JPH1099731A - Rotary atomizing head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To wash paint stuck to the outer peripheral surface of a bell cup. SOLUTION: A bell cup 11 is provided with a solvent path 16 for making a paint pool 15 and an outer peripheral surface 11G of the bell cup 11 communicate with each other, and on the outer peripheral surface 11G of the bell cup 11, an annular dam groove 17 is provided. In this way, when washing a rotary atomizing head 10, thinner discharged from a solvent feeding nozzle 6 flows into the annular dam groove 17 through the paint pool 15 and the solvent path 16, and is temporarily stored in the annular dam groove 17. After that, the thinner flows out from the annular groove 17 and flows on the outer peripheral surface 11G of the bell cup 11 toward the front end side of the bell cup 11. As a result, paint stuck on the outer peripheral surface 11G is washed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary atomizing head suitable for use in a coating machine for performing coating while changing colors.

[0002]

2. Description of the Related Art In general, an electrostatic coating machine using a rotary atomizing head includes a coating machine main body, a rotating shaft extending in the coating machine main body in an axial direction and rotatably provided, and a rotating shaft. An air motor provided on the coating machine main body for rotationally driving; a rotary atomizing head provided at the tip of the rotary shaft located outside the coating machine main body so as to be rotated by the air motor; And a supply nozzle extending in the rotary atomizing head at the distal end side. The supply nozzle discharges and supplies paint or thinner as a solvent for cleaning toward the rotary atomizing head,
The supply nozzle is connected to a color changing valve device, a thinner source, and the like via a paint pipe or the like.

Further, the rotary atomizing head is formed in a bell shape or a cup shape, and the front side of the inner peripheral surface is a paint thinning surface for thinning the paint, and the rear side of the inner peripheral surface is a paint receiving surface. A bell cup, a hub member provided on the inner peripheral side of the bell cup between the paint thinning surface and the paint receiving surface of the bell cup, and a rear surface of the hub member and the bell cup. A paint reservoir defined between the paint receiving surface and a paint reservoir for storing paint or a solvent supplied to the paint receiving surface from a supply nozzle provided in the coating machine body; And a plurality of paint outlet holes for allowing the paint or solvent supplied to the reservoir to flow to the paint thinning surface of the bell cup.

[0004] When the coating is performed by the electrostatic coating machine according to the prior art constructed as described above, first, compressed air is supplied to the air motor to rotate the rotary shaft and the rotary atomizing head at high speed.
Then, the paint is discharged from the supply nozzle toward the rotary atomizing head. As a result, the paint flows into the inner peripheral side of the bell cup of the rotary atomizing head, is thinned on the paint thinning surface, and is discharged as charged paint particles from the discharge edge. At this time, since an electrostatic field is formed between the electrostatic coating machine and the object to be coated, the charged paint particles discharged from the discharge edge of the rotary atomizing head are coated along the lines of electric force. Fly toward the object to be applied, and apply to the object.

When coating is performed by the electrostatic coating machine, the paint adheres to the paint thinner surface, the paint receiving surface, and the like of the bell cup. In order to wash the paint adhered to the paint thin film surface or the like, the thinner is discharged from the supply nozzle toward the bell cup while rotating the rotating shaft and the rotary atomizing head by the air motor. As a result, the thinner flows into the inner peripheral surface of the bell cup, and removes the paint adhered to the paint thinner surface or the like before the thinner is released from the discharge edge through the paint thinner surface.

By the way, in such an electrostatic coating machine according to the prior art, most of the paint particles discharged from the discharge edge of the bell cup at the time of coating apply to the object to be coated along the lines of electric force. However, some paint particles flow backward to the back of the bell cup and wrap around the outer periphery of the bell cup. As a result,
Paint may adhere to the outer peripheral surface of the bell cup.

That is, when the rotary atomizing head rotates at a high speed, a negative pressure region is generated on the front surface of the bell cup due to the high speed rotation, and an air pumping phenomenon occurs in which air is sucked into the negative pressure region. As a result, the paint particles flow backward toward the rear of the bell cup. Further, shaping air may be ejected in order to form a spray pattern formed by the rotary atomizing head in accordance with the coating conditions of the object to be coated. When this shaping air is used, a negative pressure is partially generated on the outer peripheral side of the bell cup due to the jet flow. As a result, the paint particles flow backward toward the rear of the bell cup.

[0008] In this way, when some paint particles flow backward and paint adheres to the outer peripheral surface of the bell cup, the paint solidifies. Therefore, depending on the coating conditions, there is a disadvantage that the solidified paint may peel off and adhere to the surface of the object as paint pieces (dust), thereby deteriorating the paint quality of the object. Further, in the electrostatic coating machine according to the related art, the thinner is supplied from the supply nozzle toward the inner peripheral side of the bell cup, so that the paint receiving surface and the paint thinning surface of the bell cup can be cleaned. However, there is a drawback that the paint adhered to the outer peripheral surface of the bell cup cannot be washed by the thinner from the supply nozzle.

In order to solve such a drawback, an electrostatic coating machine having a cleaning nozzle for discharging a thinner toward the outer peripheral surface of a bell cup is provided in a coating machine main body.
No. 9 (hereinafter referred to as “other prior art”). According to such another prior art electrostatic coating machine, the thinner is discharged from the cleaning nozzle provided in the coating machine body toward the outer peripheral surface of the bell cup while the rotary atomizing head is rotated, It is possible to wash the paint adhered to the outer peripheral surface of the bell cup.

