JP6765007B2 - Electrostatic coating machine - Google Patents

Description

The present invention relates to an electrostatic coating machine in which a high voltage is applied to a sprayed coating material to perform coating.

Generally, as an electrostatic coating machine, a rotary atomizing head type electrostatic coating machine is known. This electrostatic coating machine consists of an air motor that is held at the ground potential and rotates the rotating shaft by supplying compressed air, and a tubular body provided on the front side of the rotating shaft and held at the ground potential. A rotary atomizing head that sprays the paint supplied while rotating by the air motor from the discharge end edge at the front end, and a plurality of rotary atomizing heads that are located on the rear side of the rotary atomizing head and are provided on the outer peripheral side of the air motor. Formed in a tubular shape using an external electrode member that charges the paint particles sprayed from the emission edge of the rotary atomizing head to a negative potential by applying a negative high voltage to the electrodes, and a conductive material. At the same time, the front end is arranged on the outer peripheral side of the rotary atomizing head in a state of being located at an intermediate portion in the length direction of the rotary atomizing head, and is directed toward the paint particles sprayed from the rotary atomizing head on the front end. A large number of air ejection holes for ejecting shaping air are included in the shaping air ejection member provided over the entire circumference in the circumferential direction (Patent Document 1).

When painting is performed using the electrostatic coating machine configured in this way, the rotary atomizing head is rotated at high speed by an air motor, and the paint is supplied to the rotary atomizing head in this state. As a result, the paint supplied to the rotary atomizing head is atomized by the centrifugal force when the rotary atomizing head rotates, and is sprayed as paint particles from the emission edge. At this time, the shaping air ejection member injects the shaping air ejected from each air ejection hole onto the paint particles. As a result, the shaping air ejection member adjusts the spray pattern of the paint particles to a desired shape by controlling the motion vector component of the paint particles in the direction to be coated.

Further, the external electrode member negatively charges the paint particles sprayed from the emission edge of the rotary atomizing head by applying a negative high voltage to each electrode. As a result, the paint particles sprayed from the rotary atomizing head are indirectly negatively charged. Therefore, the electrostatic coating machine can fly the charged paint particles along the electrostatic field formed between each electrode and the object to be coated, and coat the paint particles on the object to be coated.

International Publication No. 2013/183416

By the way, the electrostatic coating machine described in Patent Document 1 includes a cover member made of an insulating resin material that covers the air motor. At this time, when a negative high voltage is applied to the external electrode, corona ions due to corona discharge are generated in the vicinity of the tip of the external electrode. Therefore, the outer surface of the cover member is charged with the negative electrode property of the discharged negative ions. In this case, if the cover member and the shaping air ring are arranged in close proximity to each other, electric charges are repeatedly discharged and charged between the cover member and the shaping air ring at the tip portion of the cover member, and tend to be easily deteriorated. In consideration of this point, in the electrostatic coating machine described in Patent Document 1, a tubular semi-conductive member made of a semi-conductive material is provided between the cover member and the shaping air ring. As a result, the electric charge charged on the cover member is discharged to the semi-conductive member, but it does not become a concentrated large current in a short time as compared with the direct discharge to the shaping air ring, and the current is slow. become. As a result, deterioration of the film-shaped cover member can be suppressed and durability can be improved.

However, even when the cover member is discharged from the semi-conductive member, the cover member may be deteriorated. In addition to this, electric discharge may occur from the semi-conductive member to the shaping air ring, and the semi-conductive member may deteriorate. Therefore, there is a problem that sufficient durability cannot be obtained due to deterioration of the cover member and the semi-conductive member.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide an electrostatic coating machine capable of increasing durability.

