KR100420221B1 - Nozzle for coating film and apparatus for coating piston of compressor having the nozzle - Google Patents

Abstract

Compressor piston coating apparatus according to the present invention is a device for forming a coating film for improving the wear resistance and airtightness on the head outer circumferential surface and the bridge surface of the piston for the compressor, the piston rotation support means for rotatably supporting the compressor piston; A first paint applying means having a first and a second nozzle descending from the piston rotation support means to the head of the piston and applying paint to a constant film thickness on the outer peripheral surface of the head by removing excess; A piston support means installed adjacent to the piston rotation support means to support the compressor piston on which the head outer peripheral surface coating is completed; And a second paint applying means having a third nozzle which descends from the piston supporting means to the bridge portion of the piston and applies the paint on the surface of the bridge portion at a constant film thickness while removing excess paint. According to the same configuration, it is possible to coat on the outer circumferential surface of the compressor piston and the surface of the bridge by a series of processes according to the dispenser method, so that the paint is coated with a constant film thickness without having a separate blade as in the prior art. Since it can apply, structural simplification of a coating apparatus can be aimed at.

Description

NOZZLE FOR COATING FILM AND APPARATUS FOR COATING PISTON OF COMPRESSOR HAVING THE NOZZLE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle for applying a coating material for forming a coating film on a surface of a product requiring wear resistance and airtightness, and in particular, a coating film forming nozzle having a coating application function and a function of expanding and applying a coated paint to maintain a constant film thickness. And a piston coating device for a compressor that uses the features of the nozzle to coat the head and bridge portions of the compressor piston in a series of continuous processes by a dispenser method.

Techniques for improving the wear resistance and airtightness by forming a coating film having a predetermined thickness on the surface of a product requiring wear resistance and airtightness have already been used in various technical fields. It is well known that an important point in this coating technique is that the applied film must maintain a constant thickness. In particular, the thickness and precision of the coating film in the cylindrical part, such as the outer diameter coating of the head portion of the compressor piston, is a control point to be very important because it greatly affects the performance of the compressor.

Coating methods for increasing the wear resistance and airtightness of the compressor piston include powder spraying, spraying and electrostatic coating. However, these coating methods are a problem because the dispersion of the coating film thickness is severe. In particular, the spray coating method has a problem that the coating process is not only difficult, but also because the paint to be sprayed is scattered, it is a problem to be coated to the area not to be coated, and thus the consumption of the paint for forming the coating film is excessive. In addition, the spray coating method has a problem that the surroundings are severely contaminated by the paint splashing during coating.

In order to solve the problems of the conventional spray coating method as described above, Japanese Patent Application Laid-Open No. 8-173893 and International Patent Application No. PCT / JP00 / 00096 include a rotation support device for rotatably supporting a cylindrical part, A paint spraying device installed on an upper circumference of the cylindrical part rotated by the rotary support device, the paint spraying device being installed on the top of the rotary support device so as to be movable; and the outer surface of the cylindrical part by the paint spraying device. Disclosed is a coating apparatus having a paint diffusion device for removing the applied excess paint liquid to diffuse the paint and maintaining the film at a constant film thickness.

However, the coating apparatus according to the related art as described above is installed in a position adjacent to the rotating cylindrical part by a separate paint diffusion device (also called a blade) for removing excess paint liquid applied to the outer peripheral surface of the cylindrical part. Since the structure is relatively complicated, as well as the operation and control of the paint spreader is complicated, there is a problem that the maintenance / maintenance and management point increases.

In addition, the coating apparatus according to the prior art can be coated on the outer diameter of the head portion of the cylindrical part, such as the compressor piston, but not the bridge portion. Therefore, in the past, the piston coated with the outer diameter of the head portion is moved to another place or another device to coat the bridge portion by the spray method instead of the dispenser method, and the problem that management is complicated by the dualization of such an applied method. There is. In addition, there is a typical problem with the spray method as is well known, that is, the problem of contamination of the peripheral equipment due to the increased paint consumption and paint scattering.

