JPH0118205Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Technical Field" The present invention relates to an electrostatic coating tank used in an electrostatic coating apparatus using a fluidized immersion method.

"Prior Art and its Problems" In an electrostatic coating apparatus using a fluidized dipping method, a fluidized tank is used in which resin powder is fluidized by an air flow. Then, the resin powder is charged with an electrode, and the object to be coated is immersed in this fluidized bath to electrostatically adhere the resin powder to the object to be coated. The object to be coated to which the resin powder has adhered in this way is heated by a high-frequency heating device or the like, so that the resin powder is welded and a coating film is formed.

However, in such conventional electrostatic coating tanks, when trying to apply resin powder to the stator of a motor, for example, if the stator's axial length is short, it is difficult to adhere the resin powder to almost the entire surface. However, as the length of the stator in the axial direction becomes longer, it becomes difficult to adhere the resin powder to the inner surface of the groove, and uneven coating tends to occur.

``Purpose of the invention'' The purpose of the invention is to make it possible to sufficiently adhere resin powder to the inner surfaces of grooves and recesses of objects to be coated that have deep grooves and recesses formed inside, such as the stator of a motor. An object of the present invention is to provide an electrostatic coating tank.

"Structure of the invention" The electrostatic coating tank of the invention is provided with powder spraying means for sucking resin powder from inside the fluidized tank and spraying it toward the object to be coated.

Therefore, the resin powder fluidized in the fluidized tank is electrostatically attached to the outer periphery of the object to be coated that is supported above the fluidized tank, and the grooves and recesses of the object to be coated are filled with the powder spraying means. By spraying the resin powder toward the surface, the resin powder can be sufficiently attached to the inner surfaces of the grooves and recesses of the object to be coated.

According to a preferred embodiment of the present invention, the powder blowing means includes a powder suction pipe supported upwardly from within the fluidized tank, and an air supply pipe connected to the upper part of the powder suction pipe. Consisting of In this case,
By introducing air into the air supply pipe, resin powder is sucked from the powder suction pipe, and the resin powder is sprayed from the tip of the air supply pipe toward the object to be coated.

"Embodiment of the Invention" In order to better understand the present invention, an example of an electrostatic coating apparatus to which the present invention is applied will first be described with reference to FIGS. 3 and 4.

As shown in FIGS. 3 and 4, this electrostatic coating device has a turntable 22 that is rotated by a drive shaft 21, and the outer periphery of the turntable 22 is coated with an object to be coated, such as the stator of a motor. Thing 23
A plurality of holding jigs 24 are attached radially. The holding jig 24 is the main drive pulley 2
5 and a large number of driven pulleys 26 to rotate around an axis via a worm gear (not shown) or the like. On the outer periphery of the turntable 22, an electrostatic coating tank 27, a first cleaning device 28,
A high frequency heating device 29 and a second cleaning device 30 are arranged. In addition, the electrostatic coating tank 27 has a chamber 31 having a fluidized tank inside, and the upper part of the chamber 31 sucks the resin powder that scatters as dust in order to prevent the resin powder from flowing outside. A discharge pipe 32 is attached, and this discharge pipe 32 is connected to a dust collector 34 via a cyclone 33. A hopper 35 is provided at the bottom of the cyclone 33, and the hopper 35 is connected to the return path 3.
6 into the chamber 31.
In addition, in the figure, 37 is a base on which each device is installed.

