JPH07132471A - Body repairing robot and body repairing method - Google Patents

Abstract

PURPOSE:To perform work such as paint separation, cutting of a corroded part, separation of an outside plate, finishing of a frame part and finishing of a weld part by one robot safely and efficiently without needing to prepare a motive power unit for each work. CONSTITUTION:A body repairing robot is formed of a movable motive power unit 2, a working base 3 elevatingly provided at the motive power unit 2, a robot 4 provided with a disc grinder 8 and disposed at the working base 3, and a robot control device 10 disposed at the non-elevated part 9 of the motive power unit 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body repairing robot for repairing a vehicle body of a train or the like, and a vehicle body repairing method using the vehicle body repairing robot.

[0002]

2. Description of the Related Art The body of an electric car, such as an electric train, has changed from an early wooden one to a half steel one to an all steel one. Recently, a corrugated steel plate is put on the underframe so that the underframe, side frame and roof are made uniform. A tension shell structure that works as one structure has been developed to reduce the weight of the vehicle body.

Since a car body of a train or the like is formed of a steel plate, the car body outer plate is corroded by long-term use.
In order to repair and manage a vehicle body such as a train, it is necessary to repair the corroded portion of the vehicle body outer plate so that the corrosion of the vehicle body outer panel does not proceed further when corrosion occurs in a part of the vehicle body outer panel. That is, when the outer skin of the vehicle body is corroded, it is necessary to repair the corroded portion by cutting the periphery of the corroded portion (normally 100 mm in length and 300 mm in horizontal length) and welding a new material to the cut portion. And In particular, the outer plate on the lower side of the vehicle body is
It is easily corroded and often requires repair work.

A conventional method for repairing a corroded portion of a vehicle body outer plate is as follows:
The repair procedure is shown in FIGS. 16 and 17. (1) Paint removal: To cut around the corroded portion 101 of the vehicle body outer plate 100, along the cut portion (standard size),
The outer plate is painted and the putty is peeled off by the usual shot blasting means. (2) Corrosion part cutting: The outer plate part 101A corresponding to the corroded part 101 of the vehicle body outer plate 100 is melt-cut by a plasma cutting device (not shown). (3) Peeling off the outer plate: The outer plate on the lower side of the vehicle body and the underframe 10
Since No. 2 is plug-welded (intervals of about 10 cm, φ8 mm), the plug-welded part 103 is melted by a gas cutting device (not shown), and the melted and cut outer plate part 101A is attached to the vehicle body outer plate 100.
Remove more. (4) Outer plate alignment: A disc grinder (not shown) is used to perform dimension adjustment so that a new material 105 having a standard size can be welded to the plasma cut portion 104 of the vehicle body outer plate 100. (5) Underframe finish: Corroded portion 101 of underframe 102
Use a disc grinder to remove the rust in the area corresponding to. (6) New material welding: A new material 105 is placed on the plasma cutting portion 104 of the vehicle body outer plate 100, and the new material 105 is welded to the vehicle body outer plate 100 and the underframe portion 102 using a CO2 welding machine (not shown). (7) Finishing of welded portion: The weld bead and plug welded portion of the new material 105 and the vehicle body outer plate 100 are ground 106 by a disc grinder to be finished.

Thereafter, putty is applied to the new material 105 and the welded portion of the vehicle body outer panel 100 and the welded portion is painted to complete the repair work.

In the above-mentioned conventional method of repairing the corroded portion of the vehicle body outer plate, the worker must ride on the elevating base of the mobile power vehicle having the elevating work base to perform each work, Also, the shot blast, plasma cutting device, gas cutting device, disc grinder, welder, etc. used in the work, in each work,
It must be done by setting up a motor vehicle equipped with each device. Further, since the worker manually cuts the outer plate by plasma cutting, the cross section melted and cut must be finished by the grinder work so that the new material can be welded.

[0007]

However, in the conventional method for repairing the corroded portion of the vehicle body outer plate, the worker has to perform each work in a high place and in a dust environment, which is so-called dangerous, tough or dirty. There was a problem of 3K work. Also, in each work such as shot blasting, plasma cutting device, gas cutting device, grinder, welder, etc., a motor vehicle equipped with each device is required, and moreover,
It was necessary to move and set the motor vehicle for each work process, and a lot of time was required for preparatory work for these works. Moreover, frequent movement of many motor vehicles in the repair shop where repair work is performed, or setting work is an obstacle to work other than repair work on the body shell, or work other than repair work. There is also a problem that it is dangerous to workers who are doing work.

