JPS6113100Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a rotary atomization electrostatic coating device.

A rotating shaft is rotatably supported within the housing, a spray head is fixed to the front end of the rotating shaft protruding from the front end of the housing, and the spray head extends forward from the rear end surface of the spray head around the front end of the rotating shaft. It has an annular space, a paint outflow hole extending radially outward from the annular space, and a cup-shaped inner circumferential surface that guides the paint flowing out from the paint outflow hole, and further includes a paint supply nozzle into which the paint flows into the annular space. A rotary atomizing electrostatic coating device is known that supplies paint and discharges the paint from the front end of a cup-shaped inner peripheral surface. However, in such a rotary atomizing electrostatic coating device, when cleaning liquid is ejected from the paint supply nozzle and then air is ejected during cleaning for color change, the spray head annular space is affected by the ejected cleaning liquid or the ejected air. A problem arises in that the paint adhering to the inner circumferential surface is blown away, and the blown paint enters the bearing of the rotating shaft, causing the bearing to stick.

Further, when the rotating shaft is supported by an air bearing, compressed air discharged from the air bearing flows out from the front end of the housing and is ejected into the annular space of the spray head. When the compressed air is ejected into the annular space in this way, the paint adhering to the inner wall of the annular space is blown away by the compressed air, and the blown paint particles are discharged from the annular space of the spray head to the outside. There is a problem in that the paint particles float in the atmosphere and then adhere to the painted surface, causing paint defects.

The present invention provides a rotary atomizing electrostatic coating device that prevents paint from being blown away and causing coating defects, and also prevents paint from penetrating into the bearing of a rotating shaft and causing the bearing to stick. It is in.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, a rotary atomizing electrostatic coating apparatus, generally designated 1, comprises a generally hollow cylindrical metal front housing 2 and a generally hollow cylindrical rear metal housing 3. Both housings 2 and 3 are firmly connected by bolts 4. A support rod 6 made of electrically insulating material is fitted into the cylindrical hole 5 of the rear housing 3, and the rear housing 3 is secured to the support rod 6 with bolts 7. This support rod 6 is supported by a base (not shown). On the other hand, a rotating shaft 8 is inserted into the front housing 2. This rotating shaft 8 has a hollow cylindrical portion 8a located in the center thereof, and a hollow cylindrical portion 8a located at the center thereof.
A shaft portion 8b is integrally formed on the front end of the rotating shaft 8, and a shaft portion 8c is fixed to the rear end of the hollow cylindrical portion 8a.A metal spray head 9 is attached to the shaft portion 8b of the rotating shaft 8. 10. The spray head 9 is composed of a spray head support 12 having an annular space 11 formed therein, and a cup-shaped spray head main body 13 fixed on the support 12. As shown in FIGS. 1 and 2, a large number of paint outlet holes 16 are provided on the outer cylindrical portion 14 of the support 12 and open into the annular space 11 and toward the inner wall surface 15 of the spray head body 13. is formed. On the other hand, an end plate 17 is fixed to the front end of the front housing 2, and a paint jetting nozzle 18 is mounted on the end plate 17. The paint spray nozzle 18 is connected to a paint tank 20 via a paint supply pump 19 , and a nozzle opening 21 of the paint spray nozzle 18 is arranged within the annular space 11 .

As shown in FIG. 1, the front housing 2 is provided with a pair of non-contact type radial bearings 22, 23 consisting of tailing pad air bearings.
A rotating shaft 8 is rotatably supported on the front housing 2 by 3 . These tailing pad air bearings 22, 23 have the same construction, so only the construction of one tailing pad air bearing 22 will be described below. Referring to FIG. 1 and FIG. 3, the tailing pad air bearing 22 consists of three pads 24, 25, 26 arranged with an extremely small gap from the outer peripheral surface of the rotating shaft hollow cylindrical portion 8a. And these pads 2
4, 25, 26, respectively.
8, 29. Each of these support pins 2
7, 28, 29 have spheres 30, 3 at their inner ends, respectively.
1 and 32 are integrally formed, and these spheres 30,
31, 32 engage within spherical recesses formed on the back surface of each pad 24, 25, 26. Therefore, each pad 24, 25, 26 corresponds to a corresponding sphere 30, 3.
1 and 32 as fulcrums. A bearing frame 33 is fixed on the outer peripheral wall surface of the front housing 2 with, for example, bolts, and support pins 28, 29
are secured to this bearing frame 33 by nuts 34 and 35, respectively. On the other hand, one end of the support arm 36 having the elastic plate-like portion 36a is fixed to the bearing frame 33 by a bolt 37, while a support pin 27 is fixed to the other end of the support arm 36 by a nut 38. It is tightened. Therefore, the pad 24 is pressed onto the rotating shaft hollow cylindrical portion 8a by the elastic force of the support arm 36.

