JP3433065B2 - Rotary atomizing head - Google Patents

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 that performs coating while changing colors.

[0002]

2. Description of the Related Art Generally, an electrostatic coating machine using a rotary atomizing head includes a coating machine main body, a rotary shaft extending axially in the coating machine main body and rotatably provided. An air motor provided in the main body of the coating machine for rotational driving, a rotary atomizing head provided outside the main body of the coating machine and provided at the tip of the rotary shaft so as to be rotated by the air motor, and the rotary shaft. It is generally configured by a supply nozzle which is inserted into the inside of the rotary atomizing head and whose tip side extends into the rotary atomizing head. 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, etc. via a paint pipe or the like.

The rotary atomizing head is formed in a bell shape or a cup shape, and the front side of the inner peripheral surface serves as a paint thinning surface for thinning the paint and the rear side of the inner peripheral surface serves as a paint receiving surface. Bell cup, a hub member located on the inner peripheral side of the bell cup and provided between the paint thinning surface and the paint receiving surface of the bell cup, the rear surface of the hub member and the bell cup. A paint reservoir, which is defined between the paint receiving surface and stores the paint or solvent supplied from the supply nozzle provided on the main body of the coating machine to the paint receiving surface, and the paint provided from the supply nozzle on the hub member. It is composed of a plurality of paint outflow holes for allowing the paint or solvent supplied to the pool to flow out to the paint thin film surface of the bell cup.

When performing coating with 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 by 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 covered along the lines of electric force. It flies toward the coating object and applies it to the coating object.

Further, when coating is performed by the electrostatic coating machine, the coating material adheres to the coating film thinning surface, the coating receiving surface, etc. of the bell cup. In order to wash the paint adhering to the paint thinning surface and the like, the thinner is discharged from the supply nozzle toward the bell cup while rotating the rotary shaft and the rotary atomizing head by the air motor. As a result, the thinner flows into the inner peripheral side of the bell cup and removes the paint adhering to the paint thinning surface and the like until the thinner is discharged from the discharge edge through the paint thinning 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 during coating adhere to the object to be coated along the lines of electric force. However, some paint particles flow backward behind the bell cup and wrap around the outer circumference of the bell cup. As a result,
Paint may adhere to the outer surface of the bell cup.

That is, when the rotary atomizing head rotates at 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 in which air is sucked into this negative pressure region occurs. As a result, the paint particles flow back 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 back toward the rear of the bell cup.

In this way, when some of the paint particles flow backward and the paint adheres to the outer peripheral surface of the bell cup, the paint solidifies. Therefore, depending on the coating conditions, the solidified paint may peel off and adhere to the surface of the object to be coated as a paint piece (pocket), which may deteriorate the coating quality of the object to be coated. Further, in the electrostatic coating machine according to the related art, by supplying thinner from the supply nozzle toward the inner peripheral side of the bell cup, the paint receiving surface, the paint thinning surface, etc. of the bell cup can be cleaned. However, there is a drawback that the paint adhering to the outer peripheral surface of the bell cup cannot be washed with the thinner from the supply nozzle.

Therefore, in order to solve such a drawback, an electrostatic coating machine in which a cleaning nozzle for discharging thinner toward the outer peripheral surface of the bell cup is provided in the coating machine main body is disclosed in Japanese Utility Model Laid-Open No. 57-6265.
It is known from Japanese Patent Laid-Open No. 9 (hereinafter referred to as other prior art). According to the electrostatic coating machine according to the other conventional technique, in a state in which the rotary atomizing head is rotated, by discharging thinner from the cleaning nozzle provided in the coating machine body toward the outer peripheral surface of the bell cup, It is possible to wash the paint adhering to the outer peripheral surface of the bell cup.

[0010]

However, in the other prior art described above, when cleaning the outer peripheral side of the rotary atomizing head,
With the rotary atomizing head rotated, the 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 bounce on the outer peripheral surface of the bell cup, and the familiarity between the thinner and the outer peripheral surface of the bell cup is poor, and the paint adhered to the outer peripheral surface of the bell cup may be removed. There is a problem that it may not be possible to surely wash.

Further, in order to eliminate the bounce of the thinner, the poor conformability, etc. and to reliably clean the paint adhering 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 is required. There is a problem that it is difficult to design and manufacture because it is necessary to precisely set etc. and advanced design and manufacturing technology are required.

Further, as in the electrostatic coating machine according to the prior art, the bell cup is provided with a structure for supplying thinner toward the inner peripheral side of the bell cup from the supply nozzle inserted through the rotary shaft. 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.

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 a rotary atomizing head capable of reliably cleaning the paint adhering to the outer peripheral surface of the bell cup. There is.

[0014]

A rotary atomizing head applied to the present invention in order to solve the above-mentioned problems is formed in a bell shape or a cup shape, and the front side of the inner peripheral surface is a coating material for thinning the coating material. A bell cup having a thin film surface and a rear side of the inner peripheral surface serving as a paint receiving surface, and provided between the paint thin film surface and the paint receiving surface of the bell cup located on the inner peripheral side of the bell cup. And a paint reservoir that is defined between the rear surface of the hub member and the paint receiving surface of the bell cup and that stores paint or solvent supplied to the paint receiving surface from a nozzle provided in the main body of the coating machine. And a plurality of paint outflow holes provided in the hub member for allowing the paint or solvent supplied from the nozzle to the paint reservoir to flow out to the paint thinning surface of the bell cup.

The feature of the configuration adopted by the invention according to claim 1 is that the inlet is located on the inner peripheral surface of the bell cup .
Along with each of the paint outflow holes , an opening is formed in the paint receiving surface at a position deeper than the paint outflow hole, and an outlet is provided in the outer peripheral surface of the bell cup.
A plurality of solvent passage communicating the plane, provided so as to surround the bell cup in a state having a peripheral surface with a gap of said bell cup, an annular guide for guiding the solvent flowing out from the outlet of the respective solvent passages And a solvent diffusion chamber which is formed over the entire circumference between the inner peripheral surface of the annular guide and the outer peripheral surface of the bell cup and which diffuses the solvent supplied from the solvent passage.

