JP2003146258A - Car body assembly method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a jig for tacking a side member to an under body lightweight and compact, reduce initial investment, and make step change work easy and quick. SOLUTION: Lower welding edges of a pair of right and left side members 4 are longitudinally placed in a state fit to the right and left welding edges of an under body 3 to the under body 3 positioned in the specified position of a car body assembly line 2. In a longitudinally placed state, at least four front and rear portions of the lower welding edges of the right and left side members and the under body 3 are connected and fixed with at least four cramp jigs 11-1 to 11-4 arranged in the specified positions. In the connected and fixed state, the under body 3 and the side member 4 are welded. Replacement of the cramp jig attendant on the change of the kind of cars is conducted with jig exchange robots 10-1, 10-2.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for assembling a vehicle body, and more particularly to an assembling method for welding left and right side members to an underbody. 2. Description of the Related Art A vehicle body is mainly composed of an underbody, a pair of left and right side members and a roof. These main members are relatively positioned using various positioning jigs, and in this positioning state, they are temporarily attached by spot welding by a welding robot, and then are additionally welded. [0003] In the conventional method of assembling a vehicle body, a large-scale positioning jig is generally used to position the main member. For example, as a jig for the side member, a folding screen-like jig which is slightly larger than the side member may be used. In the method of assembling a vehicle body using such a large jig, the jigs are arranged to be able to move forward and backward on the left and right sides of the vehicle body assembly line, and the side members are transported to the front of the jig by a transport device and set. Move the jig forward and position it in the predetermined position of the underbody,
In this state, tack welding is performed between the underbody and the side members. [0004] Since such a folding screen jig is large and heavy, not only does initial investment increase, but also when the production vehicle type is changed (changeover), the jig is replaced with another jig. Although it is necessary to attach and detach to and from the reciprocating drive mechanism, there is a disadvantage that the attaching and detaching work requires a great deal of time, and the production line must be completely stopped during that time. There is also a method of assembling a vehicle body using a rotary jig in order to quickly change the steps. However, this rotary jig has a triangular prism shape for three types of vehicles and a quadrangular prism shape for four types of vehicles. However, the size and weight of the jig are even higher than those of the folding screen jig, resulting in a further increase in initial capital investment. SUMMARY OF THE INVENTION The present invention aims to reduce the weight and size of a side member jig used for welding (temporarily attaching) side members to the left and right sides of an underbody, and to provide initial equipment. The purpose is to achieve a reduction in investment and an easy and quick changeover operation. [0007] A method of assembling a vehicle body according to the present invention is a method of assembling a vehicle body. At least four clamp jigs arranged at predetermined positions are arranged vertically with the left and right side members in the vertically placed state at least four positions in the front and rear parts and the under body in a state of being aligned with the left and right welding edges. The underbody and the side member are temporarily welded in the connected and fixed state, and the clamp jig is exchanged by a robot when the vehicle type is changed. A general-purpose robot can be used for transporting and vertically placing the side members. The general-purpose robot picks up the side members that have been transported to the vicinity of the general-purpose robot, and then moves the same to a predetermined position of the underbody and places it vertically. Then, in this state, the underbody is connected and fixed to at least four front and rear portions of the lower welding edges of the left and right side members with the four clamp jigs, and the two are welded by the welding robot. The conventional side member jig was designed to clamp the side member as a whole, and thus had to be one or two times larger than the side member. Instead of clamping the entire body, the side member sideways direction regulation is temporarily assigned to a general-purpose robot for transportation, etc., and the front / rear, left / right / up / down direction regulation of only the front and rear portions of the lower welding edge of the side member is restricted. It was made to take charge with one clamp jig.