The present invention comprises an air motor that is held at the ground potential and rotates a rotating shaft by supplying compressed air, and a tubular body provided on the front side of the rotating shaft and held at the ground potential. A rotary atomizing head that sprays the paint supplied during rotation from the emission edge of the front end, and a plurality of electrodes that are located on the rear side of the rotary atomizing head and are provided on the outer peripheral side of the air motor and are negative. It is formed in a tubular shape by using an external electrode member that charges the paint particles sprayed from the emission edge of the rotary atomizing head to a negative potential by applying a high voltage of the above, and a conductive material. Shaped air is arranged on the outer peripheral side of the rotary atomizing head with the front end located in the middle portion in the length direction of the rotary atomizing head, and is directed toward the paint particles sprayed from the rotary atomizing head on the front end. A large number of air ejection holes are provided over the entire circumference in the circumferential direction, and insulation provided on the outer peripheral side of the shaping air ejection member to cover the outer peripheral surface of the shaping air ejection member. In an electrostatic coating machine configured to include a tubular insulating member made of a material, between the shaping air ejection member and the insulating member, a space between the shaping air ejection member and the insulating member is provided. A discharge buffering member made of an annular self-healing insulating material is provided at a separating position, and the discharge buffering member has a creepage distance on the front side exposed from the insulating member and a creepage surface on the rear side covered with the insulating member. It is characterized by being formed shorter than the distance .

According to the present invention, it is possible to suppress the discharge between the insulating member and the shaping air ejection member, suppress the deterioration of the insulating member, and improve the durability.

It is sectional drawing which shows the rotary atomization head type electrostatic coating machine of the indirect charging type by embodiment of this invention. It is a perspective view which shows the rotary atomization head type electrostatic coating machine of an indirect charging type. It is sectional drawing which shows the front side part of the rotary atomization head type electrostatic coating machine enlarged. FIG. 5 is an enlarged cross-sectional view showing an insulating member, a discharge buffering member, and the like in FIG. It is sectional drawing seen from the same position as FIG. 4 which shows the insulating member, the discharge buffering member, etc. by the 1st modification. It is sectional drawing seen from the same position as FIG. 4 which shows the insulating member, the discharge buffering member, etc. by the 2nd modification. It is sectional drawing seen from the same position as FIG. 3 which shows the insulating member, the discharge buffering member and the like by the 3rd modification. It is sectional drawing which shows the rotary atomization head type electrostatic coating machine provided with the external electrode member by the 4th modification.

Hereinafter, the indirect charging type rotary atomizing head type electrostatic coating machine according to the embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 4 show embodiments of the present invention. In the present embodiment, the arrangement relationship of the rotary atomizing head type electrostatic coating machine 1 described later is described with the shaping air ejection direction as the front side and the side opposite to the front side as the rear side.

In FIG. 1, the rotary atomizing head type electrostatic coating machine 1 (hereinafter, simply referred to as the electrostatic coating machine 1) according to the present embodiment applies paint sprayed from the rotary atomizing head 4 by an external electrode member 6 described later. It is configured as an indirect charging type rotary atomizing head type electrostatic coating machine that indirectly charges a high voltage. The electrostatic coating machine 1 is attached to, for example, the tip of an arm (not shown) of a coating robot.

The coating machine support 2 is provided so as to surround the air motor 3 on the outer peripheral side of the air motor 3 described later and to extend rearward from the air motor 3. The coating machine support 2 is attached to the tip of the arm described above via the mounting cylinder 2A on the base end side. Here, the coating machine support 2 is made of, for example, a rigid insulating resin material.

A motor accommodating portion 2B is provided on the tip end side of the coating machine support 2 so as to open forward. A female screw portion 2C is provided on the opening side of the motor accommodating portion 2B. Further, the coating machine support 2 is provided with an insertion hole 2D into which the base end side of the feed tube 5 described later is inserted at the central position of the bottom portion of the motor accommodating portion 2B (coaxial with the rotation shaft 3C described later). ing.