With the above construction, when coating is performed, the rotary atomizing head is rotated and the paint is supplied from the nozzle to the paint reservoir. As a result, the paint supplied to the paint reservoir is diffused in the paint reservoir by the centrifugal force and flows out to the paint thin film surface of the bell cup through the paint outflow hole provided in the hub member. Then, this paint is made into a liquid film on the thin film surface of the paint, and is discharged as paint particles from the bell cup. Then, the paint particles fly toward the object to be coated by electrostatic force and adhere to the object to be coated. Since the paint has a higher viscosity than the solvent, all the paint supplied from the nozzle at the time of coating flows out from the paint outflow hole and does not flow into the solvent passage.

Next, in order to finish the coating of the previous color and apply the coating of the next color, it is necessary to wash the previous color paint attached to the rotary atomizing head. Therefore, 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, this solvent flows into the paint reservoir and diffuses inside the paint reservoir due to centrifugal force. Then, a part of the solvent in the paint reservoir flows out from the paint outflow hole to the paint film thinning surface, and is discharged from the discharge edge while cleaning the pre-colored paint adhering to the paint film thinning surface. this
At the time of painting, the paint discharged from the nozzle and flowing into the paint reservoir
Material flows on the rear surface of the hub member toward each paint outlet hole.
Therefore, it is opened at a position deeper than each paint outflow hole.
No paint flows into the inlet of each solvent passage.

On the other hand, when cleaning the rotary atomizing head,
Solvent that has flowed into the discharged paint reservoir is in its viscosity paints
Compared low damage to the remainder of the widely diffused solvent in the paint reservoir is readily flow into the inlet of the solvent passage, flows toward the outer circumferential side of the bell cup through said solvent passages. Then, the solvent flows out from the outlet of the solvent passage into the solvent diffusion chamber and diffuses in the solvent diffusion chamber along the entire circumference of the bell cup outer peripheral side.
Further, the solvent in the solvent diffusion chamber is guided to the front side of the bell cup by the annular guide and is sprayed toward the outer peripheral surface on the front side of the bell cup. As a result, the front color paint attached to the outer peripheral surface on the front side of the bell cup is washed.

According to a second aspect of the present invention, in the solvent diffusion chamber, the solvent flowing in the solvent diffusion chamber located between the inner peripheral surface of the annular guide and the outer peripheral surface of the bell cup is stored in the bell cup. The reason is that an annular protrusion is provided to diffuse the entire circumference.

With the above construction, when cleaning the rotary atomizing head, the solvent discharged from the nozzle flows into the solvent diffusion chamber through the paint reservoir and the solvent passage. Then, the solvent flowing in the solvent diffusion chamber is temporarily blocked by the annular protrusion, and diffuses over the entire circumference of the solvent diffusion chamber due to the dam effect. For this reason, the solvent in the solvent diffusion chamber diffuses over the entire circumference of the bell cup, then flows out toward the outer peripheral surface on the front side of the bell cup, and the paint adhering to the outer peripheral surface of the bell cup is distributed all around. Wash over.

According to a third aspect of the present invention, an annular ridge portion projecting toward the outer peripheral surface of the bell cup is provided on the inner peripheral surface of the annular guide, and the annular ridge portion is provided between the annular ridge portion and the outer peripheral surface of the bell cup. An annular throttle passage is formed in the.

With the above construction, when cleaning the rotary atomizing head,
The solvent discharged from the nozzle flows into the solvent diffusion chamber through the paint reservoir and the solvent passage. Then, the solvent flows toward the front side of the bell cup while being guided by the annular guide, and collides with the annular ridge protruding from the inner peripheral surface of the annular guide. As a result, the solvent diffuses in the solvent diffusion chamber over the entire circumference of the bell cup. In this way, the annular protrusion acts as a dam that temporarily blocks the solvent flowing in the solvent diffusion chamber. Then, the solvent in the solvent diffusion chamber diffuses over the entire circumference of the bell cup, then passes through the annular throttle passage toward the outer peripheral surface on the front side of the bell cup, and adheres to the outer peripheral surface of the bell cup. Rinse the paint all around.

Further, in the invention according to claim 4, an annular projecting portion projecting toward the inner peripheral surface of the annular guide is provided on the outer peripheral surface of the bell cup, and the annular projecting portion and the outer peripheral surface of the bell cup are formed. An annular throttle passage is formed between them.

With the above structure, as in the case described above, when cleaning the rotary atomizing head, the solvent flowing into the solvent diffusion chamber can be diffused over the entire circumference of the bell cup by the dam effect. Therefore, the paint attached to the outer peripheral surface of the bell cup can be washed over the entire circumference.

[0025]

[0026]

The invention according to claim 5 is such that each solvent passage is inclined in the direction of rotation of the bell cup as it goes from the inlet to the outlet.

With the above construction, when cleaning the rotary atomizing head,
The solvent discharged from the nozzle and flowing into the paint reservoir can easily flow into the inlet of each solvent passage. That is, when cleaning the rotary atomizing head, the bell cup is rotating in a predetermined direction, so that the solvent discharged from the nozzle and flowing into the paint reservoir also rotates in the rotation direction of the bell cup in the paint reservoir. Then flow. In this case, due to the relationship between the flow direction of the solvent rotating in the paint reservoir and the inclination of each solvent passage, this solvent easily flows into each solvent passage.

Further, the invention according to claim 6 is such that each solvent passage is inclined toward the rear side of the bell cup as it goes from the inlet to the outlet.