Therefore, when the object to be painted 23 is attached to the holding jig 24 at the position of point A in FIG. 3 and the turntable 22 is rotated, the object to be painted 23 first enters the electrostatic coating tank 27, where it is Resin powder can be attached. Next, in the first cleaning device 28 , resin powder adhering to areas not requiring painting is removed, and the resin powder is guided to a high-frequency heating device 29 . In the high-frequency heating device 29, the object to be coated 23 is heated, and the resin powder is welded to form a coating film. Finally, the resin powder is guided to the second cleaning device 30, and mainly the resin powder adhering to the holding jig 24 is removed. When the object 23 to be painted returns to point A, the object 23 to be painted is removed from the holding jig 24 and a new object 23 is attached. In this way, the object to be painted 23 can be coated continuously. Further, in FIG. 4, resin powder dust generated within the chamber 31 is sucked by the discharge pipe 32 and guided to the dust collector 34 via the cyclone 33. but,
As it passes through the cyclone 33, a considerable amount of resin powder falls into the hopper 35 and is returned to the chamber 31 through the return passage 36. Therefore, the resin powder discharged as dust can be recovered and used effectively.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In addition, in the figure, Figures 3 and 4
The same parts as in the figures are given the same reference numerals.

A first fluidization tank 38 is provided at the bottom of the chamber 31. A porous plate 39 is arranged at the bottom of the first fluidization tank 38, and the lower surface of the plate 39 forms a pressure equalization chamber 40. An air supply pipe 41 is connected to the pressure equalization chamber 40 . Inside the chamber 31 , a second fluidized tank 43 is supported above the first fluidized tank 38 via a plurality of support plates 42 . This second fluidized tank 43 also has a perforated plate 44 at the bottom like the first fluidized tank 38.
is arranged, the lower surface thereof serves as a pressure equalization chamber 45, and an air supply pipe 46 is connected to the pressure equalization chamber 45. In addition, -30 to -70KV is applied to the second fluidized tank 43.
An electrode 47 is attached. Second fluidized tank 43
The object to be painted 23 is placed above the holding jig 2.
4 is provided with a conveyance path B along which it is held and moved. A feed pipe 48 is provided to feed the resin powder from the first fluidized tank 38 to the second fluidized tank 43. The base of the feed pipe 48 is connected to the first fluidization tank 3
8, and in the center of the penetrating portion is formed a ventilate portion 49 with a slightly narrower diameter and a through hole formed therein. Further, the tip of the feed pipe 48 rises upward and faces the upper opening of the second fluidization tank 43.

In the present invention, the second fluidized tank 43 is provided with a pair of powder spraying means 51, 51 for spraying resin powder onto the object 23 to be coated. That is, a pair of powder suction tubes 52, 52 are supported so as to rise upward from inside the second fluidization tank 43, and air supply tubes 53, 53 are provided above the powder suction tubes 52, 52, respectively. is connected. Then, the tips 53a, 53 of the air supply pipes 53, 53
a is arranged so as to face both ends of the groove of the object to be coated (for example, a stator). In this case, the resin powder in the second fluidization tank 43 is sucked from the powder suction tubes 52, 52 according to the principle of the so-called Venture tube. 52 and the air supply pipes 53, 53 may be narrowed.

In the above configuration, when air flows into the pressure equalization chamber 40 from the air supply pipe 41, the air is ejected upward through the perforated plate 39 and fluidizes the resin powder in the first fluidization tank 38. Similarly, when air flows into the air supply pipe 46, the air is ejected upward through the perforated plate 44 and fluidizes the resin powder in the second fluidization tank 43. Then, when the air for feeding is passed through the feeding pipe 48, the first fluidizing tank 38 is
The resin powder is sucked into the inlet pipe 4.
8 into the second fluidization tank 43. Second
When the resin powder overflows in the fluidization tank 43, as shown by the broken line arrow in the figure, the resin powder flows into the first fluidization tank 3.
Fall to 8. Therefore, the resin powder circulates between the first fluidized tank 38 and the second fluidized tank 43, and the resin powder in the second fluidized tank 43 is always maintained in an overflow state.