The air motor 3 is provided in the motor accommodating portion 2B of the coating machine support 2. The air motor 3 uses compressed air as a power source to rotate the rotary shaft 3C and the rotary atomizing head 4, which will be described later, at a high speed of, for example, 3000 to 150,000 rpm. The air motor 3 is made of a conductive metal material such as an aluminum alloy and is held at a ground potential.

The air motor 3 includes a stepped cylindrical motor case 3A attached to the front side of the coating machine support 2 and, for example, an impeller type turbine 3B which is located near the rear side of the motor case 3A and is rotatably housed. And a rotating shaft 3C rotatably provided at the center position of the motor case 3A and attached to the turbine 3B at the rear end side.

The motor case 3A of the air motor 3 is formed as a cylindrical body coaxial with the rotating shaft 3C. The motor case 3A is a stepped cylinder formed by a large-diameter large-diameter cylinder 3A1 inserted into the motor accommodating portion 2B of the coating machine support 2 and a small-diameter small-diameter cylinder 3A2 protruding forward from the large-diameter cylinder 3A1. It is formed in a shape.

The motor case 3A is fitted in the motor accommodating portion 2B of the coating machine support 2. In this state, the motor case 3A is fixed in the motor accommodating portion 2B by the annular screw member 3D screwed to the female thread portion 2C of the coating machine support 2.

The rotating shaft 3C is formed as a hollow tubular body rotatably supported in the motor case 3A via an air bearing (not shown). The rear end side of the rotating shaft 3C is attached to the center of the turbine 3B, and the front end side protrudes from the motor case 3A to the front side. A rotary atomizing head 4 is attached to the front end portion of the rotary shaft 3C by means such as screwing.

The rotary atomizing head 4 is provided on the front side of the rotary shaft 3C of the air motor 3. The rotary atomizing head 4 is formed as a tubular body by a conductive metal material such as an aluminum alloy, and is held at a ground potential through an air motor 3. As shown in FIG. 3, the rotary atomizing head 4 is formed as, for example, a long cylindrical body, and is a mounting portion 4A whose rear side extends linearly in the axial direction. The attachment portion 4A is attached to the front end portion of the rotating shaft 3C by means such as screwing.

The front side of the rotary atomizing head 4 is an expansion site 4B that gradually expands toward the front. The inner peripheral surface of the expansion portion 4B is a paint thinning surface 4C that thins the supplied paint. Further, the tip (front end) of the paint thinning surface 4C is a discharge edge 4D that discharges the thinned paint as paint particles.

Then, when the paint is supplied through the feed tube 5 described later in a state where the rotary atomizing head 4 is rotated at high speed by the air motor 3, the paint is thinned on the paint thinning surface 4C and the discharge end is generated by centrifugal force. Spray from edge 4D. In this case, the paint particles sprayed from the emission edge 4D do not face the object to be coated (not shown) arranged in front, but are directed outward in the radial direction by the centrifugal force of the rotary atomizing head 4. Try to fly (radially).

However, the paint particles sprayed from the emission edge 4D are gradually accelerated toward the object to be coated on the front side by being sprayed with shaping air by the shaping air ejection member 9 described later from the rear side. Further, the paint particles sprayed from the emission edge 4D are negatively charged by the external electrode member 6 described later, so that an electrostatic field is formed between the paint particles and the object to be coated held at the ground potential. You can fly along.

The feed tube 5 is provided so as to be inserted into the rotating shaft 3C, and the rear end side thereof is inserted into the insertion hole 2D (see FIG. 1) of the coating machine support 2. On the other hand, the front end side of the feed tube 5 protrudes from the rotary shaft 3C and extends into the rotary atomizing head 4. A paint passage is provided in the feed tube 5, and the paint passage is connected to a paint supply source and a cleaning fluid supply source (neither shown) via a color change valve device or the like. As a result, the feed tube 5 supplies the paint from the paint supply source toward the rotary atomizing head 4 through the paint passage at the time of painting, and at the time of cleaning, color change, etc., the cleaning fluid from the cleaning fluid supply source ( (Shinna, air, etc.) is supplied.

