JPH0824766A - Method for applying viscous paint - Google Patents

Abstract

PURPOSE:To reduce the paint to be consumed and to omit a masking operation by coating only the region to be coated. CONSTITUTION:Plural minute-diameter discharge holes for discharging a viscous paint are provided to a nozzle 2 supported by a coating robot in the region corresponding to the coating width in array adjacently to one another. The nozzle is arranged with respect to a material 3 to be coated so that the discharge holes are directed in the direction orthogonal to the traveling direction of the nozzle and placed at a position P1 on this side of a coating range C. The nozzle is moved from P1 at a constant speed along the material while keeping a fixed distance L from the material, and the discharge of a viscous paint at a low pressure is started when the nozzle passes the base end P2 of the coating range. The nozzle is transiently stopped at P3 for an extremely short time and then moved to the stop P5, and the discharge of the paint is stopped at a terminal position P4 of the coating range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method which is used in a production line for machine parts of relatively small products using a highly viscous paint such as vinyl chloride resin paint.

[0002]

2. Description of the Related Art Conventionally, as a coating method of this type,
The spray coating method is generally used regardless of the viscosity of the paint. In other words, a spray gun is used to atomize the paint with compressed air at a high pressure, and spray coating on an object to be coated. In this case, usually
The hole diameter of the spray gun is in the range of 1.0 to 2.0 mm, and the spraying pressure is set to a high pressure of 80 to 150 Kgf / cm2 (for example, dictionary of paint terms, Japan Color Materials Association, 1993.1. 20 issue, Gihodo Publishing, page 209).

[0003]

However, the above-mentioned conventional coating method has the following disadvantages. That is,
When the paint has a high viscosity (for example, 150 poise or more), the paint does not atomize uniformly even if sprayed at a relatively high pressure, and it adheres to the coated surface in a granular form and is sprayed one after another onto the coated surface. The paints tend to bind to each other and the surface of the coating film tends to be uneven. For this reason, extra paint is required to secure the minimum coating thickness. In this case, the lower the spraying pressure is, the more granular the paint is, but there is a limit to increase the spraying pressure in order to prevent this, because of restrictions on the apparatus. Further, in the above-mentioned spray coating method, the paint is sprayed from the spray gun to the object to be coated with a certain spread regardless of the size and shape of the object to be coated, so that the object to be coated is smaller than the spread. Alternatively, if it has a narrow shape, the sprayed paint diffuses beyond the object to be coated, resulting in a large paint loss, and a large amount of paint is required for the coating area. Further, a masking work is required to prevent the paint from adhering to a portion such as a bolt hole to which the paint should not adhere, and this work is time-consuming. In this case, if the paint has a high viscosity, the removal work requires more work than in the case of a low-viscosity paint.Therefore, the above masking work needs to be performed accurately, and the finishing process also takes time. I need it.

In particular, when chipping-resistant coating is applied to a trailing arm of a suspension device exposed under the vehicle to protect it from collision with small stones,
Originally, it suffices to perform chipping-resistant coating only on the downward surface of the relatively narrow width of the rod-shaped trailing arm, whereas the above spray coating method causes almost all the surface to be coated. This results in an increase in quantity. Moreover, since the paint used for the chipping-resistant coating is a vinyl chloride resin paint having a viscosity of 150 poise (P) or more, the coated surface becomes uneven as described above and the appearance is deteriorated. Requires a large amount of paint to secure.

The present invention has been made in view of the above circumstances, and an object thereof is to make it possible to coat only a portion where painting is required, save consumption paint, and omit masking work. Is to try.

