JPS6012157A - Rotary atomizing type electrostatic painting apparatus - Google Patents

Abstract

PURPOSE:To prevent the generation of such an accident where seizme of bearing by the dissolution and removal of grease in the bearing caused by the penetration of a paint cleaning liquid into said bearing, in a rotary atomizing type electrostatic painting apparatus, by using a radial static pressure pneumatic bearing as the bearing of a rotary shaft equipped with a paint spray head. CONSTITUTION:A rotary shaft 8 comprising a hollow cylindrical part 8a is provided in the front housing 2 of a rotary atomizing type electrostatic painting apparatus 1 and a paint spray head main body 13 having a metal paint spray head 9, a paint outflow orifice 16 and paint flowing ring shaped space 11 is attached to the leading end thereof. This rotary shaft 8 is attached to the interior of the front housing 2 by two radial static pressure pneumatic bearings 30, 31 while a piercing hole 22 is provided to the end plate 17 provided to the front end part of the housing 2 to allow the rotary shaft 8 to forwardly protrude through the piercing hole 22. In cleaning the previous paint by a solvent such as a thinner when the paint color is changed, it prevents the thinner entering the interior of a bearing to dissolve grease and, therefore, seizure of the bearing is eliminated.

Description

[Detailed description of the invention] The present invention relates to a rotary atomizing electrostatic coating equipment company.

Prior Art A conventional rotary atomizing electrostatic coating device has a rotating shaft supported by a radial ball bearing or a radial near bearing in a housing, a cup-shaped spray head fixed to the front end of the rotating shaft, and a paint applied to the spray head. It is equipped with a paint injection nozzle for supplying paint, and by changing the color of the paint supplied from the paint injection nozzle, it is possible to apply paint of various colors.

As described above, the rotary atomizing electrostatic coating device can apply paints of various colors, but when changing the color of the paint, the spray head must be cleaned with a cleaning liquid such as thinner.゛At this time, for example, the spray head may be cleaned by spraying a cleaning liquid over the entire spray head11.

If this could be done, cleaning the spray head would be extremely easy, and the time required for cleaning would also be extremely short.

However, in conventional rotary atomizing electrostatic coating equipment, the cleaning fluid is sprayed over the entire spray head, and the cleaning fluid enters the radial ball bearing or radial near bearing, and as a result, the grease sealed inside the bearing is dissolved. This causes the problem that the bearing seizes up. Therefore, in the conventional rotary atomizing electrostatic coating device, for example, spraying is possible. The problem is that the spray head must be wiped off by hand, and cleaning the spray head takes a long time.

OBJECTS OF THE INVENTION The object of the present invention is to provide a rotary atomizing electrostatic coating device that can clean the sprayed nitrogen head in a short time and extremely easily.

Structure of the Invention The structure of the present invention includes a rotating shaft supported in a non-contact manner by a radial static air bearing in a housing of a rotary atomizing electrostatic coating device, and a central portion of an end plate covering a front end of the housing. In a rotary atomizing electrostatic coating device in which a through hole is formed in the through hole, the front end of the rotating shaft passes through the through hole and protrudes forward from the end plate, and the spray head is fixed to the protruding front end of the rotating shaft. The flange, which has an outer diameter larger than the inner diameter, is mounted on the protruding front end of the rotary shaft at a slight distance from the through hole forward.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figure 1, a rotary atomizing electrostatic coating apparatus, generally designated by the reference numeral 1, comprises a substantially hollow cylindrical metal front housing 2 and a substantially hollow cylindrical rear metal housing 3. , these two housings 2.3 are firmly connected by bolts 4. A support rod 6 made of an 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 includes a hollow cylindrical portion 8a located at the center thereof, a shaft portion 8b integrally formed at the front end of the hollow cylindrical portion 8a, and a shaft portion 8c fixed to the rear end of the hollow cylindrical portion 8a. A metal spray M9 is fixed to the shaft portion 8b of the rotating shaft 8 with a nut 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 NNi main body 13 fixed on the support 12. As shown in FIGS. 1 and 2, the outer cylindrical portion 14 of the support 12 has an opening into the annular space 11, and an inner wall surface 15 of the spray head body 13.
A large number of paint outflow holes 16 are formed which smoothly connect to the . On the other hand, an end plate 17 is fixed to the front end of the front housing 2, and a paint spray nozzle 18 is mounted on this end plate 17. This paint injection nozzle 18 is the paint supply pump 1
The nozzle opening 211 of the bifurcated paint injection nozzle 18 is connected to the paint tank 20 via the cylindrical inner periphery of the support outer cylinder 14! oriented toward the surface.

As shown in FIG. 1, a through hole 2 is provided in the center of the end plate 17.
2 is completely formed, and the through hole 22 of the shaft portion 8b of the rotating shaft 8
The end plate 17;1 protrudes forward through the end plate 17;1. Through hole 22
The inner diameter of the shaft portion 8b is slightly larger than the diameter Cm of the shaft portion 8b, so there is a slight annular spacing 2 between the through hole 22 and the shaft portion 8b.
3 is ←.