The external electrode member 6 is located on the rear side of the rotary atomizing head 4 and is provided on the outer peripheral side of the air motor 3, that is, on the outer peripheral side of the coating machine support 2. The external electrode member 6 is coated with paint particles sprayed from the emission edge 4D of the rotary atomizing head 4 by applying a negative high voltage (for example, -30 to -150 kV) to a plurality of electrodes 6C described later. Is charged to a negative potential.

A plurality of external electrode members 6 are provided on the outer peripheral side of the coating machine support 2 and are formed on an annular external electrode support cylinder 6A made of an insulating resin material and a plurality of the external electrode support cylinders 6A at equal intervals in the circumferential direction. For example, 8 to 20 electrode mounting holes 6B (only 2 are shown) and electrodes 6C mounted in each of the electrode mounting holes 6B are included. On the front side of the external electrode support cylinder 6A, a number of holes 6A1 corresponding to the needle-shaped portion 6C1 of each electrode 6C are provided.

Here, in the external electrode member 6 according to the present embodiment, in order to use the electrostatic coating machine 1 in a narrow space such as the inside of the vehicle body, the coating machine support 2 is located closer to the rear side of the coating machine support 2. It is provided near the outer peripheral side of the. Along with this, the needle-shaped portion 6C1 of each electrode 6C is arranged at a position largely separated from the rotary atomizing head 4 on the rear side in the axial direction, that is, on the outer peripheral side of the air motor 3. Further, the needle-shaped portion 6C1 of each electrode 6C is arranged at a position near the outer side in the radial direction of the outer cover member 8 described later. As a result, it is possible to prevent each electrode 6C from interfering with surrounding members during painting work.

Each electrode 6C is connected to a high voltage generator (neither shown) via a resistor. Therefore, each electrode 6C is configured to apply a negative high voltage by a high voltage generator. As a result, the external electrode member 6 causes the coating particles sprayed from the rotary atomizing head 4 to be negatively charged by the corona discharge generated at each electrode 6C.

The inner cover member 7 is formed as a tubular body whose diameter is reduced in an arc shape toward the front side by using, for example, an insulating resin material. The inner cover member 7 is provided between the outer electrode member 6 and the shaping air ejection member 9 described later so as to surround the air motor 3. The rear side of the inner cover member 7 is attached to the outer peripheral side of the coating machine support 2. On the other hand, the inner cover member 7 is attached to the rear portion of the large-diameter cylindrical portion 9B1 whose front side constitutes the outer peripheral surface 9B of the shaping air ejection member 9.

Like the inner cover member 7, the outer cover member 8 is formed as a tubular body whose diameter is reduced in an arc shape toward the front side by an insulating resin material. The outer cover member 8 is provided between the outer electrode member 6 and the shaping air ejection member 9 so as to surround the air motor 3 from the outer side of the inner cover member 7.

The rear side of the outer cover member 8 is attached between the inner cover member 7 and the inner peripheral side of the outer electrode member 6. Further, the outer cover member 8 is arranged on the front side at intermediate portions in the front and rear directions of the outer peripheral surface 9B of the shaping air ejection member 9. The outer cover member 8 can be removed when assembling or disassembling the rotary atomizing head 4, the shaping air ejection member 9, and the like.

The shaping air ejection member 9 is arranged on the outer peripheral side of the rotary atomizing head 4 with the front end located at the intermediate portion (rear side of the spreading portion 4B) in the length direction of the rotary atomizing head 4. The shaping air ejection member 9 is made of a conductive metal material such as an aluminum alloy, and is held at a ground potential via an air motor 3.