The present invention has been made in view of the above points, and uses a vehicle body repair robot that operates safely and efficiently and a vehicle body repair robot that simplifies the vehicle body repair process and improves work efficiency. The purpose is to provide a method for repairing boards.

[0009]

A vehicle body repairing robot according to the present invention is provided with a movable power vehicle, a work base provided on the power vehicle so as to be able to move up and down, and a disk grinder. And a robot controller arranged in the non-elevating part of the motor vehicle.

A method of repairing a vehicle body skin of the present invention includes a step of disposing a vehicle body repairing robot having a robot equipped with a disk grinder at a position adjacent to a vehicle body to be repaired, the vehicle body repairing robot and the vehicle body repairing vehicle. And a step of measuring the positional relationship between the disc grinder and the vehicle body by incliningly arranging the disc grinder to remove the paint or putty in a predetermined area of the vehicle body outer plate repair part, and arranging the disc grinder vertically with respect to the vehicle body Then, the step of cutting the repair portion of the vehicle body outer plate to a predetermined size, the step of cutting the plug welding portion between the vehicle body outer plate and the vehicle body underframe portion within the predetermined size by the disk grinder, and the disk grinder It consists of a process of removing rust from the underframe of the vehicle body and a process of finishing the welded portion of the new material welded to the cut portion of the vehicle body outer plate.

[0011]

In the vehicle body repair robot of the present invention, the operator does not need to directly work, so it is safe, there is no problem such as dust, and the motor vehicle is frequently moved and set for each work. Work efficiency is improved because it is not necessary.

According to the method for repairing the outer skin of the vehicle body of the present invention, there is no need for the outer skin aligning step of the work such as paint stripping, corroded portion cutting, outer skin stripping, outer shell matching, underframe finishing, and welding finish. Moreover, since it is not necessary to align the position of the vehicle body repair robot for each process, the process can be shortened and the work efficiency can be improved.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a vehicle body repair robot according to the present invention. The vehicle body repair robot 1 comprises a mobile power vehicle 2
And a work base 3 which is arranged on the motor vehicle 2 so as to be able to move up and down.
And a robot 4 installed on the work base 3. The motor vehicle 2 is of an electric tire drive system, and when moving or setting, the operator can move to any position by operating the steering base 6 while riding on the work base 3 that moves up and down. There is. The elevating work base 2 has a cantilever structure, the supporting side is supported by a linear guide or the like (not shown), and it can be moved up and down by driving a ball screw with an electric or hydraulic motor. There is. The robot 4 is of a 6-axis orthogonal coordinate type, and a disc grinder 8 is attached to the tip end thereof via a 6-axis force sensor 7. The robot 4 may be a 5-axis orthogonal coordinate type depending on the shape of the vehicle body outer plate 100.

On the other hand, a control device 10 for controlling the operation of the robot 4 is installed in the non-elevating portion 9 of the motor vehicle 2. This control device 10 is arranged on the left side from the robot 4 toward the work area. This is because when the grinder work is performed in a normal posture, dust is scattered in the normal grindstone rotation direction of the disc grinder 8 in the right-hand direction of the disc grinder 8 in order to avoid scattered dust.

The operation of the robot 4 by the control device 10 is performed, for example, by an operation box 11 or a personal computer (not shown) provided separately.
The operation box 11 is shown in a larger size than usual for the sake of explanation. Operation box 1
1 includes a joystick 12 used for manual work or teaching, and a plurality of buttons 13 for selecting each work such as paint removal and corroded portion cutting. When operating with a personal computer, paint as well,
A command for each operation such as peeling and cutting a corroded portion may be selected from the menu.

Next, a method of repairing a vehicle body skin using the vehicle body repairing robot 1 according to the present invention will be described. First, as a preparatory work for the vehicle body skin repair work, an operator drives the motor vehicle 2 to move the vehicle body repair robot 1 to a repair portion of the vehicle body 20 shown in FIG. Stop so that they are almost parallel. The stop position of the motor vehicle 2 does not need to be aligned precisely in parallel because the coordinates of the robot 4 are set later.