On the other hand, a collar 24 is arranged in front of the end plate 17 at a small distance from the front surface of the end plate 17, and this collar 24 is connected to the jet N head 9.
It is fitted and fixed to the table support shell 2.

The thickness of the sea urchin tsuba 24 shown in FIG.
4 has an outer diameter considerably larger than the diameter of the through hole 22. Further, 1. A cover plate 25 is arranged in front of the collar 24, and the outer peripheral edge of the cover plate 25 is fixed to the end plate 17. This cover plate 25 has a through hole 26 in the center thereof, and the shaft portion 8b passes through the through hole 26. The through hole 26 has an inner diameter slightly larger than the outer diameter of the shaft portion 8b, so that an empty annular gap 27 is formed between the shaft portion 8b and the through hole 25.

As shown in Figure 1, there is a pair of
Radial static air bearings 30 and 31 are arranged, and the rotary shaft 8 is rotatably supported by the radial static air bearings 30 and 31 in a non-contact manner. Each radial static air bearing 30, 31 has an annular air introduction chamber 32 therein.
, 33, each radial static pressure hollow shaft 930
, 31 are formed with an annular air introduction chamber 32 , a large number of connected air ejection holes 34 , 35 .

The air introduction hole 36 of the annular air introduction chamber 32 and the air introduction hole 37 of the annular air introduction chamber 33 are connected to an air supply pump 38.

On the other hand, as shown in FIG. 1, a pair of disk-shaped runners 39 and 40 are inserted into the shaft portion 8C of the rotating shaft 8, and these runners 39 and 40 are connected to a nut 43 via a spacer 41 and a turbine wheel 42. It is fixed to the shaft portion 8C. On the other hand, an annular plate 44 is disposed between the runners 39 and 400, and the runners 39 and 40 and the annular plate 44 constitute a non-contact type thrust air bearing. Note that each runner 39 and 40 is arranged so as to be separated from the annular plate 44 by a slight gap. The ring 4-shank plate 44 has a pair of O-rings 45,
46, and is hermetically fixed to the MiJ part housing 2. As shown in FIGS. 1 and 3, the front housing 2
An annular groove 47 is formed along the outer circumferential surface of the one-length guard plate 44 inside, and this annular groove 47 is connected to the air supply pump 49 via a compressed air introduction hole 48 formed in the front housing 2. Ru. 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 from the vicinity of the inner end of each of these air passages 500, the runners 39 and 40G are connected. Air outflow holes 51 and 52 are formed which extend toward each other.

On the other hand, a turbine nozzle holder 53 is fixed within the front housing 2 adjacent to the annular plate 44, and an annular air introduction chamber 54 is formed between the turbine nozzle holder 53 and the front housing 2. 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).
7G facing the turbine blade 5 of the turbine wheel 42
8 is placed. On the other hand, the housing inner chamber 59, in which the turbine wheel 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 by the compressor 56 is ejected into the housing inner chamber 59 through the ejection nozzle 57 . At this time, the jetted compressed air applies rotational force to the turbine wheel 42, and the rotating shaft 8 is thus rotated at a high speed. This jetted compressed air then passes 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 that defines the housing internal chamber 59, and an electrode holder 63 passing through the through hole 62 is fixed to the end wall 61. Ru. A cylindrical hole 65 coaxially curved with the rotation axis of the rotation shaft 80 is formed inside the electrode holder 63, and the inside of this cylindrical hole 6-δ is made of a material that is looser than the material of the rotation shaft 8, for example. An electrode 66 made of a metal material such as gunmetal is slidably inserted. This electrode 66 has a small diameter pin portion 66a.
and an enlarged head portion 66b, and these bottle portions 66a□l!
: The enlarged head 66b is integrally formed. The tip of the bottle portion 66a is formed into a pointed shape, and contacts the end surface of the rotating shaft portion 8C on the axis of the rotating shaft 8'. An adjustment screw 67 is screwed into the rear end of the cylindrical hole 65 of the electrode holder 63, and a compression spring 6 is installed between the enlarged head 66b of the electrode 66 and the adjustment screw 67.
8 is inserted. The tip of the electrode 66 is connected to this compression spring 68.
It is pressed onto the end face of the rotating shaft portion 8C by the spring force.

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 is connected to a high voltage generator 71 for generating a negative high voltage of -60 kV to -190 kV.

Therefore, a 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.

From the nozzle port 21 of the paint injection nozzle 18 to the support outer cylinder 14
The paint sprayed onto the inner circumferential wall surface flows out onto the inner circumferential wall surface 15 of the spray head main body 13 through the paint outlet hole 16 due to the unicentric force generated by one rotation of the spray head 9. Next, this paint reaches the tip 132 of the spray head main body 13 while spreading as a thin liquid +m,G on the inner circumferential wall surface 15. 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 (1) film form from the tip 13a of the spray head main body 13. The spray becomes charged with a negative high voltage. Normally, the voltage applied to the surface to be painted is zero, so the paint spray is attracted toward the surface by electric force, thereby coating the surface.

