JP3373375B2 - DC high voltage generator for electrostatic coating - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC high voltage generator for electrostatic coating, and more particularly to an electrostatic coating of about 60 kV equipped with a multi-stage voltage doubler rectifying circuit built in a gun for electrostatic coating. The present invention relates to a DC high voltage generator for painting.

[0002]

2. Description of the Related Art A DC high voltage generator of about 60 kV to 80 kV for electrostatic coating has a high voltage but a current of several tens of microamperes, and consumes a small amount of energy. Therefore, the circuit configuration is 20kHz to 50kHz.
The high frequency is rectified by a multi-stage voltage doubler rectifier circuit to make it compact and lightweight. And for high voltage components,
Compact and lightweight by molding with synthetic resin insulation. With such a configuration, the size and weight are reduced to the extent that it can be directly attached to a target device.

For example, in Japanese Utility Model Publication No. 50-22059,
As a coating gun for electrostatic coating, a device has been proposed in which a multistage voltage doubler rectifier is built in and a high-frequency voltage is supplied to the rectifier while the high-voltage output is connected to a charging electrode. Also, 19
French Patent Publication No. 1,542,090 issued in 1968
A similar invention is shown in the issue. (This original application is 1
It was filed in the German Federal Republic of Germany in 966 with L54968. In addition, Japanese Utility Model Publication No. 59-36282 proposes a device in which a multi-stage voltage doubler rectifier and a converter circuit for generating a high voltage of medium to high voltage are built in the coating gun and a DC low voltage is supplied to it. There is. However, none of them has proposed or disclosed in detail the insulation structure of the high voltage part. Further, Japanese Patent Publication No. 6-59423 proposes a similar coating gun, but in the column of the detailed description of the invention, a conventional power pack (a booster type power supply section) is housed at the barrel end. Then, the weight of the operator causes the operator to feel tired. Therefore, it is proposed to store it in the handle part. With this method, the moment to the operator who holds the handle is small, but the weight is not reduced, so this is not an essential solution.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a small and lightweight insulation structure with a simple structure in a DC high voltage generator used for this type of electrostatic coating gun.

[0005]

In order to solve this problem, the present invention provides, as a first means, an output from a high frequency generator for generating a high frequency of a relatively low voltage to an electrostatic coating gun by an extension cable. The high voltage boosted in the DC high voltage generator built in the electrostatic coating gun is connected to the output terminal. The DC high voltage generator has the extension cable in the primary winding. A transformer to be connected, and 2n rectifier diodes connected to the secondary winding of the transformer and connected in series in the same direction as a push-up column consisting of n capacitors and a smoothing column consisting of n capacitors And an n-stage voltage doubler rectifier circuit consisting of
The output terminal of the step-up voltage rectifier circuit is composed of a resistor connected to one end, and at least the transformer, the n-step voltage doubler rectifier circuit, and the resistor are arranged in a stretched manner to have a predetermined thickness. The above solid-insulated product is incorporated in an electrostatic coating gun, and the other end of the resistor is connected to a high voltage output terminal.

As a second means, the shape of the solid insulator that molds the component is a first rectangular parallelepiped portion, and a second rectangular parallelepiped portion having substantially the same width as the first rectangular parallelepiped portion and a small depth dimension. A second rectangular parallelepiped portion, a cylindrical portion located at the tip of the second rectangular parallelepiped portion, the transformer in the first rectangular parallelepiped portion, the n-stage voltage doubler rectifier circuit in the second rectangular parallelepiped portion, and the resistor in the cylindrical portion. By accommodating it, we propose a rational arrangement and shape to secure the electrical insulation creepage distance and reduce the size and weight.