[0010]

However, in the above-mentioned other prior art, when cleaning the outer peripheral side of the rotary atomizing head,
With the rotary atomizing head rotated, thinner is simply discharged toward the outer peripheral surface of the bell cup. For this reason, the thinner discharged to the bell cup is likely to rebound on the outer peripheral surface of the bell cup, and the thinner and the thinner paint between the thinner and the outer peripheral surface of the bell cup are poorly adapted. There is a problem that cleaning may not be performed reliably.

Further, in order to eliminate the bounce of the thinner, poor adaptation, etc., and to reliably wash the paint adhered to the outer peripheral surface of the bell cup, the mounting position of the cleaning nozzle, the direction of the cleaning nozzle, or the discharge amount of the thinner And the like must be set precisely, there is a problem that design and manufacturing are difficult, and advanced design and manufacturing techniques are required.

Further, despite the fact that the thinner is provided from the supply nozzle inserted through the rotating shaft toward the inner peripheral side of the bell cup as in the electrostatic coating machine according to the prior art, It is inefficient to separately provide a dedicated nozzle for cleaning the outer peripheral surface of the
There is a problem that the number of parts increases and the cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a rotary atomizing head capable of reliably cleaning paint adhered to the outer peripheral surface of a bell cup. I have.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a bell-shaped or cup-shaped one, and a front side of an inner peripheral surface serves as a paint thinning surface for thinning a paint. A bell cup with a paint receiving surface on the rear side of the peripheral surface,
A hub member located on the inner peripheral side of the bell cup and provided between the paint thinning surface of the bell cup and the paint receiving surface; and a hub member between the rear surface of the hub member and the paint receiving surface of the bell cup. A paint reservoir for storing paint or solvent supplied to the paint receiving surface from a nozzle provided in the coating machine body; and a paint or solvent provided to the hub member and supplied to the paint reservoir from the nozzle. And a plurality of paint outflow holes for allowing the paint to flow out to the paint thinning surface of the bell cup.

The invention according to claim 1 is characterized in that the inflow port is provided on the inner peripheral surface of the bell cup and opens to the paint receiving surface, and the outflow port is provided on the outer peripheral surface of the bell cup.
A plurality of solvent passages communicating the paint reservoir with the outer peripheral side of the bell cup; and a plurality of solvent passages provided between the outlet of the solvent passage and the discharge edge of the bell cup and provided over the entire outer peripheral surface of the bell cup. And an annular dam groove.

With the above arrangement, when performing coating, the rotary atomizing head is rotated to supply the paint from the nozzle to the paint reservoir. As a result, the paint supplied to the paint reservoir is diffused in the paint reservoir by centrifugal force, and flows out to the paint thinning surface of the bell cup through the paint outlet hole provided in the hub member. And this paint is liquid film on the paint thinning surface,
It is released as paint particles from the bell cup. And
The paint particles fly toward the object by electrostatic force and are applied to the object. Since the paint has a higher viscosity than the solvent, all the paint supplied from the nozzle at the time of painting flows out from the paint outlet hole, and the paint does not flow into the solvent passage.

Next, when the coating of the previous color is completed and the coating of the next color is to be performed, it is necessary to clean the coating of the front color adhered to the rotary atomizing head. For this reason, when cleaning the rotary atomizing head, the rotary atomizing head is rotated, and the solvent is discharged from the nozzle toward the paint reservoir. As a result, the solvent flows into the paint pool and is diffused inside the paint pool by centrifugal force. Then, a part of the solvent in the paint reservoir flows out from the paint outflow hole to the paint thinning surface, and is released from the emission edge while washing the precolor paint adhered to the paint thinning surface.

On the other hand, since the solvent has a low viscosity, the remainder of the solvent diffused in the paint reservoir flows into the inlet of the solvent passage, flows toward the outer peripheral side of the bell cup through the solvent passage, and From the outlet of the bell cup to the outer peripheral surface of the bell cup.
Then, the solvent flowing out from the outlet of the solvent passage flows into an annular dam groove provided on the outer peripheral surface of the bell cup, and is diffused in the annular dam groove over the entire circumference of the bell cup. Furthermore, the solvent in the annular dam groove flows toward the front side of the bell cup due to centrifugal force when the bell cup rotates, shaping air formed on the outer periphery of the bell cup, and the like, and from the front end of the bell cup. Released. Thereby, the precolor paint adhered to the outer peripheral surface of the bell cup is washed.

According to a second aspect of the present invention, an outlet of the solvent passage is opened at the position of the annular dam groove.

With this configuration, when the pre-color paint adhered to the rotary atomizing head is washed, the solvent supplied from the nozzle to the paint reservoir flows into the solvent passage from the paint reservoir, and the solvent passage. Flows out of the outlet directly into the annular dam groove and diffuses around the entire circumference of the bell cup in the annular dam groove. Then, the solvent diffused in the annular dam groove overflows from the annular dam groove to the outer peripheral surface of the bell cup, and the centrifugal force when the bell cup rotates, shaping air formed on the outer periphery of the bell cup, and the like. , Flows toward the front side of the bell cup and is discharged from the front end of the bell cup. Thereby, the precolor paint adhered to the outer peripheral surface of the bell cup is washed.

