 as the welding workpiece is good or not based on the total displacement of the tip 9. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic welding device for welding objects to be welded such as a plurality of covered electric wires.

[0002]

2. Description of the Related Art Various electronic devices are mounted on a vehicle as a moving body. The automobile has a wiring harness for transmitting electric power from a power source such as a battery and a control signal from a control device to the electronic device. The wire harness described above includes a plurality of electric wires and the like.

A shielded electric wire may be used for these electric wires in order to prevent noise from entering the respective core wires. The shielded electric wire includes a shield portion made of a braid having conductivity. This shield part prevents noise from entering the core wire.

In recent years, it has been desired to reduce the cost of the above-mentioned wire harness. For this reason, it has been proposed to bundle a plurality of electric wires that do not have the shield part and wind a conductor thin film sheet having a thin film conductor layer around the plurality of electric wires to form a wire harness. With such a configuration, cost reduction and noise intrusion prevention can be achieved.

Also in such a structure, it is necessary to attach a ground wire or a terminal to the conductor layer in order to take out the noise. The ground electric wire includes a conductive core wire and an insulating coating portion. The core wire is
It consists of multiple conductors. The covering portion is made of an insulating synthetic resin and covers the core wire.

In order to attach an earth wire or the like to the conductor layer, a hole is made in the conductor thin film sheet, and the end of the earth wire or the like is passed through the hole, and then a washer, a bolt,
It is conceivable to fix the conductor thin film sheet and the ground wire with a nut or the like.

In this case, a peeling operation such as removing a part of the covering portion of the ground electric wire is required, and it is considered that the number of steps for assembling increases. Moreover, since parts such as washers, bolts, and nuts are required, the number of parts increases. Therefore, it is possible that the cost will rise. Furthermore, it is conceivable that when the bolts and nuts and the like described above are tightened, the conductor layer is damaged and the earth wire described above cannot be reliably connected to the conductor layer. Therefore, it is difficult to let the noise that tries to enter the core wire of the electric wire escape to the outside.

In order to solve the above-mentioned problems, the applicant of the present invention is to superimpose a conductive thin film sheet and a grounding electric wire and apply ultrasonic vibration energy in a state where they are pressed in a direction to bring them close to each other. is suggesting. By applying ultrasonic vibration energy, the conductor layer of the conductor thin film sheet and the core wire of the ground wire are metal-bonded (joined). In this way, the conductor layer of the conductor thin film sheet and the ground wire are electrically connected. In this method, a well-known ultrasonic welding device is used.

The ultrasonic welding apparatus includes a tip (also called a tool horn), an anvil facing the tip, a vibrator (not shown), and the like. The ultrasonic welding device
A conductor thin film sheet as an object to be welded and a ground wire are sandwiched between the chip and the anvil. The ultrasonic welding device
The vibrator is vibrated, and this vibration is applied to the object to be welded through the chip. The ultrasonic welding device joins the conductor thin film sheet as the welding target and the ground wire.

At this time, the ultrasonic welding device controls the vibration state of the tip or the like based on the energy applied to the object to be welded. The oscillating time of the vibrator, that is, the oscillating time of the tip is controlled so that the ultrasonic vibration energy applied to the object to be welded is constant. The ultrasonic vibration energy is the product of the oscillation time and the work rate (working rate) that the tip applies to the object to be welded. The work rate (working rate) that the tip applies to the object to be welded is the product of the amplitude of the tip and the pressure between the tip and the object to be welded.

[0011]

In the above-mentioned conventional ultrasonic welding apparatus, the vibrator is vibrated with a predetermined amplitude in a state where the tip and the anvil are pressurized with a predetermined pressure. Then, this vibration is transmitted to the welding target through the chip. When the oscillation time of the vibrator exceeds a predetermined time, the vibrator is stopped and the welding of the objects to be welded is stopped. As described above, the conventional ultrasonic welding apparatus joins the objects to be welded based on the amplitude of the vibrator and the oscillation time of the vibrator.

Further, in the above-mentioned conventional ultrasonic welding apparatus, the quality of the welding state of the object to be welded is judged based on the oscillation time. That is, the quality is determined by whether or not the time when the vibrator actually oscillates is within a predetermined time.

