JPH081047A - Electrostatic coating apparatus - Google Patents

Abstract

PURPOSE:To miniaturize a high voltage generator while making large the creepage distance of the high voltage generator to prevent high voltage from leaking. CONSTITUTION:On the end surface on the output side of a high voltage generator 23, annular projection parts 23A and annular recessed parts 23B are formed to make large the creepage distance (surface area) of the high voltage generator 23, and also in a high voltage generator housing 22 of a housing 21, annular recessed parts 22A and annular projecting parts 22B fitted in the projection parts 23A and the recessed parts 23B of the high voltage generator 23 in a contact state respectively are formed. Therefore, the insulation of the high voltage generator 3 is improved with the same amount larger as the creepage distance is made larger by the projection parts 23A and the recessed parts 23B, and by the improvement of the insulation, the length in the axial direction of the high voltage generator 23 is shortened, and also high voltage leak due to an air layer is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic coating machine suitable for coating an object to be coated such as an automobile body and electric appliances.

[0002]

2. Description of the Related Art Generally, a coating machine for coating an object to be coated such as an automobile body includes a rotary atomizing type electrostatic coating machine, an air atomizing nozzle type electrostatic coating machine, and a hydraulic atomizing nozzle type static coating machine. There is an electric coating machine and the like, and each electrostatic coating machine is provided with a housing, a paint spraying means which is provided on the tip side of the housing and includes a rotary atomizing head for spraying paint, a nozzle tip, and the like. It is generally composed of high voltage generating means for applying a high voltage to the paint sprayed from the paint spraying means.

Therefore, a rotary atomizing type electrostatic coating machine among the electrostatic coating machines will be described as an example of the electrostatic coating machine according to the prior art with reference to FIGS. 5 and 6.

In the drawing, reference numeral 1 denotes a housing of a rotary atomizing type electrostatic coating machine. The housing 1 is formed of an insulating resin material in a stepped cylindrical shape, and a base thereof has a high voltage generator which will be described later. A high voltage generator accommodating portion 2 for accommodating 6 is formed. Further, an air motor 3 is built in the front end side of the housing 1, and the air motor 3 rotationally drives a rotary atomizing head 4 described later.

The air motor 3 includes a motor case 3A, a hollow rotary shaft 3B rotatably attached to the motor case 3A, and an air turbine integrally fixed to the base end side of the rotary shaft 3B. 3C and the like. The air motor 3 is the air turbine 3C.
Is rotated by compressed air to rotate the rotary atomizing head 4 attached to the tip of the rotary shaft 3B together with the rotary shaft 3B.

Reference numeral 4 denotes a bell-type rotary atomizing head as paint spraying means attached to the tip of the rotary shaft 3B of the air motor 3. The rotary atomizing head 4 is driven to rotate together with the rotary shaft 3B. The paint supplied through a paint valve 5 described later is sprayed as a liquid thread by centrifugal force while being charged to a high voltage, and along an electric line of force (electrostatic field) between the object to be coated (not shown). To be applied to the article to be coated.

A paint valve 5 is provided in the housing 1 and is provided on the base end side of the air motor 3. The paint valve 5 feeds paint supplied from a paint supply pipe or the like in the rotary shaft 3B. It supplies or shuts off the rotary atomizing head 4 via a tube (neither is shown).

Reference numeral 6 denotes a high voltage generator accommodating portion 2 of the housing 1.
Showing a high voltage generator housed in the high voltage generator 6
For example, as shown in Japanese Utility Model Publication No. 50-22059, it is composed of a high voltage generating circuit composed of a multiple voltage circuit (Cockcroft circuit), the outer peripheral side of which is molded with an insulating resin material, and has a cylindrical shape as a whole. Is formed in. Further, in the high voltage generator 6, it is possible to prevent the insulation property of the resin from being lowered due to the spark discharge dielectric breakdown in which the carbon in the resin is burned and carbonized (carbonized) due to the high voltage being gradually leaked. Therefore, the length in the axial direction is increased to increase the creepage distance (surface area) and enhance the insulating property. Further, the input side of the high voltage generator 6 is connected to an external power source (neither is shown) via a lead wire 7, and the output side is connected via an output terminal 8, an electrode spring 9, a paint valve 5, etc. It is connected to the air motor 3.

