JPS5831224B2 - Sadent Sou Souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic coating device, and its purpose is to facilitate the atomization of paint mist, particularly to facilitate the atomization of water-based paints, and to produce donut pattern and other coatings. To provide an electrostatic coating device that eliminates uneven coating, improves coating efficiency, enables quick coating work, can spray a jet stream suitable for the paint used, and has a simple structure and is easy to operate. .

An embodiment of the present invention will be described in detail below with reference to the drawings.

Reference numeral 1 designates a pipe-shaped rotary shaft that is rotated at high speed, has a female threaded portion 13 at its rear end, and is screwed and connected to a male threaded portion 15 at the tip of a relay pipe shaft 14 .

A disk-shaped base body 3 is integrally provided at the tip of the pipe-shaped rotating shaft 1, and the hollow part 4 tip of the pipe-shaped rotating shaft 1 is closed by the front wall of the base body 3, so that the pipe-shaped rotating shaft 1 is A first cylindrical body 5 is integrally provided around the outer end of the coaxial base body 3.

The first cylindrical body 5 has an inner peripheral surface whose diameter gradually increases in a tapered shape toward the front and back of the base 3, and the rear inner peripheral surface of the base 3 and the front inner peripheral surface of the base 3 of the first cylindrical body 5 are different from each other. It is continuous with a plurality of tunnel parts 6 provided in the base body 3, and the tunnel parts 6 and
... are formed at equal intervals in the circumferential direction on the outer peripheral end of the base body 3.

Further, a threaded portion 8 is formed at the rear portion of the outer periphery of the first cylindrical body 5, and a knife portion 7 is formed at the tip by making the taper slope of the inner circumferential surface of the first cylindrical body 5 even steeper.

The second cylindrical body 9 coaxially arranged outside the first cylindrical body 5 is
A female threaded portion 16 formed on the inner peripheral surface of the rear portion of the second cylindrical body 9 is screwed into the threaded portion 8 of the first cylindrical body 5, so that the second cylindrical body 9 can be moved back and forth relative to the first cylindrical body 5.

In addition, when the second cylinder 9 is in a position where the tips of the first cylinder 5 and the second cylinder 9 are aligned, the knife portion 7 of the first cylinder 5 and the inner circumferential surface of the tip of the second cylinder 9 are in contact with each other. However, when the second cylinder 9 is rotated with respect to the first cylinder 5 and the position of the second cylinder 9 relative to the first cylinder 5 is moved backward, the outer peripheral surface of the first cylinder 5 and the second cylinder 9 are The outer circumferential surface of the first cylindrical body 5 has a relatively gentle taper such that the gap between the inner circumferential edge of the tip and the inner circumferential edge of the first cylindrical body gradually widens.

Further, the inner circumferential surface of the second cylindrical body 9 does not have a taper at least in a certain section at its tip, and is formed parallel to the axes of the first and second cylindrical bodies 5 and 9.

Thus, the annular hollow chamber 10 formed between the outer circumferential surface of the first cylindrical body 5 and the inner circumferential surface of the second cylindrical body 9 is formed in a certain section continuous with the injection nozzle 2, that is, in a cylindrical shape. In a certain section ahead of the annular hollow chamber 10, the distance between the outer peripheral surface of the first cylinder 5 and the inner peripheral surface of the second cylinder 9 is narrower than in other parts. The shape of the rectifying hollow part 10a is formed approximately parallel to the axes of the first and second cylindrical bodies 5 and 9. On the other hand, the base body 3 has a rectifying hollow part 10a formed approximately parallel to the axes of the first and second cylindrical bodies 5 and 9. Appropriate number of communication holes 11...
is provided, and the annular hollow chamber 10 formed between the outer peripheral surface of the first cylinder 5 and the inner peripheral surface of the second cylinder 9 is connected to the communication hole 11...
It is connected to the hollow part 4 of the pipe-shaped rotating shaft 1 through the pipe.