The present invention has been made in view of the above problems, and in addition to the application of the paint in order to maintain a constant film thickness of the applied coating by removing the excess paint liquid while spreading (擴 布: including spread evenly) It is an object of the present invention to provide a nozzle for forming a film, which does not require a blade for removing excess paint liquid.

Another object of the present invention is to provide a nozzle for forming a coating film as described above, the structure is simple and easy to downsize, and also the outer diameter and the bridge portion of the compressor piston can be coated in a series of continuous processes by the dispenser method. The present invention provides a piston coating device for a compressor.

1a and 1b is a side view and a front view showing a nozzle for forming a film according to an embodiment of the present invention,

2 is a detailed view of the portion A of FIG.

3A, 3B, 3C, and 3D are enlarged bottom views showing various examples of paint spray holes of a coating film forming nozzle according to one embodiment of the present invention shown in FIG.

Figure 4 is a perspective view schematically showing a compressor piston coating apparatus according to the present invention having a nozzle for forming a film shown in Figure 1,

5 is a front view showing an extract of the piston head coating unit of the compressor piston coating apparatus according to the present invention,

6 is a detailed view of the portion B of FIG.

7 is a perspective view showing the state in which the paint is coated on the piston head portion,

Figure 8 is a side view showing an extract of the piston bridge coating unit of the compressor piston coating apparatus according to the present invention,

9 is a detailed view of portion C of FIG. 8;

10 is a front view showing a nozzle constituting the piston bridge coating unit of the compressor piston coating apparatus according to the present invention, and

11A and 11B are enlarged bottom views showing various examples of paint spray holes of the nozzle shown in FIG. 10.

<Description of Symbols for Main Parts of Drawings>

1; compressor piston 2; paint supply control valve

3,3 '; 1st and 2nd nozzle 11; Nozzle body

12; Paint sprayer 13; Blade part

21; piston rotating support means 22; first paint coating means

31; piston supporting means 32; second coating means

33; third nozzle 34; nozzle body

35; paint sprayer 36,36 '; first and second blade parts

37; guide post

In the nozzle for forming a film according to the present invention for achieving the above object, a paint spraying hole is formed through the nozzle body so that the film thickness of the coating liquid applied to the surface of the coated body is kept constant by the paint spraying hole. The blade portion for removing and applying excess paint liquid is formed integrally with the nozzle body. According to this, since the film thickness of the paint applied to the to-be-coated body can be kept constant without providing a separate blade as in the related art, the structure of the coating apparatus can be simplified and the management point can be reduced.

The blade portion has a width that is equal to or slightly larger than the width of the coating portion of the coating body, and the paint spray hole is formed through the blade portion.

The paint spray hole may be formed in one long hole shape or a plurality of independent small holes. In addition, the paint spray hole may be formed by a combination of the long hole and the small hole, the shape and quantity may be appropriately changed according to the coated body.

In addition, an inclined surface having a predetermined angle may be formed on the lower surface of the blade to facilitate the application of the paint. In this case, the inclined surface may be formed from the front surface when the surface of the blade portion in the moving direction of the coated body is called the front surface. It is preferably formed to be inclined to the rear side. The angle of inclination is preferably in the range of an acute angle, but is not necessarily limited thereto.

On the other hand, a piston coating device for a compressor for achieving another object of the present invention, the piston rotation support means for rotatably supporting the compressor piston in a horizontal state; It is installed on the upper side of the piston rotation support means so as to be movable, and while applying the paint on the outer peripheral surface of the head in the state descending to approach the head of both sides of the piston supported by the piston rotation support means, the applied paint is a constant film First paint applying means comprising first and second nozzles for applying while removing excess of the coating liquid to maintain thickness; A piston support means for supporting the compressor piston in a horizontal state for coating the bridge portion of the compressor piston on which the head portion outer circumferential surface coating is completed; And installed on the upper side of the piston supporting means so as to be movable up and down and sliding, and being applied while sliding and simultaneously coating the paint on the surface of the bridge in a state of descending close to the bridge of the piston supported by the piston supporting means. A second paint applying means having a third nozzle for removing and applying excess paint liquid so that the paint maintains a constant film thickness; a series of processes according to the dispenser method on the outer circumferential surface of the compressor piston and the surface of the bridge part; It characterized in that the coating.

