JPS5910368A - Painting method - Google Patents

Abstract

PURPOSE:To form the painted film on a surface to be painted to a uniform thickness in a painting method for the surface having a level difference, by enabling the positioning of all spray guns at the same spray distance from the surface to be painted at all times during painting. CONSTITUTION:A pulse generator is so set as to transmit one pulse when a vehicle body advances by, for example, 1cm, from the position of the limit switch in the inlet of a painting booth, and the parameters for spray guns relating to the height of respective spray guns 7a, 7b corresponding to the advance position of the vehicle body, painting colors, etc. are preset as a program in a storage device. Then, the 1st and the 2nd spray guns 7a, 7b are controlled so as to advance at a spray distance l on a hood 8 according to pulse counting.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method, and more particularly to a method for coating a surface to be coated with a step such as an automobile body.

BACKGROUND ART Conventionally, as a method for painting automobile bodies, etc., it is common to use an automatic painting apparatus as shown in FIG. 1, for example. Such an automatic coating device has vertical posts 2゜2 provided on both sides of a conveyor 1, and a lifting guide 3 between them.
, 3, and an upper gate 4 which is attached to the upper gate 4 so that it can be raised and lowered along the
A carriage 6 is provided so as to be able to reciprocate horizontally along the conveyance direction, and two spray guns 7a and 7b are fixed to the carriage 6 along the conveyance direction of the conveyance device 1. Therefore, when painting one surface to be coated and another surface to be coated that has a step with respect to this surface to be coated using such an automatic coating device, for example, the automobile body 8 is transported as the object to be coated. Then, the upper gate 4 moves up and down along the vertical posts 2, 2 in synchronization with the speed of conveyance according to the height of the horizontal part, and the carriage 6 reciprocates in the horizontal direction to move the spray guns 7a, 7b. The horizontal portion of the vehicle body 8 is painted by discharging paint from the paint.

However, with such conventional painting methods,
Since two spray guns 7a and '7b are used, even if the transport speed of the vehicle body 8 is set high, the discharge capacity is sufficiently satisfied. 7a and 7b are fixed to the carriage 6 at regular intervals in line with the conveying direction of the conveying device 8, and move simultaneously with the movement of the carriage. On the other hand, when painting an object to be coated which has a surface to be coated with a step, for example an object to be coated which has a height difference in the horizontal part such as an automobile body, the following drawbacks occur. That is, as shown in FIG. 2(A), paint is sprayed from the spray guns 7a and 7b at a predetermined spray distance Ll to the hood 9, which is the area to be coated on the object 8, to form a coating film on the hood 9. is formed. first,
A coating film thickness T is formed by the preceding spray gun 7a, and a coating film thickness T is formed on the surface by the subsequent spray gun 7b.

However, when the preceding spray gun 7a finishes painting the hood 8a of the vehicle body 8 and reaches the front window portion 10, which is a stepped portion, the spray from the preceding spray gun 7a is sprayed as shown in FIG. 2(B). It is stopped and raised to spray distance L2 to avoid collision. Therefore, for the same amount of spray from the spray gun 7b, the spray area, or so-called spray pattern, expands, so the coating film thickness decreases by that amount, and the film thickness produced by the spray gun 7b reaches T3. As the object to be coated 8 advances, the spray guns 7a and 7b further rise and the spray distance reaches L3, as shown in FIG. As shown in FIG. 2(D), when the spray distance increases to L4, the coating thickness further decreases to T1. In other words, the thickness of the coating film produced by the trailing spray gun 7b decreases as it approaches the front window 10 side, so there is a drawback that a uniform coating film cannot be obtained. Its purpose is to eliminate the above-mentioned drawbacks, and its feature is that while the automatic coating machine is moved relative to the object to be coated, it can be When painting while sequentially facing one surface to be coated and another surface to be coated with a step attached to it with a plurality of spray guns held at the same time, if the step rises. After the preceding spray gun has finished painting one surface to be coated, the spray gun is moved away from the surface to be coated, and after the subsequent spray gun has finished painting, the plurality of spray guns are moved along with the movement. Then, if the step falls, the preceding spray gun finishes painting one surface and then moves the spray gun closer to another surface. In addition, there is a method for coating a surface to be coated with a step, which comprises sequentially bringing a plurality of spray guns to face different surfaces to be coated as the spray guns move, one after the completion of coating with a subsequent spray gun.

= 4 = The present invention will be explained below based on the drawings. FIG. 3 is a perspective view of an automatic coating machine used in an embodiment of the present invention, and FIG. 4 is an explanatory diagram of an embodiment using the automatic coating machine of FIG. 3. Components having the same configuration as those in FIG. 1 are designated by the same numbers and their explanations will be omitted.