[0006]

In order to achieve the above object, the invention according to claim 1 is such that a plurality of minute discharge holes for discharging a high-viscosity paint are adjacent to each other in a range corresponding to a coating width. And a support mechanism that supports the nozzles such that their relative positions with respect to the object to be coated can be changed. Then, after aligning the row-shaped discharge holes of the nozzles in a direction orthogonal to the relative movement direction of the nozzles with respect to the object to be coated, the nozzles are lined up along the object to be coated with the nozzles maintained at a constant interval. The high-viscosity paint is discharged from each of the discharge holes at a low pressure while relatively moving at a constant speed. As the support mechanism, for example, a coating robot that can arbitrarily change the X, Y, and Z axis positions of the nozzle may be used.

According to a second aspect of the present invention, in the invention according to the first aspect, the relative movement of the nozzle with respect to the coating object is separated from the coating range base end position of the coating object with respect to the moving direction of the nozzle. Starting from the position, the high viscosity coating material is discharged from the point where the nozzle passes the base end position of the coating range, which is the middle point of the relative movement. Then, while the discharge of the high-viscosity paint is stopped at the time when the nozzle passes the tip end position of the coating range of the object to be coated, after the end of the discharge, the nozzle is further forward than the tip end position of the coating range in the moving direction of the nozzle. The relative movement of the nozzle with respect to the object to be coated is continued up to a distant position.

[0008]

According to the above-mentioned structure, according to the first aspect of the present invention,
The nozzles are arranged in the direction orthogonal to the direction of relative movement of the nozzles to the object to be coated, that is, in the coating width direction, and while the nozzles are moved relative to the object to be coated, high viscosity is achieved from each small-diameter hole. Since the paint is being discharged,
The paints discharged from the discharge holes each having a small diameter adjacent to each other are continuous with each other, and have a width corresponding to the length of the discharge holes in the row direction with respect to the object to be coated, and only the length moved by the above-mentioned relative movement. Paint is applied to the area. At this time, since the high-viscosity paint is discharged from each discharge hole at a low pressure, the high-viscosity paint can be applied only to the necessary area other than the above range without diffusion. Therefore, compared with the conventional spray coating method, the consumption paint can be reduced and the masking work can be omitted. In addition, since the high-viscosity paint is discharged from the above-mentioned row-shaped discharge holes while moving the nozzles relative to each other, the surface of the coating film becomes a smooth surface, and the granular high-viscosity paint as in the conventional spray coating method is one after another. It is prevented that the coated surface becomes uneven by being sprayed.

Further, in the invention described in claim 2, in addition to the operation according to the invention described in claim 1, the start point of discharge of the high-viscosity paint from each discharge hole of the nozzle is moved relative to the object to be coated. Since the relative movement is in the middle of the start after the start time, the occurrence of excessive coating on the object to be coated at the start of the discharge of the high-viscosity paint is avoided. That is, in order to make the coating film thickness constant, it is necessary to make both the discharge amount of the coating material and the relative moving speed of the nozzle constant, so that the coating film thickness at the relative movement start position of the nozzle is the same as that of other parts. In order to do so, it is necessary to exactly match the start of ejection and the start of relative movement. However, due to the difficulty of exactly matching both start times, if the ejection start slightly precedes the relative movement start time, a larger amount of paint will be applied to that relative movement start position than after the relative movement. Since it is a high-viscosity paint, it does not fluidize so much, and the coating film thickness increases only at that portion, resulting in overpainting. The occurrence of such excessive coating is reliably prevented by starting the discharge of the high-viscosity coating material during the relative movement as described above.

The problem of such excessive coating occurs when the relative movement stop time slightly precedes the discharge stop time as in the start time. On the other hand, the discharge is first stopped at a predetermined position in the middle of the relative movement, and the relative movement is continued for a certain amount even after the stop, so that excessive coating at the time of stopping the discharge can be reliably avoided.

Therefore, in the application of the high-viscosity coating material, the coating film thickness can be made uniform over the entire coating range from the start to the end of discharge.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a coating robot 1 for carrying out a method of applying a high-viscosity paint according to an embodiment of the present invention.
Is a nozzle supported by the tip arm 15 of the coating robot 1, and 3 is a trailing arm as an object to be coated, which is one of links constituting a suspension device of an automobile.