In the above-mentioned conventional ultrasonic welding apparatus, information about oscillation of the vibrator is used for control. Actually, when ultrasonic welding is performed, all the ultrasonic vibration energy obtained by the oscillator oscillating, such as generation of abnormal noise from the welding target object or heat generation of the welding target object, is generated. It doesn't join things. Therefore, it cannot be said that the above-described ultrasonic welding device can bond the objects to be welded with a desired strength, and the quality of the objects to be welded cannot be accurately determined.

Therefore, the ultrasonic welding device (also called an ultrasonic welding device, which is disclosed in Japanese Patent Laid-Open No. 5-206224).
In the following, it is referred to as an ultrasonic bonding device), and the amplitude when the chip vibrates is measured. In the ultrasonic bonding apparatus disclosed in the above-mentioned publication, the amplitude of the chip falls below a predetermined amplitude after the oscillator starts oscillating, that is, ultrasonic welding (also referred to as ultrasonic bonding) is started. Then, the oscillation of the vibrator, that is, ultrasonic bonding is stopped. Then, the quality is determined by whether or not the oscillation time of the vibrator is within a predetermined time.

In ultrasonic bonding, the change in the amplitude of the tip over time varies depending on the shape and size of the object to be welded. For this reason, in the ultrasonic bonding apparatus described in the above-mentioned publication, ultrasonic bonding is stopped when the amplitude of the tip falls below a predetermined amplitude, so the ultrasonic vibration energy actually applied to the welding target is Various changes will be caused by changing the object. In addition, since the quality is determined based on the oscillation time of the vibrator, it goes without saying that the welding status of the object to be welded cannot be accurately determined.

Therefore, a first object of the present invention is to provide an ultrasonic welding apparatus capable of surely welding objects to be welded with desired strength. A second object is to provide an ultrasonic welding device that can accurately determine the welding state of the welding target.

[0017]

In order to achieve the above-mentioned first object, an ultrasonic welding apparatus according to the present invention as set forth in claim 1 faces a tip vibrated by a driving source and the tip. An anvil, wherein a plurality of objects to be welded are sandwiched between the tip and the anvil, and the tip and the anvil are pressed in a direction in which they are close to each other, the tip is vibrated by the drive source to cause the vibration. In an ultrasonic welding device that welds the objects to be welded to each other by transmitting the information to the objects to be welded, a detection unit that can detect information about the vibration of the chip, and a total of the chips from the information about the vibration detected by the detection unit. Calculation means for calculating the displacement amount,
Control means for controlling the vibration of the tip based on the total displacement of the tip detected by the calculating means.

In addition to the above-mentioned first object, in order to achieve the second object, the ultrasonic welding apparatus of the present invention according to claim 2 is the ultrasonic welding apparatus according to claim 1,
It is characterized by further comprising a determining means for determining whether the welding condition of the welding target is good or bad based on the information on the total displacement amount of the tip calculated by the calculating means.

In order to achieve the above-mentioned second object, the ultrasonic welding device of the present invention according to claim 3 comprises a tip vibrated by a driving source and an anvil facing the tip, An ultrasonic welding apparatus for welding the welding objects to each other by sandwiching a plurality of welding objects between the tip and the anvil, and vibrating the chips by the drive source to transmit the vibration to the welding object. In, detecting means capable of detecting information on the vibration of the chip, calculating means for calculating the total displacement amount of the chip from the information on the vibration detected by the detecting means, and the total displacement of the chip calculated by the calculating means A determination unit that determines whether the welding status of the welding target is good or bad based on the information about the amount.

According to the ultrasonic welding apparatus of the present invention described in claim 1, the vibration of the tip, that is, the ultrasonic vibration energy applied to the object to be welded is controlled based on the total displacement of the tip. Therefore, the ultrasonic welding is controlled based on the ultrasonic vibration energy actually applied to the welding object via the tip. Therefore, desired ultrasonic vibration energy can be reliably applied to the object to be welded.

