JPS6212419Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrostatic coating machine, and particularly to a small and lightweight electrostatic coating machine.

For example, it is necessary for an electrostatic coating machine to be attached to a painting robot or the like to be smaller and lighter in order to reduce the load on the robot arm and enable it to make smaller movements during painting work. However, since a high voltage of about 30 to 100 KV is usually applied to electrostatic coating machines, simply making them smaller and lighter may result in insufficient insulation distance, resulting in high voltage leakage from the high voltage applied part to the grounded part, or This causes a decrease in proof strength, which is extremely dangerous, and at the same time, it also adversely affects the electrostatic field at the tip of the sprayer body, reducing coating efficiency. Therefore, in order to reduce the weight and size of electrostatic coating machines, it is important to consider how to take measures to insulate these high voltages.

By the way, a conventional general electrostatic coating machine stores the tip of a high voltage cable and a high resistance connected to the high voltage cable in an insulating cylinder, and attaches this to the main body of the coating machine. This conventional method prevents high voltage from leaking from the tip of a high voltage cable or a high resistance connection and secures dielectric strength. Water droplets adhere to the inner surfaces of cavities within the body, which can easily cause surface leakage of high voltage, damage to high resistance, and deterioration of dielectric strength. In order to prevent water droplets from adhering to the inner surface of the gap, a method has been proposed in which the gap inside the insulating cylinder is filled with a high electrical resistance liquid such as insulating oil. Since the liquid expands due to the Joule heat generated by the high resistance, it is difficult to completely seal and fill the liquid, making it difficult to achieve the intended purpose.

In addition to the above-mentioned problems such as leakage from the tip of the high-voltage cable, when using conductive paint such as metallic paint, high voltage may leak through the paint to unexpected places, causing dielectric breakdown. In order to avoid such situations, conventional coating equipment has been sufficiently coated with insulating material and a sufficient insulation distance has been maintained, which has resulted in heavy and large paint sprayers. Therefore, it is desired to develop a compact electrostatic coating machine that can safely coat even such conductive paints.

This invention was developed to solve the above-mentioned conventional problems, and its purpose is to provide an electrostatic coating machine that is smaller and lighter without compromising its dielectric strength, and that can perform safe and efficient painting. be.

Another object of the present invention is to provide an electrostatic coating machine that does not cause leakage of high voltage or deterioration of dielectric strength from the tips of high voltage cables or high resistance connections even when temperature and humidity change. There is a particular thing.

The compact electrostatic atomizer of the present invention has the tip of a high-voltage cable inserted into the main body of the atomizer and the high-resistance connected to the tip of the high-voltage cable sealed with a thermoplastic resin layer. That is, paint supply
The ON-OFF mechanism (paint valve) is separated from the main body of the sprayer and installed as a separate unit, and the mounting bolts of the mounting arm of the robot arm, etc., which is the closest grounding object from the high voltage application part at the tip of the sprayer, are insulated. It is characterized by being shielded with.

In the present invention, the thermoplastic resin used is one that is the same as or has similar properties to the covering insulation material of the high voltage cable. By doing so, good adhesion and adhesion with the high voltage cable can be obtained, and good insulation resistance against changes in temperature and humidity can be ensured.

The paint valve is removably installed on the back surface of an insulating support plate that holds the paint sprayer body, that is, on the support plate surface on the side opposite to the paint spouting side of the paint sprayer. By separating the paint valve, the structure of the sprayer main body is simplified, making design and manufacturing easier, and the sprayer main body can be made smaller.