With the above structure, by tilting each solvent passage toward the rear side of the bell cup, the extension direction of each solvent passage and the centrifugal direction of the bell cup (radial direction of the bell cup).
Is different from. As a result, even if the paint supplied from the nozzle to the paint reservoir during painting diffuses in the centrifugal direction of the bell cup in the paint reservoir due to the high speed rotation of the bell cup, this paint will not flow into each solvent passage. Absent.

On the other hand, the solvent has a viscosity lower than that of the coating material and has a property of easily circulating even in a thin pipe. Therefore, when cleaning the rotary atomizing head, the solvent supplied from the nozzle to the paint reservoir easily flows into each solvent passage.

[0032]

DETAILED DESCRIPTION OF THE INVENTION A rotary atomizing head according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

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. Inside the cover 1, an air motor 2 is provided.
And a rotary shaft 3 which is rotated at a high speed by the air motor 2.

Reference numeral 4 denotes a feed tube which is formed in a tubular 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 side connected to a paint source (neither is shown) via a paint valve or the like, a tip end side protruding from the tip of the rotary shaft 3, and a rotary atomizing head described later. It extends within 10. Then, the paint supply nozzle 5 supplies the paint toward the rotary atomizing head 10 during coating.

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

Reference numeral 8 is 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 in.

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

Here, the shaping air is used to form a spray pattern of the paint particles ejected from the bell cup 11 by discharging the shaping air in the direction of arrow A from each shaping air discharge port 8A. Further, this shaping air also has a role of restricting the flow direction of the thinner so that the thinner flowing out from each solvent passage 16 of the bell cup 11 is blown to the outer peripheral surface 11H of the bell cup 11, as described later. .

A rotary atomizing head 10 is 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 widens from the rear side toward the front side, as shown in FIG. The rear side is a rotary shaft mounting portion 11A that is screwed to the tip of the rotary shaft 3. At the center of the bell cup 11, there is formed a small-diameter insertion portion 11B through which the check valve 7 of the paint supply nozzle 5 and the solvent supply nozzle 6 protruding from the tip end side of the rotary shaft 3 are inserted.

Further, the inner peripheral side of the bell cup 11 is gradually expanded 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 that thins the paint
1C, and the tip end side of the paint film thinning surface 11C is the discharge edge 11D. Also, 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 and a paint receiving surface 11E.
Has become. Further, a hub mounting groove 11F for mounting a hub member 12 described later is formed between the paint thinning surface 11C and the paint receiving surface 11E. Further, a guide mounting step portion 11G is formed on the outer peripheral side of the bell cup 11 at an intermediate position in the axial direction.

12 is a hub mounting groove 11F of the bell cup 11.
The hub member 12 is formed in a disk shape, and the central axis of the hub member 12 is a rotary atomizing head 10.
Is arranged so as to coincide with the central axis (rotation axis) of the.
The front surface 12A of the hub member 12 is a flat surface 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 projection 12C is formed at the center of the paint supply surface 12B.

A plurality of paint outlet holes 13 are formed in an annular shape on the outer peripheral side of the hub member 12, and each paint outlet hole 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 is caused to flow out to the paint thin film surface 11C.

Are a plurality of solvent outflow holes penetrating from the paint supply surface 12B to the front surface 12A at the position of the conical projection 12C of the hub member 12, and the solvent outflow holes 14 are
When 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 used as the hub member 12
It flows out to the front surface 12A.

Reference numeral 15 denotes a paint reservoir. The paint reservoir 15 is provided with a hub member 12 in a hub mounting groove 11F of a bell cup 11 so that a paint supply surface 12B of the hub member 12 and a paint receiving surface 11E of the bell cup 11 are formed. Is formed between. The paint reservoir 15 is a space for temporarily collecting paint discharged from the paint supply nozzle 5 or thinner discharged from the solvent supply nozzle 6 and diffusing the paint or thinner.

Reference numerals 16, 16, ... Denote solvent passages provided, for example, 12 at predetermined intervals in the circumferential direction of the bell cup 11, and each of the solvent passages 16 has an inlet 16A.
No. 1 is opened on the paint receiving surface 11E, the outlet 16B is opened on the outer peripheral surface 11H of the bell cup 11, and the inside of the bell cup 11 is extended from the inner peripheral side to the outer peripheral side. Thus, when cleaning the rotary atomizing head 10, the thinner discharged from the solvent supply nozzle 6 and flowing into the paint reservoir 15 flows into each solvent passage 16 and flows toward the outer peripheral side of the bell cup 11. The number of the solvent passages 16 is not limited to 12, but 2 to
The number may be 11 or 13 or more.

Here, the inflow port 16A of each solvent passage 16
4, as shown in FIG. 4, is opened at a position which is recessed from each paint outflow hole 13 by a constant dimension a. That is, the inflow port 16A of each solvent passage 16 is separated from the opening position of each paint outflow hole 13 toward the rear side of the bell cup 11. As a result, at the time of coating, the paint reservoir 1 is supplied from the paint supply nozzle 5.
5 is prevented from flowing into the solvent passage 16, and at the time of cleaning, the solvent is supplied from the solvent supply nozzle 6 to the paint reservoir 15
The thinner supplied to the above is allowed to flow into the solvent passage 16.

Further, each solvent passage 16 has its inflow port 16
Bell cup 11 from A toward outlet 16B
It is inclined to the rear side. That is, the outflow port 16B of each solvent passage 16 is located on the rear side of the bell cup 11 and opened with respect to the opening position of the inflow port 16A. This allows
At the time of painting, the paint is prevented from flowing into each solvent passage 16.

Further, as shown in FIG. 3, each solvent passage 16 inclines in the rotation direction of the rotary atomizing head 10 (direction indicated by an arrow B) from the inlet 16A toward the outlet 16B, and the rotary fog is rotated. It is provided so as to be twisted in the direction of rotation of the fossil head 10. That is, each solvent passage 16 is inclined in the rotational direction so as to form a predetermined angle α in the range of 15 ° to 50 ° with respect to the radial direction of the bell cup 11. Thereby, when the rotary atomizing head 10 is cleaned, the thinner discharged from the solvent supply nozzle 6 into the paint reservoir 15 easily flows into each solvent passage 16.

