JPS63256162A - Method for rotating automobile body in coating line - Google Patents

Abstract

PURPOSE:To smoothly rotate an automobile body by aligning the center of gravity of a rotating shaft system including the automobile body with the center line of rotation with the help of a balance weight provided to the rotating shaft system of the automobile body. CONSTITUTION:The automobile body W to be coated is rotated around the horizontal axis (l) extending in the longitudinal direction of the automobile body. Prior to the rotation of the automobile body, the center of gravity G of the rotating shaft system including the automobile body is aligned with the center line of rotation with the help of the balance weight B provided to the rotating shaft 5 system and consisting of a first thread rod 41, a first weight 42, a second thread rod 43, and a second weight 44. As a result, the automobile body W can be smoothly rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of rotating an automobile body in a painting line.

(Prior art and its problems) When painting an automobile body as an object to be painted, there are a preparation process to remove dust adhering to the body, a process to apply paint to the body, and a process to dry the applied paint. and a drying step.

The body usually goes through the preparation process, painting process, and drying process while being transported by a transport vehicle, but the body is kept in a predetermined position during each process.

(Problems to be Solved by the Invention) Recently, in automobile body painting lines, for various reasons, it has become desirable to be able to rotate the body around a horizontal axis extending in the front-back direction of the body. ing. The reason why this body is rotated during transportation may be as follows, for example.

The first reason is to minimize the number of painting guns. In other words, for example, if you want to spray paint on three surfaces: the top, left side, and right side of a body, conventionally, a fixed type or reciprocating type of paint was used to spray paint on these three surfaces. Guns were placed at respective positions corresponding to the three surfaces. However, if the body is made rotatable, the surface facing the painting gun can be changed by rotating the body, and therefore the painting gun only needs to be set at a certain unidirectional position. This will be a good thing (reduction in the number of paint guns).

The second reason is that the body is uniformly heated in the baking furnace. In other words, hot air is circulated in the baking oven so that each part of the body is heated as uniformly as possible, but it is even more preferable to rotate the body within the baking oven in order to achieve uniform heating. Become something.

The third reason is the need for a new coating method. In other words, by applying the paint to a thickness that exceeds the sag limit in the painting process and rotating the object to be coated around the horizontal axis in the next drying process, the smoothness of the paint film can be made even smoother with the same thickness. This results in an increased quality painted surface, and it is also necessary to rotate the body when performing this drying method.

In this way, when rotating an automobile body, it is necessary to rotatably support the automobile body as a premise. For this reason, a rotation jig is attached to the automobile body, and the rotating shaft portion formed on the rotation jig, that is, the supported portion that is the rotation center of the automobile body, is attached to a support formed on, for example, a carrier. It is considered that the project will be supported by the department.

Thus, when rotating an automobile body, one problem is how smoothly the automobile body, which is a heavy object, can be rotated. In other words, if the center of gravity of the automatic 1F body deviates significantly from its center of rotation, rotational fluctuations will occur, increasing the load on the drive system, and making it difficult to maintain constant rotation at a predetermined speed. becomes. On the other hand, automobile bodies are large and complex in shape, and due to constraints imposed by the size of baking furnaces in painting lines, the center of gravity of the automobile body is largely shifted from its center of rotation. The situation is such that it has no choice but to be rotatably supported.

The present invention was made in consideration of the above circumstances, and
To provide a method for rotating an automobile body in a painting line, which completely eliminates or almost matches the deviation between the center of gravity of the automobile body and its center of rotation, and enables the automobile body to rotate smoothly.

(Means and operations for solving the problems) In order to achieve the above-mentioned object, the present invention has the following configuration.

A method of rotating an automobile body in a painting line in which an automobile body as an object to be coated is rotated about a horizontal axis extending in the longitudinal direction of the automobile body, the method comprising The center of gravity of the rotating shaft system including the automobile body is corrected in a direction that coincides with the center line of rotation by means of a balance weight provided in the rotating shaft system.

As described above, in the present invention, the center of gravity of the rotating shaft system of the automobile body is adjusted in advance using the balance weight so that it approaches the rotation center line, so that subsequent rotation of the automobile body can be performed smoothly. .

(Example) Hereinafter, an example of the present invention will be described based on the attached drawings.

In this example, in order to improve the smoothness of the painted surface that can be obtained with the same paint film thickness, the paint spraying in the painting process was carried out so that the paint film thickness exceeded the sag limit. In addition, during the drying process, the body is rotated around a horizontal axis. The present invention is then applied to rotate this body around the horizontal axis.