The first and second nozzles have at least one paint spray hole formed through the nozzle body, and the paint spray hole removes excess paint liquid so that the paint liquid applied to the outer peripheral surface of the head of the piston maintains a constant film thickness. The blade parts which can be applied while being applied are formed integrally with the nozzle body, respectively.

The blade portion has a width equal to or slightly larger than the width of the outer peripheral surface of the piston head portion, i.e., the coating spray hole is formed in the blade portion.

The lower surface of the blade portion may be formed with a projection for controlling the amount of paint applied to the groove at a position corresponding to the groove formed on the outer peripheral surface of the piston head portion.

In addition, an inclined surface having a predetermined angle may be formed on the lower surface of the blade to facilitate the application of the paint. Here, the inclined surface is preferably formed so as to be inclined from the front surface to the rear surface when the surface of the blade portion in the direction of rotation of the piston is the front surface, the inclination angle is preferably within the range of an acute angle, but is definitely defined within the acute angle range It is not.

The third nozzle is formed by applying a paint spraying hole for coating the paint on the nozzle body with the piston bridge portion, and removing the excess paint so that the paint applied to the piston bridge portion by the paint spraying hole maintains a constant film thickness. The pair of blade portions having a straight line shape or a predetermined radius of curvature inclined with respect to the surface of the piston bridge portion are formed integrally with the nozzle body.

Here, the pair of blade portions have a width equal to the width of the coating portion of the piston bridge portion, the paint spray hole is formed through the blade portion.

The paint spraying hole may be formed in one long hole shape or a plurality of independent small holes, and may be formed in a suitable combination of long holes and / or small holes.

In addition, an inclined surface that is inclined at a predetermined angle in a direction opposite to the nozzle moving direction may be formed on the lower surface of each blade portion to facilitate the application of the paint, wherein the inclined angle of the inclined surface is preferably an acute range, This is not necessarily a limitation.

On the other hand, the third nozzle guides the movement of the nozzle in front of the blade body of the nozzle body to guide the movement and to prevent sliding and to form a coating film of a constant film thickness so that the sliding contact with the surface of the shoe support of the piston Each may be formed and configured.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A and 1B are side and front views illustrating a nozzle for forming a coating film according to an embodiment of the present invention, FIG. 2 is a detailed view of portion A of FIG. 1, and FIGS. It is an enlarged bottom view which showed the various examples of the paint spraying hole of the nozzle for coating film formation by this.

In the drawings, reference numeral 1 is a compressor piston as a cylindrical coating body, 2 is a paint supply control valve, and 3 is a nozzle for forming a coating film according to the present invention.

The compressor piston (1) to be coated is supported by the piston rotation support means (not shown) so as to be rotated in a horizontal state, and the nozzle (3) is installed to be detachable from the paint supply control valve (2). The coating material for forming a coating film is applied to the surface of the head of the piston 1 while moving by lifting and lifting means (not shown).

Such a nozzle 3 is provided with a valve body 11, a paint spray hole 12 and a blade portion 13 in accordance with a feature of the present invention.

The valve body 11 is formed with a plurality of bolt holes (not shown) for fixing them to the paint supply control valve (2), the paint spray hole 12 is formed through the center. Therefore, the paint whose supply is controlled by the operation of the paint supply control valve 2 can be applied to the coating portion of the piston outer circumferential surface through the paint spray hole 12.

The blade portion 13 is installed on the lower side of the valve body 11, may be formed integrally with the valve body 11, may be formed separately and attached. The blade portion 13 has a width equal to the width of the head portion coated portion of the piston 1, so that the paint liquid applied to the piston head portion outer diameter by the paint spraying hole 12 maintains a constant film thickness. Removes and applies the liquid. That is, the blade portion 13 integrally provided in the nozzle replaces the role of the blade, which is conventionally installed separately. Therefore, it is not necessary to install a separate blade as in the prior art.