Therefore, the four clamp jigs can be configured to be lightweight and compact, and the initial equipment investment can be significantly reduced. In addition, since the clamp jig itself is lightweight and compact, it can be easily moved using a general-purpose robot. It is possible to realize quick and easy changeover work and low cost of changeover equipment. In addition, since the clamp jig is compact, by providing an appropriate rack facility or the like on the side of the vehicle body assembly line, a space-saving standby area for the clamp jig can be secured. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically shows a side member temporary attaching station 1, which is disposed at a predetermined position in a vehicle body assembly line 2 as shown in FIG. Body assembly line 2
Has an underbody assembly line on the upstream side of the side member temporary attachment station 1, and the underbody 3 assembled by the underbody assembly line as shown in FIG. It is transported to the side member temporary attachment station 1 by the carriage 7 moving along the assembly line 2. On the downstream side of the side member temporary installation station 1, a roof temporary installation station 5 and a roof temporary installation station 6 are also arranged in order, as shown in FIG. In addition, a roof refilling station is provided downstream of the roof tacking station 6. As shown in FIG. 1, a plurality of robots 10-1 to 6 and clamp jigs 11-1 to 4 are arranged in the side member temporary attaching station 1, Side members 4 are temporarily attached to both left and right sides of the body 3, and a cowl outer 12 is welded to a front portion. The side member temporary attachment station 1 is, in detail, a set of front and rear slide guides 14 symmetrically arranged on the left and right sides of the vehicle body assembly line 2 to guide the slide table 13, and a lift table arranged at the rear end of these slide guides 14. 15. A jig exchange robot 10- which mounts four jigs 11-1 to 4 to be used on the elevating table 15 and picks up used jigs 11-1 to 11-4 on the slide table 13.
1, 10-2, the first transfer robot 10-3 which is disposed between the jig exchange robots 10-1 and 10-2 and transfers the side member 4, and is disposed at a position one step lower between the slide guides 14; Welding robot 10-4, slide guide 1
And a second transfer robot 10-6 disposed behind the slide guide 14 and setting the cowl outer 12 at the front and rear portions of the vehicle body. More specifically, as shown in FIG. 4, the slide guide 14 is connected to the vehicle body assembly line 2 and the jig changing robots 10-1 and 10-1.
0-2, it is disposed at right angles to the vehicle body assembly line 2. The slide guide 14 is provided with a slide table 13 which is moved back and forth by slide driving means.
Jigs 11-1 to 11-4 are removably arranged on the upper side. These jigs 11-1 to 4 clamp the front and rear portions of the welding edges on the left and right sides of the underbody 3 and the front and rear portions of the lower welding edge of the side member 4, and perform relative positioning of the two and positioning with respect to a stationary system including the ground. This is performed at the same time, and details of the clamp portion are omitted. The jig 11 is provided on the upper surface of the slide table 13.
A coupler of an air system or a control electric system serving as a drive source of a clamp portion of -1 to 4 is provided (not shown), and a coupler of the jigs 11-1 to 11-4 is detachably connected to this coupler. Then, the clamp functions of the jigs 11-1 to 11-4 become operable. The elevator 15 provided at the rear end of the slide guide 14 has an upward vertical cylinder 20 as shown in FIG.
Is fixed to the upper end of the rod 21 and moves up and down by the expansion and contraction of the rod 21. A plurality of positioning pins 22 are arranged on the lift 15, and the jig 11 to be used next is
When -1 to 4 are mounted on the elevating table 15 by the jig changing robots 10-1 and 10-2, the positioning pins 22 are fitted into the holes 24 near the center of the jig base 23. On the other hand, the slide guide 14 has a lift 15
A through hole 25 slightly larger than the through hole 25 is formed, and a plurality of positioning pins 26 having a locking function are formed around the through hole 25.
Are arranged. When the slide base 13 is retracted to the end of the slide guide 14 and the lift base 15 is lowered, the jigs 11-1 to 11-4 are transferred onto the slide base 13 and the positioning pins 26 are moved to the jig base 23. Is fitted in the hole 27 along the edge of. When the elevator 15 is lowered, the elevator 15 is moved through the through hole 25 of the slide 13.
