JP2008194597A - Rotary atomizing electrostatic coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shoot the trouble that a conventional rotary atomizing electrostatic coater prevents a coating material finding its way into the gap between the outer peripheral part of a rotary shaft which rotates in one piece with a rotary atomizing head, and a housing, or a grease applied to the bearing member of the rotary shaft, leaks into the gap between the rotary shaft and the housing, from being discharged, adversely affecting the stable rotation of the rotary atomizing head. <P>SOLUTION: This rotary atomizing electrostatic coater 10 which performs an electrostatic coating process to a coated object by applying high electrostatic voltage to the rotary atomizing head 14. The rotary atomizing head 14 is fitted to one end part of the rotary shaft 17 supported, in a freely rotatable manner, by the housing 12 of the coater 10. Further, a threaded structure 35 is formed at either one or both of the outer peripheral surface of the rotary shaft 17 wrapped by a cover 12b of the housing 12 and the inner peripheral surface 12c of the cover 12b which wraps the rotary shaft 17 and is arranged opposite to the outer peripheral surface of the rotary shaft 17, on the rotary atomizing head 14 side end part of the housing 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotary atomizing electrostatic coating apparatus that applies electrostatic high voltage to a rotary atomizing head and performs electrostatic coating on an object to be coated.

  In general, painting of objects to be painted such as the body of an automobile forms an electrostatic field between both electrodes, with the object to be coated as the anode and the coating device as the cathode, and the negatively charged atomized paint is applied to the electrostatic force. It is performed by electrostatic coating, in which coating is performed by adsorbing to the object to be coated.

  As a coating apparatus for performing such electrostatic coating, for example, a rotary atomizing head to which an electrostatic high voltage is applied is driven to rotate, and the fluid paint supplied to the rotary atomizing head is atomized by centrifugal force. Rotating atomizing electrostatic coating, in which atomized particles are charged with an electrostatic high voltage applied to the rotating atomizing head, and electrostatic coating is performed by an electrostatic electric field formed between the object to be grounded There is a device.

In the rotary atomizing electrostatic coating apparatus, the rotary atomizing head is rotatably fixed integrally to the tip of the rotary shaft that is rotatably supported by the housing and protrudes from the housing. Although the paint is sprayed from the rotary atomizing head, the sprayed paint may enter the gap between the rotary shaft and the housing.
The clearance between the rotating shaft and the housing is very small, and if paint enters the clearance, it may affect the stable rotation of the rotary atomizing head. It is desirable to prevent infiltration.

Thus, a rotary atomizing electrostatic coating apparatus having a mechanism for preventing sprayed paint from entering the gap between the outer periphery of the rotary shaft that rotates integrally with the rotary atomizing head and the housing is, for example, a patent. It is devised like the rotary atomizing electrostatic coating apparatus shown in Document 1.
In the rotary atomizing electrostatic coating apparatus of Patent Document 1, an air seal mechanism is provided at the rotary atomizing head side end portion of the rotary shaft, and air is directed toward the rotary atomizing head side from the gap on the outer periphery of the rotary shaft. It blows out to form an air seal, preventing the paint from entering the gap.
JP-A-9-215948

However, as described above, when the air seal formed on the outer periphery of the rotary shaft is configured to prevent the invasion of the paint, the paint is disposed on the inner side (on the counter-rotating atomizing head side) than the air seal forming portion of the rotary shaft for some reason. If it has entered, the infiltrated paint can no longer be discharged to the outside, which will adversely affect the stable rotation of the rotary atomizing head.
In addition, when the rotating shaft is rotatably supported by the housing by the bearing member, if the grease applied to the bearing member leaks into the rotation drive unit (that is, the gap between the rotating shaft and the housing), the rotation Although there is a possibility of adversely affecting the stable rotation of the atomizing head, the above-described air seal mechanism cannot prevent leakage of grease from the bearing member to the outside.

  Therefore, in the present invention, the paint sprayed from the rotary atomizing head is prevented from entering the gap between the rotary shaft and the housing, and grease leaks to the outside through the gap from the bearing member that supports the rotary shaft. The present invention provides a rotary atomizing electrostatic coating apparatus capable of preventing the discharge.