By the way, the object to be coated 23 held by the holding jig 24 passes through the transport path B above the second fluidization tank 43. The resin powder in the second fluidization tank 43 is -30 to -
It is negatively charged by an electrode 47 of 70KV. On the other hand, the object 23 to be painted is grounded, and the resin powder adheres to the object 23 by electrostatic force based on this voltage difference. In this case, the second fluidization tank 43
Since the fluidized resin powder is always maintained in an overflow state, the distance L between the flow surface of the resin powder and the object to be coated 23 is kept constant, and the flow of the resin powder to the object to be coated 23 is kept constant. There is no variation in the amount of adhesion. Further, since the object to be painted 23 is rotating as the holding jig 24 rotates about the axis, the resin powder is uniformly attached to the entire circumference thereof. Furthermore, in the present invention, by introducing air from the air supply pipes 53, 53 of the powder blowing means 51,
The resin powder is transferred from the second fluidization tank 43 to the powder suction pipe 52,
52, and the air is sucked up through the air supply pipes 53, 5.
3 into the grooves of the object to be coated 23 from the tip portions 53a, 53a. Therefore, the resin powder is sufficiently attached to the grooves of the object 23 to be coated. In this case, as described above, the object to be coated 23 is rotating as the holding jig 24 rotates about the axis, so resin powder is filled in all the grooves on the inner circumference. adhere to.

As the resin powder is fluidized in the first fluidized tank 38 and the second fluidized tank 43, the resin powder becomes dust and scatters within the chamber 31. Therefore, the scattered resin powder is sucked through the discharge pipe 32 so that the resin powder does not flow out. As mentioned above, the cyclone 33 in FIGS. 3 and 4
The dust passes through the cyclone 33 and is collected by the dust collector 34, but a considerable amount of it falls into the hopper 35 when passing through the cyclone 33. The resin powder that has fallen into the hopper 35 is returned into the chamber 31 through the return passage 36, so that the resin powder can be used effectively.

In addition, in the embodiment, the powder suction tube 52
and an air supply pipe 53.
A pair of powder spraying means 51 are provided to spray resin powder from both ends of the groove of the object to be coated 23. However, if the object to be coated has a deep recess, for example, the powder spraying means 51 is provided. Alternatively, the resin powder may be sprayed in one direction, for example, from the opening of the recess.

Further, the powder spraying means 51 is disposed, for example, like the feed pipe 48 in FIG. , a tube with a ventilate section at its base, which sucks resin powder from the ventilate section by introducing air, and sprays the resin powder from the tip toward the object to be coated. It may be hot.

Furthermore, in the embodiment, the first fluidization tank 3
Although two fluidized tanks, ie, the fluidized tank 8 and the second fluidized tank 43, are provided, the present invention can also be applied to an electrostatic coating tank with a single fluidized tank.

Furthermore, in the embodiment described above, the electrode 47 is arranged at the lower part of the second fluidized tank to charge the resin powder, but an electrode is provided in the path of the feed pipe 48, The resin powder may be electrically charged as it passes through the feed pipe 48.

"Effects of the Invention" As explained above, according to the present invention, a powder spraying means for sucking resin powder from inside the fluidized tank and spraying it toward the object to be painted is provided, so that When grooves and recesses are formed, resin powder can be sufficiently attached to the inner surfaces of the grooves and recesses.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the electrostatic coating tank according to the present invention, Fig. 2 is a sectional view showing the main parts of the electrostatic coating tank, and Fig. 3 is an electrostatic coating apparatus to which the present invention is applied. FIG. 4 is a front view of the electrostatic coating apparatus. In the figure, 27 is an electrostatic coating tank, 23 is an object to be coated, and 5
1 is a powder blowing means, 52 is a powder suction pipe, 53
53a is an air supply pipe, and 53a is a tip.

Claims (1)

[Claims for Utility Model Registration] (1) Electrostatic coating in which the object to be coated is supported above a fluidized tank that fluidizes charged resin powder, and the resin powder is electrostatically attached to the object to be coated. An electrostatic coating tank characterized in that the tank is provided with powder spraying means for sucking resin powder from inside the fluidized tank and spraying it toward the object to be coated. (2) Utility model registration In claim 1, the powder spraying means is connected to a powder suction pipe supported upwardly from within the fluidization tank and an upper part of the powder suction pipe. An electrostatic coating tank consisting of an air supply pipe.