In addition, the paint spray hole 12 is formed through the nozzle body 11 and the blade portion 13 as shown. However, the paint spray hole 12 is not necessarily formed to penetrate the blade portion 13, the paint in front of the blade portion 13, the right side in Figure 1a when the piston rotates in the direction of the arrow in the figure When the injection hole 12 is disposed, the desired purpose desired in the present invention can be achieved.

At least one paint spray hole 12 may be formed, and as shown in FIGS. 3A to 3D, there may be various embodiments. 3A shows an example in which the paint spray hole 12 is provided in one long hole shape, and FIG. 3B shows an example formed of a plurality of independent small holes. At this time, in the case where the paint spray holes 12 are formed in a plurality of independent pores, each of the pores may be formed so as to become larger or smaller in size from one side to the other side according to the shape or structure of the coated body. It may be. In addition, the paint spray hole 12 may be formed of a combination of long holes and small holes, as shown in Figure 3c and 3d. In FIG. 3C and FIG. 3D, reference numeral 12a denotes a protrusion, which will be described later.

In addition, the nozzle according to the present invention, as shown in Figure 2, the inclined surface of a predetermined angle to facilitate the coating of the paint on the lower surface of the blade portion 13 may be formed.

The inclined surface is preferably formed so as to be inclined from the front surface to the rear surface when the blade portion surface in the rotational direction of the piston 1 is called the front surface, but is not necessarily limited thereto. Even when the inclined surface is formed opposite to the inclined direction of the illustrated example, since the piston is rotated numerous times during the coating, it is necessary to remove and apply the surplus paint liquid so that the desired purpose, that is, the applied paint has a constant film thickness. The desired purpose can be achieved. In addition, even when there is no inclined surface, there is no problem in achieving the desired purpose as before.

In the nozzle having the inclined surface as described above, the inclination angle of the inclined surface is preferably within the range of the acute angle. The more preferable inclination angle is 5 to 45 degrees, and the most preferable angle is about 25 degrees, but as described above, since the object of the present invention can be sufficiently achieved even when there is no inclination, the inclination angle of the inclined surface described above. May be any.

On the other hand, Figures 1 to 3 illustrate the structure of a preferred nozzle that is applied when the coating body rotates, that is, when a predetermined coating film is formed on the outer diameter of the head of the piston, the nozzle according to the present invention is It can be effectively applied to the plane of the coating, that is, the coating on the bridge part of the piston, through a slight structural change, so that the outer diameter and the bridge part of the compressor piston are processed in a series of continuous processes by the dispenser method. It is possible to configure a compressor piston coating device that can be coated.

Hereinafter, a compressor piston coating apparatus according to the present invention will be described with reference to FIGS. 4 to 11.

4 is a perspective view schematically showing a compressor piston coating device to which the nozzle for forming a coating film according to the present invention is applied, and FIG. 5 is a front view illustrating the piston head coating unit of the compressor piston coating device according to the present invention; 6 is a detailed view of the portion B of Figure 5, Figure 7 is a perspective view showing the state in which the coating material coating the piston head, Figure 8 is an extract of the piston bridge coating unit of the compressor piston coating apparatus according to the present invention 9 is a detailed view of the portion C of Figure 8, Figure 10 is a front view showing a nozzle constituting the piston bridge portion coating unit of the compressor piston coating apparatus according to the present invention, and Figures 11a and 11b is Figure 10 It is an enlarged bottom view which showed the various examples of the paint spraying hole of the nozzle shown in the figure.

As shown in FIG. 4, the compressor piston coating apparatus according to the present invention includes a piston head coating unit 20 and a piston bridge coating unit 30. Of course, the compressor piston coating apparatus according to the present invention, in addition to the above-described configuration, to load the piston into the piston head coating unit 20 and the piston head coating is completed, the piston bridge coating unit 30 for the piston bridge coating Although there are several units which move to and unload the coated piston, these other configurations are not significantly different from the conventional apparatus, and thus, specific description and description are omitted here and only the characteristic configurations of the present invention will be described.