First, to explain the configuration of the automatic coating machine, the upper gate 4
A gun unit mounting member 6a is fixed to the carriage 6. A plurality of cylinders, for example two cylinders 9a and 9b, are installed vertically as actuators along the traveling direction of the object 8 on the horizontal part of the gun unit mounting member 6a, and the piston rods lOa and 10b are installed vertically as actuators. is volcanic below the horizontal part of the mounting member 6a. Further, a lifting cylinder 9a is provided on the horizontal portion of the mounting member 6a.

Lifting guides lla and llb are provided in a protruding manner according to the number of 9b, and the lower ends of both guides are connected by a bracket 12. Guide bushing 1 is attached to the lifting guides lla and llb.
3a, 13b are slidably fitted into the gun coverage bracket) 15a, 15b are the respective guide bushes 13a, 13.
It is fixed at b. These spray gun mounting brackets 15a115b each have a spray gun 7a,
7b is installed.

Gate-shaped coating device 16 equipped with the spray guns 7a and 7b
is installed at a predetermined position in a painting booth 17 as shown in FIG. 16 is a driving side sprocket, and 16 is a driven side sprocket. A pulse transmitter 18 is provided which is interlocked with the drive side sprocket) la, and the pulse transmitter 18 is connected to the digitizer 23 via the opening/closing gate 19. )・Switches E, rBB, limit switch L8As for A car model selection, and limit switch L5. for starting counting. is arranged in the front stage of the gate-type automatic painting device 16 along the continuous running conveyor l, and a limit switch 152 for ending counting is arranged in the rear stage of the gate-type automatic painting device 16 along the conveyor l. do. Then, the output wires of the limit switch Ls1 and the limit switch Ls2 are connected to the input terminal of the counter 23. 2
1a and 21b are storage devices for car models A and B, each equipped with a program setting device such as a pinboard matrix or rotary switch, and the input terminal of each storage device has a limit switch for selecting the corresponding car model. The output wiring, the output wiring of the count start limit switch Ls1, and the output wiring of the counter 23 are connected, and the output wiring X of each storage device 21a, 21'b is connected to the output circuit 22.
It is connected to a control means (not shown) etc. related to the drive device of the gate-type automatic painting device 16 via.

The pulse generator is set to emit one pulse when the vehicle body 8 advances, for example, by one distance from the position of the limit switch Ls1, and the memory device for the vehicle type stores, for example, each spray gun corresponding to the advancing position of the vehicle body 8. Parameters for the spray gun, such as the height and paint color, are set in advance as a program.07 Next, a coating method using the gate-type automatic coating device will be described. In FIGS. 4 to 6, when a truck carrying a car body 8 of the type A is being conveyed to the conveyor 1, the A car type display piece provided on the truck swings the lever of the limit switch l1B)1. A signal indicating that the vehicle type has been selected is input from the same switch LSM to the vehicle type storage device 21a, and
When the trolley further advances and the limit switch L81 is activated, a signal instructing to start counting is input to the counter 23 and each memory device 21a, 21b, and the count from the counter 23 is transmitted to each memory device 21a, 21b. be done.

In response to these signals, the memory device 21a for vehicle type A starts operating, and according to the above-mentioned program, the height instruction signal of the upper gate 4, the operation start signal of the carriage, and the opening/closing of pressurized air for the lifting cylinders 9a and gb are activated. Signals to the valve and control signals for the spray gun are outputted via the output circuit 22 and each output wiring X. On the other hand, since the storage device 21b for vehicle type B does not receive the B vehicle type selection signal, it does not start operating and maintains the state in which the program is stored.

8- That is, as shown in FIG.
As time progresses, the height Hl is reached at a pulse count of 50. At this time, the first and second spray guns 7a and 7b are located slightly forward of the front edge of the hood 9, the distance between the top surface of the hood 8a and the gun head is a spray distance l, and the output from the output circuit 22 causes the spray guns to Gun 7'a, 7b
The paint needle valve and each air valve (not shown) are opened to start spraying, and the carriage 6 starts painting while repeating reciprocating motion at this height. When the count reaches 150 as the vehicle body 8 advances, the spray gun 7a moves to a position facing the rear edge of the hood 8a, and the output circuit 2
2, the first spray gun 7a rises due to the rise of the piston of the first elevating cylinder 9a (
(See Figure 4). Next, at count 170, when the trailing second spray gun 7b passes the rear end edge of the hood 8a and reaches the stepped part (front pillar 10 part), the output of the output circuit 22 causes both spray guns 7a to close.