When the total displacement of the chip exceeds a predetermined value, it is desirable to control the vibration of the chip to stop. The predetermined value of the total displacement of the tip is
It shows the total displacement amount by which the object to be welded can be welded with a desired bonding strength. Therefore, the predetermined value of the total amount of displacement of the tip depends on the welding target and the required bonding strength,
It changes variously. In this case, desired ultrasonic vibration energy can be more reliably applied to the object to be welded.

The ultrasonic vibration energy is the product of the oscillation time and the power value (W: wattage) when the power source applies the oscillator. However, actually, the ultrasonic vibration energy applied to the objects to be welded is based on the behavior of the objects to be welded. The ultrasonic welding device 1 shown in FIG. 7 includes a tip 9 vibrated by a vibrator and an anvil 10 facing the tip 9. The objects to be welded 2 and 3 are sandwiched between the tip 9 and the anvil 10, and the tip 9 is vibrated along the arrow S while being pressed in a direction in which the objects to be welded 2 and 3 approach each other. In the ultrasonic welding device 1 shown in FIG. 7, the amplitude of the tip 9 is A, the tip 9 is
The angular frequency of ω = 2πf, and the vibration speed of the chip 9 is v = ω
If A = 2πf · A, the output (power) W of the chip 9
Is expressed by Equation 1 below. Note that f is the frequency of vibration of the tip 9.

W = μF × v ... Equation 1 In the above Equation 1, μ is a coefficient of friction between the objects to be welded 2, and F is a pressure applied in a direction in which the objects to be welded 2 and 3 are brought closer to each other. It is the applied load value.

Using the above-mentioned formula 1, the objects to be welded 2, 3
The ultrasonic vibration energy E applied to is expressed by the following Expression 2. E = ∫W × dt = ∫μF × ωA × dt ... Equation 2

In the above formula 2, μF is the pressure between the objects to be welded 2, 3 and ∫ωA × dt is the total displacement of the tip 9. Therefore, the ultrasonic vibration energy E applied to the welding objects 2 and 3 is the same as the pressure between the welding objects 2 and 3.
It can be shown by the product of the total displacement of the tip 9. Therefore, based on the total displacement of the tip 9, the desired ultrasonic vibration energy is applied by ultrasonic welding to the welding object 2,
It has become clear that it can be surely applied to No. 3. further,
It has been clarified that the quality of the welding objects 2 and 3 can be reliably determined by determining the quality based on the total displacement amount of the tip 9.

According to the ultrasonic welding apparatus of the second aspect of the present invention, the quality of the welding state of the object to be welded is judged based on the total displacement of the tip. Therefore, the quality of the welding target can be determined based on the ultrasonic vibration energy actually applied to the welding target via the chip. Therefore, in addition to the effect of claim 1 described above, the welding state of the welding target can be accurately determined.

According to the ultrasonic welding apparatus of the third aspect of the present invention, the quality of the welding state of the object to be welded is determined based on the total displacement of the tip. Therefore, the quality of the welding target can be determined based on the ultrasonic vibration energy actually applied to the welding target via the chip. Therefore, the welding status of the welding target can be accurately determined.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION An ultrasonic welding apparatus 1 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 6. The ultrasonic welding apparatus 1 shown in FIG. 1 and the like is an apparatus for ultrasonically welding (also referred to as ultrasonic bonding or ultrasonic welding) a plurality of objects to be welded such as metal plates 2 and 3. As shown in FIG. 1, the ultrasonic welding device 1 includes an ultrasonic welding machine 4 and
A laser Doppler velocimeter 5 as a detection means and a control device 6 are provided.

As shown in FIG. 1, the ultrasonic welding machine 4 includes a vibrator 7 as a driving source, a horn 8, a tip 9 (also referred to as a tool horn), and an anvil 10 facing the tip 9. A pressurizer (not shown) and the like are provided. Oscillator 7
Is oscillated by being applied by a power source or the like not shown.

The horn 8 is attached to the vibrator 7. The tip 9 is attached to the tip of the horn 8. Therefore, the vibrator 7 vibrates the chip 9 along the arrow S in FIG. 1 via the horn 8 and the like. Anvil 10
Between the chip 9 and the metal plate 2, which is an object to be welded.
3 can be sandwiched. The pressurizer presses the tip 9 and the anvil 10 in a direction to bring them close to each other. The pressurizer can change the load value (pressure value) that pressurizes the tip 9 and the anvil 10.