[0021]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 to 4 show an electrostatic coating machine using a rotary atomizing head according to the first embodiment.

In FIG. 1, reference numeral 1 denotes a cover forming the outer shape of the main body of the electrostatic coating machine.
And a rotary shaft 3 that rotates at a high speed by the air motor 2.

Reference numeral 4 denotes a feed tube which is formed in a cylindrical shape and is inserted into the rotary shaft 3.
Is composed of a paint supply nozzle 5, a solvent supply nozzle 6, and the like.

Here, the paint supply nozzle 5 has a base end connected to a paint source (both not shown) through a paint valve or the like, a tip end protruding from the tip of the rotary shaft 3, and a rotary atomizing head described later. It extends into 10. The paint supply nozzle 5 supplies paint toward the rotary atomizing head 10 during painting.

The solvent supply nozzle 6 is provided coaxially with the paint supply nozzle 5 on the outer peripheral side of the paint supply nozzle 5. Further, the solvent supply nozzle 6 has a base end connected to a solvent source (neither is shown) through a solvent valve or the like, a tip end located at a tip end of the rotary shaft 3, and a rotary atomization head 10. It is growing. Further, a check valve 7 made of an elastic member is provided at the tip side of the solvent supply nozzle 6. When the solvent valve is opened at the time of cleaning the rotary atomizing head 10,
A thinner as a solvent is pressure-fed to the solvent supply nozzle 6, the check valve 7 is opened by the pressure of the thinner at this time, and the thinner is supplied to the rotary atomizing head 10.

Numeral 8 denotes a shaping air ring provided at the tip of the cover 1. The shaping air ring 8 is formed in a cylindrical shape, and a plurality of shaping air discharge ports 8A, 8A,. Is formed.

Reference numeral 9 denotes a shaping air supply passage. The shaping air supply passage 9 includes a passage 9A provided in the cover 1 and a passage 9 provided in the shaping air ring 8.
B and the like. The shaping air supply passage 9 supplies shaping air supplied from an air supply source (not shown) to each of the shaping air discharge ports 8A.

Here, the shaping air is discharged from each of the shaping air discharge ports 8A in the direction of the arrow A to form a spray pattern of paint particles flying out of the bell cup 11. Further, as described later, this shaping air is applied to the thinner so that the thinner flowing out from each solvent passage 16 of the bell cup 11 flows on the outer peripheral surface 11G of the bell cup 11 toward the front side of the bell cup 11. It also has the role of regulating the flow direction.

Reference numeral 10 denotes a rotary atomizing head attached to the rotary shaft 3. Reference numeral 11 denotes a bell cup that forms the outer shape of the rotary atomizing head 10, and the bell cup 11 is formed in a bell shape or a cup shape that expands from the rear side toward the front side, as shown in FIG. The rear portion side is a rotation shaft attachment portion 11A screwed to the tip of the rotation shaft 3. In the center of the bell cup 11, there is formed a small-diameter insertion portion 11B through which the paint supply nozzle 5 and the check valve 7 of the solvent supply nozzle 6 protruding from the tip side of the rotating shaft 3 are inserted.

Further, the inner peripheral side of the bell cup 11 gradually expands in a skirt shape from the insertion portion 11B to the front end of the bell cup 11. And the bell cup 1
1 The front side of the inner peripheral surface is a paint thinning surface 1 for thinning paint.
1C, and the leading end side of the paint thinning surface 11C is a discharge edge 11D. The rear side of the inner peripheral surface of the bell cup 11 receives the paint discharged from the paint supply nozzle 5 or the thinner discharged from the solvent supply nozzle 6.
It has become. Further, between the paint thinning surface 11C and the paint receiving surface 11E, a hub mounting groove 11F for mounting a hub member 12 described later is formed.

Reference numeral 12 denotes a hub mounting groove 11F of the bell cup 11.
The hub member 12 is formed in a disk shape, and the center axis of the hub member 12 is
Are arranged so as to coincide with the center axis (rotation axis).
The front surface 12A of the hub member 12 is a plane continuous with the paint thinning surface 11C of the bell cup 11, and the rear surface of the hub member 12 is a paint supply surface 12B. And
A conical protrusion 12C is formed at the center of the paint supply surface 12B.

Reference numerals 13, 13,... Denote a plurality of annularly formed paint outlet holes formed on the outer peripheral side of the hub member 12. Each of the paint outlet holes 13 extends from the paint supply nozzle 5 to the inner peripheral side of the bell cup 11. The discharged paint or the solvent discharged from the solvent supply nozzle 6 to the inner peripheral side of the bell cup 11 flows out to the paint thinning surface 11C.

Are a plurality of solvent outlet holes penetrating from the paint supply surface 12B to the front surface 12A at the positions of the conical protrusions 12C of the hub member 12. The solvent outlet holes 14 are
At the time of cleaning the rotary atomizing head 10, the thinner discharged from the solvent supply nozzle 6 to the inner peripheral side of the bell cup 11 is
Out to the front surface 12A of the main body.