Reference numeral 17 denotes a guide mounting step portion 1 of the bell cup 11.
1G shows an annular guide, and the annular guide 17
Has a mounting portion 17A on the base end side, and a spreading portion 17B that is spread in a bell shape or a cup shape from the mounting portion 17A to the front end side. Here, the annular guide 17
The mounting portion 17A is the guide mounting step portion 1 of the bell cup 11.
It is fixed to 1G, and the expanding portion 17B extends toward the front end side of the bell cup 11 along the outer peripheral surface 11H of the bell cup 11 while forming a constant gap with the outer peripheral surface 11H of the bell cup 11. is doing. Thereby, the annular guide 1
7 surrounds the bell cup 11 in a state where there is a gap with the outer peripheral side of the bell cup 11.

Reference numeral 18 denotes a solvent diffusion chamber formed between the inner peripheral surface of the expanding portion 17B of the annular guide 17 and the outer peripheral surface 11H of the bell cup 11, and the solvent diffusion chamber 18 is the bell cup 11.
Is formed in an annular shape over the entire circumference. Further, an outlet 16B of each solvent passage 16 is opened at the inner part of the solvent diffusion chamber 18. Then, when the rotary atomizing head 10 is cleaned, the thinner flowing from the paint reservoir 15 into each solvent passage 16 flows into the solvent diffusion chamber 18 from the outlet 16B of each solvent passage 16. Furthermore, this thinner diffuses in the solvent diffusion chamber 18 in the circumferential direction.

The rotary atomizing head 10 according to the present embodiment has the above-described structure. Next, the operation of the rotary atomizing head 10 during coating will be described.

At the time of coating, the rotary shaft 3 is rotated at high speed by the air motor 2, and the rotary atomizing head 10 is rotated at 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 the paint outflow holes 13 and flows out to the paint thinning surface 11C. Further, this paint is thinned on the paint thinning surface 11C, and is ejected as a liquid thread from the discharge edge 11D to be 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 are directed toward the object to be coated. Fly and apply to the object to be coated. Further, the spray pattern of the paint at this time is formed by the shaping air flowing out from each shaping air discharge port 8A of the shaping air ring 8.

Next, the operation of cleaning the pre-colored paint attached 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 moved together with the rotary shaft 3 by the air motor 2.
0 is rotated and thinner is supplied from the solvent supply nozzle 6. As a result, as shown in FIG. 4, the check valve 7 is opened, and thinner is discharged from the solvent supply nozzle 6 to the paint reservoir 15. Then, the thinner that has flowed into the paint reservoir 15 diffuses in the paint reservoir 15 and flows into each paint outflow hole 13, each solvent outflow hole 14, and each solvent passage 16 as indicated by the arrow in FIG. 4.

Here, the thinner that has flowed into each paint outflow hole 13 flows out and diffuses to the paint film thinning surface 11C of the bell cup 11, and is discharged while cleaning the pre-colored paint adhering to the paint film thinning surface 11C. It is emitted from the edge 11D.

Further, the thinner that has flowed into each solvent outflow hole 14 flows out and diffuses to the front surface 12A of the hub member 12, and cleans the pre-color paint attached to the hub member 12. Then, this thinner flows through the paint film thinning surface 11C and the discharge edge 11D.
Emitted from.

On the other hand, the thinner that has flowed into each solvent passage 16 is discharged from the outlet 16 B of each solvent passage 16 to the bell cup 11.
Flows radially outward. However, this thinner
It collides with the inner peripheral surface of the expanded portion 17B of the annular guide 17 and temporarily stays in the solvent diffusion chamber 18. At this time, the thinner diffuses in the solvent diffusion chamber 18 over the entire circumference of the bell cup 11.

The thinner in the solvent diffusion chamber 18 is guided to the front side of the bell cup 11 by the expanding portion 17B of the annular guide 17 so that the thinner spreads from the solvent diffusion chamber 18 to the bell cup 11.
Flows out toward the front end side of the bell cup 11 and the outer peripheral surface 11 of the bell cup 11.
Wash the pre-color paint on H.

Thus, according to the present embodiment, when the rotary atomizing head 10 is washed, the paint reservoir 1 is discharged from the solvent supply nozzle 6.
The thinner supplied to No. 5 is caused to flow into the solvent diffusion chamber 18 via each solvent passage 16, and this thinner is guided to the front side of the bell cup 11 by the annular guide 17 and blown onto the outer peripheral surface 11H of the bell cup 11. By this, the bell cup 11
The paint adhered to the outer peripheral surface 11H can be cleaned.

Further, in this embodiment, each solvent passage 16
As shown in FIG. 4, the inflow port 16A of each paint outlet 1
Since it is configured to be opened at a position that is recessed by a certain dimension a from 3 above, thinner can be made to flow into the solvent passage 16 at the time of cleaning, and paint can be prevented from flowing into the solvent passage 16 at the time of coating. .

That is, most of the paint flowing into the paint reservoir 15 at the time of coating flows toward the paint outflow holes 13 on the paint supply surface 12B of the hub member 12, so that the paint flows out from the paint outflow holes 13. The solvent does not flow into the inflow port 16A of each solvent passage 16 opened at a deeper position. Also, part of the paint that has flowed into the paint reservoir 15 is
However, since the paint has a higher viscosity than thinner, the surface tension causes the solvent passage 16
It does not flow into the inflow port 16A. Further, since each solvent passage 16 is inclined toward the rear side of the bell cup 11, there is an effect of preventing the paint from flowing into each solvent passage 16.