The coating robot 1 has a lower plate 11 fixed at a predetermined position on the trailing arm 3 manufacturing line.
An upper plate 12 supported so as to be rotatable around a vertical axis Y with respect to the lower plate 11, and a bracket 12 on the upper plate 12.
a and 12a, which supports the column 13 which is supported by the horizontal axis X1 so as to be undulated, and the base end arm 14 which is supported at the upper end position of the column 13 by the horizontal axis X2 so as to be capable of undulating. A tip arm 15 rotatably supported at the tip end position of the base end arm 14 about an axis Z orthogonal to the horizontal axes X1 and X2, and at the tip end position of the tip end arm 15 swingable about a horizontal axis X3. The rod 16 is supported, a motor (not shown) that drives each of these parts 12, 13, 14, 15, 16 and a controller (not shown) that controls the drive of each motor. In addition, the coating robot 1 is provided with a paint supply system (not shown) for supplying paint to the nozzle 2 attached to the tip of the rod 16. In addition, the controller stores previously taught data regarding the relative movement position and movement order of the nozzle 2 with respect to the coating portion of the trailing arm 3, and the paint is associated with the movement of the nozzle 2. The discharge start and stop times are stored, and the relative movement of the nozzle 2 with respect to the trailing arm 3 and the start and stop of the discharge of the paint from the nozzle 2 are controlled based on this. A support mechanism that supports the nozzle 2 is configured by the coating robot 1 described above.

The nozzle 2 is a body 21 which is attached to the rod 16, as shown in detail in FIGS.
And a flat tip 22 welded to and integrated with the main body 21. Inside the main body 21,
A main passage 23 that communicates with a supply passage of a paint supply system in the rod 16, and a first reservoir 24 that communicates with the main passage 23,
A plurality of communication passages 25, 25, ... Communicating from the first reservoir 24 to the second reservoir 26 on the side of the flat tip 22 are formed, and inside the flat tip 22,
A plurality (seven in the illustrated example) of which one end communicates with the second reservoir 26 and the other end respectively opens at the tip surface of the nozzle 2.
, Discharge holes 27 are formed. Each discharge hole 2
7 have a small diameter of, for example, about 0.3 to 0.5 mm, and are arranged in parallel in the flat tip 22 so as to be adjacent to each other at a small interval (an interval equal to or slightly larger than the hole diameter of the discharge hole). Thus, the openings of the respective discharge holes 27 are arranged in a straight line on the tip surface of the nozzle 2.

As shown in FIG. 4, the trailing arm 3 has a pair of circular rubber bushes 3 arranged at both ends.
1, 31 and a rod-shaped member 32 connecting the pair of rubber bushes 31, 31 to each other. In each of the rubber bushes 31, a metal inner cylinder 33 and an outer cylinder 34 are connected to each other by an annular rubber body 35, and the outer cylinder 34 and the rod-shaped member 32 are welded to each other. Such a trailing arm 3 is temporarily held by a holding member (not shown) in a state in which the surface (downward surface) arranged downward when mounted on an automobile is directed upward, and the trailing arm 3 is sequentially transferred to the coating robot 1. It is designed to be transported.

The downward facing surface of the trailing arm 3 is relatively thick (for example, 500 μm) with anti-chipping paint to improve anti-chipping property by the painting robot 1.
m or more). For this reason, a high-viscosity (for example, about 220P) vinyl chloride resin paint is supplied as the chipping-resistant paint from the paint supply system to the nozzle 2.

Next, a coating procedure for the trailing arm 3 by the coating robot 1 will be described with reference to FIG. In the following description, one side of the case where two coating ranges C and D are set with the center of the trailing arm 3 in the longitudinal direction as a boundary and the coating is performed separately for each coating range C and D The coating procedure for part (right half) C will be described.