[0007]

[0008]

Embodiment An embodiment of a DC high voltage generator for electrostatic coating according to the present invention will be described with reference to FIGS. 1 and 2. Fig. 1 shows a circuit diagram of a DC high voltage generator for electrostatic painting with an output of -60 kV. A high frequency of about 40 kHz with a peak value of 18 V is generated from the high frequency generator 3, and this high frequency voltage is extended by the extension cable 5.
The distance of about 10 meters is extended and the DC high voltage generator 8 boosts and rectifies the target output to -60 kV. Extension cable 5 is connected to connector 9 and push-pull connected to terminals A, B, C
Is connected to the primary winding of the transformer 7 and boosted in the secondary winding to generate a high frequency voltage of about 6 kVpp. This high frequency voltage passes through terminals 15 and 17 and is
It is boosted to 60kV and sent to terminal 43. A target DC high voltage is generated from the terminal 43 through the resistor 11 and the output terminal 13. The multi-stage voltage doubler rectifier circuit 4 is called a smoothing column and has capacitors C1, C2, ..., C10 connected in series,
It consists of capacitors K1, K2, ..., K10 and diodes D1, D2, ..., D20 which are called push-up columns and are connected in series.

FIG. 2 is a diagram showing a component arrangement and the like of the DC high voltage generator 8. In FIG. 2, the epoxy resin 6 is used for molding, but the internal parts are shown except for the epoxy resin 6. All the components of the DC high voltage generator 8 are inserted in the insulating case 2 made of synthetic resin. The insulating case 2 has a first rectangular parallelepiped part 201, a second rectangular parallelepiped part 202 having the same width as the first rectangular parallelepiped part 201 and a small depth dimension, and a cylindrical part 203 positioned at the tip of the second rectangular parallelepiped part 202. The shape. First, the cylindrical part
The resistor 11 is attached to 203, one lead wire of which is passed through the second rectangular parallelepiped portion 202, and the other end of which is projected as a high voltage output terminal 13 from the cylindrical portion 203. In this state, the epoxy resin 6 is cast into the cylindrical portion 203 and a curing process is performed.

Next, all the remaining parts are attached. As shown in FIG. 2, the connector 9 is attached to the end portion of the first rectangular parallelepiped portion 201. The transformer 7 is arranged in the first rectangular parallelepiped portion 201. Next, the multistage voltage doubler rectifier circuit 4 is arranged in the length direction of the second rectangular parallelepiped portion 202. Second rectangular parallelepiped part
The smooth columns C1, C2, ..., C10 are arranged on the right side of the 202, and the lifting columns K1, K2, ..., K10 are arranged on the left side. Diodes D1, D2, ..., at each connection point of these capacitors
Connect D20. The starting point 17 of the smoothing column C1 and the starting point 15 of the lifting column K1 are connected to the secondary winding of the transformer 7. The output point 43 of the multistage voltage doubler rectifier circuit 4 is connected to one end of the lead wire of the resistor 11. This completes the installation and connection of all parts.

Next, the insulating case 2 is laid horizontally and the opening 220 (see FIG. 3) is directly above, so that the epoxy resin 6
Inject. Predetermined curing processing is performed to complete the DC high voltage generation unit 8.

In the case of manufacturing the above, the soldering of the electric components is finished in a round shape so that there is no sharpness. In addition, it is necessary to take care so that oil, grease, and moisture do not adhere to the hands of workers in any process, and to perform a cleaning process and a drying process immediately before resin molding.

Generally, the requirements for the insulation structure of a DC high voltage generator are as follows: first, when molding with a synthetic resin material, maintaining a necessary insulation layer thickness with respect to the zero potential point of the surroundings; 2 to maintain the insulation creepage distance between each part
It is necessary to meet one. However, in the case of a DC high-voltage generator that is built in the target device, the first requirement is that the necessary insulating layer can be secured on the device side.
The only requirement is to maintain the insulation creepage distance, which is the requirement of. In the first means of the present invention, the transformer 7, the multi-stage voltage doubler rectifier circuit 4, and the resistor 11 are arranged in a stretched manner, so that the insulation creepage distance (second requirement) between each component is almost the same. Can be charged automatically. Further, even if the thickness of the insulating case 2 is made as thin as possible, the insulating condition of the surrounding zero potential point can be satisfied by the insulating layer of the device to be housed.