Further, in this embodiment, the bell cup 11 is used.
Since the annular guide 17 is provided so as to surround the outer peripheral side of the solvent, when cleaning the pre-colored paint adhering to the rotary atomizing head 10, it flows through each solvent passage 16 and The thinner that tends to scatter in the centrifugal direction from the outflow port 16B can be made to collide with the inner peripheral surface of the expanding portion 17B of the annular guide 17 and be temporarily retained in the solvent diffusion chamber 18. As a result, all the thinner flowing out from each solvent passage 16 can be guided to the front side of the bell cup 11 by the annular guide 17 and sprayed onto the outer peripheral surface 11H of the bell cup 11.

Therefore, when cleaning the paint adhering to the outer peripheral surface 11H of the bell cup 11, the thinner is not wasted,
It can be used efficiently, the amount of thinner used can be minimized, and the cleaning efficiency can be greatly improved.

The annular guide 17 allows the thinner flowing out of the solvent diffusion chamber 18 from each solvent passage 16 to be diffused along the outer peripheral surface 11H of the bell cup 11. Thereby, the paint adhered to the outer peripheral surface 11H of the bell cup 11 can be washed over the entire circumference.

Further, in the present embodiment, each solvent passage 1
Since 6 is formed by twisting so as to be inclined in the rotation direction of the rotary atomizing head 10, when cleaning the rotary atomizing head 10, the thinner that has flowed into the paint reservoir 15 is surely transferred to each solvent passage 16. And a large amount can be made to flow. That is, when the rotary atomizing head 10 rotates in the direction of arrow B, the paint pool 15
Due to its viscosity, the thinner inside flows so as to rotate in the same direction as the rotating direction of the rotary atomizing head 10 (direction indicated by arrow C).
Therefore, the thinner can surely flow into each solvent passage 16 formed to be twisted in the arrow B direction. As a result, the thinner can be reliably and in large quantity sprayed onto the outer peripheral surface 11H of the bell cup 11 via each solvent passage 16 and the solvent diffusion chamber 18, and the paint adhered to the outer peripheral surface 11H of the bell cup 11 can be effectively treated. Can be washed as desired.

Further, according to the present embodiment, the excellent cleaning ability as described above can be obtained only by providing the bell cup 11 with the solvent passages 16, the annular guide 17 and the like. As a result, in the so-called center feed tube type electrostatic coating machine in which the nozzle is inserted in the rotary shaft, only the rotary atomizing head needs to be improved, and the coating machine body side need not be modified. Therefore, the improvement is easy, and the cleaning ability can be improved without increasing the cost and complicating the structure.

Next, a rotary atomizing head according to a second embodiment of the present invention will be described with reference to FIGS. The feature of this embodiment is that an annular ridge protruding toward the outer peripheral surface of the bell cup is provided on the inner peripheral surface of the annular guide, and an annular throttle passage is provided between the annular ridge and the outer peripheral surface of the bell cup. Has been formed. In the present embodiment, except for the annular guide, the same components as those of the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 5, reference numeral 21 denotes a rotary atomizing head according to this embodiment. 22 is a guide mounting step portion 1 of the bell cup 11.
The annular guide according to the present embodiment fixed to 1G is shown. The annular guide 22 has a mounting portion 22 on the base end side thereof in substantially the same manner as the annular guide 17 according to the above-described first embodiment.
A, and from the attachment portion 22A to the front end side, there is an expanded portion 22B that is expanded in a bell shape or a cup shape. The annular guide 22 is provided so as to surround the bell cup 11 with a gap from the outer peripheral side of the bell cup 11. As a result, a solvent diffusion chamber 23 is formed between the inner peripheral surface of the expanded portion 22B of the annular guide 22 and the outer peripheral surface 11H of the bell cup 11.

Reference numeral 24 denotes an annular ridge portion provided on the inner peripheral surface of the expanded portion 22B of the annular guide 22.
Is located on the front end side of the expanding portion 22B and protrudes from the inner peripheral surface of the expanding portion 22B toward the outer peripheral surface 11H of the bell cup 11. Then, the annular protrusion 24 is provided in the annular guide 2
An annular throttle passage 25 is formed between the annular protrusion 24 and the outer peripheral surface 11H of the bell cup 11 and is formed in an annular shape over the entire circumference of the bell cup 2.

Here, when the rotary atomizing head 21 is cleaned, the annular projection 24 flows out from the outlet 16B of each solvent passage 16 and faces the front side of the bell cup 11 in the solvent diffusion chamber 23. The thinner that flows through the open portion 22B of the annular guide 22.
It functions as a dam that temporarily blocks at the front end.

The rotary atomizing head 21 according to the present embodiment has the above-mentioned structure, and there is no particular difference in the operation during painting and the basic operation during washing from the first embodiment described above. .

Therefore, the rotary atomizing head 2 according to this embodiment is used.
In No. 1, when cleaning the previous color paint adhered to the rotary atomizing head 21 at the time of color change, the rotary atomizing head 30 is moved by the air motor 2
Is rotated to supply thinner from the solvent supply nozzle 6 toward the paint reservoir 15. As a result, the thinner that has flowed into the paint pool 15 has the paint outflow holes 13, the solvent outflow holes 14,
It flows into each solvent passage 16. The thinner that has flowed into each paint outflow hole 13 cleans the pre-colored paint that has adhered to the paint thinning surface 11C of the bell cup 11, and the thinner that has flowed into each solvent outflow hole 14 has the front surface 12A of the hub member 12.
Wash the pre-colored paint that has adhered to the.

On the other hand, the thinner that has flowed into each solvent passage 16 is discharged from the outlet 16 B of each solvent passage 16 into the solvent diffusion chamber 23.
Spill to. Then, the thinner flows in the solvent diffusion chamber 23 toward the front end side of the annular guide 22 while being guided by the annular guide 22, and collides with the annular protruding portion 24. As a result, the thinner is temporarily blocked by the dam effect of the annular protruding portion 24, and the bell cup 11 in the solvent diffusion chamber 23 is blocked.
Spread all around.