As shown in FIGS. 5 to 7, the piston head coating unit 20 includes a piston rotation support means 21 for rotatably supporting the compressor piston 1 in a horizontal state, and the piston rotation support means. And a first paint applying means 22 for applying paint to the outer diameter of the head portion of the piston which is supported and rotated.

The piston rotation support means 21 includes a pair of support members for supporting both end side rotation centers of the piston, and a rotating device for rotating the piston by rotating at least one of the support members. Since this structure is a conventional structure, detailed description is abbreviate | omitted here.

The first paint coating means 22 is installed on the upper side of the piston rotation support means 21 so as to be movable, and on both outer diameters of both head portions of the piston 1 supported by the piston rotation support means 21. The first and second nozzles 3 and 3 ', which can be applied while removing the surplus paint liquid so that the paint is applied to the outer diameter of the head and the thickness of the applied paint is kept constant while being lowered close to each other, Equipped.

The first and second nozzles 3 and 3 '(the same structure is described below only for the first nozzles and the second nozzles are referred to by the reference numerals in place of the descriptions), and the nozzle body 11 and The paint spraying hole 12 and the blade part 13 are provided.

The nozzle body 11 is attached to the paint supply control valve 2 so that attachment and detachment are possible, and the blade body 13 is integrally or assembled to the nozzle body 11. The paint spray hole 12 is formed to communicate with the paint supply control valve 2 through the nozzle body 11 and the blade portion 13. This structure is the same as the configuration of the coating film forming nozzle of the present invention shown in Figures 1 to 3 described above. Therefore, the description above is replaced by this. In this case, however, the projection 12a for controlling the amount of paint applied to the groove is formed at the position of the nozzle corresponding to the outer diameter structure of the head of the piston 1, which is the coated body, that is, the groove 1a formed on the head. There is a characteristic. According to this, a coating film having a constant film thickness corresponding to the structure of the piston head outer diameter can be formed. Here, the thickness of the coating film can be determined by the gap between the outer diameter of the head portion and the nozzle end, the present invention is provided with a device for adjusting the film thickness that can arbitrarily adjust the above-described gap is installed in each nozzle, not shown in the drawings Doing.

As shown in FIGS. 4 and 8 to 11, the piston bridge coating unit 30 supports the compressor piston 1 in a horizontal state to coat the bridge portion of the compressor piston in which the head portion outer diameter coating is completed. A piston support means 31 provided adjacent to the piston rotation support means 21, and a second paint application means 32 for applying the paint to the bridge portion of the piston fixed to the piston support means 31. .

The piston support means 31 is composed of a pair of support members for supporting both end side rotation center of the piston, the piston support means 31 only supports the piston in a horizontal state. Here, the piston movement from the piston rotation support means 21 to the piston support means 31 is made by a separate piston movement means.

The second paint applying means 32 is installed on the upper side of the piston support means 31 so as to be movable in the shanghai-dong and axial directions, so that the piston 1 supported by the piston support means 31 It is provided with the 3rd nozzle 33 which can be apply | coated, removing surplus paint liquid so that the applied paint may maintain a fixed film thickness, while coating and sliding a coating material at the bridge part in the state which descended close to a bridge part. .

The third nozzle 33 has a paint spray hole 35 for coating the paint on the nozzle body 34 with the piston bridge portion, and the paint applied to the piston bridge portion by the paint spray hole 35 has a constant film. A pair of blades 36 and 36 ′ having a straight line or a predetermined radius of curvature inclined with respect to the radius of curvature of the piston bridge to remove and apply excess paint liquid to maintain the thickness are applied to the nozzle body 34. It is formed integrally. Here, the end shape of the third nozzle 33 preferably has the same radius of curvature as the radius of curvature of the piston bridge, but is not necessarily limited thereto, and has a straight shape or a constant radius of curvature inclined at a predetermined angle as described above. It is also possible. In other words, since the piston in which the coating film is formed by the coating apparatus is processed to have a constant film thickness through post-processing, the coating film formed in the coating apparatus only needs to obtain the required minimum film thickness. Therefore, the end of the nozzle does not necessarily need to be the same as the radius of curvature of the piston bridge portion.