First, when a sensor (not shown) detects that the trailing arm 3 has been conveyed to the coating position by the coating robot 1, the coating robot 1 is controlled by the controller and the nozzle 2 is moved to P1 in FIG. Move to the front position shown. This front position P1 is above the nozzle 2 from the base end position (see P2 in the same figure) of the set coating range shown by C in the same figure.
Is set to a predetermined distance before the moving direction (see the arrow in the figure). The distance from the base end position P2 to the front end position P1 is accurately set at the base end position at the time of the discharge start control in consideration of the supply delay of the paint from the paint supply system to each discharge hole 27 of the nozzle 2. It may be determined that the discharge of the paint is started from P2. In addition, the nozzle 2 at the front position P1 is positioned such that the plurality of discharge holes 27, 27, ... Are in a direction orthogonal to the moving direction, and the tip of the nozzle 2 and the trailing arm 3 ( (Painted surface)
Are set to face each other with a relatively small fixed interval L (for example, 5 to 10 mm).

Next, the rod-shaped member 32 is maintained with the nozzle 2 maintaining a constant distance from the front position P1 to the painted surface.
Along the line, a movement is started to a boundary position P3 described later at a predetermined constant speed (for example, 300 mm / sec). Then, when the nozzle 2 passes the base end position P2, the discharge of the coating material is started, and thereafter a predetermined constant low pressure (for example, 17 Kgf / cm2).
To continue the discharge of paint. Therefore, the nozzle 2 from the front position P1 to the base end position P2 is in the idling state in which the nozzle 2 only moves without discharging the paint.

Then, at the boundary position P3 which is the welded portion 36 of the rod-shaped member 32 and the outer cylinder 34, the boundary position P3 is obtained by temporarily stopping for a minute time while the discharge of the paint is continued.
Increase the amount of paint discharged in 3 by a predetermined amount, and
The area around 6 should be covered with paint. Then, with the nozzle 2 slightly tilted in the radial direction of the outer cylinder 34 along the outer peripheral surface of the outer cylinder 34, the tip position P of the coating range C is obtained.
The nozzle 2 is moved to a stop position P5 that is a predetermined distance away from the forward side of 4 and reaches this stop position P5.
Stop moving. During this movement, the discharge of the paint is stopped when the nozzle 2 passes the tip position P4. That is, the nozzle 2 from the tip position P4 to the stop position P5 becomes idle.

Subsequently, the nozzle 2 is moved and coating is performed on the left half coating area D of the trailing arm 3 in the same procedure as described above.

In the case of the above-mentioned coating method, since the discharge holes 27 of the nozzle 2 are arranged adjacent to each other at a minute interval and continuously arranged in a straight line, the discharge holes adjacent to each other by one movement of the nozzle 2 are formed. The coating materials discharged from 27 can be combined with each other to form a coating film (see E in FIG. 4) having a smooth surface with a width substantially corresponding to the length of the flat tip 22 with respect to the coating surface. Moreover, since the discharge holes 27 are formed to have a small diameter and the paint is discharged from the discharge holes 27 having a small diameter at a low pressure, even if the discharged paint has a high viscosity, it is uniform. It is possible to apply only a predetermined coating area without sagging and spreading with a coating film of various thickness. Therefore, compared with the conventional spray coating method in which the paint is diffused to the object to be coated, it is possible to significantly reduce the consumption of the paint, and it is possible to save labor by omitting the masking work. Moreover, the appearance of the painted surface can be improved. In the present embodiment, the flat tip 2 of the nozzle 2 is provided with a predetermined number of discharge holes 27, 27, ... In a row corresponding to the width of the coating range of the trailing arm 3. The coating method of the embodiment is particularly suitable as a coating method for an object to be coated which has a rod-like shape such as the trailing arm 3 and whose coating range is limited to a relatively narrow width, It is possible to obtain an extremely high degree of effect such as paint saving as compared with the conventional spray coating method.