Referring again to FIG. 1, the shaft portion 8 of the rotating shaft 8
A pair of disc-shaped runners 39, 40 are inserted into the shaft 8c, and these runners 39, 40 are secured to the shaft portion 8c with a nut 43 via a spacer 41 and a turbine wheel 42. On the other hand, an annular plate 44 is disposed between the runners 39 and 40, and the runners 39 and 40 and the annular plate 44 constitute a non-contact type thrust air bearing. In addition, each runner 39, 40
is arranged so as to be separated from the annular plate 44 by a slight gap. The annular plate 44 has a pair of O-rings 45, 4
6 to the front housing 2 in a sealing manner. As shown in FIGS. 1 and 4, an annular groove 47 is formed in the front housing 2 along the outer circumferential surface of the annular plate 44, and this annular groove 47 is used for compressed air formed in the front housing 2. It is connected to an air supply pump 49 via an introduction hole 48 . On the other hand, a large number of air passages 50 are formed in the annular plate 44 and extend radially inward from the annular groove 47, and air flows from the vicinity of the inner end of each of these air passages 50 toward the runners 39 and 40, respectively. Air outflow holes 51 and 52 are formed that extend from one side to the other.

On the other hand, a turbine nozzle holder 53 is fixed in the front housing 2 adjacent to the annular plate 44, and this turbine nozzle holder 53 and the front housing 2
An annular air introduction chamber 54 is formed therebetween. This air introduction chamber 54 is connected to a compressor 56 via a compressed air introduction hole 55. The air introduction chamber 54 has a compressed air jet nozzle 57 equipped with a large number of guide vanes (not shown), and the turbine blades 5 of the turbine wheel 42 face the jet nozzle 57.
8 is placed. Meanwhile, the housing interior chamber 59 in which the turbine impeller 42 is disposed is connected to the atmosphere through an exhaust hole 60 formed in the rear housing 3. The compressed air introduced into the air introduction chamber 54 from the compressor 56 is ejected into the housing internal chamber 59 via the ejection nozzle 57. At this time, the jetted compressed air gives rotational force to the turbine wheel 42,
In this way, the rotating shaft 8 is rotated at high speed. This jetted compressed air then flows through the exhaust hole 60.
is emitted to the atmosphere via

On the other hand, a through hole 62 is formed in the end wall 61 of the rear housing 3 defining the housing internal chamber 59, and an electrode holder 63 passes through the through hole 62.
is secured to the end wall 61 by bolts 64.
A cylindrical hole 65 coaxial with the rotation axis of the rotation shaft 8 is formed inside the electrode holder 63.
An electrode 66 made of a wear-resistant conductive material such as carbon is movably inserted into the cylindrical hole 65. Further, a compression spring 67 is inserted between the electrode 66 and the electrode holder 63, and the spring force of the compression spring 67 presses the tip end surface 68 of the electrode 66 onto the end surface of the rotating shaft portion 8c. On the other hand, a terminal 69 is fixed on the outer wall surface of the rear housing 3 with a bolt 70, and this terminal 69 has a voltage of -60KV to -90KV.
High voltage generator 7 for generating a negative high voltage of
Connected to 1. Therefore, a high negative voltage is applied to the front housing 2 and the rear housing 3, and a high negative voltage is also applied to the spray head 9 via the electrode 66 and the rotating shaft 8.

The charge sprayed from the nozzle opening 21 of the paint injection nozzle 18 onto the inner peripheral wall surface of the support outer cylinder 14 passes through the paint outlet hole 16 into the spray head main body 13 due to the centrifugal force generated by the rotation of the spray head 9. It flows out onto the peripheral wall surface 15. Next, this paint spreads as a thin liquid film on the inner circumferential wall surface 15 while spraying the spray head main body 1.
3 reaches the tip 13a. As mentioned above, a negative high voltage is applied to the spray head 9, and therefore, the centrifugal force generated by the rotation of the spray head 9 causes the paint to spread in a thin film form from the tip 13a of the spray head main body 13. The spray becomes charged with a negative high voltage. usually,
Since the surface to be painted is at zero potential, the paint spray is attracted toward the surface by electric force, thereby painting the surface.