, From the top to the bottom, moves to a position slightly lower than the horizontal movement locus of the slide base 13 and stops. In the vicinity of the jig changing robots 10-1 and 10-2, a plurality of types of jigs 11-1 to 11-4 are stocked for step change, and one of these jigs 11-1 to 11-4 is shown in FIG. As shown by 7, the jigs are picked up by the jig changing robots 10-1 and 10-2 and mounted on the lift 15. The jigs 11-1 to 11-4 mounted on the lift table 15 are transferred onto the slide table 13 waiting at the end of the slide guide 14 by the lowering of the lift table 15 as described above. The electrical system is coupler connected. Jigs 11-1 to 4
Is moved forward by the slide driving means, and the underbody 3 transported to the side member temporary attaching station 1 and the first transport robot 10- The side member 4 conveyed in step 3 is clamped at a total of four places, two places at the front and rear portions of the welded edge in contact with each other. After the underbody 3 and the side members 4 are temporarily attached by the welding robots 10-4 and 10-5 in this clamped state, the jig 1
In steps 1-1 to 1-4, the clamp is released, and the slide stand 13 is slightly retracted from the position indicated by the dashed line to the position indicated by the solid line in FIG. Then, it waits for the temporary attachment of the next underbody 3 and side member 4. At the time of changing the jigs, the jigs 11-1 to 11-1 are used in this standby position as in the jig changing robots 10-1 and 10-2.
The picked-up jigs 11-1 to 11-4 are returned to predetermined positions in a jig stock area near the jig changing robots 10-1 and 10-2. Jig exchange robot 10-
Since the jigs 11-1 and 10-2 are used after the jigs 11-1 to 11-4 are mounted on the lift 15, the same robot 10
The jigs 11-1 to 11-4 are picked up using -1 and 10-2. As described above, the jig is changed using one jig exchange robot 10-1 (10-2) for one jig, but the next jigs 11-1 to 11-4 have already been lifted and lowered. 15 and are prepared for step change, the used jigs 11-1 to 11-4 are used.
After picking up as described above, if the slide base 13 is retracted and the elevating base 15 is lowered, then the slide base 13 is simply advanced, and the clamp operation of the next model can be immediately started.
Tact time can be very short. Since the jigs 11-1 to 11-4 are very compact as compared with the conventional ones, the stock jigs 11 for the changeover are provided.
-1 to 4 can be always kept near the jig changing robots 10-1 and 10-2, and the jig changing robots 10-1 and 10-2 immediately need the jig 11 when changing the stage. -1 to 4 can be picked up. In this respect, it is difficult to keep the conventional large jig right next to the vehicle body assembly line 2 in terms of space. Therefore, it is usually required to wait at a position slightly away from the vehicle body assembly line 2 and use a dedicated transfer line. It is transported to the side member tacking station 1. Therefore, if the compact jigs 11-1 to 11-4 are used as in the present embodiment, the conventional jig transport line becomes unnecessary. The first transfer robot 10-3 receives the side member 4 transferred by a work transfer means (not shown) as shown in FIG. 1, and transfers the under member transferred to the side member temporary attaching station 1 as shown in FIG. The side member 4 is set at a predetermined position of the body 3. By this set of side members 4, side members 4
And the left and right welding edges of the underbody 3 contact each other. At this stage, the side member 4 is positioned with a certain degree of accuracy by the first transfer robot 10-3. However, since the positioning accuracy is limited by the robot, the side member 4 using the four jigs 11-1 to 11-4 is used as described above. The member 4 is precisely positioned. Conventionally, a side member 4 for a jig is used.
Set, clamp of side member 4 by jig,
Underbody 3 of side member 4 due to jig advance
Although the three operations of setting the side member 4 to the underbody 3 were required in this embodiment,
Since only two operations of clamping the side member 4 by the jig are required, the number of times the side member 4 is delivered is reduced by one, so that the tact time is greatly improved. The possibility of damage can be reduced. Next, the roof temporary storage station 5 will be described with reference to FIG. This station 5 is for temporarily placing the roof 31 on the upper end of the side member 4 temporarily attached to the left and right sides of the underbody 3 so as to span the roof 31 and additionally striking the space between the underbody 3 and the side member 4. It is. Roof temporary storage station 5
Is a third transfer robot 32 for transferring the roof 31 and setting it on the side member 4, and two welding robots 3 on one side and four welding robots 3 on both sides for additionally punching the lower welding edge of the side member 4.