Insulating shielding of bolts on mounting arms such as robot arms is achieved by attaching caps made of insulating material to the bolt heads. Attachment may be carried out by directly fitting a cap onto the bolt head, or by fitting or screwing using an insulating member, such as a fixing stand, that surrounds the mounting bolt.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a side cross-sectional view of a small automatic electrostatic coating machine showing one embodiment of the present invention. In the approximate center of the coating machine body 1 made of an insulating material such as acetal resin, there is a high voltage cable 2. The tip of the cable and the high resistance 3 connected to the tip are sealed with a thermoplastic resin layer 5 made of the same material as the insulating layer 4 of the high voltage cable 2, and are inserted into the cable holder 6. It is attached to the coating machine body 1. Furthermore, at the tip of the high resistance 3, a small metal fitting 7 having an inner cavity is also embedded in the thermoplastic resin layer 5 while in contact with the high resistance 3, and the inner cavity of the metal fitting 7 has a metal fitting 7. A coil spring 8 is inserted into the thermoplastic resin layer 5 with its tip portion exposed to the outside.
In front of the coil spring 8, there is a coating machine body 1.
A conductive sealing member 9 fixed inside is located, and a high voltage supplied from the high voltage cable 2 through the high resistance 3, the metal fitting 7, and the coil spring 8 is connected to a conductive sealing member 9 provided in front of the sealing member 9. It is electrically connected to the needle-shaped charging electrode 11 at the front via the coil spring 10. The sealing member 9 also prevents paint from flowing through a high resistance 3 from a paint flow path 12 in which a coil spring 10 and a needle-like charging electrode 11 extend.
It plays the role of preventing water from penetrating into the sides. On the other hand, a sheath (outer skin) holder 13 is screwed to the rear end of the cable holder 6, and works in cooperation with the sleeve 14 to cover the high voltage cable 2 and to cover the high voltage cable 2 with a grounded conductive or semiconductive material. A sheath (outer skin) 15 is fixed.

In the present invention, the tip of the high voltage cable 2 and the connection part with the high resistance 3 are formed by a thermoplastic resin layer 5.
, there is no risk of high voltage leaking from there. Therefore, the problem regarding high voltage insulation measures is the most extreme part of the high resistance 3, in this example, the metal fitting 7 and Since the part where the coil spring 8 is present can be considered as the starting point, the mounting position of the conductive or semiconductive grounded sheath 15 can be shortened by a distance substantially equivalent to the length of the high resistance 3. The length of the coating machine main body 1 can be shortened accordingly.

A paint atomizing air supply path 16 is further formed in the paint sprayer body 1, and compressed air supplied through this passes through a connecting air path 17 to an annular atomizing compressed air jet. The paint ejected from the outlet 18, passed through the paint flow path 12, and discharged from the paint discharge hole 19 is atomized, and the atomized paint is charged by the needle-shaped charging electrode 11. Furthermore, another air supply passage (not shown) is bored in the sprayer main body 1 in parallel with the air supply passage 16, and the compressed air supplied from this air supply passage is
The air is ejected through the two air passages 20, 20' from the air injection holes 21, 21' for adjusting the coating pattern, changing the coating pattern of the coating machine from a round pattern to a flat pattern, that is, the atomized paint from the coating machine is ejected. Regulate and adjust direction.

The coating machine body 1 is fixed to an insulating support plate 22 with mounting screws 23, and is further fixed to an arm 25 of the painting robot via an insulating fixing base 24 with fixing bolts 2.
It is fixed at 6. The arm 25 is made of metal in order to firmly hold the paint sprayer, and the fixing bolt 26 is also often made of metal since it is required to have considerable strength. The arm 25 is normally grounded, and especially when a small electrostatic sprayer is used as in the case of the present invention, the tip of the sprayer and the arm 25 are grounded.
and the distance from the fixing bolt 26 becomes shorter,
If there is a grounded object near the needle-shaped charged electrode 11 at the tip of the paint sprayer to which a high voltage is applied, it may adversely affect the composition of the electrostatic field and cause a decrease in coating efficiency, or the grounded object may Since paint often adheres to objects and contaminates equipment, it is important to cover the fixing bolts 26 with insulating caps 27 for shielding as in the present invention.

A metering valve 29 for ON/OFF control of paint supply is removably attached to the back surface 28 of the insulating support plate 22, and a paint supply pipe (both not shown) from the paint supply source is attached. ) is connected to the paint inlet 30, and the paint outlet 31 located at the bottom of the metering valve 29 communicates with the paint flow path 12 via a paint passage 32 bored in the support plate 22. 33 is connected. Many of the metering valves 29 are made of metal, so when they are charged, the accumulated charge can instantly discharge and cause a spark discharge, which is dangerous, so they are usually grounded. 29 is the back side 2 of the insulating support plate 22
8, the support plate 22 acts as an insulating shield for the needle-shaped charged electrode 11 at the tip of the sprayer to which high voltage is applied, so that the tip of the sprayer and the metering valve 29 can be connected to each other. This makes it possible to shorten the distance between the two, which is very useful in making the coating machine itself more compact.