The high voltage generator 6 converts the voltage supplied from the external power source into a predetermined high voltage, and the high voltage is supplied from the motor case 3A of the air motor 3 to the rotary atomizing head via the rotary shaft 3B. 4, and a high voltage is directly applied to the paint through the rotary atomizing head 4.

On the other hand, 10 is an optical fiber cable consisting of a light projecting cable and a light receiving cable (neither of which is shown). The optical fiber cable 10 has its tip end intruding into the housing 1 and an intermediate portion in the axial direction of the rotary shaft 3B. It is arranged on the outer circumference of the part, and the base end side is connected to a rotation detector (not shown) composed of a light emitting element, a light receiving element and the like. And the rotation detector is
The light projected onto the outer peripheral surface of the rotating shaft 3B through the light projecting cable of the optical fiber cable 10 and reflected by, for example, a reflection tape (not shown) attached to the outer peripheral surface is received by the light receiving element through the light receiving cable. By receiving the light, the number of rotations of the rotating shaft 3B is detected.

The rotary electrification type electrostatic coating machine of the direct charging type has the above-mentioned construction, and the feed valve is opened by rotating the rotary atomizing head 4 by the air motor 3 and opening the paint valve 5. The coating material discharged from the tube is sprayed as a liquid thread while being charged to a high voltage by the high voltage generator 6 from the rotary atomizing head 4 to become charged particles, and the charge between the rotary atomizing head 4 and the object to be coated. It flies along the lines of electric force and is applied to the object to be coated.

At the time of coating, the rotation shaft 3B is held at an appropriate rotation speed by feedback control based on the rotation speed of the rotation shaft 3B detected by the rotation detector.

[0013]

By the way, in the rotary atomizing type electrostatic coating machine according to the above-mentioned prior art, in order to improve the insulation property of the high voltage generator 6, the axial length of the high voltage generator 6 is increased. Since the length dimension is increased to increase the creepage distance, there is a problem that the length dimension of the high voltage generator 6 is increased and the electrostatic coating machine as a whole is increased in size.

Further, in order to detect the number of rotations of the rotary shaft 3B of the air motor 3, since light is applied to the outer peripheral surface of the rotary shaft 3B having an arc shape, the reflected light is scattered around. However, there is a problem in that the light cannot be reliably received and accurate rotation detection cannot be performed.

Therefore, as another rotary atomizing type electrostatic coating machine, as shown in FIG. 6, a high voltage generator accommodating portion 12 is provided on the outer peripheral side of the housing 11, and the high voltage generator accommodating portion 1 is provided.
2 has a deformed high voltage generator 13 housed therein, supplies a high voltage to the air motor 3 via the electrode plate 14, and disposes the optical fiber cable 15 in the center of the housing 11 so that the high voltage generator 13 By increasing the creepage distance to shorten the axial length dimension while ensuring insulation, and detecting the rotation speed of the rotating shaft 3B by applying detection light to the end face of the air turbine 3C of the air motor 3. There is known an electrostatic coating machine that improves the rotation detection accuracy of the shaft 3B.

However, in the electrostatic coating machine as shown in FIG. 6, although the axial length dimension can be shortened as compared with the electrostatic coating machine as shown in FIG. 5, the high voltage generator 13 is surrounded by the outer periphery. There is a problem that the outer diameter dimension of the electrostatic coating machine increases by the amount of the shift to the side.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to reduce the size of the high voltage generator while preventing the leakage of the high voltage by increasing the creepage distance of the high voltage generator. It aims at providing the electrostatic coating machine which was made

[0018]

In order to solve the above-mentioned problems, an electrostatic coating machine according to the invention of claim 1 employs a housing and a paint sprayer which is provided on the tip side of the housing and sprays paint. Means and a high voltage generator attached to the high voltage generator housing of the housing and applying a high voltage to the paint sprayed from the paint spraying means, wherein the high voltage generator has an output side and And a plurality of uneven portions are formed on the end surface.

Further, it is preferable that the high-voltage generator accommodating portion of the housing is provided with a concavo-convex portion located on a surface facing the concavo-convex portion of the high-voltage generator and fitted to each other.