The paint needle valve (not shown) at 7b closes to stop spraying and the upper gate 4 begins to rise. When the count reaches 230, the upper gate reaches the height I (2, and the second elevating cylinder 9b positions the second spray gun 7b at the top dead center (dotted chain line in FIG. 4), and the output circuit 22 The output opens a paint needle valve (not shown) and sprays a distance l while reciprocating the carriage 6.
Start spraying the roof 8b. When the count reaches 420, the spray gun 71 reaches a position where it has passed the rear edge of the roof 81), stops spraying, and the upper gate 4 begins to descend. When the count reaches 450, the first spray gun 7a is lowered by lowering the piston of the first elevating cylinder 9a due to the output of the output circuit 22, and only the first spray gun starts spraying (as shown in the dashed line in Fig. 4). reference). Then, when the count reaches 4.70, the upper gate 4
reaches a height of ■1°, and the spray gun 7b reaches the front edge of the trunk lid 8C, and the second lifting cylinder 7b
As the piston descends, the second spray gun 7b also descends and starts spraying at a spray distance l, and the carriage 6
The trunk lid 8C is painted by the reciprocating movement of the trunk lid 8C. When the count reaches 570, the output of the output circuit 22 closes the paint needle valve (not shown) to stop spraying, and the upper gate 3 begins to rise, and the count reaches 6.
00, the height Ho is reached and the painting process ends. However, the limit switch L82 for ending the count on the car body 8
When it passes through, this turns on and the contact of the opening/closing gate 19 opens and the count ends. Note that after the painting is completed, the gun should be cleaned in the usual manner.

If the next object to be coated 8 is the same car model, then! , the painting can be repeated using the same program, but if it is a B car type, the same painting will be performed by operating the memory device 21b for the B car type. It should be noted that the above-mentioned heterostatic robot can also be used as an automatic coating machine, and as a spray gun, an electrostatic air spray gun, a rotary electrostatic coating gun, etc. can also be used.

As explained above, according to the present invention, a plurality of sprayers are arranged in such a manner that the automatic coating machine is moved relative to the object to be coated and maintained in a front-back relationship with respect to the moving direction. When painting while sequentially facing one surface to be coated with a gun and another surface to be coated with a step attached to this surface, if the step rises, the preceding spray gun After finishing painting one surface to be coated, the spray gun is moved away from the surface to be coated, and after waiting for the subsequent spray guns to finish painting, the plurality of spray guns are sequentially applied to different surfaces as they move. In addition, if the step falls, after the preceding spray gun has finished painting one surface to be coated, move the spray gun closer to another surface and prevent the subsequent spray gun from painting. Since it was decided to wait for the completion of the painting and have these multiple spray guns confront different surfaces to be coated one after another as they move, each of the spray guns mentioned above is always positioned at a spraying distance from the surface to be coated during painting. This has the effect of making it possible to make the coating thickness uniform between one coated surface and another coated surface that has a step with respect to this coated surface. In addition to the above-mentioned common effects, the embodiments also have the following effects: near the rear end edge of the hood, near the front end edge of the roof, near the rear end edge of the roof, near the front end edge of the trunk lid in the painting line of an automobile body. This has the effect of greatly reducing the number of touch-up painting steps needed to correct unevenness in the paint film.

[Brief explanation of the drawing]

Figure 1 is a perspective view of an automatic coating device that is often used in conventional painting methods, Figures 2 (A) to (D) are cross-sectional views showing painting defects in conventional painting methods, and Figure 3 is the embodiment of the present invention. A perspective view of an automatic coating machine used in the example, FIG. 4 is an explanatory diagram of an embodiment using the automatic coating device of FIG. 3, and FIG. 5 shows an automatic coating machine and its control mechanism used in an embodiment of the present invention. This is an overall explanatory diagram, and FIG. 6 is an explanatory diagram showing the relationship between the height of the gun and the object to be coated according to changes in the count number in the embodiment of the present invention. 1... Conveyance device, 2... Vertical post, 4... Upper gate, 6... Carriage, 7a, 7b - Spray gun, 8... Vehicle body, 8a Hood, 8b... Roof, 8c... ...Trunk lid, 9a, 9b...Actuator, 16...Gate type automatic painting device, 17...Painting booth, 18...Pulse transmitter, ]9...Opening/closing gate,
21a... Memory device for vehicle type, 21b... Memory device for B vehicle type, 22... Output circuit, 23... Counter. Patent applicant Nissan Motor Co., Ltd. 15- Figure 1

Claims (1)

[Claims] The automatic coating machine is moved relative to the object to be coated, and multiple spray guns held in front-back relationship with respect to the moving direction are used on one surface to be coated and another spray gun with a step attached to the surface to be coated. When painting while sequentially confronting the surfaces to be coated, if the step rises, move the spray gun away from the surface after the preceding spray gun finishes painting one surface to be coated. At the same time, wait for the succeeding spray gun to finish painting, and then move these multiple spray guns to confront different surfaces to be coated one after another. Also, if the step falls, the preceding spray gun After finishing painting the surface to be coated, the spray gun is brought closer to another surface to be coated, and after waiting for the subsequent spray gun to finish painting, the plurality of spray guns are sequentially moved to coat another surface. A method of painting a surface to be coated with a step, which is characterized by facing the surface.