Thereafter, this thinner rides over the annular projection 24, passes through the annular throttle passage 25, and passes through the bell cup 11
Is blown onto the outer peripheral surface 11H. Thereby, the paint adhered to the outer peripheral surface 11H of the bell cup 11 can be completely washed over the entire circumference.

Here, FIG. 6 is a view of the rotary atomizing head 21 according to the present embodiment as viewed obliquely from the rear side, and shows a state in which thinner is discharged from the solvent supply nozzle 6 for 2 seconds. According to FIG. 6, the paint that has adhered to the outer peripheral surface 11H of the bell cup 11 is completely washed off over the entire circumference, and no paint has adhered to the outer peripheral surface 11H. This is because the thinner diffuses all over the outer peripheral surface 11H of the bell cup 11 due to the dam effect of the annular projection 24 provided on the annular guide 22, and as shown by the arrow in FIG. 1
This is because the thinner is ejected from all over the circumference.

On the other hand, FIG. 7 is a view of the rotary atomizing head 10 according to the above-described first embodiment as seen obliquely from the rear side.
Similarly to the rotary atomizing head 21 shown in FIG.
4 shows a state in which the thinner is discharged for 2 seconds. According to FIG. 7, the coating material P (hatched portion) remains partially attached to the outer peripheral surface 11H of the bell cup 11. This is because the annular guide 17 of the rotary atomizing head 10 according to the first embodiment is not provided with the annular ridge portion as described in the present embodiment, so that the thinner is reduced to 2 seconds. Was not sufficiently diffused over the entire circumference of the bell cup 11. Even in the rotary atomizing head 10 according to the first embodiment, if the discharge time of the thinner is extended to about 5 seconds, the thinner diffuses over the entire circumference in the solvent diffusion chamber 18 during that time. , Bell Cup 11
The paint adhered to can be washed sufficiently.

As described above, according to the rotary atomizing head 21 of the present embodiment, by providing the annular protrusion 24 on the inner peripheral surface of the annular guide 22, the cleaning ability can be further improved. It is possible to ensure the cleaning, shorten the cleaning time, and reduce the amount of thinner used.

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 an outer peripheral surface of the bell cup is provided with an annular protruding portion projecting toward the inner peripheral surface of the annular guide, and an annular throttle passage is provided between the annular protruding portion and the outer peripheral surface of the bell cup. Has been formed. In addition, in the present embodiment, the same components as those of the above-described first embodiment except the bell cup are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 31 indicates 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, and the bell cup 32 is formed in a bell shape or a cup shape, and has a rotary shaft mounting portion 32A, an insertion portion 32B, a coating film thinning surface 32C, and a discharge end. It is composed of a rim 32D, a paint receiving surface 32E, a hub mounting groove 32F, a guide mounting step portion 32G, an outer peripheral surface 32H, and the like.

The hub mounting groove 32 of the bell cup 32
A 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.

Further, in the bell cup 32, as in the first embodiment, the inflow port 34A is opened to the paint receiving surface 32E of the bell cup 32, and the outflow port 34B is opened to the outer peripheral surface 32H of the bell cup 32. A plurality of solvent passages 34 are formed. Further, the guide mounting step 32G of the bell cup 32
An annular guide 17 is provided on the inner surface of the bell cup 32, and a solvent diffusion chamber 18 is formed between the outer peripheral surface 32H of the bell cup 32 and the inner peripheral surface of the expanded portion 17B of the annular guide 17.

Although the above points are the same as those of the bell cup 11 according to the first embodiment described above, the annular projection 35 is formed on the outer peripheral surface 32H of the bell cup 32 according to the present embodiment.
Is provided, which is different from the bell cup 11 according to the first embodiment. That is, the annular protruding portion 35 is provided on the outer peripheral surface 32H of the bell cup 32 at a position facing the front end of the expanded portion 17B of the annular guide 17. Then, the annular protrusion 35 is formed in an annular shape over the entire circumference of the bell cup 32, and the annular protrusion 35 and the annular guide 1 are formed.
An annular throttle passage 36 is formed between the expansion opening 17 </ b> B and the expansion opening 17 </ b> B.

Here, when the rotary atomizing head 31 is cleaned, the annular projection 35 flows out from the outlet 34B of each solvent passage 34 and is directed to the front side of the bell cup 32 in the solvent diffusion chamber 18. This serves as a dam that temporarily blocks the thinner that flows through the front end side of the annular guide 17.

Also with the rotary atomizing head 31 according to the present embodiment configured as described above, as in the first embodiment described above, the reliability of cleaning, the shortening of the cleaning time and the reduction of the amount of thinner used can be achieved. Can be planned.

Next, a rotary atomizing head according to a fourth embodiment of the present invention will be described with reference to FIG. A feature of the present embodiment is that an annular guide that surrounds the outer peripheral side of the bell cup is formed integrally with the bell cup. In addition, in the present embodiment, the hub member, the paint outflow hole, the solvent outflow hole, and the like, which are the same constituent elements as those in the first embodiment, are
The same reference numerals as those in the first embodiment are attached, and the description thereof will be omitted.

Reference numeral 41 indicates a rotary atomizing head according to this embodiment. Reference numeral 42 denotes a bell cup forming the outer shape of the rotary atomizing head 41. The bell cup 42 is formed in a bell shape or a cup shape as in the first embodiment described above, and has a rotary shaft mounting portion. 42A, insertion part 42B, paint thinning surface 42C, discharge edge 42D, paint receiving surface 42E, hub mounting groove 42F, and outer peripheral surface 42G. And
The hub member 12 is provided in the hub mounting groove 42F,
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.