The ultrasonic welding machine 4 comprises a tip 9 and an anvil 1.
The metal plates 2 and 3 as the object to be welded are sandwiched between 0 and 0, and the vibrator is vibrated by vibrating the vibrator 7 in a state in which these chips 9 and the anvil 10 are pressed by a pressurizing machine in a direction to bring them close to each other. Transmit to chip 9 via horn 8. Then, the ultrasonic welding machine 4 applies ultrasonic vibration energy to the metal plates 2 and 3 as the welding object sandwiched between the tip 9 and the anvil 10 to weld the object.

The ultrasonic vibration energy referred to in this specification indicates the energy applied to the object to be welded when the ultrasonic welding apparatus 1 welds the object to be welded. The ultrasonic vibration energy is, for example, the electric power value (W: wattage) when the power source applies the oscillator 7 to the oscillator 7.
Is the energy obtained over the time applied to the. Further, the ultrasonic vibration energy that is actually applied to the metal plates 2 and 3 as the objects to be welded is, as shown in the above-mentioned equation 2,
It is the product of the total displacement of the tip 9 and the pressure between the metal plates 2 and 3.

The laser Doppler velocimeter 5 comprises a laser oscillator 11, a beam splitter 12, and a laser focusing head 1.
3, a reflection mirror 14, a detector 15, and an optical fiber 1
6 and. The laser oscillator 11 emits laser light. The beam splitter 12 guides the laser light emitted from the laser oscillator 11 to the laser focusing head 13. The laser focusing head 13 sends the laser light to the anvil 1 of the chip 9.
The light is emitted toward the tip near 0. Laser focusing head 1
3 receives the laser beam reflected by the tip of the tip 9 near the anvil 10.

The laser light received by the laser focusing head 13 is guided to the detector 15 via the beam splitter 12 and the reflection mirror 14. The optical fiber 16 optically connects the beam splitter 12 and the laser focusing head 13. The detector 15 calculates the speed of the chip 9 along the arrow S described above from the Doppler frequency (frequency change) of the received laser light and outputs information based on this speed to the control device 6.

Thus, the laser Doppler velocimeter 5 detects the frequency change (Doppler frequency) proportional to the speed of the tip 9 by irradiating the tip of the tip 9 with laser light. The laser Doppler velocimeter 5 calculates the velocity of the chip 9 along the arrow S by detecting the above-mentioned frequency change (Doppler frequency). In this way, the laser Doppler velocimeter 5 detects information regarding the vibration of the tip 9 (velocity of the tip 9).

The control device 6 is a well-known RAM, ROM, C
A computer equipped with a PU or the like, which is connected to the ultrasonic welding machine 4 and the laser Doppler velocimeter 5 described above,
By controlling these, the overall control of the ultrasonic welding device 1 is controlled. The control device 6 includes a calculation unit 17 as a calculation unit, a control unit 18 as a control unit, and a determination unit 19 as a determination unit. The calculation unit 17 is connected to the detector 15.

The calculating unit 17 calculates the displacement amount of the tip 9 by integrating the speed of the tip 9 as information on the vibration of the tip 9 inputted from the detector 15. The calculation unit 17 accumulates the calculated displacement amounts of the chips 9 and calculates the total displacement amount of the chips 9 from the start of ultrasonic welding (start of welding of the pair of metal plates 2 and 3). The calculation unit 17 outputs information regarding the calculated total displacement amount of the tip 9 to the control unit 18.

The controller 18 determines whether or not the total displacement of the tip 9 exceeds a predetermined value. When the control unit 18 determines that the total displacement amount of the chip 9 exceeds the predetermined value, the control unit 18 stops the vibrator 7. The control unit 18
When it is determined that the total displacement amount of the chip 9 does not exceed the predetermined value, the vibrator 7 is driven as it is. In this way, the control unit 18 controls the vibration of the tip 9 based on the total displacement amount of the tip 9. In addition, the control unit 18 obtains information regarding the total displacement amount of the chip 9 when the vibrator 7 is stopped, from the determination unit 19.
Output toward.