In the figure, 17 is a screw that fixes the positional relationship between the first cylindrical body 5 and the second cylindrical body 9, and 18 is a paint supply pipe such as water-based paint, and the paint is supplied from the tip 18a to the first cylinder. The rear part of the supply pipe 18 is connected to a paint supply section 19 consisting of a paint pump, a paint tank, etc., and the paint is continuously supplied. When using a highly conductive paint such as water-based paint, the paint supply section 19 should be insulated with high voltage resistance.020 is an air motor 21.
A fixed tube is fixedly installed coaxially with the motor shaft 22 on the front surface of the fixed tube 20. A bearing tube 23 is disposed at the tip of the fixed tube 20, and two bearings 24. 2
4 and a metal portion 25 between these bearings 24 ; 24 , and the rear end of the relay pipe shaft 14 is connected to the tip of the motor shaft 22 via a joint 26 .

The relay pipe shaft 14 has a hollow portion 27 whose rear end is closed, and the rear end of the hollow portion 27 is communicated with a through hole 28 that opens on the outer peripheral surface of the relay pipe shaft 14 .

An annular groove 29 is formed on the inner circumferential surface of the metal part 25 corresponding to the opening 28a of the through hole 28, and a connecting hole 30 is connected to the annular groove 29, and an air tube 3 is connected to the rear end of the connecting hole 30.
1, high-pressure air is fed into the annular groove 29 from the high-pressure air generation source 12, and the high-pressure air is also fed from the annular groove 29 into the hollow parts 27, 4 of the relay pipe shaft 14 and the pipe-shaped rotating shaft 1. , the annular hollow chamber 1 through the communication hole 11 of the base body 3.
0, and the air pressure in this annular hollow chamber 10 formed between the first and second cylindrical bodies 5 and 9 is made high.

On the other hand, the high pressure air supplied to this annular hollow chamber 10 is
The annular hollow is guided and rectified by the inner circumferential surface of the second cylindrical body 9 parallel to the axes of the second cylindrical bodies 5 and 9 and the outer circumferential surface of the first cylindrical body 5 having a taper that slowly expands in diameter. room 10
It is introduced into the rectifying hollow part 10a at the tip, and this rectifying hollow part 1
At 0a, the high-pressure air is rectified into an airflow in a direction parallel to the axes of the first and second cylindrical bodies 5 and 9, and then the injection nozzle 2
It is something that is emitted from the air.

However, the jet stream ejected from the injection nozzle 2 is transmitted to the first and second cylindrical bodies 5 and 5 on the outer circumference of the knife part.
As a jet stream of rotating air that flows in the direction of the object to be coated along a path substantially parallel to the axis of the cylinder 9 and has a rotational force that rotates coaxially with the first and second cylindrical bodies 5 and 9 in a spiral shape. There will be a jet of water.

Further, the terminal screw 33 provided on the bearing tube 23 is for connecting the other end of the lead wire 35 whose one end is connected to the high voltage generation source 34, and connects the object A to be painted, the fixed tube 20, and the relay pipe. A high voltage is applied between the shaft 14, the pipe-shaped rotating shaft 1, the first cylindrical body 5, the base body 3, the second cylindrical body 9, etc. ○38 in the figure.
39 is an insulating arm rod, and 39 is a support attachment portion of the insulating arm rod 38.

In the above embodiment, however, the paint is supplied from the paint supply section 19 to the supply pipe 18 via the paint tube 36, and is continuously supplied to the first cylinder 5 in small amounts from the opening at the tip 18a of the supply pipe 18. The paint is made to flow down on the inner peripheral surface of the rear part. On the other hand, the high-pressure air flow supplied from the high-pressure air source 12 through the air tube 37 rotates the air motor 21, which causes the pipe-shaped rotating shaft 1, the base body 3, and 1st
, the second cylindrical bodies 5 and 9, the motor shaft 22, the relay pipe shaft 14, etc. are rotated at high speed.