Referring to FIG. 1, a first annular partition plate 72 is fixed on the front end surface of the end plate 17. As shown in FIG. This first annular partition plate 72 has a circular opening 73 in its center,
The shaft portion 8b of the rotating shaft 8 passes through the circular opening 73. Therefore, a narrow annular gap 74 is formed between the inner peripheral edge of the first annular partition plate 75 and the shaft portion 8b. On the other hand, a second annular partition plate 75 is fixed behind the first annular partition plate 72 with a slight interval therebetween. This second annular partition plate 7
5 is formed to be slightly larger than the diameter of the circular opening 73 of the first annular partition plate 75. The end plate 17 also has a circular opening 76, and a narrow annular gap 77 is also formed between the inner peripheral surface of the end plate 17 and the shaft portion 8b. As can be seen from FIG. 1, the second annular partition plate 75
The annular portion 17a of the end plate 17 and the second annular partition plate 72
An annular space 78 located between the second annular partition plate 72 and the end plate annular portion 17a communicates with the outside air through a paint discharge hole 79 formed at the lower end of the end plate 17.

During cleaning work for changing the paint color, while rotating the rotary shaft 8, cleaning liquid, ie, thinner, is first jetted out from the paint jetting nozzle 18, and then drying air is jetted out from the paint jetting nozzle 18. At this time, even if the paint adhered to the inner wall surface of the spray head annular space 11 is blown off by the jetted cleaning liquid or the jetted air, the blown paint is removed by the first annular partition plate 72 into the front housing 2. Even if this blown paint passes through the annular gap 74 of the first annular partition plate 72, the paint is blown away in the radial direction by the second annular partition plate 75 and is discharged. Since the paint is discharged to the outside from the hole 79, it is possible to completely prevent the paint from entering the front housing 2. On the other hand, air flowing out from the air outlet hole 52 of the thrust bearing passes through the front housing 2 and blows out from the annular gap 77 of the end plate 17, but this air is directed outward by the second annular partition plate 75. The paint is discharged from the paint outlet hole 79 to the outside. In this way, the air discharged from the thrust bearing does not flow into the spray head annular space 11, so that the paint adhered to the inner wall surface of the annular space 11 flows out from the annular space 11 rearward due to this air. can be prevented.

As described above, according to the present invention, by providing the first annular partition plate and the second annular partition plate, it is possible to prevent paint from entering the front housing during cleaning work for changing the paint color. Can be done. In this way, the paint does not enter into the bearing of the rotating shaft, so that it is possible to prevent the bearing from becoming stuck due to the intruding paint. Furthermore, the air discharged from the thrust bearing does not flow into the spray head annular space, thus preventing paint from flowing out of the rear opening of the spray head annular space due to this incoming air during painting operations. Can be done. This spilled paint causes paint defects on the painted surface, but the present invention can prevent such paint from flowing out, resulting in a clean painted surface.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a rotary atomizing electrostatic coating device according to the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a sectional view taken along the - line in Fig. 1. FIG. 8... Rotation shaft, 9... Spray head, 11... Annular space, 15... Cup-shaped inner peripheral surface, 16... Paint outflow hole, 17... End plate, 18... Paint injection nozzle, 7
2...first annular partition plate, 75...second annular partition plate.

Claims (1)

[Scope of utility model registration request] The rotary atomizing electrostatic coating device has a rotary shaft rotatably supported within a housing, a spray head is fixed to a front end of the rotary shaft protruding from a front end of the housing, and the spray head is fixed to a front end of the rotary shaft. The spray head has an annular space extending forward from the rear end surface of the spray head, a paint outflow hole extending radially outward from the annular space, and a cup-shaped inner peripheral surface for guiding the paint flowing out from the paint outflow hole. Further, in the rotary atomizing electrostatic coating device, further comprising a paint supply nozzle for supplying paint into the annular space, an end plate is fixed to the front end of the housing, and a circular opening is formed on the end plate. , the front end of the rotating shaft passes through the circular hole to form a narrow annular gap between the inner peripheral surface of the circular hole and the front end of the rotating shaft, and the rotating shaft is mounted in the housing by an air bearing. The compressed air discharged from the air bearing is caused to flow out of the annular gap through the space between the housing and the rotating shaft, and a first insulator is attached to the front end of the end plate between the annular gap and the rear end surface of the spray head. While fixing the annular partition plate, a circular aperture is formed on the first annular partition plate, and the front end of the rotating shaft passes through the circular aperture of the first annular partition plate to form an inner periphery of the circular aperture. A second annular partition plate having a narrow annular gap formed between the surface and the front end of the rotating shaft, and having an outer diameter larger than the inner diameter of the annular gap of the end plate and the annular gap of the first annular partition plate, A rotary atomizing electrostatic coating device fixed on a front end of a rotating shaft between the gaps, and communicating an annular space formed around the second annular partition plate with the outside air in the annular gaps.