The predetermined value of the total displacement is the total displacement capable of joining the metal plates 2 and 3 as the objects to be welded with a desired strength, and before joining the metal plates 2 and 3. Is a predetermined value. Further, the predetermined value of the total displacement amount changes variously depending on the object to be welded, the required bonding strength, and the like.

The determination unit 19 determines whether or not the total displacement amount of the chip 9 when the vibrator 7 is stopped exceeds a predetermined second value. When the determination unit 19 determines that the total displacement amount of the tip 9 exceeds the predetermined second value,
The welding status of the welding target is determined to be defective. When determining that the total displacement amount of the tip 9 does not exceed the predetermined second value, the control unit 18 determines that the welding status of the welding target object is good. In this way, the control unit 18 determines the quality of the welding target based on the total displacement amount of the tip 9.

When welding the metal plates 2 and 3 as the objects to be welded by using the ultrasonic welding apparatus 1 having the above-mentioned structure,
First, the metal plates 2 and 3 are sandwiched between the tip 9 and the anvil 10. Then, in step S1 in FIG. 2, the pressurizing device pressurizes the tip 9 and the anvil 10 with a desired load value (pressure) in a direction to bring them closer to each other, vibrates the vibrator 7, and proceeds to step S2. Then, the tip 9 vibrates along the arrow S and the metal plate 2 vibrates along the arrow S. Since the metal plates 2 and 3 are in contact with each other, the metal plates 2 and 3 are metal-bonded to each other in a solid phase without gradually melting.

In step S2, the laser Doppler velocimeter 5 detects the speed of the tip 9, and the process proceeds to step S3.
In step S3, the calculation unit 17 of the control device 6 causes the chip 9
The total displacement amount of is calculated and the process proceeds to step S4.

In step S4, the controller 18 causes the chip 9
It is determined whether or not the total (cumulative) displacement amount of is above a predetermined value. If the total displacement amount of the tip 9 does not exceed the predetermined value, the process returns to step S1 and steps S1 to S4.
repeat. When the total displacement amount of the tip 9 exceeds a predetermined value, the process proceeds to step S5. In step S5, the vibrator 7 is stopped and the process proceeds to step S6.

In step S6, the determination unit 19 causes the chip 9
It is determined whether or not the total displacement amount of is greater than a predetermined second value. If the total displacement of the tip 9 exceeds a predetermined second value, the welding target is determined to be defective. If the total displacement amount of the tip 9 does not exceed the predetermined second value, the welding target is determined to be a good product. Thus, the metal plates 2 and 3 are joined to each other by so-called ultrasonic welding (also called ultrasonic welding or ultrasonic joining).

According to this embodiment, the controller 18 controls the vibration of the tip 9, that is, the ultrasonic vibration energy applied to the object to be welded, based on the total displacement of the tip 9. Therefore, the ultrasonic welding is controlled based on the ultrasonic vibration energy actually applied to the welding target through the tip 9. Therefore, desired ultrasonic vibration energy can be reliably applied to the object to be welded. Therefore, the objects to be welded can be welded so that the desired bonding strength can be obtained.

The judging section 19 judges whether the welding condition of the object to be welded is good or bad based on the total displacement of the tip 9. Therefore, the quality of the welding target can be determined based on the ultrasonic vibration energy actually applied to the welding target via the chip 9. Therefore, the welding status of the welding target can be accurately determined.

Next, the inventors of the present invention welded various objects to be welded under various conditions with the above-described ultrasonic welding apparatus 1, and then bond strength of these objects to be welded (in the figure, Is referred to as tensile strength) and various parameters were investigated. The results are shown in FIGS. 3 to 6. FIG. 3 shows the maximum power value during vibration of the vibrator 7 (described as peak power in the figure).
And the bond strength. FIG. 4 shows a vibrator 7
Shows the relationship between the vibration time (denoted as oscillation time in the figure) and the bonding strength. FIG. 5 shows the total displacement of the tip 9 and
The relationship with the bonding strength is shown. FIG. 6 shows the relationship between the distance between the tip 9 and the anvil 10 and the bonding strength.