Reference numeral 15 denotes a hub mounting groove 11F of the bell cup 11.
By attaching the hub member 12 to the
Paint supply surface 12B and paint reception surface 11E of bell cup 11
And the paint pool formed between the two. This paint pool 15
Is a space for temporarily storing the paint discharged from the paint supply nozzle 5 or the thinner discharged from the solvent supply nozzle 6 and diffusing the paint or the thinner.

Reference numerals 16, 16,... Denote a plurality of solvent passages provided at predetermined intervals in the circumferential direction of the bell cup 11, for example, twelve solvent passages. The outlet 16B opens to the surface 11E, and the outlet 16B opens to the outer peripheral surface 11G of the bell cup 11. Each of the solvent passages 16 extends in the bell cup 11 from the inner peripheral side to the outer peripheral side in parallel with the discharge end edge 11D of the bell cup 11. Thus, when the rotary atomizing head 10 is washed, the solvent is discharged from the solvent supply nozzle 6 and the paint pool 15 is discharged.
Flows into the solvent passages 16 and flows toward the outer peripheral side of the bell cup 11. The solvent passage 1
6 is not limited to 12, but may be 2 to 11, or 13 or more.

Here, the inlet 16A of each solvent passage 16
As shown in FIG. 4, each is opened at a position which is deeper than each paint outflow hole 13 by a certain dimension a. That is, the inlet 16 </ b> A of each solvent passage 16 is separated from the opening position of each paint outlet 13. This prevents the paint supplied from the paint supply nozzle 5 to the paint reservoir 15 from flowing into the solvent passage 16 at the time of coating, and the thinner supplied from the solvent supply nozzle 6 to the paint reservoir 15 at the time of cleaning. It is configured to allow the solvent to flow into the solvent passage 16.

As shown in FIG. 3, each of the solvent passages 16 is inclined in the direction of rotation of the rotary atomizing head 10 (in the direction of arrow B) from the inlet 16A to the outlet 16B. It is provided so as to be twisted in the rotation direction of the head 10. That is, each solvent passage 16 is provided to be inclined in the rotational direction so as to form a predetermined angle α in a range of, for example, 15 degrees to 50 degrees with respect to the radial direction of the bell cup 11. This makes it easier for the thinner discharged from the solvent supply nozzle 6 into the paint reservoir 15 to flow into each solvent passage 16 when the rotary atomizing head 10 is washed.

Reference numeral 17 denotes an outlet 16B between the outlet 16B of each solvent passage 16 and the discharge edge 11D of the bell cup 11.
B shows an annular dam groove provided around the entire outer peripheral surface 11G of the bell cup 11 and the annular dam groove 17 has a V-shaped cross section as shown in FIG. The shape is triangular.

Here, the annular dam groove 17 has one end face formed as a vertical face 17A so that the outlet 16 of each solvent passage 16 is formed.
B is open, and the other end surface is a collision surface 17B against which a thinner colliding to flow toward the front side of the bell cup collides. As a result, the solvent flowing out from the outlet 16B of each solvent passage 16 is temporarily stored in the annular dam groove 17, and then flows out so as to be uniformly diffused to the outer peripheral surface 11G of the bell cup 11.

The rotary atomizing head 10 according to the present embodiment has the above-described configuration.
The operation at the time of painting 0 will be described.

When performing the coating, the rotary shaft 3 is rotated at a high speed by the air motor 2, and the rotary atomizing head 10 is rotated at a high speed in the direction of arrow B in FIG. Then, the paint is discharged from the paint supply nozzle 5 toward the paint reservoir 15 of the rotary atomizing head 10. As a result, the paint flowing into the paint reservoir 15 passes through each paint outlet 13 and flows out to the paint thinning surface 11C. Further, the paint is thinned on the paint thinning surface 11C, jumps out of the discharge edge 11D as a liquid thread, and is atomized as paint particles.

At this time, since a high voltage is applied between the rotary atomizing head 10 and the object to be coated, the charged paint particles atomized by the rotary atomizing head 10 move toward the object to be coated. Fly and apply to the substrate. The spray pattern of the paint at this time is formed by shaping air flowing out of each shaping air discharge port 8A of the shaping air ring 8.

Next, the operation of cleaning the precolor paint adhered to the rotary atomizing head 10 will be described. At the time of cleaning the rotary atomizing head 10, the rotary atomizing head 1 is rotated by the air motor 2 together with the rotary shaft 3.
0 is rotated to supply thinner from the solvent supply nozzle 6. Thereby, as shown in FIG. 4, the check valve 7 is opened, and the thinner is discharged from the solvent supply nozzle 6 to the paint reservoir 15. Then, the thinner flowing into the paint reservoir 15 diffuses in the paint reservoir 15 and flows into the paint outlet holes 13, the solvent outlet holes 14, and the solvent passages 16 as indicated by arrows in FIG.

Here, the thinner flowing into each paint outlet 13 flows out and diffuses into the paint thinning surface 11C of the bell cup 11, and discharges the precolor paint attached to the paint thinning surface 11C while washing it. It is released from the edge 11D.

The thinner flowing into each of the solvent outlet holes 14 flows out and diffuses to the front surface 12A of the hub member 12, and cleans the precolor paint adhered to the hub member 12. Then, this thinner flows through the paint thinning surface 11C and the discharge edge 11D
Released from

On the other hand, the thinner flowing into each of the solvent passages 16 flows in each of the solvent passages 16 toward the outer peripheral side of the bell cup 11, and flows out of the outlet 16B of each of the solvent passages 16 into the annular dam groove 17. , Is temporarily stored in the annular groove 17.