To explain the above points, first, one of the criteria for evaluating the quality of a painted surface is smoothness (flatness), and the higher the smoothness, the less uneven the painted surface, and the better the painted surface. becomes. It is already known that in order to improve the smoothness of the painted surface, it is sufficient to increase the thickness of the paint film, that is, the film thickness of the applied paint.

On the other hand, paint sag is a factor that impairs the quality of painted surfaces. This sagging occurs when the applied paint waves downward under the influence of gravity, and the thicker the paint coated at one time, the more likely it is to sag.The cause of this sagging is , in the end, it is a shadow of gravity, so it tends to occur on the so-called vertical planes of the body that extend in the vertical direction.

Therefore, the thickness of the paint applied to the horizontally extending surfaces of the body, that is, the so-called lateral surfaces, where the amount of "sagging" of the paint is less of a problem, can be made larger than that of the vertical surfaces. In addition, even if the thickness of the paint film on the horizontal surface and the thickness of the paint film on the vertical surface are the same, the unevenness on the horizontal surface will be reduced due to slight flow of the paint that does not cause sagging.
This results in better smoothness than in the vertical plane.

From the above-mentioned viewpoint, conventionally, in order to obtain a coated surface as smooth as possible while preventing "sagging" of the paint, a paint with as little fluidity as possible was used for painting. The so-called "sagging limit" at which "sagging" of the paint occurs on the vertical surface is, for example, a maximum coating thickness of about 40 pm for thermosetting paints. More specifically, "sagging" of thermosetting paints tends to occur at the beginning of the setting process and at the beginning of the baking process, especially at the beginning of the baking process. The thickness of the paint to be applied is determined, and the maximum value of this determined thickness, that is, the sagging limit value, is approximately 40 gm. Therefore, in order to obtain a painted surface with even greater absolute smoothness, with conventional painting methods, it is necessary to repeat the series of steps from the painting process to the baking process multiple times, for example by applying two coats. was there.

However, by applying more than the aforementioned sag limit and then horizontally rotating the body, the direction of gravity acting on the paint applied to the body is changed by rotating the body horizontally. , the paint will dry without "sagging".

As a result, the film thickness of the paint applied per coat can be made much thicker than conventionally, and it is possible to obtain an extremely good coated surface whose smoothness far exceeds the level conventionally considered to be the limit.

Further, even when the thickness of the coating film is the same as that of the conventional coating, the fluidity of the coating material can be utilized to obtain an excellent coated surface with smaller irregularities, that is, greater smoothness.

Furthermore, if you try to obtain a painted surface with the same smoothness, for example, the same level of smoothness as that obtained with conventional painting methods,
The film thickness of the paint to be applied can be made thinner than in the conventional method, and the amount of paint used can be reduced by the amount that can be made thinner.

Of course, a paint that causes "sag" even in a thin film can be obtained by reducing a predetermined proportion of components that inhibit fluidity in conventional paints.

Figure 1 shows the overall process for painting an automobile body W as an object to be coated, and each process is indicated by PI-P4.

First, the body W, which has been completely undercoated by electro-M painting in a known manner, is sent to the preparation step Pi while being held on a trolley. In this preparatory step P1, dust inside and outside the body W is removed, for example, by air blowing or vacuum suction.Next, in step P2, paint (thermosetting paint in the embodiment) is sprayed onto the body W, and then The paint is dried in a setting step P3 and a baking step P4.

It is preferable to remove dust in the dust removal step P1 while rotating the body W around the horizontal axis as shown in FIG. After the rotation of the body W is stopped and the dust is removed, as shown in Fig. 2 (b).
), the body W is stopped at this position, and the dust is removed again. In this way, the second
Dust is removed while the body W is intermittently rotated as shown in (c), (d)--(i) of the figure.

In this way, by removing dust while rotating the body W, it is possible to remove dust adhering to closed sections such as the inside corners of the roof panel and side sills of the body W, i.e., if the body W is not rotated. It is possible to completely remove even the garbage that does not fall.

The rotation range of the body W is 36 degrees as shown in FIG.
It may be rotated by 0°, but it may be rotated by an appropriate angle, such as by rotating within a range of 180° (the range shown in Fig. 2 (a) and (e)), in accordance with the rotation of the body W in the drying process that will be explained later. can be taken as a thing.