The shaping air ejection member 9 is formed as a stepped cylindrical body surrounding the rotary atomizing head 4. The inner peripheral surface 9A of the shaping air ejection member 9 faces the outer peripheral surface of the rotary atomizing head 4 with a slight gap. On the other hand, the outer peripheral surface 9B of the shaping air ejection member 9 includes a large-diameter cylindrical portion 9B1 located on the rear side and a tapered portion 9B2 whose diameter is gradually reduced from the front end of the large-diameter cylindrical portion 9B1 toward the front. It is composed of a small-diameter cylindrical portion 9B3 having a small diameter extending linearly from the front end of the tapered portion 9B2 toward the front.

The front portion of the inner cover member 7 is attached to the rear portion of the large-diameter cylindrical portion 9B1 in an outer fitting state. The tapered portion 9B2 and the small-diameter cylindrical portion 9B3 are covered with an insulating member 14 described later.

The rear end portion of the shaping air ejection member 9 is a cylindrical mounting screw portion 9C, and the mounting screw portion 9C is screwed to the female screw portion 2C of the coating machine support 2. As a result, the shaping air ejection member 9 is attached to the front portion of the coating machine support 2 by using the attachment screw portion 9C.

Further, as shown in FIGS. 2 to 4, the front end (front portion) of the shaping air ejection member 9 is a flat annular front portion 9D. A first air ejection hole 10 and a second air ejection hole 12 are opened in the front surface portion 9D. The front surface portion 9D is arranged around the rear position of the spread portion 4B of the rotary atomizing head 4.

A large number of first air ejection holes 10 are provided at equal intervals over the entire circumference in the circumferential direction, located near the outer diameter side of the front surface portion 9D. The first air ejection hole 10 is connected to a first shaping air supply source (not shown) through a first shaping air passage 11. The first air ejection hole 10 ejects the first shaping air toward the vicinity of the emission edge 4D of the rotary atomizing head 4.

A large number of the second air ejection holes 12 are provided on the front surface portion 9D at equal intervals over the entire circumference in the circumferential direction, which are located inside the first air ejection holes 10 in the radial direction. The second air ejection hole 12 is connected to a second shaping air supply source (not shown) through a second shaping air passage 13. The second air ejection hole 12 ejects the second shaping air toward the back surface of the rotary atomizing head 4.

As a result, the first shaping air ejected from the first air ejection hole 10 and the second shaping air ejected from the second air ejection hole 12 are discharged from the emission edge 4D of the rotary atomizing head 4. The liquid yarn of the paint to be coated is sheared to promote the formation of paint particles, and the spray pattern of the paint particles sprayed from the rotary atomizing head 4 is shaped. At this time, the spray pattern can be changed to a desired size and shape by appropriately adjusting the pressure of the first shaping air and the pressure of the second shaping air. Further, the first and second shaping airs are sprayed by centrifugal force onto the paint particles flying outward in the radial direction from the emission edge 4D of the rotary atomizing head 4, so that the direction of the paint particles is gradually covered. Accelerate paint particles while aiming at the coating.

Next, the configurations of the insulating member 14 and the discharge buffering member 15, which are the characteristic parts of the present embodiment, will be described in detail.

The insulating member 14 is provided on the outer peripheral side of the shaping air ejection member 9. The insulating member 14 covers the outer peripheral side of the tapered portion 9B2 and the small-diameter cylindrical portion 9B3 of the outer peripheral surface 9B of the shaping air ejection member 9. The insulating member 14 is formed as a tubular body made of a highly insulating material (for example, a volume resistivity of 10 ¹⁶ to 10 ¹⁸ Ωcm) such as a tetrafluorinated ethylene resin. The insulating member 14 may be formed of a highly insulating material other than the tetrafluorinated ethylene resin.

Here, the surface of the insulating member 14 is formed by the charged ion particles generated by the needle-shaped portion 6C1 (corona discharge electrode) of the electrode 6C moving along the electric lines of force extending toward the shaping air ejection member 9. It becomes charged. When the paint particles charged with the same polarity are unintentionally approached, the charged insulating member 14 electrically generates a repulsive force to prevent the particles from adhering to the charged insulating member 14 to reduce the stain.