Further, it is preferable that the concavo-convex portion of the high voltage generator and the concave cylindrical portion of the high-voltage generator accommodating portion of the housing are a plurality of annular concavo-convex portions formed coaxially.

[0021]

According to the structure of claim 1, the creepage distance of the high-voltage generator is increased by the uneven portions on the output side on which the high-voltage acts, so that the insulation of the high-voltage generator is improved and Leaks are prevented.

Further, the high-voltage generator accommodating portion of the housing is provided with a concave-convex portion which is located on a surface facing the concave-convex portion of the high-voltage generator and is fitted to the concave-convex portion of the high-voltage generator. And the concavo-convex portion of the housing on the high voltage generator accommodating portion side are fitted in contact with each other to increase the contact area of each other,
Further, it prevents the generation of an air layer due to contact with each other, and enhances the function of preventing high voltage leakage.

Further, by forming the concavo-convex portion of the high voltage generator and the concave tubular portion of the housing of the high voltage generator into a plurality of annular concavo-convex portions formed coaxially, the concavo-convex portion of the high voltage generator and the housing are formed. The fitting property of the high voltage generator accommodating part with the concave cylinder part is improved, the mutual contact area is increased, and even if the high voltage generator is simply inserted into the high voltage generator accommodating part, the unevenness The parts can be fitted securely, and the assemblability is improved.

[0024]

1 to 3, a rotary atomizing type electrostatic coating machine will be described as an example of an electrostatic coating machine according to an embodiment of the present invention.

First, FIGS. 1 and 2 show a direct charging type rotary atomizing type electrostatic coating machine as a first embodiment. In addition,
In the embodiment, the same components as those of the prior art shown in FIG. 5 described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 21 denotes a housing according to the present embodiment, which is formed of an insulating resin material into a stepped cylindrical shape and has a stepped cylindrical shape on the base end side thereof, substantially the same as the housing 1 described in the prior art. Is a high voltage generator 2 described later.
A high voltage generator accommodating portion 22 in which 3 is accommodated is formed. However, the housing 21 has an axial length dimension shorter than that of the conventional housing 1.
In addition, at the bottom of the high-voltage generator accommodating portion 22, annular concave portions 22A, 22A and convex portions 22B, 22B that fit into the convex portions 23A and the concave portions 23B of the high-voltage generator 23 are coaxial, and the diameters are sequentially expanded. A plurality of them are formed.

Reference numeral 23 denotes the high voltage generator according to the present embodiment housed in the high voltage generator housing portion 22 of the housing 21, and the high voltage generator 23 has been described in the prior art as shown in FIG. Almost the same as the high voltage generator 6, it is composed of a high voltage generating circuit composed of a multiple voltage circuit (Cockcroft circuit), the outer peripheral side of which is molded with an insulating resin material and is formed into a columnar shape as a whole. . But,
The high-voltage generator 23 has a convex portion 23A, 23A and a concave portion 23B, 23B which are fitted to the concave portion 22A and the convex portion 22B of the high-voltage generator accommodating portion 22 on the output side end face thereof, and the diameters thereof are sequentially expanded. It is different from the prior art high voltage generator 6 in that it is formed as described above. Further, in the high voltage generator 23, the creepage distance (surface area) is increased by the projections 23A and the recesses 23B, whereby the axial length dimension is shortened.

On the other hand, 24 is an optical fiber cable according to the present embodiment, and the optical fiber cable 24 has its proximal end connected to a rotation detector (not shown) as in the prior art optical fiber cable 10. There is. However, the tip end side of the optical fiber cable 24 enters the housing 21 from the outer peripheral side of the housing 21 so as to avoid the high voltage generator 23, and the end face of the air turbine 3C of the air motor 3 passes through the bent portion 24A in the middle. It is located in.

The rotary atomizing type electrostatic coating machine according to this embodiment has the above-mentioned construction, and its basic operation is not different from that of the prior art.

Therefore, in this embodiment, the high voltage generator 23
Since the annular convex portions 23A and the concave portion 23B are formed on the output side end face of the high voltage generator 23 to increase the creeping distance, the convex portions 23A and the concave portion 23B increase the creeping distance. Only, the axial length of the high voltage generator 23 can be shortened.