Spraying and Drying of Paint First, the paint is sprayed in P2 so that the thickness of the paint film is at least the sag limit. In other words, in conventional thermosetting paints, the maximum thickness of the paint that does not cause "sag", that is, the sag limit value, is about 40 gm, but in P2, the thickness is much higher than this sag limit of 40 gm. so that the coating is as thick as possible (e.g. 65 lm)
Paint is sprayed so that

After this P2, the process immediately proceeds to the setting process of P3. In this setting process P3, as shown in FIG.
As shown in ~(i), the body W is rotated in the horizontal direction. That is, the body W is rotated around a rotating shaft 6 extending in the horizontal direction, and in the embodiment, this rotating shaft edge stand extends in the front-rear direction of the body W. Note that the temperature atmosphere in this setting step P3 is set to room temperature in the example, but it can be set to an appropriate temperature within a temperature range lower than the temperature atmosphere in the next baking step P4, such as 40° to 606°C. . Of course, this setting process P3 is
This is to volatilize the low-quality seafood in the paint in advance.
This prevents the occurrence of pinholes on the painted surface due to rapid volatilization of low-boiling seafood in the next baking step P4.

In the baking step P4, the paint is baked in an atmosphere at a temperature of 140° C., for example. Even in this P4, P
Similarly to the setting process in step 3, perform steps C &) to (i) in Figure 2.
The body W is rotated in the horizontal direction as shown in FIG.

Due to the horizontal rotation of the body W at P3 and P4 described above, even if the paint is sprayed to a thickness exceeding the sag limit at P2, the paint dries without sagging. As a result, a high-quality coated surface with extremely high smoothness that could not be obtained with conventional coating methods can be obtained.

Relationship between coating film thickness, sagging limit, smoothness, and horizontal rotation FIG. 3 shows the influence of coating film thickness on the sagging limit, focusing on thermosetting paints. FIG. 3 shows three cases of coating film thickness: 40Jim, 53JLm, and 65JLm. It is understood that for any of these thicknesses, peaks of "sag" occur both at the beginning of the setting process and at the beginning of the baking process. In addition, the sag limit is the value when sagging of 1 to 2 mm occurs per minute (visually inspected and the painted surface is considered defective if it sag of 2 mm or more for 7 minutes). The maximum film thickness that can be obtained in the following range is 4.
It is about 0gm.

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 rotated. In Fig. 4, A shows the state in which the body W is not rotated (conventional painting method), and Fig. 4 B shows the state in which the body W is not rotated.
Figure 4C shows the case of rotating 90° and then reversing it (forward and reverse rotation between Figure 2 (a) and (C)).
This figure shows the case where the body W is rotated 135" and then reversed (forward and reverse rotation between Figure 2 (a) and (d)). The fourth diagram shows the case where the body W is rotated 180 degrees and then reversed. Fig. 4E shows the case where the body W is rotated in the same direction continuously (forward and reverse rotation between Fig. 2 (a) and (e)). Figure 2 (a), (b), (
C)... Take the posture in the order of (i) and return to (a) again).

As is clear from Fig. 4, if the thickness of the coating is the same, it is better to rotate the body W (Fig. 4 B, C, D, E).
), thicker smoothness can be obtained than in the case of no rotation (FIG. 4A). Furthermore, it is understood that even if the rotation is the same, it is preferable to rotate 360 degrees in the same direction in order to improve the smoothness. Of course, if the body W does not rotate,
Since there is a limit to the thickness of the coating film, there is a limit to how much smoothness can be increased.

By the way, assuming the thickness of the paint film is 65JLm, the body W is 3
When rotated by 60", the obtained smoothness is "87" at a mapping sharpness of 1.G (PGD value of 1, lower limit of O)
And, when the thickness of the coating film is 40 gm,
If the body W does not rotate, 1. r58J in G (P
The lower limit of GD value is 0.7), whereas when the body W is rotated 360 degrees, it is 1. r88J in G (PG
The lower limit of D value is 0.8).

As is well known, IC (image gloss) in image sharpness indicates the ratio of sharpness to a specular surface (black glass) of 100, and PGD indicates the degree of discrimination of a reflected image to 1. ．． This is a value at which the smoothness of the painted surface decreases as it decreases from o.