The insulating member 14 is located on the rear side and covers the outer peripheral side of the tapered portion 9B2, and the front side of the tapered cover portion 14A so as to cover the outer peripheral side of the small diameter cylindrical portion 9B3 from the front portion having a small diameter. It is composed of a tubular cover portion 14B extending to the surface. On the inner peripheral side of the tubular cover portion 14B, a fitting portion 14C into which the discharge buffer member 15 described later is fitted is formed. Further, the front end portion 14B1 of the tubular cover portion 14B serves as a base point C (see FIG. 4) between the discharge path A and the discharge path B, which will be described later.

The discharge buffer member 15 is provided between the shaping air ejection member 9 and the insulating member 14. Specifically, the discharge buffer member 15 is formed as an annular cylinder that surrounds the shaping air ejection member 9.

The discharge buffer member 15 is an insulating material, and is formed by using a self-healing insulating material such as ceramic. Therefore, when the electric charge moves intermittently (that is, partially discharges) from the insulating member 14 which is charged toward the grounded shaping air ejection member 9, a discharge is generated through the discharge buffer member 15. The discharge buffer member 15 can be formed by using a self-healing insulator such as glass, mica, or alumina in addition to ceramic. The discharge buffer member 15 made of ceramic has a porous property. The discharge buffer member 15 uses a porous structure to retain moisture in the air on its surface, thereby lowering the apparent resistivity and slowly moving charges like a semi-conductive material. It can relieve electrical stress.

The front end portion 15A of the discharge buffer member 15 projects to the front side of the front end of the insulating member 14. On the other hand, the rear end portion 15B of the discharge buffer member 15 is inserted into the fitting portion 14C of the insulating member 14.

Here, the arrangement relationship of the shaping air ejection member 9, the insulating member 14, and the discharge buffer member 15 in the axial direction (front and rear directions) will be described. As shown in FIGS. 3 and 4, the dimension H is defined from the front end portion 9D of the shaping air ejection member 9 to the front end portion 15A of the discharge buffer member 15, and the front end portion 15A of the discharge buffer member 15 to the front end portion 14B1 of the insulating member 14. Is dimension J, and the dimension K is from the front end portion 14B1 of the insulating member 14 to the rear end portion 15B of the discharge buffer member 15. In this case, the dimensions H and K will be described with reference to the dimension J from the front end portion 15A of the discharge buffer member 15 to the front end portion 14B1 of the insulating member 14. That is, the dimension J and the dimension K have the following relationship of the number 1. If the discharge buffer member 15 can be arranged on the shaping air ejection member 9, the dimension K may be twice or more the value of the dimension J.

As a result, the electric charge charged in the insulating member 14 can flow to the shaping air ejection member 9 through the discharge path A on the front side where the creepage distance is short on the surface of the discharge buffer member 15. Further, the dimension H is set as shown in the following equation 2.

That is, the front end portion 15A of the discharge buffer member 15 can be arranged so as to be aligned with the front portion 9D of the shaping air ejection member 9.

Here, the discharge buffer member 15 is formed of a ceramic having a porous property. Therefore, the discharge buffer member 15 can utilize the porous property to leave water or the like on the surface. In particular, since the inside of the painting booth where painting is performed is maintained at a high humidity, moisture and the like tend to remain on the surface. The discharge buffer member 15 can enable minute charging or galvanism on the surface by utilizing the water remaining on the surface. As a result, the electric charge charged on the insulating member 14 gradually flows through the moisture on the surface of the discharge buffer member 15 and can reach the shaping air ejection member 9.