Thus, according to this embodiment, each convex portion 23
Since the axial length of the high voltage generator 23 can be shortened by A and the recess 23B, the axial length of the housing 21 can be shortened without increasing the outer diameter, and electrostatic coating can be performed. The overall size of the machine can be reduced.

Moreover, the concave portion 22A and the convex portion 22B are provided on the housing 21 side of the high voltage generator accommodating portion 22, and the convex portion 23A and the concave portion 23B of the high voltage generator 23 are fitted to each other to make contact with each other over the front surface. Therefore, the contact area between the two can be increased, and the same electric potential can be held electrically. Further, by making the concave portions 22A and the convex portions 22B of the high voltage generator accommodating portion 22 and the convex portions 23A and the concave portions 23B of the high voltage generator 23 contact with each other, it is possible to secure a long creeping distance between them, so that The function of preventing voltage leakage can be enhanced.

Further, each concave portion 22A and convex portion 22B of the high voltage generator housing portion 22 and convex portion 23A of the high voltage generator 23,
Since the concave portion 23B and the concave portion 23B are formed in a coaxial ring shape, it is only necessary to insert the high-voltage generator 23 into the high-voltage generator accommodating portion 22 so that the concave portions 22A and the convex portions 22B and the convex portions 23A and the concave portions 2 are formed.
3B can be securely fitted, the contact area can be increased, and the assemblability can be improved.

On the other hand, since the optical fiber cable 24 is inserted into the housing 21 from the outer peripheral side of the housing 21 and the tip portion thereof is arranged on the end surface of the air turbine 3C of the air motor 3 via the bent portion 24A, The high-voltage generator 23 can be arranged in the central portion of the housing 21 without deteriorating the rotation detection accuracy of the rotating shaft 3B. For example, a paint pipe or an air pipe (neither is shown).
And the like can be efficiently arranged, and this can also promote miniaturization of the electrostatic coating machine.

Next, FIG. 3 shows a second embodiment of the present invention. The feature of this embodiment is that an indirect charging type rotary atomization type electrostatic coating machine is used as the rotary atomization type electrostatic coating machine. I have something to say. In the embodiment, the same components as those in the first embodiment shown in FIG. 1 described above are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 31 denotes a housing according to the present embodiment, which is formed of an insulating resin material in a stepped cylindrical shape, and a high voltage generator 23 is housed at the base end side thereof. A high voltage generator housing 32 is formed. Further, at the bottom of the high-voltage generator accommodating portion 32, annular concave portions 32A, 32A and convex portions 32B, 32B that fit into the convex portions 23A and the concave portions 23B of the high-voltage generator 23 are coaxial,
In addition, the diameter is gradually increased. Further, a plurality of external electrode mounting portions 33, 33 (only two of which are shown) are provided at an axially intermediate portion of the housing 31 so as to project radially outward.
Are provided integrally.

Reference numerals 34 and 34 denote support arms attached to the external electrode attachment portions 33 of the housing 31. The support arms 34 are bent in a V shape toward the tip side, and the external electrodes 35 are provided at the tip portions thereof. Buried, high resistance 3 to prevent spark discharge in the middle
6 is provided. The external electrodes 35 are connected to the output terminals 38 of the high voltage generator 23 via the lead wires 37 and the like.
It is connected to the.

The rotary atomizing type electrostatic coating machine of the indirect charging type according to the present embodiment has the above-mentioned structure. First, the high voltage generator 23 outputs each through the output terminal 38, each lead wire 37 and the like. A high voltage is applied to the external electrodes 35 to form a corona discharge region in front of each external electrode 35. Then, by spraying the paint from the rotary atomizing head 4 while rotating the rotary atomizing head 4, the paint is charged to a high voltage in the corona discharge region and follows the lines of electric force between the object and the object to be coated. And flies and is applied to the object to be coated.

Thus, in this embodiment having the above-described structure, it is possible to obtain substantially the same effect as that of the first embodiment, but the indirect charging method by each external electrode 35 is adopted, and therefore the water-based paint is used. Suitable for coating low resistance paint such as metallic paint.

