JP3031395U - Seam positioning device - Google Patents

Abstract

(57) Abstract: A seam position determining device for determining a welding seam position of an object on a rotary table, the welding seam positioning is automated, and work efficiency can be improved, and a reinforcing component is attached. The accuracy can be improved. A seam position determination device of the present invention outputs a low-frequency magnetic field from a transmission coil toward an object 1, receives a reflected magnetic field from the object 1 with a receiving coil, and changes the received reflected magnetic field. A seam detection device 10 for detecting the welding seam 1a based on the above, table rotating means (6, 12, etc.) for rotating the rotary table 5 and causing the seam detection device 10 to scan the welding seam 1a, The position of the welding seam 1a is determined based on the rotation amount of the rotary table 5, the position information of the seam detection device 10 and the seam detection information from the seam detection device 10, and the rotary table 5 is rotated based on the position of the welding seam 1a. And a seam position determining means (10, 12, etc.) for directing the welding seam 1a in a predetermined direction.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a seam position determining device that determines a welding seam position of an object on a rotary table.

[0002]

[Prior art]

 When a handle 101 as shown in FIG. 8 is attached to the can 100 formed by seam welding, a reinforcement component 102 for inserting the handle 101 is projection welded to a specified position on the side surface of the can 100. This projection welding process is automatically performed by using a projection welder, and the mounting position of the reinforcing component 102 at that time is determined based on the position of the seam (seam weld portion) 103 of the can 100. There is. Therefore, it is necessary to align the seam 103 in a predetermined direction before starting the projection welding process. However, there is no such method for detecting the position of the seam 103, and the worker can pick up the can 100 in his hand. At present, the seams 103 are visually checked and set in a predetermined direction.

[0003]

[Problems to be solved by the device]

 However, when the position of the seam 103 is detected by relying on human hands in this way, continuous working time is limited, work efficiency is poor, and mistakes easily occur. The mounting accuracy was not so good. The present invention has been proposed in view of the above, and the seam position determination device that can automate the positioning of the welding seam without relying on the eyes to improve the work efficiency and also improve the mounting accuracy of the reinforcing component. The purpose is to provide.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the seam position determining device of the present invention is a seam position determining device for determining the welding seam position of an object placed on a rotary table. A magnetic field transmitting means for outputting a magnetic field, a reflected magnetic field receiving means for receiving a reflected magnetic field from the object by a receiving coil, and a seam detecting means for detecting a welding seam based on the change in the received reflected magnetic field. A seam detecting device having the same, a table rotating means for rotating the rotary table to cause the seam detecting device to scan the welding seam, a rotation amount of the rotary table, position information of the seam detecting device, and a seam. The position of the welding seam is determined based on the seam detection information from the detector, and the rotary table is rotated based on the position of the welding seam to perform welding. And the seam position determining means for unsuitable a predetermined direction over arm was by having Unishi.

[0005]

[Embodiment of device]

 An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory view of a can setting system for automatically aligning the directions of cans. In the figure, the can 1 formed by seam welding is carried from the previous process conveyor 13 to the next process can setting system and placed on the turntable 5, and after the completion of the process, it is carried to the next process conveyor 15, For example, projection welding is performed on the next process conveyor 15. The movement of the can 1 is performed by using the auto hand 20 which operates in response to a command from the control unit 12.

The above can setting system (seam position determining device) is a system constructed to detect the seam 1 a of the can 1 and align its direction in a fixed direction. The seam detection centering on the control unit 12 is used. It is composed of a device 10, a rotary table 5, a servomotor 6 for rotating the rotary table 5, and a pressing plate 2 for pressing the can 1 from above.

The pressing plate 2 has a center of rotation on a coaxial line with the rotary table 5 and presses the can 1 from above to suppress positional displacement of the can 1, and is fixed to the piston tip end of the cylinder 3. Therefore, it can be moved up and down. That is, an electromagnetic valve 4 is connected to the cylinder 3, and when the solenoid valve 4 is opened in response to a command from the control unit 12, compressed air flows into the cylinder 3, whereby the cylinder 3 moves down the pressing plate 2. Then, the can 1 on the rotary table 5 is pressed from above. The pressing amount is adjusted so lightly that the can 1 can be rotated integrally with the rotary table 5.