The rotary atomizing electrostatic coating apparatus that solves the above problems has the following characteristics.
That is, according to claim 1, there is provided a rotary atomizing electrostatic coating apparatus that applies electrostatic high voltage to a rotary atomizing head and performs electrostatic coating on an object to be coated. Is attached to one end of a rotary shaft rotatably supported by the housing of the rotary atomizing electrostatic coating apparatus, and the outer periphery of the rotary shaft covered by the housing at the rotary atomizing head side end of the housing A screw structure is formed on either or both of the surface and the inner peripheral surface of the housing that covers the rotary shaft and is opposed to the outer peripheral surface of the rotary shaft.
As a result, the screw structure allows the foreign matter that has entered the gap between the rotating shaft and the housing to be discharged from the gap, and enables stable rotation of the rotary atomizing head that can rotate integrally with the rotating shaft. It can prevent adverse effects.
For example, when the screw formation direction of the screw structure is a direction in which foreign matter is moved to the rotary atomizing head side, the sprayed paint that has entered the gap can be discharged to the outside by the screw structure. It is possible to prevent adverse effects on the stable rotation of the rotary atomizing head.
Further, when the rotating shaft is supported by a bearing member located on the counter-rotating atomizing head side with respect to the screw structure, and the screw forming direction of the screw structure is set to a direction in which foreign matter is moved to the counter-rotating atomizing head side The screw structure allows the lubricating member such as grease that has entered the gap from the bearing member to be returned to the bearing member side, preventing adverse effects on the stable rotation of the rotary atomizing head. it can.

According to a second aspect of the present invention, the screw structure is disposed in the middle of the rotary shaft from a location where a bearing member that rotatably supports the rotary shaft to a rotary atomizing head side end of the housing. The screw formation direction is different between the bearing member side portion of the screw structure and the rotary atomizing head side portion, and the screw tightening direction of the screw structure located on the bearing member side is the rotation direction of the rotary shaft. The screw tightening direction of the screw structure located on the rotary atomizing head side is configured in the direction opposite to the rotation direction of the rotary shaft.
Thus, by rotating the rotary shaft, the paint that has entered the gap between the rotary shaft and the housing from the rotary atomizing head side and the grease that has leaked from the bearing member side and entered the gap are provided. It is possible to simultaneously discharge from the gap, and it is possible to easily and reliably hold the stable rotation of the rotary atomizing head.

  According to the present invention, the screw structure allows the foreign matter that has entered the gap between the rotary shaft and the housing to be discharged from the gap, and the rotary atomizing head that can rotate integrally with the rotary shaft is stable. Can be prevented from adversely affecting the rotation.

  Next, modes for carrying out the present invention will be described with reference to the accompanying drawings.

A coating apparatus 10 shown in FIG. 1 is configured as a rotary atomizing electrostatic coating apparatus, and a rotary atomizing head 14 serving as a paint ejection port is rotatably attached to one side of the housing 12 (left side in FIG. 1). A cartridge 16 filled with paint is detachably mounted on the other side of 12 (the right side in FIG. 1).
As the paint filling the cartridge 16, for example, a water-based paint (aqueous paint) is used.

In the cartridge 16, a cylinder (not shown) filled with paint and a medium for extruding the paint is formed, and a piston (not shown) is slidably fitted in the cylinder. .
The rotary atomizing head 14 is fixed to a rotary shaft 17 protruding from the housing 12, and the rotary shaft 17 is rotatably supported by the housing 12.
Then, by sliding the piston with the pushing medium, the paint filled in the cylinder is pushed out of the cylinder and supplied to the rotary atomizing head 14 through the paint supply pipe 19 penetrating the rotary shaft 17. It is configured as follows.

  A high voltage generator (cascade) 20 is provided in the housing 12, and an electrostatic high voltage generated by the high voltage generator 20 is applied to the rotary atomizing head 14. The electrostatic high voltage applied to the rotary atomizing head 14 is, for example, about −90 kV.

  The rotary atomizing head 14 is rotationally driven by a servo motor 13 which is an electric motor accommodated in the housing 12, and the rotational driving force from the servo motor 13 is also accommodated in the housing 12. After being increased through the gearbox 15, it is transmitted to the rotary atomizing head 14.

When a high voltage is applied and paint is supplied to the rotary atomizing head 14 that is rotationally driven by the servo motor 13, the paint is charged by the rotary atomizing head 14 and is centrifugally atomized to be charged. Sprayed as paint particles.
The charged paint particles fly along an electrostatic field formed between the rotary atomizing head 14 applied with a high voltage and the workpiece to be grounded, and are applied to the workpiece. .
In this example, the rotary atomizing head 14 and the rotary shaft 17 are configured to be driven to rotate counterclockwise when viewed from the rotary atomizing head 14 side when the paint is sprayed.

Further, since the servo motor 13 is electrically connected to the rotary atomizing head 14 via the speed increaser 15, the electrostatic high voltage applied to the rotary atomizing head 14 is also applied to the servo motor 13. It will be applied similarly.
A power source 24 is supplied to the servo motor 13 through a lead wire 26.

  Here, in the coating apparatus 10, the speed increaser 15 is electrically connected to the rotary atomizing head 14 to which an electrostatic high voltage is applied by the high voltage generator 20. Also, an electrostatic high voltage equivalent to that of the rotary atomizing head 14 is applied. Further, the electrostatic high voltage from the high voltage generator 20 is also applied to the cartridge 16.