.. denote solvent passages provided in the circumferential direction of the bell cup 42, for example, 12 solvent passages 44, and each solvent passage 44 is the solvent passage 1 according to the first embodiment.
Similar to 6, the inflow port 44A is opened to the paint reservoir 43, and the outflow port 44B is opened to the outer peripheral surface 42G of the bell cup 42.

Reference numeral 45 denotes an annular guide which is located at an axially intermediate portion of the bell cup 42 and is provided on the outer peripheral side of the bell cup 42. The annular guide 45 is the annular guide 17 according to the first embodiment described above. The annular guide 45 is formed integrally with the bell cup 42, although it is formed in substantially the same manner. A solvent diffusion chamber 46 is formed between the outer peripheral surface 42G of the bell cup 42 and the inner peripheral surface of the annular guide 45.

The rotary atomizing head 41 according to the present embodiment configured as described above also has substantially the same operational effects as those of the first embodiment described above. In particular, the annular guide 45
By integrally forming the bell cup 42 with the bell cup 42, the number of parts can be reduced.

Next, a rotary atomizing head according to a fifth embodiment of the present invention will be described with reference to FIG. A feature of this embodiment is that a bell cup having a long tubular shape on the front side is provided with a plurality of solvent passages and an annular guide.

Reference numeral 51 indicates a rotary atomizing head according to this embodiment. Reference numeral 52 denotes a bell cup forming 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 thin film surface 52C, and a discharge end. It is similar to the bell cup 11 according to the above-described first embodiment in that it is composed of the edge 52D, the paint receiving surface 52E, the hub mounting groove 52F, the guide mounting step 52G, and the outer peripheral surface 52H. However, the bell cup 52 according to the present embodiment is different from the bell cup 11 according to the first embodiment in that the front side thereof is formed into a substantially long tube shape and has a shape close to a cylinder as a whole. .

53 is a hub mounting groove 52F of the bell cup 52
The hub member 53 is formed of a disc portion 53A formed in a disc shape and a cylindrical portion 53B formed in a cylindrical shape. Further, the front surface 53C of the disk portion 53A is formed in a flat shape, and the rear surface of the disk portion 53A is a paint supply surface 53D.

Further, a plurality of paint outflow holes 54 are formed in a ring shape in the hub member 53 near the boundary between the disk portion 53A and the cylindrical portion 53B. Further, a conical projection 53E is formed on the hub member 53 at the center side of the disk portion 53A, and a plurality of solvent outflow holes 55 are formed in the conical projection 53E.

Further, the hub mounting groove 52 of the bell cup 52
A hub member 53 is provided at F, and a paint reservoir 56 is formed between the paint supply surface 53D of the hub member 53 and the paint receiving surface 52E of the bell cup 52.

Denote 57 solvent passages, for example, 12 provided in the circumferential direction of the bell cup 52, and each of the solvent passages 57 has its inlet 57A opened to the paint receiving surface 52E of the bell cup 52. The outlet 57B is open to the outer peripheral surface 52H of the bell cup 52. Further, the intermediate portion of each solvent passage 57 penetrates the cylindrical portion 53B of the hub member 53.
That is, the solvent passages 5 are formed in the cylindrical portion 53B of the hub member 53.
A communication hole 53F forming a part of 7 is formed.

Reference numeral 58 is a guide mounting step 5 of the bell cup 52.
The annular guide provided in 2G is shown, and the annular guide 58
Is composed of a mounting portion 58A located on the base end side and an expanding portion 58B located on the front end side and expanding along the outer peripheral surface 52H of the bell cup 52. The bell cup 52 is surrounded in a held state. Then, the outer peripheral surface 52H of the bell cup 52 and the annular guide 58
A solvent diffusion chamber 59 is formed between the inner peripheral surface of the expanded portion 58B.

With the rotary atomizing head 51 according to the present embodiment having the above-described structure, it is possible to obtain the same effects as those of the above-described first embodiment.

In the second embodiment described above, as shown in FIG. 5, the annular projection 24 is provided on the front end side of the expanding portion 22B of the annular guide 22. But,
The present invention is not limited to this, and the annular ridge portion may be arranged on the inner peripheral surface of the expanded portion 22B of the annular guide 22 at any position of the intermediate portion or the rear portion in the axial direction. That is, as in the modification shown in FIG. 11, the annular ridge portion 24 ′ may be provided at the axially intermediate portion of the annular guide 22.

Further, in the above-described third embodiment, as shown in FIG. 8, the annular protruding portion 35 faces the front end side of the expanded portion 17B of the annular guide 17 on the outer peripheral surface 32H of the bell cup 32. It has been described that it is provided at the position. But,
The present invention is not limited to this, and the annular protruding portion may be arranged at a position facing the axially intermediate portion or rear portion of the expanding portion 17B of the annular guide 17. That is, as in the modification shown in FIG. 12, the annular protruding portion 35 ′ may be provided at a position facing the axially intermediate portion of the annular guide 17.

Further, in each of the above embodiments, the rotary atomizing head according to the present invention is applied to a center feed type electrostatic coating machine in which the paint supply nozzle 5 and the solvent supply nozzle 6 are provided in the rotary shaft 3. I explained using an example. But,
The present invention is not limited to this, and is also applied to an electrostatic coating machine in which a paint supply pipe and a solvent supply pipe are provided outside the rotary shaft, and the paint and thinner are supplied from each supply pipe toward the inside of the rotary atomizing head. it can.