At this time, on the outer peripheral side of the bell cup 11,
As shown in FIG. 1, the shaping air discharged from each shaping air discharge port 8A flows in the arrow A direction. Exhaust air used to rotationally drive the rotary shaft 3 by the air motor 2 flows out of the gap between the rotary shaft 3 and the air motor 2 in the direction of arrow D toward the front side of the bell cup 11. doing.

As a result, the thinner temporarily stored in the annular dam groove 17 is subjected to the centrifugal force generated when the bell cup 11 rotates, the shaping air A, and the exhaust air D.
It flows out so as to spread uniformly on the outer peripheral surface 11G of the bell cup 11, flows toward the front side of the bell cup 11, and is discharged from the discharge edge 11D of the bell cup 11. Thereby, the pre-color paint adhered to the outer peripheral surface 11G of the bell cup 11 can be washed.

Thus, according to the present embodiment, when cleaning the rotary atomizing head 10, the thinner supplied from the solvent supply nozzle 6 to the paint reservoir 15 is applied to the outer peripheral surface of the bell cup 11 via each solvent passage 16. Outflow, the outer peripheral surface 1 of the bell cup 11
By circulating the 1G on the front side of the bell cup 11, the paint adhered to the outer peripheral surface 11G of the bell cup 11 can be washed.

At this time, the annular dam groove 17 has an effect as a dam for temporarily blocking thinner which is to flow on the outer peripheral surface 11G of the bell cup 11, and
Accordingly, the thinner can be diffused over the entire outer circumference 11G of the bell cup 11, and the paint adhered to the outer circumference 11G of the bell cup 11 can be completely washed over the entire circumference.

Further, in the present embodiment, as shown in FIG. 4, the inlet 16A of each solvent passage 16 is opened at a position which is recessed from the paint outlet 13 by a certain dimension a. The thinner can flow into the solvent passage 16 at the time of washing, and the paint can be prevented from flowing into the solvent passage 16 at the time of painting.

That is, most of the paint that has flowed into the paint reservoir 15 at the time of coating flows on the paint supply surface 12B of the hub member 12 toward each of the paint outflow holes 13; It does not flow into the inlet 16A of each of the solvent passages 16 opened at a position deeper than the inside. A part of the paint flowing into the paint reservoir 15 is
However, since the paint has a higher viscosity than the thinner, the surface tension causes each solvent passage 16E to spread.
Does not flow into the inlet 16A.

Furthermore, in this embodiment, since each solvent passage 16 is formed so as to be twisted so as to be inclined in the direction of rotation of the rotary atomizing head 10, when the rotary atomizing head 10 is washed, the paint pool 15 is formed. The thinner flowing into the solvent passage 16 can be surely and largely flown into each solvent passage 16. That is, when the rotary atomizing head 10 rotates in the direction of arrow B, the thinner in the paint reservoir 15 flows so as to rotate in the same direction as the rotational direction of the rotary atomizing head 10 (direction of arrow C) due to its viscosity. . Therefore, the thinner surely flows into each of the solvent passages 16 formed to be twisted in the direction of arrow B. Accordingly, a large amount of thinner can be surely flown to the outer peripheral surface 11G of the bell cup 11 through each solvent passage 16, and the paint adhered to the outer peripheral surface 11G of the bell cup 11 can be effectively washed. it can.

Further, according to the present embodiment, the bell cup 11
Only by providing each solvent passage 16, annular dam groove 17, etc.
The excellent cleaning ability as described above can be obtained. As a result, in a so-called center feed tube type electrostatic coating machine in which a nozzle is inserted in the rotating shaft, it is only necessary to improve the rotary atomizing head, and there is no need to modify the coating machine body. Therefore, improvement is easy, cost increases,
The cleaning ability can be improved without complicating the configuration.

Next, a rotary atomizing head according to a second embodiment of the present invention will be described with reference to FIG. The feature of this embodiment is that the solvent passage is inclined toward the rear side of the bell cup from the inlet to the outlet.
In the present embodiment, the same components as those of the first embodiment described above, that is, the hub member, the paint outlet, and the solvent outlet, are denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted. It shall be omitted.

Reference numeral 21 denotes a rotary atomizing head according to this embodiment.
Reference numeral 22 denotes a bell cup forming the outer shape of the rotary atomizing head 21. The bell cup 22 is formed in a bell shape or a cup shape, and has a rotary shaft mounting portion 22A, an insertion portion 22B, a paint thinning surface 22C, a discharge end. It is composed of an edge 22D, a paint receiving surface 22E, a hub mounting groove 22F, an outer peripheral surface 22G, and the like.

The hub mounting groove 22 of the bell cup 22
A hub member 12 is provided in F, and a paint reservoir 23 is formed between a paint supply surface 12B of the hub member 12 and a paint receiving surface 22E of the bell cup 22.

The bell cup 22 is provided with an inflow port 24A in the paint receiving surface 2 of the bell cup 22, as in the first embodiment.
2E, a plurality of solvent passages 24 are formed in which an outlet 24B is opened on the outer peripheral surface 22G of the bell cup 22. Further, an annular dam groove 25 is formed on the outer peripheral surface 22 </ b> G of the bell cup 22.