Therefore, the paint that has flowed down onto the inner circumferential surface of the first cylindrical body 5 is
Due to the high speed rotation of the cylinder 5, centrifugal force acts, which spreads on the rear inner peripheral surface of the first cylinder 5 and simultaneously moves toward the tip along the taper of the inner peripheral surface of the first cylinder 5 while becoming a thin film. , finally passes through the tunnel part 6 of the base body 3 and is supplied to the front inner peripheral surface of the first cylinder 5, and further spreads in the inner peripheral direction on the front inner peripheral surface of the first cylinder 5. It is supplied in the form of a thin film along the taper toward the knife portion 7.

The paint thus formed into a thin film is supplied to the knife section 7, where the thin film of paint is atomized.

That is, the thin film-like paint supplied to the knife part 7 is atomized by centrifugal force due to the high speed rotation of the first cylinder 5 and electrostatic atomization due to the high voltage applied to the first cylinder 5. It receives the acting force and the atomizing force due to the rotating air jet flow ejected from the injection nozzle 2 and jetted around the outer periphery of the knife portion 7, and is atomized into fine particles by the synergistic effect of these acting forces.

On the other hand, the above-mentioned rotating air jet flow forms a rotating ring tube air flow extending from this annular injection nozzle 2 to the object A to be coated, and inside the rotating ring tube air flow extending to the object A to be coated in a tube shape. The atomized paint flies toward the object A to be coated.

By the way, as mentioned above, the particles of the atomized paint atomized in the knife part 7 receive an initial velocity toward the object to be coated from the rotating air jet flow at the same time as this atomization, and are formed by the rotating annular air flow. The atomized paint, which was initially atomized in an annular shape along the shape of the knife part 7, is immediately dispersed into the hollow interior of the rotating annular air stream. The paint is evenly dispersed in the paint, forming a tail stream of atomized paint.

In this way, the atomized paint that is synergistically atomized by the centrifugal force, electrostatic force, and compressed air blowing force in the knife part 7 receives the force from the rotating annular air flow. At the same time, the atomization is promoted, and at the same time, the atomized paint is confined within this rotating annular air flow. Therefore, the atomized paint is shaped as a tail stream wrapped in the rotating annular air stream, and inside this tail stream, the atomized paint is In addition to being uniformly dispersed, the rotating cylinder airflow prevents the atomized paint from scattering in unnecessary directions, and furthermore, the flying direction of the atomized paint is uniform in the direction of the object A to be painted. Due to the initial velocity applied by the rotating air jet flow and the Coulomb force acting on the fine particles of the atomized paint, the atomized paint flies onto the object to be painted, and the surface of the object A is coated uniformly. It is deposited in a pattern.

In addition, when using an oil-based paint as the above-mentioned paint, since such oil-based paint generally has low conductivity and can be charged relatively easily, a relatively large electrostatic atomization force can be obtained, and a thin film can be formed. There is no need to increase the force of the jet stream to atomize and atomize the paint.

Therefore, the role of the jet stream that flows in a spiral shape to form the rotating cylinder air stream is to further atomize the atomized paint,
The main purpose is to control the spread of atomized paint within a certain range, and there is no need to form a particularly high-speed jet stream.
Rather, the second cylinder 9 is moved backward relative to the first cylinder 5 to widen the width of the gap between the two jet nozzles that serve as the jet air outlet, thereby thickening the part of the rotating ring cylinder air flow and preventing the donut pattern from occurring. This method appropriately regulates the spread of the flying atomized paint to obtain the desired spread of the coating pattern.On the other hand, if the above paint is conductive like water-based paint, relatively small static Since only the electro-atomizing force can be obtained, the width of the gap forming the injection nozzle 3 between the outer peripheral surface of the first cylinder 5 and the inner peripheral edge of the tip of the second cylinder 9 is narrowed to 2 mm or less. The injection nozzle 2 is positioned within 10 mm behind the knife part T, and the flow velocity of the annular jet stream ejected from the injection nozzle 2 and flowing in a spiral is increased, and the jet ejected from the injection nozzle 2 is The water-based paint supplied to the knife part 7 is atomized by the wind pressure of the airflow, and an initial velocity is given to the atomized water-based paint, and further, the atomized water-based paint is caused to fly toward the object to be coated by the action of the electrostatic field. It is.