It is supported by a thrust air bearing consisting of a plate 44 and a pair of radial static pressure air bearings 3 (1, 3i).

Radial static pressure □ Air bearings 30 and 31 have air jet holes 3
The bearing 30 is heated by compressed air blown out from 4°35.
An air layer is formed between the inner peripheral surface of the rotating shaft 31 and the outer peripheral surface of the rotating shaft hollow cylindrical portion 8a, and the rotating shaft 8 is supported by this air layer in a non-contact state. On the other hand, in the above-mentioned thrust bearing, the compressed air introduced into the annular groove 47 from the air supply pump 49 is blown out from the air outlet holes 51 and 52 through the air passage 50 into the gap between the annular plate 44 and the runners 39 and 40. , the pressure necessary to maintain the minute gap between the annular plate 44 and the runners 39, 40 is generated within this gap. Therefore, the rotating shaft 8 is supported by a pair of radial bearings and a thrust bearing in a non-contact manner with a small air layer interposed therebetween. As is well known, the viscosity coefficient of air is approximately one tenth of the viscosity coefficient of lubricating oil. Therefore, an air bearing that uses air as a lubricant has extremely low friction loss, and therefore, the amount of heat generated by the friction loss is extremely small, making it possible to rotate at a considerably high speed. In the embodiment shown in FIG.
, p, and m.

On the other hand, the air flowing out from the air jet hole 35 of the radial static pressure electric bearing 31 forms an air layer between the inner circumferential surface of the bearing 31 and the outer circumferential surface of the rotary shaft hollow cylindrical portion 8a, as described above, and then this air It is discharged from the axial end of the bearing 31 to the left and right. At this time, the air discharged from the bearing 31 to the right in FIG. Flows radially outward within a small gap formed in the This air then passes around the outer peripheral edge of the collar 24, flows into the annular gap 27 formed between the cover plate 25 and the shaft portion 8b, as indicated by arrow A, and is then discharged to the outside. When changing the color of the paint, cleaning liquid is supplied from the paint spray nozzle 18 while rotating the rotary shaft 8, and at the same time, the cleaning liquid is sprayed from the outside toward the spray head 9. At this time, even if the cleaning liquid passes through the annular gap 27, flows along the outer peripheral surface of the shaft portion 8b, and enters the inside of the cover plate 25, the flow of this cleaning liquid is blocked by the collar 24. Therefore, the cleaning liquid
7 can be prevented from entering the interior. Also,
Even if the cleaning liquid flows radially outward on the front surface of the flange 24, the cleaning liquid will not enter between the flange 24 and the end plate 17 because air is ejected at high speed as shown by arrow A. In this way, it is possible to completely prevent the cleaning liquid from entering the edge of the end plate 17. Especially the blow NIi+11
Even when the rotary atomizing electrostatic coating body 1 is arranged so that the axis of rotation 8 is vertical and the rotation axis 8 is at the top, the cleaning liquid is applied to the end plate 1 by the airflow flowing as shown by arrow A.
Infiltrate the inside of 7. can be completely prevented.

Effects of the invention By using the radial static air bearing, the rotating shaft can be rotated faster than the conventional rotary atomizing electrostatic coating device, and at the same time, the air discharged from the radial static air bearing can cause cleaning liquid to flow inside the housing. can be completely prevented from entering. Therefore, the spraying and cleaning work becomes simple and the cleaning time can be shortened. In addition, when a radial double bearing or a radial near bearing is used as in the past, if the cleaning liquid enters the inside of the housing, the bearing will seize as described above, but when a radial static pressure air bearing is used, the inside of the housing will If the cleaning liquid enters the bearing, it will cause problems such as staining and damage of the bearing, so even if a radial static pressure thrust bearing is used, it is of course necessary to completely prevent the cleaning liquid from entering.

40. , Brief Description of the Drawings FIG. 1 is a side sectional view of the rotary atomization electrostatic coating apparatus according to the present invention, FIG. 2 is a sectional view taken along line nn of FIG. 1, and FIG. It is a sectional view taken along the line m-at in the figure.

2.3... Housing, 8... Rotating shaft, 9... Spray head, 18... Paint injection nozzle, 24... Tsuba, 30
, 31...Radial static pressure bearing.

Claims (1)

[Claims] The rotary atomizing electrostatic coating device is equipped with a rotating shaft supported in a non-contact manner by a radial static air bearing in the housing, and a through hole is provided in the center of the end plate covering the front end i of the housing leg. In a rotary atomizing electrostatic coating device, the front end of the rotating shaft passes through the through hole and protrudes forward from the end plate together with the knurl forming the rotary shaft, and the spray head is fixed to the protruding front end of the rotating shaft,
A rotary atomizing electrostatic coating device in which a collar having an outer diameter larger than the inner diameter of the through hole is mounted on the protruding front end of the rotating shaft at a slight distance forward from the through hole.