In each of the above embodiments, the high voltage generator 2
3 has an annular convex portion 23A, 23A, and a concave portion 23 on the output side end surface thereof.
Although the case where B and 23B are formed is illustrated, for example, the convex portion and the concave portion may be formed linearly and arranged in parallel, and if the creepage distance can be increased by forming the concave and convex, these shapes are formed. There is no limit.

Further, in each of the above-described embodiments, the case where the high voltage generator 23 is attached to the rotary atomizing type electrostatic coating machine as the electrostatic coating machine has been described as an example, but for example, the modification shown in FIG. As in the example, an air atomizing nozzle type electrostatic coating machine having a high voltage generator accommodating portion 42 at the base end side of the housing 41 and an atomizing nozzle 43 as a paint spraying means at the tip end portion, or a liquid The high voltage generator 23 of this embodiment may be attached to a pressure atomizing nozzle type electrostatic coating machine or the like.

[0042]

As described above in detail, according to the present invention, the creepage distance of the high voltage generator is increased by forming a plurality of uneven portions on the end face which is the output side of the high voltage generator. It is possible to improve the insulation of the high voltage generator by increasing it on the output side on which the high voltage acts, so that it is possible to reduce the axial length dimension of the high voltage generator while preventing high voltage leakage. The electrostatic coater can be downsized.

Further, by providing a concavo-convex portion on the surface of the high-voltage generator accommodating portion of the housing that faces the concavo-convex portion of the high-voltage generator, the concavo-convex portion on the high-voltage generator side is fitted to the concavo-convex portion on the high voltage generator side. And the concavo-convex portion of the housing on the high voltage generator accommodating portion side can be fitted in contact with each other to increase the contact area of each other, and also to prevent an air layer from being formed by contacting each other. As a result, the effect of preventing high voltage leakage can be increased.

Further, by forming the concavo-convex portion of the high voltage generator and the concave tubular portion of the housing of the high voltage generator into a plurality of annular concavo-convex portions formed coaxially, the concavo-convex portion of the high voltage generator and the housing are formed. It is possible to improve the fitting property of the high voltage generator accommodating part with the concave cylinder part and to increase the contact area with each other, and by simply inserting the high voltage generator into the high voltage generator accommodating part, Can be securely fitted and the assembling property can be improved.

[Brief description of drawings]

FIG. 1 is a partially broken external view showing a rotary charging type electrostatic coating machine of a direct charging type according to a first embodiment of the present invention.

FIG. 2 is an external perspective view showing a high voltage generator in FIG. 1 in an enlarged manner.

FIG. 3 is a partially broken external view showing an indirect charging type rotary atomizing type electrostatic coating machine according to a second embodiment of the present invention.

FIG. 4 is a partially broken external view showing a direct charging type air atomizing nozzle type electrostatic coating machine according to a modification of the present invention.

FIG. 5 is a partially broken external view showing a rotary electrification type electrostatic coating machine of a direct charging type according to the prior art.

FIG. 6 is a partially broken external view showing a rotary charging type electrostatic coating machine of a direct charging type according to another conventional technique.

[Explanation of symbols]

 4 Rotary atomizing head (paint spraying means) 21, 31, 41 Housing 22, 32, 42 High voltage generator housing 22A, 23B, 32A, 42A Recess 22B, 23A, 32B, 42B Convex 23 High voltage generator 43 Atomizing nozzle (paint spraying means)

Claims (3)

[Claims] 1. A housing, a paint spraying means for spraying paint, which is provided on the front end side of the housing, and a high voltage generator accommodating portion of the housing, which is mounted on a paint sprayed from the paint spraying means. An electrostatic coating machine, comprising: a high voltage generator for applying a voltage, wherein the high voltage generator is provided with a plurality of concave and convex portions located on an end face which is an output side. 2. The static voltage generator according to claim 1, wherein the high-voltage generator accommodating portion of the housing is provided with an uneven portion which is located on a surface facing the uneven portion of the high-voltage generator and is fitted to each other. Electric coating machine. 3. The electrostatic coating machine according to claim 2, wherein the concavo-convex portion of the high-voltage generator and the concave cylinder portion of the high-voltage generator accommodating portion of the housing are a plurality of annular concavo-convex portions formed coaxially.