Then, the work base 3 is moved up and down to adjust the height so that the operation area of the robot 4 falls within the repair area of the vehicle body outer plate 21. The vehicle body 20 shown in FIG. 2 is a so-called 103 series vehicle body in which the lower portion of the side surface of the vehicle body is vertical, but depending on the vehicle type, there is also a so-called 113 series vehicle body in which the lower portion of the vehicle body 20 is inclined inward. In this case, the Y axis is slightly tilted with respect to the vertical direction.

Next, the controller power is turned on, the robot 4 is started up, the origin return adjustment is performed if necessary, and the robot is made operable. Since the vehicle body repair robot 1 is basically a mobile robot, it is necessary to clarify the positional relationship between the robot 4 and the vehicle body 20 before starting work. In order to make the following work easier, for example, a vehicle body outer plate 21 as shown in FIG.
Set the coordinate system (vehicle body coordinate system) along the. When the coordinate system is set, it can be set by giving three points, but in order to set the coordinate system along the surface of the vehicle body outer plate 21, a plurality of points are contacted as described below to make contact with the three points. And set the coordinate system.

The disc grinder 8 is guided by the joystick 12, for example, to the lower left side of the area 22 to be repaired, which is shown by a dotted line in FIG. In this case, the grinder posture is a posture in which the grindstone hits the surface of the vehicle body outer plate 21 vertically as shown in FIG. This grinder attitude is
The position differs slightly depending on the vehicle type. For example, a vehicle that leans inward has a posture as shown in FIG.

Then, a coordinate setting button or command is selected from the operation box or the man-machine interface (MMI) computer, and the subsequent coordinate setting operation is automatically performed. A series of operations for setting coordinates is as follows.

The disc grinder 8 is moved upward from the lower left side of the area to be repaired (the grinder position in FIG. 3) to detect the lower end of the vehicle body outer plate 21. At this time, it can be easily determined from the detection value of the force sensor 7 that the upper surface of the grindstone comes into contact with the lower portion of the vehicle body.

Next, the lower end of the surface of the vehicle body outer plate 21 is contacted and detected by the tip of the grindstone with reference to the detected lower end of the vehicle body outer plate 21, and this point is designated as P1. Then, the position P2 on the vehicle body surface above P1 is detected. Next, as in the case where P1 is detected, it is automatically guided to the lower right of the area 22 to be repaired, the disc grinder 8 is moved upward, and the lower end of the vehicle body outer plate 21 is detected. The lower part of the surface of the vehicle body outer plate 21 is detected based on the detected lower end, and this point is designated as P3. P
The positional relationship of 1 to P3 is as shown in FIG. 3 on the body surface
Since the points are detected, the Z-axis direction (the normal direction of the vehicle body)
Can be easily calculated. In the X-axis direction, the vector P1
It can be easily calculated from P3. Furthermore, the calculated Z axis, X
The Y axis can be easily calculated from the axes. The height P3 ′ at the same position as P2 may be set as P3, and the X-axis direction may be calculated from the vector P2P3 ′. In this case, since the coordinate system is set by contacting the vicinity of the cutting position in the lateral direction, the cutting in the lateral direction can be performed more accurately.

It should be noted that the points P1 to P3 to be detected do not necessarily have to be on the cutting line, but the error can be reduced by making contact on or near the cutting line as compared with the case of making contact at a position apart from the cutting line. . In some cases,
Instead of guiding the disc grinder 8 to the lower left side of the area 22 to be repaired with the joystick 12 first, the disk grinder 8 may be guided to the left cutting line of the area 22 to be repaired. In this case, since the guide position is easily seen by the operator, it is possible to easily guide the operator, and the burden on the operator can be reduced. As shown in FIG. 8, the disk grinder 8 can be automatically guided to the lower left position of the repair area 22 by automatically repeating the operation of contacting the vehicle body surface downward at a predetermined interval. If the vehicle moves a predetermined amount in the direction of the vehicle body and no longer contacts the vehicle body, the repair area 22
It can be determined that it is the lower left position. After that, the vehicle body is contacted by the same procedure as the previous method.