The above points are the same as those of the bell cup 11 according to the first embodiment described above, but each solvent passage 24 according to the present embodiment has a bell cup 22 of the bell cup 22 from the inlet 24A to the outlet 24B. It is inclined to the rear side.
That is, the outlet 24B of each solvent passage 24 is connected to the inlet 24
The opening is located on the rear side of the bell cup 22 from the opening position of A.

With the rotary atomizing head 21 according to the present embodiment having the above-described configuration, the same operation and effect as those of the first embodiment can be obtained.

However, in this embodiment, each solvent passage 24
Is inclined to the rear side of the bell cup 22 from the inflow port 24A to the outflow port 24B, so that the following operation and effect can be obtained.

In some cases, coating is performed using a coating material having a lower viscosity than a normal coating material due to the material and color of the material to be coated. In this case, when the paint is supplied from the paint supply nozzle toward the paint reservoir 23 at the time of painting, the viscosity of the paint is low, so that it is assumed that a part of the paint flows into each solvent passage 24.

However, in this embodiment, each solvent passage 24
Is inclined toward the rear side of the bell cup 22 from the inlet 24A toward the outlet 24B, so that the extending direction of each solvent passage 24 is different from the centrifugal direction of the bell cup 22. As a result, a part of the paint becomes
Even if the paint is diffused in the centrifugal direction of the bell cup 22, the paint does not flow into each solvent passage 24 inclined differently from the centrifugal direction. In this manner, by inclining each solvent passage 24 toward the rear side of the bell cup 22, it is possible to prevent a part of the paint from flowing into each solvent passage 24.

Even when the paint has such a low viscosity, the viscosity of the thinner is particularly low when the viscosity of the paint is compared with the viscosity of the thinner. Therefore, the rotary atomizing head 2
At the time of washing 1, the thinner supplied from the solvent supply nozzle to the paint reservoir 23 easily flows into each solvent passage 24.

Next, a rotary atomizing head according to a third embodiment of the present invention will be described with reference to FIG. The feature of the present embodiment is that the inlet of the solvent passage is retracted and opened at a position deep in the paint reservoir, and the solvent passage is inclined toward the front side of the bell cup from the inlet to the outlet. I did it. In the present embodiment, the same components as those of the first embodiment described above, that is, the hub member, the paint outlet, and the solvent outlet, are denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted. It shall be omitted.

Reference numeral 31 denotes a rotary atomizing head according to this embodiment.
Reference numeral 32 denotes a bell cup that forms the outer shape of the rotary atomizing head 31. The bell cup 32 is formed in a bell shape or a cup shape, and has a rotation shaft mounting portion 32A, an insertion portion 32B, a paint thinning surface 32C, and a discharge end. It is composed of an edge 32D, a paint receiving surface 32E, a hub mounting groove 32F, an outer peripheral surface 32G, and the like.

The hub mounting groove 32 of the bell cup 32
The hub member 12 is provided at F, and a paint reservoir 33 is formed between the paint supply surface 12B of the hub member 12 and the paint receiving surface 32E of the bell cup 32.

As in the first embodiment, the bell cup 32 is provided with an inflow port 34A for the paint receiving surface 3 of the bell cup 32.
A plurality of solvent passages 34 are formed, which are open at 2E and whose outlets 34B are open at the outer peripheral surface 32G of the bell cup 32. Further, an annular dam groove 35 is formed on the outer peripheral surface 32 </ b> G of the bell cup 32.

The above points are the same as those of the bell cup 11 according to the first embodiment described above, but each solvent passage 34 according to the present embodiment has an inflow port 34A corresponding to the solvent passage 16 according to the first embodiment. As compared with the inflow port 16 </ b> A, an opening is provided at a position retreated at the back of the paint pool 33. That is, in the first embodiment, the inlet 16A of each solvent passage 16 is opened at a position separated from each paint outlet 13 by the dimension a, whereas the inlet 16A of each solvent passage 34 according to the present embodiment is opened. 34A is
Each paint outlet hole 13 is separated from the paint outlet hole 13 by a distance larger than the dimension a, and is opened from the paint outlet hole 13 to a position of the dimension b. That is,
Dimension a <dimension b. Thereby, each solvent passage 34 according to the present embodiment is inclined toward the front side of the bell cup 32 from the inlet 34A toward the outlet 34B.

According to the rotary atomizing head 31 according to the present embodiment configured as described above, the inlet 34A of each solvent passage 34 is opened at a position recessed from the paint outlet 13 by a certain dimension b. The solvent passage 34 extends from the inlet 34A to the outlet 3
4B, the bell cup 32 is inclined toward the front side as it goes. As in the second embodiment,
Even when a low-viscosity paint is used, a part of the paint can be prevented from flowing into each solvent passage 34.

Next, a rotary atomizing head according to a fourth embodiment of the present invention will be described with reference to FIG. The feature of this embodiment is that the outlet of the solvent passage is opened in the annular dam groove, and the annular dam groove is formed in a U-shaped cross section. In the present embodiment, the same components as those of the first embodiment described above, that is, the hub member, the paint outlet, and the solvent outlet, are denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted. It shall be omitted.