In this case, the electric charge charged on the insulating member 14 is gradually flowed to the shaping air ejecting member 9 through the surface of the discharge buffering member 15, so that the electric charge between the insulating member 14 and the shaping air ejecting member 9 is discharged. Can be suppressed. On this basis, even if a discharge occurs between the insulating member 14 and the shaping air ejection member 9, the discharge buffer member 15 arranged between them is formed of ceramic having excellent rigidity, heat resistance, and the like. Therefore, there is no electrical deterioration due to discharge.

Thus, during the painting work by the electrostatic coating machine 1, electric lines of force are formed between each electrode 6C and the outer peripheral surface of the insulating member 14. Since the insulating member 14 is charged with a high voltage by the electric lines of force, an electric discharge occurs between the insulating member 14 and the shaping air ejection member 9. If this discharge is repeated, the front end portion of the insulating member 14 may be electrically deteriorated.

Therefore, according to the electrostatic coating machine 1 according to the present embodiment, a tubular ceramic is placed between the shaping air ejection member 9 and the insulating member 14 at a position separating the shaping air ejection member 9 and the insulating member 14. A discharge buffer member 15 made of (self-healing insulating material) is provided. As a result, even if a discharge is generated from the insulating member 14 to the shaping air ejection member 9, the discharge buffer member 15 arranged between them is made of ceramic having excellent rigidity, heat resistance, and the like. Durability can be improved by a function that can prevent electrical deterioration due to discharge, or a function that gradually discharges electric charge to eliminate partial discharge.

Further, the discharge buffer member 15 is formed so that the creepage distance (discharge path A) on the front side exposed from the insulating member 14 is shorter than the creepage distance (discharge path B) on the rear side covered with the insulating member 14. More specifically, as a path through which the charged charge flows on the surface of the insulating member 14, the shaping air ejection member 9 passes through the front end portion 15A of the discharge buffering member 15 with the front end portion 14B1 of the insulating member 14 as the base point C. There is a discharge path A that reaches the outer peripheral surface 9B, and a discharge path B that reaches the outer peripheral surface 9B of the shaping air ejection member 9 from the base point C through the rear end portion 15B of the discharge buffer member 15. In this case, the discharge path B is formed longer than the discharge path A due to the size of the insulating member 14 in the length direction (front and rear directions) covering the discharge buffer member 15. Therefore, it is possible to promote the discharge by the discharge path A as compared with the discharge path B, prevent the electrical deterioration of the insulating member 14 due to the galvanism in the discharge path B, and improve the durability and reliability. Can be done.

On the outer peripheral side of the air motor 3, a coating machine support 2 that surrounds the air motor 3 and extends rearward from the air motor 3 is provided. In addition to this, the external electrode member 6 is provided on the outer peripheral side of the coating machine support 2 and is provided around the annular external electrode support cylinder 6A made of an insulating resin material and the front end side of the external electrode support cylinder 6A. It is configured to include a plurality of electrodes 6C arranged in the direction. As a result, the external electrode member 6 can be arranged in an insulated state on the outer peripheral side of the coating machine support 2. Further, since the plurality of electrodes 6C can be compactly assembled, the external electrode member 6 can be miniaturized, and a coating machine suitable for coating in a narrow place can be obtained.

An inner cover member 7 and an outer cover member 8 which are formed in a tubular shape by an insulating material and surround the air motor 3 are provided between the external electrode member 6 and the shaping air ejection member 9. Therefore, the air motor 3 can be covered by the cover members 7 and 8. Further, the outer cover member 8 formed in a smooth arc shape can surely clean the adhered paint in a short time even if the paint adheres.

In the above embodiment, a case where the insulating member 14 is provided with the fitting portion 14C and the discharge buffer member 15 is fitted to the fitting portion 14C is illustrated. However, the present invention is not limited to this, and may be configured as in the first modification shown in FIG. 5, for example. According to the first modification, the shaping air ejection member 21 is configured in the same manner as the shaping air ejection member 9 according to the embodiment, and has an inner peripheral surface 21A, an outer peripheral surface 21B, and a front portion serving as a front end (front portion). It has 21C. However, an annular recess 22 is formed on the outer peripheral surface 21B of the shaping air ejection member 21, and the discharge buffer member 23 is fitted in the annular groove 22. In this case, the insulating member 24 omitting the fitting portion is attached so as to cover the outer peripheral surface of the discharge buffer member 23.