In addition, before and after the discharge of the paint from each discharge hole 27 for each coating range C and D is started,
The nozzle 2 is set in an idle state before each of the coating ranges C and D to start the discharge of the paint on the way, and the nozzle 2 is set to the idle state without stopping the movement of the nozzle 2 even after the discharge is stopped. Therefore, it is possible to avoid the occurrence of excessive coating at the discharge start position and the discharge stop position of the paint. In particular, by avoiding the occurrence of this excessive coating, it is possible to prevent the coating from fluidizing too much due to its high viscosity, and to prevent the coating thickness from thickening only at that portion. It is possible to make the coating film thickness uniform over the entire coating range from the start to the stop.

The present invention is not limited to the above embodiment, but includes various other modifications. That is, in the above embodiment, the rod-shaped trailing arm 3 is used as the object to be coated and the coating range is relatively narrow, but the shape of the object to be coated is not limited.

Further, the number of discharge holes provided in the nozzle 2 in the above embodiment may be determined according to the width of the required coating range of the object to be coated.

[0027]

As described above, according to the method of applying the high-viscosity paint in the invention described in claim 1, the nozzles in which a plurality of discharge holes each having a small diameter are adjacent to each other and are continuously arranged in a row Since the paint is discharged at a low pressure from each of the small-diameter discharge holes, even if the discharged paint has a high viscosity, it is a coating film with a uniform film thickness and drips around. It is possible to apply only to the width that substantially corresponds to the length of the row-shaped discharge holes without expanding, and thus it is possible to apply only to the required coating range. Therefore, compared with the conventional spray coating method in which the paint is diffused to the object to be coated, it is possible to significantly reduce the consumption of the paint, and it is possible to save labor by omitting the masking work. The present invention is particularly suitable as a coating method for an object to be coated whose required coating range is limited to a relatively narrow width, and is extremely high in the degree of effect such as paint saving as compared with the conventional spray coating method. You can get things.

According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, it is possible to avoid the occurrence of excessive coating at the start and end of the discharge of the paint, and the paint is Since it has a high viscosity, it does not fluidize so much and it is possible to prevent the coating film thickness from being thickened only at that portion. Therefore, when applying high-viscosity paint,
The coating film thickness can be made uniform over the entire coating range from the start to the end of discharge.

[Brief description of drawings]

FIG. 1 is a perspective view showing a coating robot for carrying out an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a nozzle.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is an explanatory diagram of a coating order.

[Explanation of symbols]

 1 Painting robot (support mechanism) 2 Nozzle 3 Trailing arm (object to be coated) 27 Discharge hole C, D Coating range P1 Front position (position away from you) P2 Coating range base position P4 Coating range tip position P5 Move Stop position (away from the front)

Claims (2)

[Claims] 1. A nozzle in which a plurality of small-diameter discharge holes through which a high-viscosity paint is discharged are arranged in a row adjacent to each other in a range corresponding to the coating width, and the nozzles are positioned relative to an object to be coated. And a support mechanism for variably supporting the nozzles, the nozzles are arranged at regular intervals with respect to the object to be coated after the row-shaped ejection holes of the nozzle are oriented in a direction orthogonal to the relative movement direction of the nozzle with respect to the object to be coated. A method for applying a high-viscosity paint, characterized in that the high-viscosity paint is discharged from each of the discharge holes at a low pressure while relatively moving along the object to be coated while maintaining the above condition. 2. The method according to claim 1, wherein the relative movement of the nozzle with respect to the object to be coated is started from a position farther to the front side than the base end position of the coating range of the object to be coated with respect to the moving direction of the nozzle, and the relative movement Discharge of the high-viscosity paint is started from the time when the nozzle passes the base end position of the coating range at an intermediate point, and the high-viscosity paint is discharged when the nozzle passes the position of the front end of the coating range of the object to be coated. On the other hand, the high-viscosity paint characterized by continuing the relative movement of the nozzle with respect to the object to be coated to a position farther to the front side in the moving direction of the nozzle than the tip end position of the coating range after stopping the discharge. How to apply.