3-1 and 33-2. In order to prevent mutual displacement between the roof 31 and the side members 4 in the front-rear direction, a conventional engagement structure having a concave-convex relationship is provided. Next, the roof tacking station 6 is shown in FIG.
This will be described with reference to FIG. The station 6 positions and temporarily attaches the roof 31 temporarily placed between the side members 4 at the roof temporary placing station 5 to the side members 4, and is a Yakura-like frame body disposed across the vehicle body assembly line 2. 34, a pair of front and rear beam jigs 35 and 36 that are detachably hung on the frame body 34, and fourth transport robots 37-1 and 37-3 that transport the beam jigs 35 and 36.
7-2, the welding members 38-1 and 38-2 for spot welding the side member 4 and the roof 31 to each other. The present embodiment is also applicable to a case where a so-called transverse member such as a header or a frame back is mounted between the left and right side members 4 in addition to the roof 31. That is, the header and the frame back may be attached to the lower surface of the roof 31 in advance, or may be attached to the front side and the rear side between the side members 4 before attaching the roof 31 to the side members 4. Embodiments are applicable. The yakura-shaped frame body 34 is composed of a pair of left and right gate-shaped portions 34a and a connecting portion 34b connecting the central portions of the gate-shaped portions 34a to each other so as to straddle the vehicle body assembly line 2. Jigs 35, 36 at predetermined positions on the upper surface of
A positioning portion for detachably mounting both end portions of the recording medium is formed. The connecting portion 34b is for improving the lateral rigidity of the frame body 34, and is not necessarily required if sufficient lateral rigidity is secured only by the gate-shaped portion 34a. In other words, the term “yakura-shaped” here does not necessarily require the connecting portion 34b, and the strict meaning of “yakura-shaped” also applies to the portal portion 34a as long as substantially sufficient rigidity is secured. Any structure can be adopted without being bound. As shown in FIG. 11, a pair of right and left clamp jigs 39 is provided on the lower surface near both ends of the beam-like jigs 35 and 36.
Are arranged. The clamp jigs 39 connect the front and rear portions of the upper welding edge of the side member 4 and the front and rear portions of the right and left welding edges of the roof 31 to each other by opening and closing claws driven by an air cylinder. 39 is connected to an air system and a control electric system as a common power source for synchronizing the opening and closing timing, and these air systems and the electric system are arranged at positioning portions on the lower surfaces of both ends of the beam-shaped jigs 35 and 36. The jigs 35 and 36 are mounted on the Yakura-shaped frame body 34, and at the same time, the couplers are detachably connected to couplers of the air system and the electric system on the Yakura-shaped frame body 34 side. It has become. The underbody 3 and the side members 4 are welded and integrated in the previous step.
Is positioned and fixed to a stationary system including the ground. In this state, the roof 31 and the side member 4 temporarily placed between the upper end portions of the side members 4 are provided.
Are connected to each other by the beam-shaped jigs 35 and 36, a total of four welding edge portions of the roof 31 and the side members 4 are positioned and fixed to the stationary system via the yakura-shaped frame body 34. Accordingly, the upper and lower welding edges of the four sides of the side member 4 and the eight sides of the both sides are all positioned with respect to the stationary system, and all the four welding edges of the four corners of the roof 31 are also positioned with respect to the ground side. Since the side member 4 and the roof 31 are temporarily attached in this positioning state, no distortion occurs in the front window opening 40 and the rear window opening 41, and the intended front window opening 4
0 shape and the shape of the rear window opening 41 are obtained. In the conventional method of temporarily attaching the roof 31, the roof 31 is placed in a state where the left and right side members 4 are clamped by large jigs, respectively, so that the upper welding edge of the left side member 4 and the roof 31 come into contact at the same time. The upper welding edge of the right side member 4 and the roof 31 come into contact at the same time. However, in this case, there is a possibility that the clamp timing of the left and right side members 4 with respect to the roof 31 may be slightly shifted, and the front window opening 40 and the rear window opening 4
1 tends to be distorted. In this regard, in this embodiment, two clamp jigs 3 on the left and right of one beam-like jig 35, 36 are used.