As described above, the present invention forms an annular hollow chamber rotating together with the first cylindrical body on the outer periphery of the first cylindrical body, connects this annular hollow chamber to a high-pressure air generation source, and connects the annular hollow chamber to a high-pressure air generation source behind the knife portion at the tip of the first cylindrical body. Since the injection nozzle is arranged in the high-pressure air supply path, there is no loss of high-pressure air in the middle of the high-pressure air supply path, and the flow rate of the jet stream ejected from the injection nozzle is increased to accelerate the flow velocity of this jet stream and generate a large acting force. It is possible to obtain a jet stream having the following characteristics, and the acting force of the jet stream is synergistic with the acting force of the electrostatic field due to the high voltage applied to the first cylindrical body and the centrifugal acting force based on the high speed rotation of the first cylindrical body. As a result, a thin film of paint is atomized from the knife part, and even when the voltage applied to the paint through the first cylinder is relatively low, the paint is sufficiently atomized into a fine mist. In addition to making it possible to atomize water-based paints and other conductive paints that are normally difficult to atomize using only electrostatic force, it is possible to sufficiently atomize the paint into a fine atomization and statically. It has the effect of being able to perform electric coating, and since it is designed to apply the initial velocity of the jet stream to the atomized paint, the voltage applied between the object to be coated and the first cylindrical body is Even if the pressure is relatively low, the fine particles can be sufficiently transported to the object to be coated.

Further, in the present invention, a certain section of the annular hollow chamber that is continuous with the injection nozzle is formed into a thin cylindrical shape with a narrow space between the inner and outer circumferential walls, and is formed as a rectifying hollow section substantially parallel to the first cylinder axis. Since the jet air stream is ejected in a direction substantially parallel to the axis of the first cylinder, the jet air stream ejected from the ejection nozzle can be ejected in a well rectified state approximately parallel to the axis of the first cylinder. This jet airflow causes the jet stream to flow toward the object to be coated along a path approximately parallel to the axis of the first cylinder on the outer periphery of the knife part, and has a rotational force that rotates coaxially with the first cylinder, causing the jet to flow in a spiral shape. capable of forming an air jet flow,
As mentioned above, the jet airflow that has contributed to atomization or atomization in the knife part forms a rotating cylindrical airflow to form a good virtual tube to guide the atomized paint, and this knife The rotating air jet flowing along a path substantially parallel to the first cylinder axis on the outer periphery expands its radius of rotation as it approaches the object to be coated due to the action of centrifugal force acting on the rotating air jet itself.
The expanding diameter of the rotating annular airflow can be set to an appropriate diameter at the position of the object to be painted, and therefore the rotating annular airflow formed by the jet stream spreads over the rotating annular airflow that covers the outer periphery of the atomized paint. By forming a cylinder air flow, a final flow of the atomized paint from the knife part to the object to be painted is formed, and losses due to paint scattering in unnecessary directions can be greatly reduced. The rotating annular airflow gives an initial velocity to the atomized paint, so that the atomized paint is uniformly dispersed within the virtual tube formed by the rotating annular airflow, which is different from the conventional rotating annular airflow. It has the effect of being able to obtain a uniform coating pattern without producing a doughnut-shaped coating pattern, which is a characteristic and drawback of cup-type electrostatic coating machines, and it also has the effect of making it possible to obtain a uniform coating pattern. It has the effect of eliminating concentrated uneven coating.