As described above, the rotary table 5 is rotationally driven by the servo motor 6, and the servo motor 6 is driven by the motor control section 7 which operates in response to a command from the control unit 12. Rotate at the signal. Further, the servo motor 6 is provided with an encoder 61 for detecting its rotation amount, and a detection signal of the encoder 61 is fed back to the control unit 12 as rotation amount information of the rotary table 5.

The seam detection device 10 is a device for detecting the seam (seam welded portion) 1 a of the can 1, is fixed to the tip of the piston of the cylinder 8 and is movable in the horizontal direction. That is, the solenoid valve 9 is connected to the cylinder 8, and when the solenoid valve 9 is opened in response to a command from the control unit 12, compressed air flows into the cylinder 8, which causes the cylinder 8 to move the piston toward the can 1. Stop it by projecting to. At that time, the seam detection device 10 and the can 1 are preliminarily adjusted so as to maintain a certain distance such that the seam detection device 10 can accurately detect the seam, and the seam when stopped at the detection position. The position information of the detection device 10 is stored in the control unit 12 as a memory. When the process is completed, the solenoid valve 9 is closed and the cylinder 8 is retracted from its piston to retract the seam detection device 10 to a position sufficiently away from the can 1 so as not to hinder the movement of the can 1.

A signal processing unit 11 is connected to the seam detection device 10. The waveform signal received by the seam detection device 10 is sent to the signal processing unit 11 for processing, and then further sent to the control unit 12. To be

The control unit 12 detects the seam 1 a based on the signal from the seam detection device 10 sent via the signal processing unit 11, detects the seam 1 a, and rotates the rotary table 5. From the information and the position information of the seam detection device 10, the moving angle for orienting the seam 1a in a certain direction is obtained, and the rotary table 5 is rotated by the moving angle to align the cans 1 in the same direction.

FIG. 2 is a diagram schematically showing the configuration of the seam detection device. As shown in the figure, the seam detection device 10 has a central transmission coil 10a and two reception coils 10b and 10c provided on both sides of the transmission coil 10a, and is lower than the transmission coil 10a at the time of measurement. A frequency magnetic field is output, and the reflected magnetic field is received by the receiving coils 10b and 10c on both sides. As described above, each received signal is sent from the seam detection device 10 to the control unit 12 via the signal processing unit 11.

In general, when a metal object is present in the magnetic field generated by the transmitter coil, the electromagnetic induction action causes a magnetic flux to pass through the surface of the object and an eddy current in the vertical direction to flow, which changes the magnetic field of the receiver coil.

Since the material of the can 1 is uniform except for the welded portion (seam 1a), if the distance between the can 1 and the seam detection device 10 is constant, the outputs of the receiving coils 10b and 10c will not change unless the material changes. Does not change and remains constant (Fig. 3). On the other hand, since the thickness and the material of the seam 1a are slightly different from those of the other portions, the magnetic resistance changes due to the eddy current loss in the seam 1a portion, and as a result, as shown in FIG. A change appears in each output waveform of 10b and 10c.

As described above, the output signal of the seam detection device 10 is sent to the control unit 12 via the signal processing unit 11, and the control unit 12 catches the above-mentioned change point appearing in the output waveform. Then, the rotation angle corresponding to the change point is read and the rotation angle is recognized as the position information (detection information) of the seam 1a. Then, from the position information of the seam 1a, the rotation angle information of the rotary table 5, and the position information of the seam detection device 10, the movement angle for orienting the seam 1a in the predetermined direction is obtained, and the movement angle portion is calculated. A signal is sent to the servo motor 6 via the motor control unit 7 to rotate the rotating table 5. As a result, the cans 1 are aligned in a direction such that the seam 1a is in a predetermined direction, and are conveyed to the next process conveyor 15 in that state.