The test conditions for the data shown in FIGS. 3 and 4 are as follows, and these test conditions indicate the conditions when overcoating is performed at P2.

a, Paint: Melamine alkyd (black) Viscosity: Ford cup #4, 22 seconds/20" C b, Coating machine: Minibell (16,000 rpm) Shaping air 9.2, okg, cm2 C1 discharge amount: 2 times The first time was sprayed in several parts...
100cc/min 2nd time, 150~200cc/min, Setting time: 10 minutes x room temperature e, Baking conditions: 140" CX25 molecules, Base smoothness: 0.6 (PGD value) (Intermediate coating, PE on the tape) g00 rotation or reversal operating range: Setting (10 minutes) to baking (10 minutes) h, painted on the side of a rectangular cylinder with a knee side of 30 cm, rotatably supported in the center i, coated Object rotation speed: 6rpm, 30rpm, 60r
pm, but no differences were found due to differences in rotational speed.However, if the paint is a two-component curing type that uses a main resin and a curing agent, sagging occurs only in setting step P3. In addition, if the paint is a powder coating, sagging occurs only in the baking process P4, so the rotation of the body W should be performed only in the setting process P3 or baking process P4, where this sagging occurs. Further, in the case of powder coatings, since they do not contain solvents, a setting process is unnecessary.

(Margin below) 1 hour This is a trolley with a function to rotate the body W.

In FIG. 5, the bogie has a base 21 and runs on a road surface (rail) 23 using wheels 22. A pair of front and rear stays 24 protrudes downward from the base 21, and a traction wire 25 is connected to each stay 24.
is fixed.

This wire 25 is driven by a motor (not shown) installed in a safe place from an explosion-proof point of view.
The bogie is driven to travel via 5.

On the other hand, a pair of boxes 26 and 27 are fixed on the base 21 at its front and rear ends (left and right ends in FIG. 5). This pair of boxes 26 and 27 is a rotating jig 1 which will be described later.
The box 26, 27 serves as a support portion that rotatably supports the body W via the box 26, 27. For this purpose, bearings 28, 29 are fixedly arranged on the upper surface of each box 26, 27, respectively. The space between the pair of boxes 26 and 27 is a support space (rotation space) 30 that is slightly larger than the longitudinal length of the body W. Note that the rotational drive portion will be described later.

Rotating jig The rotating jig 1, as shown in FIGS. 5 and 6, is roughly divided into a front portion IF, a rear portion IR, and a reinforcing connecting portion 2 that connects the inner portion. The front part IF is the 8th
As shown in the figure, it has a continuous part 3 formed by bending a single iron plate, etc., and a pair of left and right mounting parts 4, and a cylindrical column joined to this continuous part 3 by welding or the like. −
It has a rotating shaft part 5 of 5. This rotating shaft portion 5 has a bearing 28
The rotation shaft portion 5 is rotatably supported by the box 26 via the link J9 portion 3, and the rotation of the rotating shaft portion 5 is transmitted to the mounting portion 4 via the link J9 portion 3. In the embodiment, the attachment portion 4 is configured to be detachably attached to the front end portions of a pair of left and right front side frames 11 (see FIG. 5) of the body W using, for example, bolts. It has become.

Since the rear portion IR of the rotation jig l is also configured in substantially the same manner as the front portion IF, corresponding components will be designated by the same reference numerals and a description thereof will be omitted. However, the mounting portion 4 of the rear portion IR is shaped so that it can be inserted into the rear end opening of the rear side frame 12 (see FIG. 5) of the body W without play. Of course, the rotating shaft portion 5 of the rear portion IR is rotatably supported by the box 27 via a bearing 29.

Both the front and rear rotating shaft parts 5 are configured to extend horizontally on the same straight line in the front and rear direction of the body W with the body W in between, and the axis of the rotating shaft part 5 rotates. This is the 6th sentence in middle school.

The reinforcing connecting portion 2 of the rotating jig 1 is joined to each of the connecting portions 3 of the front portion IF and the rear portion IR by welding or the like. In the embodiment, this reinforcing connecting portion 2 is formed by using two hollow square iron members on the left and right sides. The joining position for the reinforcing connection portion 2 is set as close to the attachment portion 4 as possible. A side frame 11.12 is at least partially seated on such a reinforcing connection part z, so that parts other than the mounting part 4 share the weight of the body W and support it. In addition, the reinforcing connecting part 2 is fixed to the front side frame 11 and the rear side frame 12 by bolts or the like using a bracket 6 at a position apart from the mounting part 4, so that the body W can rotate more reliably without rattling. It is connected to the jig l.

Rotary drive A drive unit K (path shown) is arranged in each of the boxes 26,27. This drive unit)K
includes at least a drive source such as an air motor,
An output shaft 31 to which power from the drive source is transmitted extends outside the box 26 or 27. and,
Each output shaft 31 is transmitted to the front and rear rotating shaft portions 5 via a transmission mechanism 32 consisting of a sprocket and a tune.