The servo motor 13 is connected to the speed increaser 15 via a spacer 18 made of an electrical insulator such as resin. The servo motor 13, the speed increaser 15 and the rotary atomizing head 14 are connected. Is electrically insulated.
Further, the connecting portion 16a of the cartridge 16 with the servo motor 13 is made of an electrical insulator such as resin, and the servo motor 13 and the cartridge 16 are electrically insulated.

  As described above, the servo motor 13 is electrically insulated from the rotary atomizing head 14, the speed increaser 15, and the cartridge 16 to which an electrostatic high voltage is applied. No voltage is applied (the electric potential of the servo motor 13 is about 0 kV, for example), and the electrostatic high voltage applied to the rotary atomizing head 14 and the gearbox 15 is supplied through the servo motor 13 as a power source. The power supply 24 is not leaked, and the power supply 24 is not burdened.

  Further, as shown in FIG. 2, in the housing 12 that rotatably supports the rotary shaft 17, a cover 12b that covers the periphery of the rotary shaft 17 is attached to the end of the housing body 12a on the rotary atomizing head 14 side. The rotary shaft 17 protrudes from the cover 12b to the rotary atomizing head 14 side.

A bearing 31 is interposed between the housing body 12 a and the rotating shaft 17, and the rotating shaft 17 is rotatably supported by the housing body 12 a via the bearing 31.
The bearing 31 is located at the end of the housing main body 12a on the side of the rotary atomizing head 14 (the boundary between the housing main body 12a and the cover 12b) in the axial direction of the rotary shaft 17.

The cover 12b has a through hole 12c through which the rotary shaft 17 passes, and a slight gap is formed between the outer peripheral surface of the rotary shaft 17 and the inner peripheral surface of the through hole 12c facing the outer peripheral surface. In a state in which the rotary shaft 17 is provided, the rotary shaft 17 passes through the through hole 12c.
A screw structure 35 is formed in a portion where the rotary shaft 17 is covered with the cover 12b.

  As shown in FIG. 3, the screw structure 35 includes a first screw 35 a formed in a substantially half on the rotary atomizing head 14 side of a portion covered with the cover 12 b of the rotary shaft 17, and the rotary shaft 17. A second screw 35b formed on a substantially half of the portion covered with the cover 12b on the bearing 31 side is provided.

The first screw 35a and the second screw 35b have different screw directions, and the first screw 35a rotates the rotary shaft 17 counterclockwise as viewed from the rotary atomizing head 14 side. It is formed on the screw in the direction of tightening.
In other words, if the first screw 35a is screwed into the cover 12b, the rotary shaft 17 moves toward the bearing 31 by turning the first screw 35a counterclockwise as viewed from the rotary atomizing head 14 side. It is formed on the screw in the forward direction.
Further, the screw tightening direction of the first screw 35 a is the same as the rotation direction of the rotary shaft 17.

On the other hand, the second screw 35b is formed as a screw that is tightened when the rotary shaft 17 is rotated clockwise as viewed from the bearing 31 side.
In other words, if the second screw 35b is screwed into the cover 12b, the second screw 35b is rotated clockwise as viewed from the bearing 31 side (that is, counterclockwise as viewed from the rotary atomizing head 14 side). The rotating shaft 17 is formed as a screw in a direction to advance toward the rotating atomizing head 14 side.
Further, the screw tightening direction of the second screw 35 b is opposite to the rotation direction of the rotary shaft 17.

  As described above, since the rotary shaft 17 is configured to be driven to rotate counterclockwise when viewed from the rotary atomizing head 14 side when spraying paint, the first screw 35a and the second screw 35b are When the paint is sprayed, both of them rotate in the direction of tightening (the first screw 35a is advanced toward the bearing 31 and the second screw 35b is advanced toward the rotary atomizing head 14).

When the foreign matter 38 is present in the gap between the rotating shaft 17 and the cover 12b rotating as described above, the foreign matter located in the formation portion of the first screw 35a is moved to the rotary atomizing head 14 side by the first screw 35a. The foreign matter located at the formation portion of the second screw 35b is moved to the bearing 31 side by the second screw 35b.
That is, the first screw 35a and the second screw 35b are not actually screwed into the cover 12b, and even if the rotary shaft 17 rotates, the rotary shaft 17 moves to the rotary atomizing head 14 or the bearing 31 side. Therefore, when the foreign matter 38 is applied to the first screw 35a or the second screw 35b, the foreign matter 38 moves in a direction opposite to the direction in which the first screw 35a and the second screw 35b are tightened.

  As described above, when the foreign matter 38 is present in the portion where the first screw 35a is formed in the gap between the rotary shaft 17 and the cover 12b when spraying the paint, the foreign matter is moved to the rotary atomizing head 14 side. It is discharged to the outside through a gap between the rotary shaft 17 and the cover 12b. Further, when the foreign matter 38 is present in the portion where the second screw 35b is formed in the gap between the rotary shaft 17 and the cover 12b when the paint is sprayed, the foreign matter is moved toward the bearing 31 and reaches the portion of the bearing 31. .