In addition, when using conductive paint such as metallic paint, in order to ensure insulation, it is necessary to connect the paint supply path from the paint flow path 12 to which high voltage is applied to the grounded metering valve 29. The distance, that is, the length of the paint supply pipe 33, is required to be longer than a predetermined value (100 mm or more, preferably 150 mm or more). and ON− for paint supply.
By not providing an OFF mechanism and by supplying paint through a paint supply pipe 33 using a separately provided metering valve 29 and through a paint passage 32 in the support plate 22, the paint sprayer main body 1 Despite the miniaturization, a sufficient insulation distance for the paint supply path can be maintained, and therefore no problems arise when using conductive paints such as metallic paints.

Furthermore, as shown in FIG.
9 makes it easier to reduce the insulation distance of the paint supply path, that is, the length of the paint supply pipe 33, even though the sprayer main body 1 is made smaller and the tip of the sprayer and the metering valve 29 are brought closer together. This is advantageous because the paint supply pipe 33 can maintain its own shape even when the paint machine is moved for painting work.

The present invention has been described above with reference to an example of an air atomizing electrostatic atomizer that is attached to a painting robot, etc., but the present invention is not limited to the above example, and can be applied to hydraulic atomizers, electrostatic atomizers, etc. It can be similarly suitably applied to various electrostatic coating machines such as the type.

As mentioned above, in the present invention, the tip of the high voltage cable and the high resistance connection part are completely insulated with the insulation layer of the high voltage cable without creating any gaps. Surface leakage of high voltages from resistive connections, ie surface discharges, can be completely prevented. Therefore, it is necessary to consider the degree of safety against creeping discharge from the high-resistance tip rather than from the high-voltage cable tip, so the high-voltage cable tip, the high-voltage cable grounding shield, and the grounding part of the sprayer body need to be considered. Since the distance between the paint and the paint can ensure dielectric strength, the length of the paint sprayer body can be shortened. In addition, the paint valve is not built into the sprayer body, but is attached as a separate piece to the back of the insulating support plate in a detachable manner, which simplifies the sprayer body, making it easier to design, making it smaller and lighter, and allowing the paint to be used more easily. Remove only the valve for repair, inspection,
Since it can be replaced, there is no need to remove the entire coating machine from a robot or the like as in the past, and there is no reduction in work efficiency.

Furthermore, since the paint valve is attached to the insulating support plate of the sprayer body, it is possible to avoid the inconvenience of the relative positional relationship between the paint valve and the sprayer body changing depending on the movement of the robot when it is attached to a robot, etc. I can do it. In addition, in this invention, the paint valve is attached to the back of the insulating support plate, so even if the paint valve is grounded, the discharge electrode at the tip of the paint sprayer body, which is the high voltage application part, and the paint, which is the ground conductor, will be connected. Since there is an insulating wall between the valve and the valve, the distance between the two can be shortened due to the insulating effect of the support plate, and the overall size of the atomizer can be made smaller. The support plate also serves as a shielding plate for the ionic current and charged paint particles flowing from the discharge electrode to the paint bulb, greatly contributing to safety and stain prevention during painting.

Furthermore, in this invention, the smaller the electrostatic atomizer is, the more insulated the arm of the robot, etc. and the mounting bolt to the arm, which is the closest grounding object to the high voltage application part of the electrostatic atomizer. Since it is shielded with a material, the sprayer can be made smaller and lighter, and the distance between the sprayer body and the mounting arm can be shortened, making it easier to move the tip of the sprayer and the mounting arm during automation. It has many advantages, such as not having to take into account the differences between the two.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of one embodiment of the coating machine of the present invention. FIG. 2 shows a front view of the same embodiment. In the figure, 1... Painter main body, 2... High voltage cable, 3... High resistance, 4... Insulating coating layer, 5... Thermoplastic resin layer, 6... Cable holder, 7... Metal fittings, 8 ...Coil spring, 9...Sealing member, 11...
...Acicular charged electrode, 12...Paint flow path, 22...Insulating support plate, 29...Metering valve, 33
...Paint supply pipe.

Claims (1)

[Scope of utility model registration request] The tip of the high voltage cable and the resistor connected to the tip of the high voltage cable are coated and molded with a thermoplastic resin layer and inserted into the main body of the atomizer, and the main body of the atomizer is held with an insulating support plate. At the same time, a paint valve for controlling the supply of paint is removably attached to the back of the support plate, and a cap made of insulating material is attached to the head of a mounting bolt of a mounting arm of a robot, etc. that fixes the main body of the paint sprayer. A small automatic electrostatic coating machine.