Reference numeral 41 denotes a rotary atomizing head according to this embodiment.
Reference numeral 42 denotes a bell cup which forms the outer shape of the rotary atomizing head 41. The bell cup 42 is formed in a bell shape or a cup shape, and has a rotary shaft mounting portion 42A, an insertion portion 42B, a paint thinning surface 42C, a discharge end. It is composed of an edge 42D, a paint receiving surface 42E, a hub mounting groove 42F, an outer peripheral surface 42G, and the like.

The hub mounting groove 42 of the bell cup 42
A hub member 12 is provided at F, and a paint reservoir 43 is formed between the paint supply surface 12B of the hub member 12 and the paint receiving surface 42E of the bell cup 42.

Reference numerals 44, 44,... Indicate, for example, twelve solvent passages provided in the circumferential direction of the bell cup 42. The solvent passages 44 have an inlet 44A opening to the paint receiving surface 42E and an outlet 44B having a bell 44. It is located on the outer peripheral side of the cup 42 and opens into an annular dam groove 45 described later. Thus, each of the solvent passages 44 communicates between the paint reservoir 43 and the annular dam groove 45.

The solvent passages 44 are inclined in the direction of rotation of the bell cup 42 from the inlet 44A to the outlet 44B, similarly to the solvent passages 24 according to the second embodiment described above. The solvent passages 44 are inclined toward the rear of the bell cup 42 from the inlet 44A to the outlet 44B.

Reference numeral 45 denotes an annular dam groove provided on the outer peripheral surface 42G of the bell cup 42. The annular dam groove 45 has a U-shaped cross section and opens toward the rear side of the bell cup 42. . The bottom of the annular dam groove 45 has an outlet for each solvent passage 44.

The rotary atomizing head 41 according to the present embodiment has the above-described configuration, and the operation at the time of painting is the same as that according to the first embodiment.

Next, the painting of the previous color is completed, and the rotary atomizing head 4
The operation of cleaning the precolor paint adhered to 1 will be described. First, the rotary atomizing head 41 is rotated, and thinner is discharged from the solvent supply nozzle toward the paint reservoir 43. As a result, the thinner that has flowed into the paint reservoir 43 flows from the paint reservoir 43 into each of the solvent passages 44, and the outlet 4 of the solvent passage 44.
4B, flows out into the annular dam groove 45, and
In 5, it spreads over the entire circumference of the bell cup 42. The solvent diffused in the annular dam groove 45 overflows from the annular dam groove 45 to the outer peripheral surface 42 </ b> G of the bell cup 42, forming a centrifugal force when the bell cup 42 rotates, and forming on the outer periphery of the bell cup 42. Depending on the shaping air
Flow toward the front side of the bell cup 42,
Released from the front end of the

As described above, the rotary atomizing head 4 according to the present embodiment is used.
According to the first embodiment, the precolor paint adhered to the outer peripheral surface 42G of the bell cup 42 can be washed in substantially the same manner as in the first embodiment.

Next, a rotary atomizing head according to a fifth embodiment of the present invention will be described with reference to FIG. The feature of this embodiment is that the outlet of the solvent passage is opened to the rear side of the bell cup, and the annular dam groove is arranged to retreat to the rear side of the bell cup.

Reference numeral 51 denotes a rotary atomizing head according to this embodiment.
Reference numeral 52 denotes a bell cup which forms the outer shape of the rotary atomizing head 51. The bell cup 52 is formed in a bell shape or a cup shape, and has a rotary shaft mounting portion 52A, an insertion portion 52B, a paint thinning surface 52C, a discharge end. An edge 52D, a paint receiving surface 52E, a hub mounting groove 52F, an outer peripheral surface 52G, and the like are provided.

The hub mounting groove 52 of the bell cup 52
A hub member 12 is provided at F, and a paint pool 53 is formed between a paint supply surface 12B of the hub member 12 and a paint receiving surface 52E of the bell cup 52.

Reference numerals 54, 54,... Indicate, for example, 12 solvent passages provided in the circumferential direction of the bell cup 52. In each of the solvent passages 54, an inlet 54A opens to the paint receiving surface 52E, and an outlet 54B opens. The point of opening in an annular dam groove 55 described later is the same as that of each solvent passage 44 according to the above-described fourth embodiment. However, each solvent passage 54 according to this embodiment is
As compared with the solvent passages 44 according to the fourth embodiment, the outlet 54B is opened at a position retracted to the rear side of the bell cup 52, and each solvent passage 54 is greatly inclined to the rear side of the bell cup 52. ing.

Reference numeral 55 denotes an annular dam groove provided on the outer peripheral surface 52G of the bell cup 52. The annular dam groove 55 is different from the annular dam groove 45 according to the above-described fourth embodiment in that the bell cup 52 has a larger diameter. It is formed at a position retracted to the rear side.

With the rotary atomizing head 51 according to the present embodiment configured as described above, substantially the same operation and effect as those according to the above-described fourth embodiment can be obtained. In particular, according to the present embodiment, the outlet 54B of the solvent passage 54 is opened to the rear side of the bell cup 52, and the annular dam groove 55 is formed.
Of the bell cup 52 is arranged to be retracted to the rear side of the bell cup 52.