Therefore, for example, when the coating apparatus 10 is spraying paint, even if the scattered paint enters the gap between the rotary shaft 17 and the cover 12b, the portion of the rotary shaft 17 covered by the cover 12b The first screw 35a formed on substantially the half of the rotary atomizing head 14 side moves the infiltrated paint to the rotary atomizing head 14 side and discharges it to the outside.
As a result, the paint that has entered the gap between the rotary shaft 17 and the cover 12b does not remain in the gap as it is, and the stable rotation of the rotary atomizing head 14 (the rotary shaft 17) is adversely affected by the entered paint. You can prevent it.

Further, as the rotation shaft 17 continues to rotate, the grease applied to the bearing 31 leaks from the bearing 31 and enters the gap between the rotation shaft 17 and the cover 12b. is there.
In such a case, the rotary shaft 17 is rotationally driven when the paint is sprayed, so that the second screw 35b formed in the substantially half on the bearing 31 side of the portion of the rotary shaft 17 covered with the cover 12b. Thus, the infiltrated paint is moved to the bearing 31 side and returned to the bearing 31.
As a result, the grease that has leaked into the gap between the rotary shaft 17 and the cover 12b does not remain in the gap as it is or leaks to the outside from the gap. The stable rotation of the shaft 17) can be prevented from being adversely affected.

  In particular, in the case of this example, since both the first screw 35a and the second screw 35b having different screw forming directions are formed on the rotary shaft 17, the rotary shaft 17 can be rotated to drive the rotary shaft. The paint that has entered the gap between the rotary atomizing head 14 and the grease that has entered from the bearing 31 side into the gap between the cover 17 and the cover 12b can be discharged simultaneously from the gap, and the rotary atomizing head 14 can be stabilized. The rotation can be easily and reliably maintained.

  In this example, the screw structure 35 is composed of the first screw 35a and the second screw 35b formed on the outer peripheral surface of the rotary shaft 17. However, the present invention is not limited to this. A screw may be formed on the inner peripheral surface of the covering cover 12b. Moreover, it is also possible to form screws on both the outer peripheral surface of the rotating shaft 17 and the inner peripheral surface of the cover 12b.

  In the case of this example, since the rotary shaft 17 is configured to be driven to rotate counterclockwise when viewed from the rotary atomizing head 14 side when the paint is sprayed, the first screw 35a is connected to the rotary shaft 17. When the rotary shaft 17 is turned counterclockwise as viewed from the rotary atomizing head 14 side, the second screw 35b is formed into a screw that is tightened. When the rotary shaft 17 is turned clockwise when viewed from the bearing 31 side, the second screw 35b is tightened. However, when the rotary shaft 17 is configured to be driven to rotate clockwise as viewed from the rotary atomizing head 14 side when the paint is sprayed, the first screw 35a and the second screw 35b The direction to cut the screw is the opposite direction.

It is a side cross section which shows the coating machine comprised in a rotary atomization electrostatic coating apparatus. It is side surface sectional drawing which shows the rotation atomization head side edge part of a rotating shaft. It is side surface sectional drawing which shows the part covered with the cover of the housing of a rotating shaft.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Coating machine 12 Housing 12a Housing main body 12b Cover 14 Rotating atomizing head 17 Rotating shaft 31 Bearing 35 Screw structure 35a First screw 35b Second screw 38 Foreign matter

Claims (2)

A rotary atomizing electrostatic coating apparatus that applies electrostatic high voltage to a rotary atomizing head and performs electrostatic coating on an object to be coated,
The rotary atomizing head is attached to one end of a rotary shaft that is rotatably supported by a housing of the rotary atomizing electrostatic coating apparatus,
An outer peripheral surface of the rotating shaft covered by the housing and an inner peripheral surface of the housing that covers the rotating shaft and is opposed to the outer peripheral surface of the rotating shaft at the rotary atomizing head side end of the housing. A screw structure is formed on one or both of
A rotary atomizing electrostatic coating apparatus characterized by that. The screw structure is formed in the middle of the rotating shaft and is formed between the location of the bearing member that rotatably supports the rotating shaft and the end portion on the rotary atomizing head side of the housing.
The screw formation direction is different between the bearing member side portion and the rotary atomizing head side portion of the screw structure,
The screw tightening direction of the screw structure located on the bearing member side is configured in the same direction as the rotation direction of the rotary shaft,
The screw tightening direction of the screw structure located on the rotary atomizing head side is configured in a direction opposite to the rotating direction of the rotating shaft,
The rotary atomizing electrostatic coating apparatus according to claim 1.

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