9 can be simultaneously clamped in the vicinity of the upper left and right corners of the front window opening 40 or the rear window opening 41 by driving the common air system, so that the front window opening 40 and the rear window opening 41 can be distorted. Can be effectively reduced. Further, in the conventional method of assembling the side member 4 and the roof 31, there is a possibility that the side member 4 may be slightly distorted in two passes until the left and right side members 4 reach the underbody 3. In addition, there is a possibility that the clamp position with respect to the roof 31 may be slightly shifted due to such distortion. On the other hand, the roof 31 is lowered and set on the upper edge of the side member 4 while being clamped and supported on the lower surface of the large jig. Control requires complex mechanisms and advanced maintenance techniques. Finally, in the prototype, the front window opening 4
0 and the fit of the windshield to the rear window opening 41 is checked. However, in the inspection and adjustment of each jig to correct a defective fitting, the cause of the defect is the underbody 3, the side It is difficult to determine which of the members 4 or the roof 31 is due to a positioning error, even by analysis using precision equipment. In this regard, in the present embodiment, the possibility that the side member 4 is distorted when the number of delivery times of the side member 4 is at least one is small,
Further, since the four corners of the roof 31 and the front and rear portions of the upper welding edge of the side member 4 are clamped on the basis of the stationary system, the reliability of the shape and dimensions of the front and rear window openings 40 and 41 is extremely high. In particular, since the roof 31 has an upwardly convex shape and can be elastically extended and crimped to some extent, the front and rear portions of the upper welding edge of the side member 4 are grounded via the beam-like jigs 35 and 36 and the yakura-like frame body 34. As long as it is accurately positioned with respect to the stationary system, even if some distortion or warpage remains in the shape of the roof 31 after pressing except at the edges of the openings 40 and 41, the roof 4 has openings 4 in the front and rear windows.
Since the 0,41 shape is not affected at all, even if a defect such as a poorly fitted windshield occurs,
Analysis work and correction work for investigating the cause are much easier than before. The clamp jigs 39 provided on the beam-like jigs 35 and 36 are exclusive products for each type of vehicle, and a new clamp jig 39 is required when there is a step change. Here, the entire beam-shaped jigs 35 and 36 including the clamp jig 39 are dedicated to the vehicle type,
Fourth transfer robot 37-
It is made to stand by as stock in the vicinity of 1,37-2.
The beam-shaped jigs 35 and 36 are high in the height of the yakura-shaped frame 3.
4, the stock areas of the beam-shaped jigs 35, 36 and the robots 37-1, 37-
2 are mounts 42-1 and 42 which are adjacent to the vehicle body assembly line 2 and have substantially the same height as the yakura frame body 34 as shown in FIG.
-2 is preferably constructed and arranged on the frames 42-1 and 42-2. The stock areas of the beam-shaped jigs 35 and 36 and the transfer robots 37-1 and 37-2 may be disposed on one of the frames 42-1 or 42-2. In order to be able to cope with shortening of the replacement tact time, a frame 42-2 is constructed on the opposite side, and
A stock area and transfer robots 37-1 and 37-2 may be provided on 2-2 as shown in FIG. Basically, one transfer robot 37-1 (37-2) is responsible for both attaching and detaching the beam jig 35 (36). It is more reasonable to handle the attachment and detachment of the beam-shaped jigs 35 and 36 by, for example, another transport robot on the opposite side base 42-2. Since the beam-shaped jigs 35 and 36 are disposed at the front and rear portions of the roof 31, the front and rear beam-shaped jigs 35 and 36 face the side member 4 in a state facing the side member 4.
A relatively large space accessible to the weld edge between the side member 4 and the side member 4 is created. Therefore, when the welding robot is provided between the transfer robots, the roof 31 and the side member 4 can be temporarily attached with a relatively short reach, so that the welding robots 38-1 and 38-2 can be reduced in size and welded. The jig structure can be simplified. In addition, since the accessibility between the roof 31 and the side members 4 is good, an additional welding robot can be provided in addition to the tack welding robot. 2, the number of stations can be reduced, and the body assembly line 2 can be shortened. By the way, when the beam-shaped jigs 35 and 36 are compared with the conventional roof jig, the conventional roof jig is slightly larger than the roof 31 like the side member 4 jig. However, the initial capital investment was large and the changeover time was long. In this regard, the roof jig of the present embodiment is elongated and takes up little space, and the transfer robots 37-1 and 37-2.
If a suitable rack equipment is provided near the space, various types of beam-shaped jigs 35 and 36 can be stocked in an extremely compact area, thereby shortening the changeover time and omitting the jig transport equipment. be able to. Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the side member 4 is connected to the first transfer robot 10. -3 for underbody 3
However, a transfer machine other than the transfer robot 10-3 may be used as long as it has substantially the same function as the transfer robot 10-3, or the four jigs 11-
1 to 4 may be used in four or more numbers depending on the type of vehicle and the like. As described above, according to the present invention, at least four front and rear portions of the lower welding edge of the left and right side members set on the underbody and the underbody are arranged at least in four positions. Since the underbody and the side member were welded together in a fixed state with the clamp jig, the jig was compared to the conventional assembly method using a large jig that clamps the entire side member. Significant downsizing has been achieved, drastically reducing initial capital investment and speeding up the changeover operation, and conventionally, the side member has been set on the jig, the side member has been clamped by the jig, and the side has been moved by moving the jig. 3 movements of the set to the underbody of the member were necessary,
In the present invention, since only two operations of setting the side member to the underbody and clamping the side member by the jig are required, the number of side member deliveries is reduced by one, so that the tact time is greatly improved, and the number of deliveries is one. By reducing the number of members, the possibility of the side members being damaged by delivery can be reduced. In addition, according to the present invention, since the clamp jig is replaced by a robot in accordance with the change of the vehicle type in accordance with the reduction in the weight of the clamp jig, the changeover work can be facilitated quickly and the changeover equipment can be reduced in cost. it can. In addition, since the clamp jig is compact, by providing an appropriate rack facility or the like on the side of the vehicle body assembly line, a space-saving standby area for the clamp jig can be secured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a side member tacking station. FIG. 2 is a perspective view of an underbody and side members of the vehicle body. FIG. 3 is a side view of the side member at a side member tacking station. FIG. 4 is a plan view of a temporary attaching station for side members. FIG. 5 is a schematic plan view of a vehicle body assembly line. FIG. 6 is a side view of a jig mounting slide base and a lifting base. FIG. 7 is a side view showing the movement exchange operation of the side member jig. FIG. 8 is a perspective view of a roof temporary storage station. FIG. 9 is a perspective view of a roof tacking station. FIG. 10 is a side view of a roof tacking station. FIG. 11 is a front view of a roof tacking station. FIG. 12 is a plan view of a roof tacking station. [Description of Signs] 1 Side member temporary attachment station 2 Body assembly line 3 Underbody 4 Side member 5 Roof temporary placement station 6 Station 7 Bogie 10 Robots 10-1, 10-2 Jig exchange robots 10-4, 10-5 Welding robots 11-1 to 4-4 Clamping jigs 12 Cowl outers 13 Slide bases 14 Slide guides 15 Elevating bases 20 Vertical cylinders 23 Jig pedestals 31 Roofs 32 Transport robots 33-1 and 33-2 Welding robots 34 Yakura-shaped frame bodies 35 and 36 Beam-shaped jigs 37-1, 37-2 Transfer robots 38-1, 38-2 Welding robot 39 Clamp jig 40 Front window opening 41 Rear window openings 42-1, 42-2 Mount

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Claims (1)

Claims: 1. A pair of left and right side members are vertically arranged with respect to an underbody positioned at a predetermined position of a vehicle body assembly line, with lower welding edges of the side members aligned with the left and right welding edges of the underbody. Then, at least four front and rear parts of the lower welding edges of the left and right side members in the vertically placed state and the underbody are connected and fixed with at least four clamp jigs arranged at predetermined positions. While tack-welding the body and side members,
A method for assembling a vehicle body, wherein the clamp jig is replaced by a robot when the vehicle type is switched.