The pair of blades 36 and 36 'has a width equal to the width of the coating portion of the piston bridge portion, and the paint spray hole 35 penetrates through the blade portions 36 and 36'.

The paint spray hole 35 may be formed in one long hole shape as shown in FIG. 11A, or may be formed of a plurality of independent small holes as shown in FIG. 11B.

In addition, an inclined surface inclined at a predetermined angle in a direction opposite to the nozzle moving direction may be formed on the lower surface of each of the blade parts 36 and 36 ′ so that the paint can be spread evenly. This is not necessarily limited, and there is no problem in applying the paint even when there is no inclined surface. Here, when the inclined surface is formed, the angle is preferably within the range of an acute angle, and more preferably 5 to 45 degrees, particularly about 25 degrees, most preferably, this inclination angle can be appropriately changed according to the shape of the coated body. have.

On the other hand, the third nozzle 33 as described above is to slide to one side while applying the paint in the lowered state to the piston bridge portion, at this time, the flow should not occur during the sliding operation. To this end, the third nozzle 33 has a pair of guide posts 37 as a means for guiding its movement, and the pair of guide posts 37 is in front of the blade portion of the nozzle body 34. It is formed so as to slide in contact with the outer diameter of the shoe support portion of the piston. It is thereby possible to prevent the flow of the nozzle during the sliding movement of the nozzle. In addition, the pair of guide posts 37 serves to determine the thickness of the coating film by contacting the piston bridge portion at both ends thereof when the nozzle is lowered. In other words, the length of the guide post is slightly longer than the length of the nozzle. Therefore, the gap between the piston bridge portion and the nozzle end when the end of the guide post contacts the piston bridge portion when the nozzle is lowered has a thickness of the coating film. In this state, the coating is applied while the nozzle is sliding while being guided by the guide post. Thus, a coating film having a constant thickness can be formed.

Hereinafter, the operation of the compressor piston coating apparatus according to the present invention configured as described above.

When one piston is supported by the piston rotating support means 21 by a piston loading means (not shown), the first paint applying means 22 on the upper side is lowered, and at this time, the first paint applying means 22 The ends of the nozzles 3 and 3 'of the lower side stop and lower so as to maintain the piston head portion outer diameter and a predetermined gap. Then, the piston rotates at a predetermined speed by the piston rotation support means 21, and at the same time, paint is applied to the piston head portion outer diameter from the nozzles 3 and 3 '. At this time, since the blade portion 13 of the nozzle is positioned with an appropriate gap between the piston outer diameter, the excess paint liquid applied to the outer diameter of the piston head portion is uniformly expanded as a whole while being removed by the blade portion 13.

When the coating on the outer diameter of the piston head portion is completed by the above process, the piston is moved to a piston support means 31 adjacent thereto by a moving device (not shown) so that the piston is in a horizontal state (with the piston bridge portion upward). Is supported by. Then, the paint is sprayed through the nozzle while the second paint applying means 32 is lowered such that the end of the nozzle 33 maintains a constant gap with the piston bridge portion, and the nozzle moves in the axial direction of the piston. As a result, paint is applied to the piston bridge portion, and at the same time, it is expanded to a constant film thickness. When the formation of the coating film is completed in the bridge portion, the piston on which the coating film is formed by the unloading device is unloaded.

In the above work process, the piston head coating unit and the piston bridge coating unit have different operations at the same time, so that the coating on the outer diameter and the bridge of the piston head can be carried out in a series of continuous processes. . That is, in the related art, after the coating by the dispenser method for the piston head part, the dispenser coating for the bridge part is impossible and the piston having the outer diameter coating of the head part is completed is moved to another place or another device, for example, the bridge by the spray method. Although the secondary coating had to be performed, according to the present invention, the piston head portion outer diameter and the bridge portion can be coated in a series of continuous processes by the dispenser method.

Therefore, the coating of the piston head part does not require a separate blade device as in the prior art, and also enables coating of the piston bridge part in a series of continuous processes, thereby achieving structural simplification and miniaturization of the device. Of course, the management point is reduced and the maintenance / maintenance of the device is easy.