In these figures, the solid lines P1, P2,
P3 and P4 indicate regression lines (straight lines passing through the center of the data within the period). The highest correlation coefficient with the solid lines P1, P2, P3 and P4 is shown in FIG. The correlation coefficient at this time exceeds 0.8. Therefore, it has been clarified that the objects to be welded can be bonded so as to have a desired bonding strength based on the total displacement of the tip 9. Further, it has been clarified that the joining state of the objects to be welded can be accurately determined based on the total displacement amount of the tip 9.

[0049]

As described above, according to the present invention described in claim 1, the vibration of the tip, that is, the ultrasonic vibration energy applied to the object to be welded is controlled based on the total displacement of the tip. Therefore, the ultrasonic welding is controlled based on the ultrasonic vibration energy actually applied to the welding object via the tip. Therefore, desired ultrasonic vibration energy can be reliably applied to the object to be welded. Therefore, the objects to be welded can be welded so that the desired bonding strength can be obtained.

According to the second aspect of the present invention, the quality of the welding condition of the object to be welded is determined based on the total displacement of the tip. Therefore, the quality of the welding target can be determined based on the ultrasonic vibration energy actually applied to the welding target via the chip. Therefore, in addition to the effect of claim 1 described above, it is possible to accurately determine the welding state of the welding target.

According to the third aspect of the present invention, the quality of the welding condition of the object to be welded is determined based on the total displacement of the tip. Therefore, the quality of the welding target can be determined based on the ultrasonic vibration energy actually applied to the welding target via the chip. Therefore, the welding status of the welding target can be accurately determined.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of an ultrasonic welding device according to an embodiment of the present invention.

FIG. 2 is a flow chart when the ultrasonic welding apparatus shown in FIG. 1 performs ultrasonic welding.

FIG. 3 is a diagram showing a relationship between a peak power and a tensile strength when a welding object is welded by the ultrasonic welding device shown in FIG.

FIG. 4 is a diagram showing a relationship between an oscillation time and a tensile strength when an object to be welded is welded by the ultrasonic welding device shown in FIG.

5 is a diagram showing the relationship between the total displacement of the tip and the tensile strength when the object to be welded is welded by the ultrasonic welding device shown in FIG.

FIG. 6 is a diagram showing the relationship between the distance between the tip and the anvil and the tensile strength when the object to be welded is welded by the ultrasonic welding device shown in FIG.

FIG. 7 is an explanatory view schematically showing a state in which an object to be welded is welded by the ultrasonic welding device of the present invention.

[Explanation of symbols]

1 Ultrasonic welding device 2,3 Metal plate (welding target) 5 Laser Doppler velocimeter (detection means) 7 oscillator (driving source) 9 chips 10 anvil 17 calculation unit (calculation means) 18 Control unit (control means) 19 Judgment unit (judgment means)

Claims (3)

[Claims] 1. A tip, which is vibrated by a drive source, and an anvil facing the tip, wherein a plurality of objects to be welded are sandwiched between the tip and the anvil, and the tip and the anvil are close to each other. In the ultrasonic welding device that welds the welding targets to each other by vibrating the chips by the drive source in a pressurized state and transmitting the vibrations to the welding targets, information about the vibration of the chips can be detected. A detection means, a calculation means for calculating the total displacement of the chip from the information on the vibration detected by the detection means, and a vibration of the chip is controlled based on the total displacement of the chip detected by the calculation means. An ultrasonic welding device, comprising: 2. The determination means for determining whether or not the welding status of the welding target is good or bad based on the information on the total displacement amount of the tip calculated by the calculation means. Ultrasonic welding device. 3. A tip vibrated by a driving source, and an anvil facing the tip. A plurality of objects to be welded are sandwiched between the tip and the anvil, and the tip is vibrated by the driving source. In the ultrasonic welding device that welds the objects to be welded to each other by transmitting the vibration to the object to be welded, a detecting unit that can detect information about the vibration of the chip, and information about the vibration detected by the detecting unit. From the above, there is provided a calculating means for calculating the total displacement amount of the tip, and a determining means for determining whether the welding state of the welding target is good or bad based on the information regarding the total displacement amount of the tip calculated by the calculating means. An ultrasonic welding device characterized in that