Further, according to the second means of the present invention, the cross-sectional area is gradually reduced from the root portion of the DC high-voltage generating portion 8 where the flow of energy handled electrically is large to the tip portion where it is reduced. So it is rational and economical.
At the same time, this shape is mechanically stable and robust.

Further, according to the present invention, only the terminal connected to the primary winding of the transformer and the high voltage output terminal of the DC high voltage generator are exposed at both ends, and the whole is molded with an insulating resin. Since the cylindrical portion 203 on the high voltage output side is provided with the corrugated portion 204, the insulating action can be more effectively achieved, and the unit can be easily handled.

[0016]

EFFECTS OF THE INVENTION The present invention has the characteristics as described above, and a relatively low frequency high frequency is applied to the extension cable 5 that connects the high frequency generating section and the high voltage DC generating section. It is possible to deal more safely with accidents such as breaks and short circuits on the way. The insulation structure of the DC high voltage generator is rational and economical. Therefore, as a DC high-voltage generator for electrostatic painting to be built in the gun, it can be reliably made compact and lightweight at low cost.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of a DC high voltage generator for electrostatic coating of -60 kV output according to the present invention.

FIG. 2 is a component layout view of a DC high voltage generator in the DC high voltage generator for electrostatic coating according to the present invention.

FIG. 3 shows a side view of a DC high voltage generator in the DC high voltage generator for electrostatic coating according to the present invention.

[Explanation of symbols]

1 ... DC high voltage generator 2 ... Insulation case 3 ...
High frequency generator 4 ... Multistage voltage doubler rectifier 5 ... Extension cable 6 ...
Epoxy resin 7 ... Transformer 8 ... DC high voltage generator 9 ...
Connector 11 ... Resistor 13 ... High voltage output terminals C1, C2, ..., C10 ... Smoothing column K1, K2, ..., K10 ... Push-up column

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Nakae 1-18-1 Takada, Toshima-ku, Tokyo Orijin Electric Co., Ltd. (72) Inventor Yukio Shimoda 1-1-18 Takada, Toshima-ku, Tokyo Ori Jin Denki Co., Ltd. (72) Inventor, Shinji Uchida 1-1-18 Takada, Toshima-ku, Tokyo Orijin Electric Co., Ltd. (72) Inventor, Nobuyoshi Morita 55 Shiba-cho, Kanazawa-ku, Yokohama-shi, Kanagawa (72) Invention Katsumasa Iwasawa 3-41-16 Rokuura, Kanazawa-ku, Yokohama, Kanagawa Prefecture (56) References JP-A-57-110354 (JP, A) JP-A-6-320063 (JP, A) Jitsuko Sho-59-36282 ( JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B05B 5/00-5/16

Claims (2)

(57) [Claims] 1. A DC high voltage generator for an electrostatic coating gun, which is supplied with a high frequency generator for generating a high frequency of a relatively low voltage and an extension cable connected to the output of the high frequency generator. In the same direction as the transformer to which the extension cable is connected to the primary winding, the push-up column consisting of n capacitors and the smoothing column consisting of n capacitors connected to the secondary winding of the transformer. An n-stage voltage doubler rectifier circuit consisting of 2n rectifier diodes connected in series with each other, and a resistor connected to the output terminal of the n-stage voltage doubler rectifier circuit,
A DC high voltage generator is built in an electrostatic coating gun, in which at least the transformer, the n-stage voltage doubler rectifier circuit, and the resistor are arranged in a stretched form and encased in a solid insulator having a predetermined thickness. And a DC high voltage generator for an electrostatic coating gun in which the other end of the resistor is connected to a high voltage output terminal. 2. The solid insulator comprises a first rectangular parallelepiped part, a second rectangular parallelepiped part having a width substantially the same as the first rectangular parallelepiped part and a small depth dimension, and a cylindrical part located at the tip of the second rectangular parallelepiped part. And the transformer is housed in the first rectangular parallelepiped portion,
The DC high voltage generator for an electrostatic coating gun according to claim 1, wherein the step-up voltage rectifier circuit is housed in the second rectangular parallelepiped part, and the resistor is housed in the cylindrical part.