A series of coordinate setting operations is guided by a coordinate system determined by the attitude of the grinder (usually referred to as a tool coordinate system, herein referred to as a grinder coordinate system). When the first motor vehicle is installed, the motor vehicle and the vehicle body are installed almost parallel to each other, and the vehicle body is almost horizontal. Therefore, considering the range of the installation error, even if the vehicle is guided by the grinder coordinate system, there is a particular problem. Absent. Further, the coordinate system of the general vehicle body may be set in advance and the vehicle may be guided along the coordinate system. In order to set the coordinates when the parallelism between the vehicle and the vehicle is even worse, it is necessary to first contact two or three appropriate points on the surface of the vehicle to determine the parallelism between the vehicle and the vehicle. . In this case, the grinder posture is corrected if necessary.

In the above description, the position guided by the joystick 12 was described as the lower left side of the repair area 22, but it goes without saying that the coordinate system along the vehicle body surface can be set on the right side or the center.

After setting the coordinate system, the actual repair work is performed. First, as shown in FIG. 9, a predetermined area 24 is peeled off along the cutting line 23 with the coating and putty on the surface of the vehicle body outer plate 21. This peeling area is an area almost similar to that of the conventional shot plast. Further, the paint and putty of the plug welding portion 25 are also peeled off. Since the position of plug welding differs depending on the repair location, it is necessary to set the peeling location depending on the work location. If the position of the plug welding is known accurately, it is sufficient to peel off only the vicinity of the plug welding portion. Such coating and peeling of the putty are performed by feeding the disc grinder 8 at a constant speed while controlling the force so that the pressing force is constant. In this case, when the disc grinder 8 is fed in the X-axis direction, work is performed in the posture shown in FIG. 10, and the disc grinder 8 is moved to the Y direction.
When feeding in the axial direction, the work is performed in the posture as shown in FIG. Thereby, the scattering direction of dust can be limited, and the dustproof effect can be enhanced.

Next, the vehicle body outer plate 21 is cut into a predetermined size. A cutting operation is performed by applying a grindstone substantially perpendicularly to the vehicle body outer plate 21. In this case, by performing the work in the posture as shown in FIG. 12, the scattering direction of the dust can be limited and the dustproof effect can be enhanced, as in the case of the coating peeling. In order to carry out the cutting work efficiently, a relatively thin grindstone (about 2 mm or 3 mm) may be used. In the same posture, the vehicle body outer plate 21
The vehicle body outer plate 21 can be cut by performing force control so that a constant pressing force is exerted in the normal direction (-Z direction) and reciprocating in the cutting range at a constant speed. In this case, since the vehicle body outer plate 21 is plug-welded to the underframe 102, which is a structural member, the cut amount in the −Z direction is limited so as not to damage the underframe 102, and the cut amount is not more than the predetermined amount. Need to do so.

As another cutting method, there is a method in which a predetermined amount is cut in the -Z direction from the end of the cutting range, and the disc grinder 8 is fed from that position to a predetermined amount in the -Z direction at the other end for cutting. is there. At this time, if the disc grinder 8 is fed at a constant speed, it will be overloaded and work efficiency will be deteriorated. Therefore, the feeding speed is changed by the pressing force of the disc grinder 8 and the grinder load.

In any of the cutting methods, since the work is performed in the vehicle body coordinate system, the work can be performed without damaging the underframe 102.

Next, the vehicle body underframe 1 in the repair area 22
The plug welding portion 103 with 02 is carved. When cutting the plug-welded portion 103, basically the same method as cutting is performed. For example, if plug welding is about φ8 mm, 3
When cutting with a grindstone having a thickness of mm, the underframe 102 is carved without damaging as in the case of cutting, and the cutting position is shifted in parallel by about the thickness of the grindstone (for example, 3 mm). Make a cut. By repeating this operation three or four times, the plug welding portion 103 can be efficiently carved. With this operation, the outer plate of the corroded portion 22 can be peeled off.

Either of the cutting work, the plug welding portion and the shaving work may be performed first.

Next, the portion of the vehicle body underframe 102 of the peeled outer plate is usually corroded, so the work of removing rust is performed. As in the case of paint removal, rust can be removed by performing force control so as to obtain a constant pressing force and sending the disc grinder 8 at a constant speed. This completes the pre-welding work.