In order to rotate this body W, in addition to using a separate dedicated actuator, it can also be done by using a traveling trolley. In this case, for example, the wheels 22 and the rotating shaft part 5 of the rotating jig J11 are All you have to do is let it happen.

The 6th sentence while the balance weight body W is rotating is the body W including the rotating jig 1.
It is preferable to pass through the center of gravity G (see Fig. 5).

That is, by matching the sentence and G, rotational fluctuations can be prevented. However, as described above, it is practically difficult to make the center of gravity G, which includes the body W and the rotating jig 1, coincide with the center of gravity G during rotation. For this reason, a balance weight is provided on the rotation shaft system of the body W including the rotation jig 1.

An example of such a balance weight B is shown in FIG. Reference numeral 41 in FIG. 8 denotes a first screw forest, which is installed between the pair of left and right mounting portions 4 in the front portion IF of the rotation jig l. A first weight 4 is attached to this first threaded rod 41.
2 are screwed together, and one end of a second screw cup 43 is fixed to this first weight 42. This second threaded rod 43
extends in a direction perpendicular to the first threaded rod 41, and
screw,! A second weight 44 is screwed to 443. Note that 45 and 46 in FIG. 8 are lock nuts.

Therefore, by changing the screwing position of the first weight 42 to the first threaded rod 41, the position of the composite center of gravity including the body W, the rotation jig l, and the balance weight B, that is, the rotation axis system G', in the vehicle width direction can be changed. Adjustments are made. Also, the second
By adjusting the screwing position of the second weight 4 with respect to the threaded rod 43, the vertical position of the center of gravity G' of the rotating shaft system can be adjusted. Furthermore, by adjusting the circumferential position of the first weight 42 with respect to the first threaded rod 41, not only the forward and backward directions but also the downward position adjustment and upward position adjustment of the center of gravity G' of the rotating shaft system by the second weight 44 can be performed. The position can be adjusted over a wide range of variation (the height position of the first weight 42 is adjusted in advance so that the center of gravity G, which does not include the balance weight B, passes near the height of the first weight 42). In this way, the position of the center of gravity G' of the rotating shaft system is adjusted so that the center of gravity G' coincides with the position that must be seen during rotation.

More specifically, in FIG. 5, when the combined center of gravity G of the body W and the rotating jig L is above the required position during rotation, the center of gravity G' of the rotating shaft system is
is moved downward to match the G' with the sentence.

Of course, the adjustment using this balance weight B is
Although this can be carried out at an appropriate time before the body W is rotated, in the embodiment, it is carried out before the preparation step PL and at the same time as when the body W is placed on the trolley.

Fig. 16 shows an example in which the balance weight B is attached to the front frame 11 (or the rear frame 12) of the body W, and the same components as those shown in Fig. 8 are the same. The reference numeral ``'' will be added to omit the redundant explanation. In the case of this embodiment, the first threaded rod 41
A bracket 47 is welded to each end of the rod, and the bracket 47 is used to attach it to the front frame 11 (the first threaded rod 41 is installed on the left and right pair of front frames 12). For example,
Rotation jig l used before mounting body W on the trolley
Taking this into consideration, the positions of the weights 42 and 44 can be set in advance.

Supplementary explanation In the above embodiments, the rotating jig l is placed on a trolley,
The body W is attached to the rotating jig l attached to this trolley.
Although we have previously explained the case where the rotating jig 1 is attached to the body W in advance, it is also possible to attach the set of the body W and the rotating jig L to the trolley. good. For this purpose, for example, the rotating shaft portion 5 of the rotating jig 1 may be made to be able to be engaged with and disengaged from (the supporting portion of) the cart D from above in FIG.

Examples for this purpose are shown in FIGS. 9 to 14. In these figures, the rotational drive is transmitted only from the front rotating shaft 5, and the rear rotating shaft 5 is always transmitted. It is of a type that rotates as the body W rotates. and,
In order to intermittent the rotational force from the transmission mechanism 32 to the front rotating shaft portion 5, a connecting shaft 40 is provided on the box 26 and is constantly rotated (for example, splined) with respect to the transmission mechanism 32.
It is designed to be slidably held.

Based on the above, a notch 26a is formed on the box 26 (see FIGS. 9 to 9).
11), and a notch 27a opening on the upper end surface of the box 27 is also formed (see FIGS. 9, 13, and 14).