Furthermore, as mentioned above, the end stream of the atomized paint is formed by being covered by the rotating annular air flow, so compared to the annular air flow that flows in a straight line, it is difficult to make the air flow into a cylindrical shape. The holding force is strong, and even if the first cylindrical body is moved while being used, the rotating annular cylinder air flow will not collapse from its cylindrical shape due to its movement, and the tail stream of paint mist will always be retained, eliminating waste. It has the effect of not causing paint scattering, and therefore can be used when painting a wide area of an object or many small objects at once while swinging or moving the first cylinder etc. As mentioned above, since the rotating cylinder airflow envelops the end stream of the atomized paint, the end flow of the atomized paint is accurately directed toward the object to be coated, and this atomized paint does not scatter, and the rotary cup This has the effect that so-called reciprocating painting work, in which painting is performed while moving, can be easily performed.

Furthermore, since the rotating annular air flow is formed by the rotating air jet flow toward the object to be coated, which is formed by the jet flow jetting around the outer periphery of the knife part, the jet air flow is generated at each point of the annular injection nozzle. Even if there are variations in the strength of the rotating cylinder, the effect is that the direction of the rotating cylinder air flow itself will not deviate from the direction of the object to be painted, which will increase the scattering of the atomized paint.

As mentioned above, in the present invention, it is possible to obtain a circular painting pattern without causing uneven coating, and it is not doughnut-shaped, and it is possible to perform reciprocating painting work, so there is less loss. It has the advantage that the painting work can be done quickly and with a small amount, and the resulting painted surface is of high quality, and also conductive paints such as water-based paints can be used. A chamber is formed between the first cylindrical body and the second cylindrical body, and the position of the second cylindrical body with respect to the first cylindrical body is configured to be adjustable, thereby appropriately setting the size of the gap through which the jet stream is ejected. When a water-based paint is used, the flow velocity of the jet stream can be increased to easily achieve atomization of the water-based paint, and when a regular oil-based paint is used, the cylindrical part of the jet stream can be made thicker. It has the effect of forming an annular and cylindrical jet stream suitable for the paint used.

[Brief explanation of the drawing]

Fig. 1 is a front view of the head section according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line X-X of the same head section, Fig. 3 is a sectional view of the relay pipe shaft section of the same above, and Fig. 4 is the entire same as above. 1 is a reduced schematic diagram of the device, 1 is a pipe-shaped rotating shaft, 2 is a gap, 3 is a base body, 4 is a hollow part, 5 is a first cylindrical body, 6 is a tunnel part, 7 is a knife part, 8 is a screw part, 9 is a second cylindrical body, 10 is an annular hollow chamber, 11 is a communicating element, 12 is a high pressure air generation source, and A is an object to be coated.

Claims (1)

[Claims] 1. A first cylinder made of metal whose inner peripheral surface expands in diameter in a tapered shape toward the front is connected to a high-speed rotation drive device, and the outer peripheral surface of the first cylinder expands in a direction substantially parallel to the axis of the first cylinder. A second cylinder having a tapered surface with a gentle diameter and having an inner circumferential surface parallel to the axis of the first cylinder is provided on the outer periphery of the first cylinder so that its position can be freely adjusted back and forth in the axial direction of the first cylinder. An annular hollow chamber rotating together with the first cylindrical body is formed between the bodies, and this annular hollow chamber is connected to a high-pressure air generation source, and a ring communicating with the annular hollow chamber is formed behind the knife portion at the tip of the first cylindrical body. A slit-shaped injection nozzle is arranged and formed, and a certain section of the annular hollow chamber that is continuous with the injection nozzle is formed into a thin cylindrical shape with a narrow gap between the inner and outer circumferential walls and a rectifying hollow formed approximately parallel to the first cylinder axis. As a part, a jet air stream is ejected from an injection nozzle in a direction substantially parallel to the axis of the first cylinder, and a paint supply device supplies paint to the inner circumferential surface of the first cylinder, and a high voltage generator applies a high voltage to the first cylinder. An electrostatic coating device characterized by comprising a voltage generator.