Next, a new material 105 having a predetermined size is welded. This welding work is performed by a welding robot or manual work. The preparatory work of the vehicle body repair robot 1 is performed again, and finally the finishing work of the peripheral welding bead on which the outer plate is welded and the plug welding portion to the vehicle body underframe portion is performed. Grinding of the weld bead is performed by controlling the force so that a constant pressing force is exerted, and sending the grinder at a constant speed along the weld bead. Grinding of plug welds is done by grinding only the convex parts so as not to cut new material unnecessarily. For example, the finished surface may be detected by contacting the new material 105, and grinding may be performed along the finished surface.

With the above, the repair work by the body repair robot is completed. In the above embodiment, the robot equipped with the grinder has been described, but if a welding torch can be replaced by a tool changer and the welding machine is mounted together with a controller or the like, a series of all operations can be performed by one vehicle body. Work can be done with repair robots. By doing this, it is not necessary to evacuate the vehicle body repair robot, work with the welding power vehicle, install the vehicle body repair robot again, and do the preparation work. The work can be carried out efficiently, and the coordinate data necessary for the welding work can be shared.

In the above embodiment, the method of cutting by the car body repair robot has been described, but it is also sufficient to perform the work (outer plate matching) of finishing the end face of the plasma cutting manually performed by the operator to the specified dimension. It is possible. In this case, it is possible to accurately detect the position for finishing to the designated dimension by contacting the plasma cutting end face.

13 to 15 show another embodiment of the vehicle body repairing robot according to the present invention. In the vehicle body repairing robot 30 shown in FIG. 13, the control device 6 is provided on the back of the supporting portion 31 of the elevating base 3. When installed, the support portion 31 also serves as a dustproof wall. In this case, it is preferable to install a steering wheel (not shown) on the back of the support portion 31.

In the vehicle body repairing robot 40 shown in FIG. 14, a 6-axis Cartesian coordinate robot 4 is installed on the lifting work base 3, and a dustproof fence 41 for covering the work area is provided on the work area side of the work base 3. A dust suction port 42 for sucking dust generated by work is formed below the dustproof fence 41. A bellows portion 43 is provided on the work area side of the dust-proof fence 41 so as to be in close contact with the side surface of the vehicle body, so that dust and the like do not leak. The dust-proof fence 41 may be used as a slide mechanism and pressed against the side surface of the vehicle body to be brought into close contact therewith. The end surface of the bellows portion 43 or the sliding portion which is in contact with the vehicle body can be brought into closer contact with the side surface of the vehicle body by providing rubber, a sponge layer, a magnet or the like. By configuring the bellows portion 43 or the slide portion to be moved electrically, the burden on the operator can be further reduced.

Further, a curtain 44 is arranged on the robot side of the dustproof fence 41 so as to prevent dust from scattering to the robot side. As a result, even if the robot 4 moves to the left and right, it is possible to prevent dust from leaking as much as possible without causing a large opening.

Further, an automatic grindstone changing device 45 is arranged in the operation area of the body repair robot 40. A new grindstone is stored in the grindstone automatic changing device 45. This new whetstone may be of several types, if desired. Like the controller, the automatic grindstone changing device 45 is arranged on the left side of the robot from the robot toward the work area, and replaces the grindstone when the work wears or the kind of the grindstone is changed.

Further, a dust suction device main body 46 is arranged in parallel with the control device 10 arranged in the non-elevating portion of the power vehicle 2. The dust suction device body 46 and the dust suction port 42 are connected by a suction hose 47, and the dust in the dust barrier 41 is sent from the dust suction port 42 through the suction hose 47 to the dust suction device body 46 so that the dust is stored there. ing. Further, by arranging a plurality of suction hoses under the dust suction port 42, or by arranging the suction hose 48 (illustrated by a dotted line) not only in the lower portion of the dust suction port 42 but also from the robot toward the work area, in the right hand. , The dust absorption effect can be improved.

In the vehicle body repairing robot 50 shown in FIG. 15, the robot 51 has a 6-axis cylindrical coordinate form.
In this case, the curtain 4 provided on the robot side of the dustproof fence 41
The curtain 4 does not need to have a movement amount equal to the linear movement amount of the robot in the left-right direction unlike the orthogonal robot, and the curtain 4
The movement amount of 4 can be reduced.