Thus, when the rotary atomizing head 51 is washed, the annular dam groove 55 is formed through the outlet 54B of each solvent passage 54.
The thinner flowing into the inside of the bell cup 52 is caused to flow out from the annular dam groove 55 toward the front end of the outer peripheral surface 52G of the bell cup 52, so that the thinner can flow over a wide range from the rear side to the front end side of the bell cup 52. The outer peripheral surface 52G of the cup 52 can be cleaned over a wide area.

In each of the above embodiments, a case where the rotary atomizing head according to the present invention is applied to a center-feed type electrostatic coating machine in which a paint supply nozzle 5 and a solvent supply nozzle 6 are provided in a rotating shaft 3 will be described. However, the present invention is not limited to this, and a paint supply pipe and a solvent supply pipe are provided outside the rotating shaft, and paint and thinner are supplied from each supply pipe toward the inside of the rotary atomizing head. It can also be applied to electrostatic coating machines.

[0089]

As described above in detail, according to the first aspect of the present invention, a plurality of solvent passages for communicating the paint reservoir with the outer peripheral side of the bell cup are provided, and the outlet of the solvent passage and the bell cup are provided. It is located between the discharge end edge of the bell cup and the annular dam groove extending to the entire circumference of the outer peripheral surface of the bell cup. The resin is allowed to flow out onto the outer peripheral surface of the bell cup through the solvent passage, and the paint adhered to the outer peripheral surface of the bell cup can be washed using the solvent.

Further, while the solvent flowing out on the outer peripheral surface of the bell cup flows toward the discharge edge of the bell cup,
By flowing the solvent into the annular dam groove, the solvent can be diffused over the entire outer peripheral surface of the bell cup.
Therefore, the solvent can be flowed all around the outer peripheral surface of the bell cup, and the paint adhered to the outer peripheral surface of the bell cup can be reliably washed over the entire outer periphery.

According to the second aspect of the present invention, the outlet of the solvent passage is opened at the position of the annular dam groove.
At the time of cleaning the rotary atomizing head, the solvent supplied from the nozzle is stored in the paint and flows directly into the annular dam groove via the solvent passage, and the solvent is diffused around the entire circumference of the bell cup in the annular dam groove. After that, it can be discharged to the outer peripheral surface of the bell cup. Therefore, the solvent can flow over the entire outer peripheral surface of the bell cup, and the outer peripheral surface of the bell cup can be thoroughly cleaned over a wide range.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a rotary atomizing head according to a first embodiment of the present invention together with a rotating shaft, a shaping air ring, and the like.

FIG. 2 is a longitudinal sectional view showing a rotary atomizing head in FIG.

FIG. 3 is a cross-sectional view of the rotary atomization head in FIG. 2 as viewed from the direction of arrows III-III.

FIG. 4 is an enlarged vertical sectional view of a main part in FIG. 1 showing a state in which the rotary atomizing head is being cleaned.

FIG. 5 is a longitudinal sectional view showing a rotary atomizing head according to a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a rotary atomizing head according to a third embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a rotary atomizing head according to a fourth embodiment of the present invention.

FIG. 8 is a longitudinal sectional view showing a rotary atomizing head according to a fifth embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 cover 3 rotating shaft 5 paint supply nozzle 6 solvent supply nozzle 10, 21, 31, 41, 51 rotary atomizing head 11, 22, 32, 42, 52 bell cup 11C, 22C, 32C, 42C, 52C paint thinning surface 11D, 22D, 32D, 42D, 52D Release edge 11E, 22E, 32E, 42E, 52E Paint receiving surface 11G, 22G, 32G, 42G, 52G Outer peripheral surface 12 Hub member 13 Paint outflow hole 15, 23, 33, 43, 53 paint pool 16, 24, 34, 44, 54 solvent passage 16A, 24A, 34A, 44A, 54A inlet 16B, 24B, 34B, 44B, 54B outlet 17, 25, 35, 45, 55 annular dam groove

Claims (2)

[Claims] 1. A bell cup formed in a bell shape or a cup shape, wherein a front side of an inner peripheral surface is a paint thinning surface for thinning paint and a rear side of the inner peripheral surface is a paint receiving surface; A hub member located on the inner peripheral side of the bell cup and provided between the paint thinning surface of the bell cup and the paint receiving surface; and a hub member between the rear surface of the hub member and the paint receiving surface of the bell cup. A paint pool that is defined and stores a paint or solvent supplied to a paint receiving surface from a nozzle provided in a coating machine main body, and a paint or solvent provided to the hub member and supplied to the paint pool from the nozzle by the nozzle. In the rotary atomizing head comprising a plurality of paint outlet holes to be discharged to the paint thinning surface of the bell cup, an inlet is located on the inner peripheral surface of the bell cup and opens to the paint receiving surface, and an outlet is provided. An opening is provided on the outer peripheral surface of the bell cup, A plurality of solvent passages for communicating the paint reservoir with the outer peripheral side of the bell cup; and an outer peripheral surface of the bell cup which is located between an outlet of the solvent passage and a discharge edge of the bell cup. A rotary atomizing head comprising an annular dam groove provided over the rotary atomizing head. 2. The rotary atomizing head according to claim 1, wherein an outlet of the solvent passage is opened at a position of the annular dam groove.