It should be noted that it is possible to detect only the changing points appearing in the output waveform of the seam detecting device 10 by only one of the receiving coils 10b and 10c. However, when these are actually detected, the can 1 is placed on the rotary table 5 and the can 1 is rotated to detect the seam position. At this time, the center of the can 1 is displaced from the center of the rotary table 5. Eccentricity occurs when rotated. The magnetic field changes in inverse proportion to the distance between the seam detection device 10 and the can 1, and becomes smaller as the distance increases. Therefore, as shown in FIG. 4, undulation occurs in the detection waveform of the receiving coil when it is eccentric, and the position of the seam 1a cannot be detected accurately. Therefore, in this embodiment, two receiving coils are used and the difference between the outputs is taken to cancel the drift due to the eccentricity.

FIG. 5 shows detection waveforms of the receiving coils 10b and 10c. If the characteristics of the receiving coils 10b and 10c are adjusted to be the same, the same waveforms that are out of phase by the amount of the distance in which the receiving coils 10b and 10c are separated in the seam detection device 10 are converted into angles are obtained. Output from the coils 10b and 10c, and by taking the difference between the outputs, the drift due to eccentricity can be canceled, and the seam position P can be specified more accurately (FIG. 6).

Although the seam position can be detected by the above method, an unnecessary signal due to a dent or a scratch on the can 1 is still mixed and may cause an erroneous detection. Therefore, in this embodiment, in order to further improve the detection accuracy, a method of passing this signal through a differentiating circuit and detecting only the change amount of the signal has been put to practical use. As a result, as shown in FIG. 7, the low signal variation is canceled and only the seam position signal can be accurately detected, and the seam position P can be specified with higher accuracy.

As described above, in this embodiment, the seam 1a of the can 1 can be detected and set in a predetermined direction automatically without relying on visual observation, so that the working efficiency can be improved and Since the setting can be performed with high precision, it is possible to attach reinforcing parts and the like in the next process with high precision.

Since the seam detection device 10 uses the two receiving coils 10b and 10c, even if the can 1 is eccentric on the rotary table 5, the detection error due to the eccentricity can be canceled and the seam The detection accuracy of 1a can be improved.

[0021]

[Effect of device]

 As described above, according to the seam position determining device of the present invention, it is possible to automatically detect the welding seam of an object and set it in a certain direction without relying on visual observation, thus improving work efficiency. Can be raised. Further, since the setting can be performed with high accuracy, the reinforcing parts and the like can be attached with high accuracy in the next process.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a can setting system that automatically aligns the directions of cans.

FIG. 2 is a diagram schematically showing a configuration of a seam detection device.

FIG. 3 is a diagram showing a basic signal waveform of a receiving coil.

FIG. 4 is a diagram showing a case where undulation occurs in a waveform of a receiving coil due to eccentricity of a can.

FIG. 5 is a signal waveform of two receiving coils.

FIG. 6 is a signal waveform when the difference between two receiving coils is taken.

FIG. 7 is a waveform obtained by differentiating a signal from a receiving coil and extracting only a signal having a large change amount.

FIG. 8 is a view showing a case where a handle is attached to a can.

[Explanation of symbols]

 1 can 1a seam 2 pressing plate 3,8 cylinder 4,9 solenoid valve 5 rotary table 6 servo motor 7 motor control unit 10 seam detection device 10a transmission coil 10b, 10c reception coil 11 signal processing unit 12 control unit 20 auto hand

Claims (1)

[Scope of utility model registration request] 1. A seam position determining device for determining a welding seam position of an object placed on a rotary table, comprising: a magnetic field transmitting means for outputting a low frequency magnetic field from a transmitting coil toward the object; Seam detecting device having a reflected magnetic field receiving means for receiving the reflected magnetic field of the receiving coil by a receiving coil and a seam detecting means for detecting a welding seam based on the change of the received reflective magnetic field, and the seam for rotating the rotary table. Table rotation means for causing the detection device to scan the welding seam, and the position of the welding seam is determined based on the rotation amount of the rotary table, the position information of the seam detection device, and the seam detection information from the seam detection device. And a seam position determining means for rotating the rotary table based on the position of the weld seam and directing the weld table in a predetermined direction. A seam position determining device comprising: