JP2540537B2 - How to paint a car body - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for painting an automobile body.

(Prior art and its problems) When painting an automobile body as an object to be coated, a preparation process for removing dust adhering to the automobile body, a painting process for applying a paint to the automobile body, and the applied paint And a drying step of drying.

In the above-mentioned painting step, the paint is applied to the inner plate of the automobile body, for example, the inner face of the door, the inner face of the trunk room, the inner face of the engine room, etc., and then the outer plate of the automobile body, for example, the fender, the outer face of the door, the outer face of the hood, etc.
Further, for example, in the case of a thermosetting paint, the drying step is performed in two steps including a setting step and a baking step. The setting step is performed before the baking step, at a temperature lower than this baking step, for example, at room temperature or calcination. As is also called, it is performed in a temperature atmosphere of 40 ° to 60 ° C (the baking temperature in the baking process is usually around 140 ° C).

Then, the automobile body normally undergoes the above-mentioned preparation process, painting process, and drying process while being conveyed by a conveyance means such as a trolley, but the posture of the automobile body is maintained while maintaining a predetermined posture in each process. It is being appreciated.

By the way, smoothness (flatness) is one of the criteria for evaluating the quality of the coated surface. The higher the smoothness, the smaller the degree of unevenness of the coated surface, and the better the coated surface. In order to improve the smoothness of the painted surface, particularly the smoothness of the automobile body outer plate, which has a great influence on the commercial property, it has already been necessary to increase the thickness of the coating film, that is, the thickness of the applied coating material. Are known.

On the other hand, there is "drip" of the paint that hinders the quality of the painted surface. This dripping occurs when the applied paint flows downward due to gravity and causes 1
The larger the film thickness of the paint applied at one time, the more likely it is to cause "sag". The cause of this "sag" is, after all, the effect of gravity, so it occurs on the vertically extending surface of the automobile body, the so-called vertical surface. It will be easy.

Therefore, the horizontally extending surface of the automobile body, that is, the so-called horizontal surface, in which the "drip" of the paint is not a serious problem, can make the thickness of the applied coating larger than that of the vertical surface. Even if the thickness of the coating film on the horizontal surface is the same as the thickness of the coating film on the vertical surface, the unevenness is reduced by the slight flow of the paint that does not cause sagging on the horizontal surface, resulting in smoothness on the vertical surface. The smoothness is better than the degree.

In view of the above, conventionally, in order to obtain a painted surface with as large a smoothness as possible while preventing "sagging" of the paint, painting has been performed using a paint with as low fluidity as possible. The so-called "drip limit" in which "drip" of the paint occurs on the vertical surface is, for example, in the case of the thermosetting paint, the maximum thickness of the coating film is about 40 µm. More specifically, paint "drip" is likely to occur in the baking process in the setting process and the baking process, and the thickness of the paint applied in the painting process is determined so that "drip" does not occur at this time. The maximum value of the determined thickness, that is, the sag limit value is about 40 μm. Therefore, in order to obtain a coated surface having even greater smoothness, it is necessary to repeat a series of processes from the coating process to the baking process a plurality of times in the conventional coating method, such as twice coating. was there.

The present invention has been made in view of the above circumstances, and provides a coating method for an automobile body in which a coated surface with even greater smoothness can be obtained with the same coating thickness. The purpose is to:

(Means and Actions for Solving Problems) The present invention basically aims to improve the fluidity of a paint by appropriately changing the direction of gravity acting on the paint applied to the automobile body. By making the most of it, it is possible to obtain a coated surface with greater smoothness if the coating film thickness is the same. Specifically, it has the following configuration. That is, the inner plate of the automobile body as the object to be coated, the inner plate painting step of applying the paint to a thickness within the sagging limit, and the outer panel of the car body after the sagging limit thickness after the inner plate painting step. An outer panel coating step of applying paint to the vehicle body, and after the outer panel coating step, before the paint drip of the coating material applied to the outer panel of the vehicle body is caused by gravity, the vehicle body surface shifts from a substantially vertical state to a substantially horizontal state. A drying step of drying the paint while preventing the occurrence of paint sag by rotating the vehicle body around a substantially horizontal axis at such a rotation speed, and a door after the inner plate coating step and before the drying step. A lock step of locking the lid such as a lid with a locking jig in a closed state is provided.

Thus, in the present invention, the direction of gravity acting on the paint applied to the automobile body is changed by rotating the automobile body in the horizontal direction, so that the paint is dried without causing "sag". Will be done.

According to the present invention, it is possible to obtain a very good painted surface whose smoothness far exceeds the level which has been conventionally regarded as the limit by making the thickness of the coating applied at one time much thicker than before. it can.

Also, even when the thickness of the coating film is the same as the conventional one,
By utilizing the fluidity of the coating material, it is possible to obtain an excellent coated surface having a smaller unevenness, that is, a higher smoothness.

Furthermore, if it is intended to obtain a coated surface having the same smoothness, for example, the same smoothness as that obtained by a conventional coating method, the thickness of the paint to be applied can be made thinner than the conventional one, The amount of paint used can be reduced by the amount that can be made thinner.

Of course, paints that cause "sags" even with thin coatings
What is necessary is just to obtain from the conventional paint by reducing the component which obstructs fluidity by a predetermined ratio.

In addition to this, in the present invention, prior to the rotation of the automobile body, the lids such as doors and bonnets that are opened and closed are locked in a closed state by a locking jig, so that care is not taken during this rotation. It is possible to reliably prevent such a situation that the lid is opened.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings. In the examples, it is premised that the paint used is a thermosetting type.

Overview of Overall FIG. 1 shows the overall steps of coating an automobile body W, and each step is indicated by P1 to P5.

First, the body W, whose undercoating has been completed by known electrodeposition coating, is sent to the preparatory step P1 while being held by the carriage D. In this preparation step P1, dust inside and outside the body W is removed by, for example, air blow or vacuum suction. Next, in step P2, the paint is sprayed onto the inner plate of the body W, and subsequently in step P3 the paint is sprayed onto the outer plate of the body W. Furthermore, in process P4, lids such as doors, bonnets, and trunk lids are locked in a closed state by using a locking jig. Then, the paint is dried in the drying step P5.

When the processes P1 to P5 are for intermediate coating, after the process P5, the body W is sent to a top coating process. In addition, steps P1 to P5
Is for overcoating, the body W is transported to the assembly line as is known.

Dust Removal The dust removal in the process P1 may be performed while rotating the body W around the horizontal axis l, as shown in FIG. That is, for example, first, after the rotation of the body W is stopped in the state shown in FIG. 2A to remove dust, the posture of the body W is changed to the state shown in FIG. It stops at the position and the dust is removed again. In this way,
As shown in (c), (d), (i) of FIG. 2, dust is removed while the body W is intermittently rotated.

In this way, by removing dust while rotating the body W, for example, dust that adheres to the inner surface corners of the body W or the closed cross section of the side sill, that is, the body W must be rotated. It is possible to completely remove dust that does not fall.

The rotation range of the body W is 36 mm as shown in FIG.
The rotation may be 0 °, but may be adjusted to the rotation angle range of the body W in the drying process described later.

Spraying and drying of paint First of all, the spraying of paint on the inner plate at P2 is performed in the same way as before, with the lids such as doors open, to a thickness within the sagging limit. This is because the quality of the coated surface of the inner plate portion of the body W is practically not a problem. On the other hand, the spraying of the paint to the outer plate of the body W at P3 is performed so that the thickness of the coating film is equal to or more than the sagging limit. That is, in the conventional thermosetting paint that has been generally used, the maximum thickness of the paint that does not cause "sag", that is, the sag limit value is about 40 μm, but in the process P3, the sag limit is much smaller than 40 μm. The paint is sprayed to give a thick coating (eg 65 μm).

Locking of lids such as doors at P4 is performed by connecting the doors and the like to the body body in a closed state using a locking jig described later.

The drying process at P5 consists of a setting process and a baking process as in the past. In the setting process and the baking process, the body W is horizontally rotated within the maximum angle range of 360 ° shown in FIGS. 2 (a) to (i). That is,
The body W is rotated about a rotation axis l extending in the horizontal direction. In the embodiment, the rotation axis l extends in the front-rear direction of the body W. The temperature atmosphere in this setting step is room temperature in the embodiment, but it can be set to an appropriate temperature in the range of 40 ° to 60 ° C. lower than the temperature atmosphere in the next baking step. Of course, this setting step is to volatilize the low-boiling point component in the paint in advance, which prevents the occurrence of pinholes on the painted surface due to rapid volatilization of the low-boiling point component in the next baking step. It In the baking process, the paint is baked in a temperature atmosphere of 140 ° C, for example.

Due to the horizontal rotation of the body W in the drying step P5 described above, even if the paint is sprayed to a thickness exceeding the sagging limit in P2, the paint is dried without sagging. As a result, a high-quality coated surface with extremely high smoothness, which cannot be obtained by the conventional coating method, can be obtained.

The reason why the body W is rotated in both the setting step and the baking step is that a thermosetting paint that causes sagging is used in both of these steps, and in the case of powder paint, only the baking step (powder Since the body paint does not include a solvent, it does not have a setting step). In the case of a two-component curing type paint, it is sufficient to perform this rotation only in the setting step.

FIG. 3 shows the effect of the coating film thickness on the sag limit when focusing on a thermosetting coating material.
In FIG. 3, the coating thickness is 40 μm, 53 μm, 65
The three cases of μm are shown. It is understood that in any of these thicknesses, "dag" peaks occur both at the beginning of the setting process and at the beginning of the baking process. In addition, the sag limit usually means a value when a sag of 1 to 2 mm is generated in one minute (a paint surface is defective if sag of 2 mm / min or more is visually observed). Maximum coating thickness obtained in the range is 40μm with conventional paint
It is a degree.

On the other hand, FIG. 4 shows the influence on the smoothness when the body W is rotated in the horizontal direction and when it is not. A in FIG. 4 shows a state in which the body W is not rotated (conventional coating method). FIG. 4B shows a case where the body W is rotated by 90 ° and then reversed (forward and reverse rotation between FIGS. 2 (a) and (c)). FIG. 4C shows
The case where the body W is rotated by 135 ° and then reversely rotated (forward and reverse rotation between FIGS. 2 (a) and (d)) is shown. Fourth
FIG. D shows a case in which the body W is rotated 180 ° and then reversed (forward and reverse rotation between FIGS. 2 (a) and (e)). FIG. 4E shows a case where the body W is continuously rotated in the same direction (FIGS. 2 (a) and 2 (b)).
(C) ... Take the order of (i) and return to (a) again).

As is apparent from FIG. 4, if the coating film has the same thickness, it is better to rotate the body W (see FIGS. 4B, C, D, and
E), the smoothness is larger than that when not rotated (FIG. 4A).

Note that, as is known, the IG in the image clarity of FIG.
(Image gloss) is 100 with mirror surface (black glass)
It indicates the ratio of sharpness to that, and also PGD
Is a value at which the smoothness of the painted surface decreases as the degree of discrimination of the reflected image decreases from 1.0.

The test conditions for the data shown in FIGS. 3 and 4 are as follows, and the test conditions show the conditions for performing overcoating with P3.

Paint: Melamine alkyd (black) Viscosity: Ford cup # 4 22 seconds / 20 ℃ b. Coating machine: Minibell (16,000 rpm) Shaping air ..2, 0kg / cm ² c. Discharge rate: 2 times 1st time ... 100cc / min 2nd time ... 150 to 200cc / min d. Setting time: 10 minutes x room temperature e. Baking conditions: 140 ° C x 25 minutes f. Substrate Smoothness: 0.6 (PGD value) (intermediate coating, on PE tape) g. Rotating or reversing working area: Setting (10 minutes) to baking (10 minutes) h. Car body: Painting on the side of a 30 cm square cylinder, Rotatably supported at the center i. Rotation speed of automobile body: 6 rpm, 30 rpm, and 60 rpm, but there was virtually no difference due to the difference in rotation speed. Rotating jig Next, the body W was trolleyed. A specific example of a jig used to support the D in a rotatable manner in the horizontal direction will be described.

FIG. 5 shows a front jig attached to the front of the body W.
Shows 1F. The jig 1F includes a pair of left and right mounting brackets 2, a pair of left and right stays 3 welded to the left and right brackets 2, a connecting bar 4 for connecting the pair of left and right stays 3, and a connecting bar 4. It has the integrated rotating shaft 5. Such a jig 1F, the bracket 2 part,
It is fixed to a front strength member of the body W, for example, a front end of the front side frame 11. That is, since a bracket 12 for mounting a bumper (not shown) is usually welded to the front side frame 11, the bracket 2 is bolted (not shown) to the bracket 12 on the body W side.
Use to fix.

On the other hand, the rear jig 1R attached to the rear part of the body W
It is shown in FIG. This rear jig 1R is also the front jig 1F
The configuration is similar to that of the above, and the components corresponding to the front jig 1F are denoted by the same reference numerals. The rear jig 1R is attached to the body W by fixing the bracket 2 to the floor frame 13 as a strength member at the rear end of the body W with bolts. Of course, at the rear end of the floor frame 13, a bumper mounting bracket is welded in advance because the bumper is generally mounted, so that the rear jig 1R is Mounting can also be performed.

The front and rear jigs 1F and 1R are arranged such that the rotating shafts 5 of the front and rear jigs 1F and 1R are located on the same straight line extending in the front-rear direction of the body W when mounted on the body W. This same straight line becomes the rotation axis l of the body W. Preferably, this rotation axis l is the center of gravity G of the body W (see FIG. 7).
It is supposed to pass through. Since the rotation axis l passes through the center of gravity G, when the body W rotates, large fluctuations in the rotation speed are prevented. As a result, it is possible to prevent the body W from being impacted by the rotation fluctuation, which is more preferable in terms of preventing sagging.

In addition, the front and rear jigs 1F and 1R are for vehicle type (type of body W)
Special items are prepared in advance according to the requirements.

Truck A truck having a function of rotating the body W.

In FIG. 7, the dolly D has a base 21, and the base 21
Wheels 22 attached to the vehicle are run on a road surface 23. This base 21 is a front column that extends upward from the front side to the rear side (right side to left side in FIG. 7) in the traveling direction.
24, two intermediate columns 25 and 26, and one rear column 27 are provided, and a space between the intermediate columns 25 and 26 and the rear column 27 is a support space 28 that is largely spaced in the front-rear direction. .

The body W is disposed in the support space 28, and the front portion of the body W is rotatably supported on the intermediate support column 26 by using the front jig 1F, while the rear portion thereof uses the rear jig 1R. Then, the rear support 27 is rotatably supported.

The front and rear jigs 1F and 1R (rotating shaft 5 thereof) can be engaged with and disengaged from the columns 26 and 27 in the vertical direction, and the rear jigs
1R is immovably engaged in the direction of the rotation axis l. For this reason, the notch 26a which opens in the upper end surface is formed in the intermediate support | pillar 26 (refer FIG. 10-12), The notch 27a which opens in the upper support surface is formed in the rear support | pillar 27. (First
(See Figures 0, 14 and 15). These two notches 26a, 27a
Is sized so that the rotary shaft 5 of the jigs 1F and 1R can be fitted therein. Then, the flange 5a is provided on the rotary shaft 5 of the rear jig 1R.
On the other hand, the rear strut 27 is formed with a notch 27b having a shape corresponding to the flange portion 5a communicating with the notch 27a. As a result, the rear jig 1R is notched in the rear strut 27.
It is engaged with and disengaged from the vertical direction with respect to 27a and 27b, and is immovable in the front-rear direction with respect to the rear support column 27 by the stopper action of the flange portion 5a. The rotational force is applied to the body W via the rotary shaft 5 of the front jig 1F. Therefore, the tip of the rotary shaft 5 of the front jig 1F has a connecting portion 5b to be described later.
(See also FIG. 5).

A stay 29 projects downward from the base 21, and a pulling wire 30 is connected to a lower end portion of the stay 29. The wire 30 is of an endless type and is driven in one direction by a motor (not shown), which drives the carriage D in a predetermined transport direction. Of course, the motor is installed in a safe place from the viewpoint of explosion protection.

In the embodiment, the rotation of the body W is performed using the movement of the bogie D, that is, using the displacement of the bogie D with respect to the traveling road surface 23. A rotation take-out mechanism 31 for taking out the displacement of the carriage D as a rotation is configured as follows. That is, the rotating take-out mechanism 31 includes a rotating shaft 32 that extends vertically and is rotatably supported on the base 21, a sprocket 33 fixed to a lower end of the rotating shaft 32, and a sprocket 33.
And a chain 34 meshed with. The chain 34 is arranged in parallel with the wire 30 in a stationary state with respect to the traveling road surface 23. Thus, when the trolley D is pulled through the wire 30, the chain 34 is immovable, so that the sprocket 33 meshing with the chain 34 and thus the rotary shaft 32 is rotated.

A transmission mechanism 35 for transmitting the rotation of the rotation shaft 32 to (the rotation shaft 5 of) the front jig 1F is configured as follows. That is, the transmission mechanism 35 includes a casing 36 fixed to the rear surface of the front support column 24 and a rotation shaft 37 rotatably supported on the casing 36 by extending in the lateral direction (front-back direction).
A pair of bevel gears 38 and 39 that interlock the rotating shaft 37 and the upper rotating shaft 32, and a connecting shaft 40 that is held rotatably and slidably in the front-rear direction with respect to the intermediate column 25. Have. The connecting shaft 40 is spline-coupled to the rotating shaft 37 (this engaging portion is shown by reference numeral 41 in FIG. 7), and when the rotating shaft 32 is rotated by this, the connecting shaft 40 is also rotated. become. Of course, the rotary shaft 37 and the connecting shaft 40 are installed so as to be located on the rotary axis l.

The connecting shaft 40 is engaged with and disengaged from the rotary shaft 5 of the front jig 1F. That is, as shown in FIGS. 10 to 12, a cross-shaped connecting portion 5b is formed at the tip of the rotary shaft 5 for the front jig 1F, while at the end of the connecting shaft 40, As shown in FIGS. 10 and 13, a box portion 40a having an engaging recess 40c into which the connecting portion 5b is fitted without rattling is formed. Thus, for example, a pneumatic cylinder 42 may provide a rod 43
By sliding the connecting shaft 40 via the box part 40a (engaging recess 40c) and the connecting part 5b, the connecting shaft 40 and the rotary shaft 5 can be integrally rotated when engaged. It is said that The rod 43 is fitted in an annular groove 40b formed on the outer periphery of the box portion 40a so as not to hinder the rotation of the connecting shaft 40, as shown in FIG.

With the configuration described above, the body W is lowered with respect to the carriage D in a state where the connecting shaft 40 is displaced to the right in FIG. 7, so that the rotary shafts 5 of the front and rear jigs 1F and 1R are moved to the middle. The columns 26 and 27 are rotatably supported in the front-rear direction in an immovable state. Then, the connecting shaft 40 (locking recess 40c) is engaged with (the connecting portion 5b of) the rotating shaft 5 in the front jig 1F.
Accordingly, when the carriage D is pulled through the wire 30, the body W is rotated about the predetermined horizontal axis l. It should be noted that the body W can be removed from the dolly D in the reverse order of the procedure described above.

Locking jig This is for connecting to the body so that the lids such as doors are not opened.

In FIG. 16 showing an example of the locking jig K, 81 is an outer cylinder, 82 is an inner cylinder, and one end side of the inner cylinder 82 is slidably fitted in the outer cylinder 81. The outer cylinder 81 has a pair of slits 83 formed at 180 ° symmetrical positions over a predetermined length. On the other hand, a plate-shaped bracket 84 is welded to the inner end of the inner cylinder 82. The bracket 84 is formed by the pair of slits.
83, so that the inner cylinder 82 is locked in the range of the length of the slit 83 with respect to the outer cylinder 81 so that the outer cylinder is not rotated.
The stroke is movable with respect to 81. Then, the inner cylinder 82 is urged by a return spring 85 arranged in the outer cylinder 81 in a projecting direction, that is, an extending direction in which the entire lengths of the both cylinders 81 and 82 are increased. In FIG. 16, 86 is the inner cylinder 82.
A ring-shaped stopper that constitutes the stroke end in the direction of extension of the spring, and 82 is a pin that serves as a spring seat at one end of the spring 85,
Both 86 and 87 are fixed to the outer cylinder 81.

Engaging hooks 88 or 89 are welded to the inner and outer cylinders 81 and 82 at the end portions separated from each other. One of the locking hooks 88 and 89 is locked to a lid WO such as a door, and the other is locked to the body WB.

One end 90a of a band 90 having a shape as shown in FIG. 18 is rotatably attached to the bracket 84 at a portion extending to the outside of the outer cylinder 81 through the slit 83. A bracket 91 is welded to the outer periphery of the outer cylinder 81, and an operating lever 92 is rotatably connected to the bracket 91 by a pin 93. The other end 90b of the band 90 is rotatably connected to the operation lever 92. As a result, when the operation lever 91 is in the state shown in FIG. 16, the inner cylinder 82 is in an extended state in which it is projected more than the outer cylinder 81,
That is, the locking hooks 88 and 89 are in the unlocked state in which the distance between them is large. On the contrary, from the state shown in FIG. 16, swing the operating lever 92 clockwise around the pin 93 to move the band.
If the other end 90b of 90 is set to the position shown by the alternate long and short dash line in FIG. 10,
The inner cylinder 82 is in a locked state in which it is deeply inserted into the outer cylinder 81 against the spring 86. In this locked state, the straight line connecting the two ends 90a and 90b of the band 90 is the operating lever 92.
Located below the pin 93, which is the pivot of
The locked state is maintained against the biasing force of the spring 85. In the band 90, the distance between the pair of left and right connecting portions 90c connecting the both ends 90a and 90b is such that the outer tube 81 does not interfere with the outer tube 81 in the locked state.
Is slightly larger than the outer diameter of.

The lock jig K as described above is used as follows. First, one lock hook, for example 88, is locked to the body WB in the unlocked state in which the distance between the lock hooks 88 and 89 is increased. Then the other locking hook 89
Is a position where it can be engaged with the closed lid KO.
After that, by canceling the operation lever 92 to bring it into a locked state, the distance between the two locking hooks 88 and 89 becomes smaller,
The lid WO is locked in the closed state with respect to the body WB.

21 to 23 show a concrete example of the state in which the jig is locked by the locking jig K.

FIG. 21 shows a state in which the trunk lid 101 as the lid WO is locked. At this time, as the portion where the locking hooks 88 and 89 are locked, on the trunk lid 101 side, the appropriate opening 101a formed in this is used as it is, and on the body WB side, it is for mounting the tail lamp. The mounting hole 100a is used.

FIG. 22 shows a state in which the bonnet 102 as the lid WO is locked. At this time, the bonnet 102 side uses the anchor 102a for locking the bonnet as it is as the portion where the locking hooks 88 and 89 are locked. On the side of the body WB, the opening 99a formed in the center stay mounting bracket 99 is used.

FIG. 23 shows a state in which the door 103 serving as the lid WO is about to be locked. At this time, as the portion where the locking hooks 88 and 89 are locked, on the door 103 side, a window opening / closing arm and an opening 103a formed for weight reduction are formed.
Is used as it is. Also, the body body
On the WB side, an appropriate opening 98a formed in the floor panel 98 for weight reduction or the like is used.

FIG. 19 shows another example of the locking jig K, and the same components as those shown in FIG. 16 are designated by the same reference numerals. In the case of this example, compared to the one shown in FIG.
Instead of separately providing the inner cylinder 82, the locking hook 89 is extended as it is and inserted into the outer cylinder 81. Then, the piston-shaped slider 94 is fixed to the tip of the locking hook 89 inserted in the outer cylinder 81, and the slider 94 is biased by the spring 95 arranged in the outer cylinder 81. is there. In addition,
The biasing force of the spring 95 is different from that of FIG. 16 in that it acts in such a direction that the distance between the hooks 88 and 89 becomes smaller.

The locking jig K of this embodiment is used as follows. First, as shown in FIG. 20, an operator grasps the outer cylinder 81 and hooks one locking hook, for example 89, on the lid WO in the closed state. Then, the grasped outer cylinder 81 is pulled away from the hooked portion (see the arrow in FIG. 20), and the other locking hook 88 is hooked on the body WB. After this, if the worker separates from the outer cylinder 81, the spring 95
Due to the urging force of (2), both locking hooks 88 and 89 receive a force in a direction of approaching each other, and the lid WO is maintained in the closed state.

Supplementary explanation Regardless of whether the trolley D is running or stopped, the body W can be switched between rotation and stop, and the rotation direction can be changed by using a separate dedicated actuator such as an air motor. be able to. First, in the example of FIG. 7, a pair of first and second chains (corresponding to the chain 34) are provided on the sprocket 33 from the opposite side in the radial direction, and each chain can be driven appropriately. I will do it. With such a configuration, the rotation of the body W is controlled according to the following driving mode.

The first chain is stopped and the second chain is free: In this case, the body W is rotated in one direction as the bogie D travels.

First chain free and second chain stop: In this case, the body W is rotated in the opposite direction as the carriage D travels.

Both chains are free: in this case, the body W is not rotated with the movement of the truck D.

Driving the first chain in one direction and freeing the second chain: In this case, the body W is rotated in one direction even when the carriage D is stopped.

Driving the first chain in the other direction and freeing the second chain (the same applies when the first chain is free and the second chain is driven in the other direction): In this case, even if the bogie D is stopped,
The body W is rotated in the direction opposite to the above case.

Note that the above is the same even when a rack bar is used instead of the chain. When the rack bar is always arranged in a fixed state (in this case, the traveling of the bogie D is a prerequisite for the rotation of the body W), the rack bar is intermittently arranged, or the position at which the rack bar is arranged is left and right By setting arbitrarily, the body W can be rotated in an arbitrary direction according to the traveling position of the cart D, and the rotation of the body W can be stopped at an arbitrary position. Further, in this embodiment, the lock process P4 for the door etc. is provided after the outer plate coating process P3,
It may be provided between the inner plate coating process P2 and the outer plate coating process P3.

(Effects of the Invention) As is apparent from the above description, the present invention utilizes the application of a coating material having a thickness greater than the sagging limit and the rotation of the object to be coated, so that the same coating material thickness can be obtained. It is also possible to obtain a high quality painted surface with high smoothness.

Also, when rotating the object to be coated, a lid or other lid is locked in a closed state by using a locking jig, so that the lid may be inadvertently opened during rotation of the body. It can be surely prevented. This is advantageous in preventing sagging due to the impact caused by opening the lid, and in preventing the opened lid from interfering with surrounding members during rotation. Become.

In addition to the above, paint is applied to a thickness above the sagging limit only for the outer plate that is required to have a good appearance, and for the inner plate, the thickness is within the sagging limit. It is possible to prevent unnecessarily high quality painted surfaces. Also, since the paint is applied to the outer plate after the paint is applied to the inner plate, that is, the paint application with a thickness exceeding the sagging limit is made as late as possible, the car body is rotated to prevent paint sag. This is preferable for preventing paint dripping by shortening the time between steps as much as possible.

[Brief description of drawings]

FIG. 1 is an overall process diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing a state in which the posture of the automobile body, which is an object to be coated, changes as the automobile body rotates. 3 and 4 are graphs showing the relationship between the thickness and sag of the coating material, the smoothness of the coated surface, and the rotation. 5 and 6 are perspective views showing examples of jigs used to rotate the body. FIG. 7 is a side view showing an example of a trolley for carrying a body in which the body is rotated. FIG. 8 is a partially cutaway plan view showing a state below the traveling path of the carriage. FIG. 9 is a sectional view taken along line X9-X9 of FIG. FIG. 10 is a side sectional view showing a connecting portion between the rotating jig and the carriage. FIG. 11 is a sectional view taken along the line X11-X11 in FIG. FIG. 12 is a plan view of FIG. FIG. 13 is a sectional view taken along line X13-X13 of FIG. FIG. 14 is a sectional view taken along line X14-X14 in FIG. FIG. 15 is a plan view of FIG. FIG. 16 is a sectional view showing an example of a locking jig. FIG. 17 is a sectional view taken along the line X17-X17 in FIG. FIG. 18 is a perspective view showing a band used in FIG. FIG. 19 is a sectional view showing another example of a locking jig. 20 to 23 are views showing a state in which the lid is locked or is about to be locked by the locking jig. P1 to P5: Process W: Body (object to be coated) l: Rotation axis D: Transport carriage 1F, 1R: Rotating jig K: Locking jig WO: Lid WB: Body 88, 89: Locking hook 101: Trunk lid (lid) 102: Bonnet (lid) 103: Door (lid)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Maruta 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (56) References JP 61-97072 (JP, A) JP 60 -223717 (JP, A) British patent 584432 (GB, A)

Claims (1)

(57) [Claims] 1. An inner plate coating step of applying a paint to an inner plate of an automobile body as an object to be coated to a thickness within a sag limit, and an outer plate of the automobile body having a sag limit of more than a sagging limit after the inner plate painting step. Coating step of applying paint to the thickness of the vehicle body, and after the coating step of the outer panel, before the paint drip of the paint applied to the outer panel of the car body occurs due to gravity, the surface of the car body is changed from a substantially vertical state to a substantially horizontal state. A drying step of drying the paint while preventing the occurrence of paint sag by rotating the car body around a substantially horizontal axis at a rotation speed that shifts to, and after the inner plate coating step and before the drying step. In addition, a method for painting an automobile body, further comprising: a locking step of locking lids such as doors in a closed state by a locking jig.