Electrostatic coating device and system
PROBLEM TO BE SOLVED: To evolve a spark discharge preventing effect of an electrostatic coating device. SOLUTION: One coating robot has an arm equipped with a plurality of electrostatic coating devices 100 close to each other and the plurality of the electrostatic coating devices 100 is connected in parallel with each other to one high-voltage generator 102 . A hollow rotary shaft 108 driven by an air motor 104 is disposed with nine plate-shaped resistors 120 arranged circumferentially at intervals. The nine plate-shaped resistors 120 are connected in series and a high voltage is applied via the resistors 120 to a rotary atomization head 110 . The rotary atomization head 110 is made of a semiconductive resin.
1. An electrostatic coating system having an electrostatic coating device configured to charge coating particles by applying to a discharge electrode a voltage generated by a voltage generator controlled by a controller, the electrostatic coating system comprising:
a first resistance;
a second resistance; and
an air motor made of a conductive material between the first resistance and the second resistance, the first and second resistances and the air motor making up a voltage application path between the voltage generator and the discharge electrode;
a rotary shaft configured to transmit a rotating force of the air motor, wherein the rotary shaft is made of an electrically insulating materials, and wherein the second resistance couples directly to the rotary shaft;
wherein the first resistance and the second resistance are connected in series;
wherein the first resistance is between the voltage generator and the second resistance along the voltage application path;
wherein the second resistance is between the discharge electrode and the first resistance along the voltage application path; and
wherein a resistance value of the second resistance is larger than a resistance value of the first resistance.
2. The electrostatic coating system of claim 1 , wherein the electrostatic coating device is a rotary atomization type electrostatic coating device, and
wherein the discharge electrode is a rotary atomization head of the rotary atomization type electrostatic coating device.
3. The electrostatic coating system of claim 2 , wherein the rotary shaft is configured to transmit the rotating force of the air motor to the rotary atomization head.
4. The electrostatic coating system of claim 3 , wherein the second resistance is made up of a plurality of resistors connected in series to each other, and
wherein the plurality of resistors is arranged in a circumferential direction of the rotary shaft at regular intervals.
5. The electrostatic coating system of claim 4 , wherein each of the plurality of resistors is plate-shaped,
wherein each of the plurality of plate-shaped resistors is fit into a groove formed on an outer circumferential surface of the rotary shaft, and
wherein each of the plurality of plate-shaped resistors is disposed on the rotary shaft in a standing state from the outer circumferential surface of the rotary shaft.
6. The electrostatic coating system of claim 5 , wherein the rotary atomization head is made of a semiconductive material.
7. The electrostatic coating system of claim 6 , wherein the rotary shaft is made up of a hollow rotary shaft made of the electrically insulating material,
wherein a feed tube is disposed inside the hollow rotary shaft, and
wherein a coating material is supplied through the feed tube to the rotary atomization head.
8. The electrostatic coating system of claim 1 , wherein the voltage generator is incorporated in the electrostatic coating device.
9. The electrostatic coating system of claim 1 , wherein the voltage generator is disposed outside the electrostatic coating device.