Further, it may be configured as in the second modification shown in FIG. In the second modification, the insulating member 31 excluding the fitting portion is attached so as to cover the outer peripheral surface of the discharge buffer member 15.

Further, according to the embodiment, the outer cover member 8 surrounding the air motor 3 and the insulating member 14 covering the outer peripheral side of the shaping air ejection member 9 are formed separately from each other. The present invention is not limited to this, and for example, as in the third modification shown in FIG. 7, a single insulating member 41 is formed so as to cover the outer peripheral side of the shaping air ejection member 9 and surround the air motor 3. You may.

Further, according to the embodiment, the external electrode member 6 is equidistantly spaced in the circumferential direction from the annular external electrode support cylinder 6A provided on the outer peripheral side of the coating machine support 2 and the external electrode support cylinder 6A. An example is shown in which a plurality of electrode mounting holes 6B arranged in the above and electrodes 6C mounted in each of the electrode mounting holes 6B are included. However, the present invention is not limited to this, and may be configured as in the fourth modification shown in FIG. 8, for example. That is, the external electrode member 51 according to the fourth modification has the annular external electrode support cylinder 51A provided on the outer peripheral side of the coating machine support 2 and the front portion of the external electrode support cylinder 51A in the circumferential direction. A plurality of electrodes are arranged at equal intervals and include electrodes 51B extending forward.

It is needless to say that the above-described embodiment and each of the modified examples are examples, and partial replacement or combination of the configurations shown in different modified examples is possible.

1 Rotary atomizing head type electrostatic coating machine 2 Coating machine support 3 Air motor 3C Rotating shaft 4 Rotary atomizing head 4D Emission end edge (front end)
6,51 External electrode member 6C, 51B Electrode 9,21 Shaping air ejection member 9B, 21B Outer peripheral surface 9D, 21C Front part (front part)
10 First air ejection hole (air ejection hole)
12 Second air ejection hole (air ejection hole)
14, 24, 31, 41 Insulation member 15, 23 Discharge buffer member

Claims (2)

An air motor that is held at the ground potential and rotates the rotating shaft by supplying compressed air,
A rotary atomizing head, which consists of a tubular body provided on the front side of the rotating shaft and held at the ground potential, and sprays paint supplied while rotating by the air motor from the emission end edge of the front end.
It is located on the rear side of the rotary atomizing head and is provided on the outer peripheral side of the air motor, and is sprayed from the emission end edge of the rotary atomizing head by applying a negative high voltage to a plurality of electrodes. An external electrode member that charges the paint particles to a negative potential,
It is formed in a tubular shape using a conductive material, and is arranged on the outer peripheral side of the rotary atomizing head with the front end located at an intermediate portion in the length direction of the rotary atomizing head. A shaping air ejection member in which a large number of air ejection holes for ejecting shaping air toward the paint particles sprayed from the head are provided over the entire circumference in the circumferential direction.
In an electrostatic coating machine provided on the outer peripheral side of the shaping air ejection member and configured to include a tubular insulating member made of an insulating material that covers the outer peripheral surface of the shaping air ejection member.
Between the shaping air ejection member and the insulating member, a discharge buffering member made of an annular self-healing insulating material is provided at a position separating the shaping air ejection member and the insulating member .
The electrostatic coating machine is characterized in that the discharge buffer member is formed so that the creepage distance on the front side exposed from the insulating member is shorter than the creepage distance on the rear side covered with the insulating member . The electrostatic coating machine according to claim 1, wherein the discharge buffer member is formed as an annular cylinder that surrounds the shaping air ejection member.

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