Both notches 26a and 27a are sized to fit the rotating shaft portion 5 therein. A flange portion 5a is formed on the rear rotating shaft portion 5, and a notch 27b having a shape corresponding to the flange portion 5a and communicating with the notch 27a is formed in the box 27. As a result, the rear rotating shaft portion 5 is inserted into the notches 27a and 27b of the box 27.
The box 27 is engaged with and disengaged from above and below, and is immovable in the axial direction with respect to the box 27 due to the stopper action of the flange portion 5a.

The connecting shaft 40 is engaged with and disengaged from the rotating shaft portion 5 on the front side. That is, as shown in FIGS. 9 to 12, a cross-shaped connecting portion 5b is formed at the tip of the rotating shaft portion 5, while a cross-shaped connecting portion 5b is formed at the end of the connecting shaft 40. As shown in FIG. 12, a box portion 40a is formed which has an engaging recess 40c into which the connecting portion 5b is fitted without rattling.

Therefore, for example, by sliding the connecting shaft 40 through the rod 43 using the pneumatic cylinder 42 or manually, the box portion 40a (the engaging recess 40C
) and the connecting portion 5b are engaged and disengaged, and at the time of engagement, the connecting shaft 40
The front rotating shaft portion 5 and the rotating shaft portion 5 are integrally rotatable. In addition,
As shown in FIG. 9, the rod 43 is fitted into an annular groove 4Ob formed on the outer periphery of the box portion 40a so as not to inhibit the rotation of the connecting shaft 40.

With the above configuration, by lowering the body W, in which the rotation jig 1 is set in advance, with respect to the trolley while the connecting shaft 40 is displaced to the right side in FIG. The shaft portion 5 is supported by the boxes 26, 27 in a rotatable and immovable manner in the longitudinal direction. After this, the connection 4i40 (locking recess 40C) is engaged with (the connection part 5b of) the front rotating shaft part 5 (the body W is rotatable), and of course, the body W can be removed from the trolley. may be performed in the reverse order to that described above.

Note that the rotation jig 1 may be configured to be divided into a front portion IF and a rear portion IR (without the reinforcing connection portion 2).

(Effect of the invention) As is clear from the above description, the present invention has been made.

By aligning the center of gravity of the rotation axis system of the body W with the rotation center or as close as possible to the rotation center, the body W can be smoothly rotated.

[Brief explanation of drawings]

FIG. 1 is an overall process diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing a state in which the posture of an automobile body as an object to be coated changes as it rotates. Figures 3 and 4 are graphs showing the relationship between paint thickness and sag, paint surface smoothness, and rotation. FIG. 5 is a side view showing an example of a body transporting trolley and a rotating jig which are adapted to rotate the body. FIG. 6 is a plan view of FIG. 5 showing the cart and the rotating jig. Figure 7 is a left side view of Figure 5. FIG. 8 is a perspective view showing the front part of the rotation jig to which the balance weight is attached. FIG. 9 is a side cross-sectional view showing the other side of the joint between the rotating jig and the truck. FIG. 10 is a sectional view taken along the line Xll-Xll in FIG. 9 (7). FIG. 11 is a plan view of FIG. 1O. FIG. 12 is a sectional view taken along the line X13-X13 in FIG. 9. FIG. 13 is a sectional view taken along the line X14-X14 in FIG. 9 (7). FIG. 14 is a plan view of FIG. 13. FIG. 15 is a perspective view showing an example of a crane weight to be attached to an automobile body. FIG. 1816 is a front view showing the balance weight of FIG. 15 attached to an automobile body. PiNF4: Process W: Automobile body fL 2-rotation axis D = Transport trolley: Drive unit B: Balance weight 1 for 2-rotation #box 1F = Front part IR: Rear part 2: Reinforcement connection part 3: Continuous part 4 : Mounting part 5: Rotating shaft part 11: Front side frame 12: Rear side frame 26.27: Box (supporting part) 28.29: Bearing 30: Support space 31: Transmission mechanism 41: First threaded rod 42: First weight 43: Second threaded rod 44: Second weight 45.46: Lock nut 47: Bracket G: Center of gravity (before modification) G': Center of gravity (after modification) Yo A1 Iku 1 shot! ! ,L1m'

Claims (1)

[Claims] (1) A method for rotating an automobile body in a painting line in which an automobile body as an object to be coated is rotated around a horizontal axis extending in the longitudinal direction of the automobile body, and the method includes: A method for rotating an automobile body in a painting line, comprising: correcting the center of gravity of the rotating shaft system including the automobile body in a direction that coincides with its rotation center line using a balance weight provided on the rotating shaft system.