In common with the above embodiments, when the work base is unstable, an outrigger (not shown)
The motor vehicle or work base may be supported, and the work base may be supported at both ends instead of in a cantilever structure. Further, the robot may be a polar coordinate type robot or an articulated type robot.
When it is difficult for the worker to monitor the work area and work state, a CCD camera or the like may be appropriately installed and the work area and work state may be monitored by the TV monitor.

[0043]

As described above, according to the vehicle body repairing robot of the present invention, it is possible to perform work such as paint stripping, corroded part cutting, outer plate stripping, underframe part finishing, and welding part finishing on one vehicle body. It can be done by a repair robot, there is no need to prepare a motor vehicle for each work, there is no need to move and set the motor vehicle frequently for each work, and
Workers do not need to work directly, so they are safe and do not have problems such as dust.

Further, according to the vehicle body repairing method of the present invention, the steps of aligning the outer plates include the steps of removing paint, corroding parts, removing outer plates, aligning the outer plates, finishing the underframe, and finishing the welded parts. It is not necessary, and since it is not necessary to position the vehicle body repair robot for each process, the process can be shortened and the work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a vehicle body repair robot according to the present invention.

FIG. 2 is a perspective view showing a vehicle body to be repaired and a vehicle body coordinate system.

FIG. 3 is a diagram showing a position where a grinder is guided when coordinates are set.

FIG. 4 is a view showing positions of a grinder and a vehicle body to be repaired.

5 is a diagram showing the positions of the grinder and the vehicle body to be repaired in the vehicle body different from FIG.

FIG. 6 is a diagram showing positions P1 to P3 and P3 ′ that come into contact with the vehicle body surface.

7 is a sectional view of the vehicle body in FIG.

FIG. 8 is a diagram showing a position where a grinder is guided when coordinates are set.

FIG. 9 is a diagram showing a region where coating and putty are peeled off.

FIG. 10 is a view showing a grinder posture at the time of coating, peeling putty, and the like.

FIG. 11 is a view showing another grinder posture when painting, peeling putty, or the like.

FIG. 12 is a view showing a grinder posture when performing a cutting operation.

FIG. 13 is a perspective view showing another embodiment of the vehicle body repair robot according to the present invention.

FIG. 14 is a perspective view showing another embodiment of the vehicle body repair robot according to the present invention.

FIG. 15 is a perspective view showing another embodiment of the vehicle body repair robot according to the present invention.

FIG. 16 is a front view showing a conventional working method.

FIG. 17 is a side view showing a conventional working method.

[Explanation of symbols]

 1 Body repair robot 2 Motor vehicle 3 Work base 4 6-axis Cartesian coordinate robot 7 6-axis force sensor 8 Disc grinder 9 Non-elevating part 10 Controller 20 Body 21 Body shell 22 Repair area 41 Dust fence

Front Page Continuation (72) Inventor Makoto Kamino 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center (72) Inventor Taku Yoshimi Komu-shi Toshiba-cho, Kawasaki-shi, Kanagawa Incorporated Toshiba Research and Development Center (72) Inventor Katsuhiro Maeda 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Incorporated Toshiba Research and Development Center

Claims (2)

[Claims] Claim: What is claimed is: 1. A movable power vehicle, a work base provided on the power vehicle so as to be able to move up and down, a robot having a disk grinder and disposed on the work base, and a non-elevating portion of the power vehicle. A robot for repairing a vehicle body, which has a robot controller. 2. A step of disposing a vehicle body repairing robot equipped with a robot having a disk grinder at a position adjacent to a vehicle body to be repaired, and a step of measuring a positional relationship between the vehicle body repairing robot and the vehicle body. , A step of arranging the disc grinder obliquely with respect to the vehicle body to remove coating and putty in a predetermined range of a vehicle body skin repair portion, and disposing the disc grinder vertically with respect to the vehicle body to repair the vehicle body skin repair portion. A step of cutting to a predetermined dimension, a step of cutting a plug welded portion between a vehicle body outer plate and a vehicle body underframe portion within a predetermined dimension by the disc grinder, and a step of removing rust on the vehicle body underframe portion by the disc grinder And a step of finishing a welded portion with a new material welded to a cut portion of the vehicle body outer plate, the method for repairing a vehicle body outer plate.