According to the present invention as described above, since the blade portion which serves to apply the paint to the nozzle for spraying the paint is integrally formed, a separate blade as in the prior art is not necessary, and thus, the device of removing the blade It is possible to achieve structural simplification and miniaturization, and to simplify the maintenance and control of the device.

In addition, according to the present invention, the head coating and the bridge coating can be carried out in a series of continuous processes in one apparatus when coating the piston, so that the productivity and quality can be improved. Since the dispenser method is applied, it is possible to fundamentally prevent excessive paint consumption and contamination of peripheral equipment caused by paint scattering.

While the invention has been described and illustrated in connection with a preferred embodiment for illustrating the principles of the invention, the invention is not limited to the configuration and operation as such is shown and described. Rather, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

Claims (20)

delete delete delete delete delete delete delete An apparatus for forming a coating film for improving the wear resistance and airtightness on the head outer peripheral surface of the compressor piston and the surface of the bridge portion, Piston rotation support means for rotatably supporting the compressor piston; It is installed to be movable up and down on the piston rotation support means, and descends close to the head of the piston supported by the piston rotation support means to apply paint on the outer circumferential surface of the head portion with a constant film thickness while removing the excess of the paint. A first coating means having a first nozzle and a second nozzle to make; A piston support means installed adjacent to the piston rotation support means to horizontally support the compressor piston on which the head portion outer peripheral surface coating is completed; And It is installed to move upward and downward on the piston support means, and descends close to the bridge portion of the piston supported by the piston support means to apply paint on the surface of the bridge portion with a constant film thickness while removing the excess of the paint. Compressor piston coating apparatus comprising a; 2nd paint coating means having a third nozzle. The method of claim 8, The first and second nozzles, respectively, A nozzle body through which a paint spraying hole capable of spraying a coating liquid is formed; Compressor piston coating apparatus formed integrally with the nozzle body; the blade portion for applying a constant film thickness of the paint sprayed from the paint spray hole to the outer peripheral surface of the head of the piston while removing the excess. The method of claim 9, The blade portion has a width greater than the length of the piston head portion, the compressor piston coating apparatus, characterized in that the paint spraying hole is formed in the front end from the nozzle body. The method of claim 10, Compressor piston coating device characterized in that the front end of the blade is formed with a projection for controlling the amount of paint in a position corresponding to the groove of the outer peripheral surface of the piston head. The method of claim 10, Compressor piston coating apparatus characterized in that the inclined surface is formed on the tip of the blade portion, the paint is easily applied in the rotation direction with respect to the rotating piston head portion. The method of claim 12, The inclined surface is a compressor piston coating apparatus, characterized in that formed to be inclined at an angle in the acute angle range to the rear with respect to the front blade portion. The method of claim 8, The third nozzle, A nozzle body through which a paint spraying hole capable of spraying a coating liquid is formed; A pair of integrated parts on both sides of the nozzle body, having a straight portion or curvature corresponding to the surface shape of the piston bridge portion and applying a paint sprayed from the paint spray hole to the surface of the piston bridge portion while removing the excess Compressor piston coating device characterized in that it comprises a blade portion. The method of claim 14, Each of the blades has a width greater than or equal to the width of the piston bridge portion, the piston coating device, characterized in that the paint spraying hole formed from the nozzle body to the front end. The method of claim 15, The paint spraying hole is a compressor piston coating device, characterized in that consisting of one long hole (長 孔). The method of claim 15, The paint spraying hole is a compressor piston coating device, characterized in that consisting of a plurality of independent small holes. The method of claim 15, Compressor piston coating device, characterized in that the inclined surface is formed on the tip of the blade portion to facilitate the coating of the paint in the direction of the piston bridge. The method of claim 18, The inclined surface is a compressor piston coating apparatus, characterized in that formed to be inclined at an angle in the acute angle range to the rear with respect to the front blade portion. The method according to any one of claims 14 to 19, Compressor piston coating further comprises; a guide post for sliding contact with the outer peripheral surface of the shoe support portion of the piston in front of the blade body of the nozzle body, to guide the moving nozzle so that the coating film thickness is kept constant Device.