[0103]

As described above in detail, according to the invention of claim 1, when the inflow port is located on the inner peripheral surface of the bell cup.
Both are open on the paint receiving surface at a position deeper than each paint outflow hole
The outlet is opened to the outer peripheral surface of the bell cup, and a plurality of solvent passages are provided to connect the paint reservoir formed in the bell cup and the outer peripheral surface of the bell cup.
An annular guide is provided so as to surround the bell cup in a state with a surface and a gap, and a solvent diffusion chamber is provided between the inner peripheral surface of the annular guide and the outer peripheral surface of the bell cup. At the time of cleaning the atomizing head, the solvent supplied from the nozzle collects the paint, is guided to the solvent diffusion chamber through the solvent passage, and can be sprayed from the solvent diffusion chamber toward the outer peripheral surface of the bell cup. The paint attached to the outer peripheral surface can be reliably washed. Also, the inlet of each solvent passage
Is opened at a position deeper than each paint outflow hole
From, it is discharged from the nozzle and flows into the paint reservoir during painting.
It is possible to prevent the paint from accidentally flowing into each solvent passage,
When cleaning the rotary atomizing head, paint is discharged from the nozzle
It is easy to allow the solvent that has flowed into the solvent to flow into each solvent passage.
it can.

Further, the solvent flowing out from the solvent passage is temporarily retained in the solvent diffusion chamber and then flows toward the front side of the bell cup, so that all the solvent flowing out from the solvent passage is removed. It can be used for cleaning the outer peripheral surface of the bell cup without waste. Therefore, the use efficiency of the solvent can be improved, and the cleaning efficiency can be significantly increased.

According to the second aspect of the invention, in the solvent diffusion chamber, the solvent flowing between the solvent diffusion chamber located between the inner peripheral surface of the annular guide and the outer peripheral surface of the bell cup is charged into the bell cup. Since the annular ridge portion for diffusing over the entire circumference is provided, the solvent flowing from the solvent passage into the solvent diffusion chamber can be diffused in the circumferential direction of the bell cup by the dam effect of the annular ridge portion. . As a result, the solvent can be sprayed over the entire circumference of the bell cup outer peripheral surface, and the paint adhered to the outer peripheral surface of the bell cup can be completely washed over the entire peripheral surface.

According to the third aspect of the present invention, an annular ridge protruding toward the outer peripheral surface of the bell cup is provided on the inner peripheral surface of the annular guide, and the annular ridge and the outer peripheral surface of the bell cup are formed. Since the annular throttle passage is formed therebetween, the solvent flowing from the solvent passage into the solvent diffusion chamber can be diffused in the circumferential direction of the bell cup by the dam effect of the annular protrusion.

Further, as in the invention according to claim 4, an annular ridge protruding toward the inner peripheral surface of the annular guide is provided on the outer peripheral surface of the bell cup, and the annular ridge and the outer peripheral surface of the bell cup are provided. Even if the annular throttle passage is formed between the two, the solvent flowing into the solvent diffusion chamber from the solvent passage can be diffused in the circumferential direction of the bell cup by the dam effect of the annular protrusion.

[0108]

According to the fifth aspect of the present invention, each solvent passage is inclined in the direction of rotation of the bell cup as it goes from the inlet to the outlet, so that when cleaning the rotary atomizing head, the solvent passes from the nozzle. The solvent discharged and flowing into the paint reservoir can easily flow into each solvent passage, and a large amount of solvent can be sent toward the outer peripheral side of the bell cup.

According to the sixth aspect of the present invention, since each solvent passage is inclined toward the rear side of the bell cup as it goes from the inlet to the outlet, at the time of coating, the solvent is discharged from the nozzle into the paint reservoir. It is possible to prevent the paint that has flowed in from flowing into each solvent passage and toward the outer peripheral side of the bell cup, and at the time of cleaning the rotary atomizing head, the solvent discharged from the nozzle and flowing into the paint reservoir can easily flow into each solvent passage. Inflow,
It can be distributed toward the outer peripheral side of the bell cup.

[Brief description of drawings]

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

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

3 is a cross-sectional view of the rotary atomizing head in FIG. 2 as seen 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 washed.

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

FIG. 6 shows a rotary atomizing head according to a second embodiment,
It is a perspective view showing the state where the peripheral face of a bell cup is washed with thinner.

FIG. 7 is a rotary atomizing head according to the first embodiment,
It is a perspective view showing the state where the peripheral face of a bell cup is washed with thinner.

FIG. 8 is a longitudinal sectional view of an essential part showing a rotary atomizing head according to a third embodiment of the present invention.

FIG. 9 is a vertical sectional view showing a rotary atomizing head according to a fourth embodiment of the present invention.

FIG. 10 is a vertical sectional view showing a rotary atomizing head according to a fifth embodiment of the present invention.

FIG. 11 is a longitudinal cross-sectional view of essential parts showing a modified example of the rotary atomizing head according to the second embodiment, in which an annular protrusion is provided at an axially intermediate portion of the annular guide.

FIG. 12 is a longitudinal cross-sectional view of essential parts showing a modified example in which an annular projection is provided at a position facing an axially intermediate portion of an annular guide in the rotary atomizing head according to the third embodiment.

[Explanation of symbols]

1 cover 3 rotation axes 5 Paint supply nozzle 6 Solvent supply nozzle 10, 21, 31, 41, 51 rotating atomizing head 11,32,42,52 Bell cup 11C, 32C, 42C, 52C Paint thin film surface 11D, 32D, 42D, 52D Emission edge 11E, 32E, 42E, 52E Paint receiving surface 11H, 32H, 42G, 52H outer peripheral surface 12,53 Hub member 13,54 Paint outflow hole 15, 33, 43, 56 Paint reservoir 16,34,44,57 Solvent passage 16A, 34A, 44A, 57A inlet 16B, 34B, 44B, 57B outlet 17,22,45,58 Annular guide 18,23,46,59 Solvent diffusion chamber 24,35 annular protrusion 25,36 annular throttle passage

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-33859 (JP, A) European patent application publication 715896 (EP, A 1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B05B 5/00-5/16 B05B 3/00-3/18

Claims (6)

(57) [Claims] 1. A bell cup formed in a bell shape or a cup shape, the front side of the inner peripheral surface being a paint thinning surface for thinning the paint and the rear side of the inner peripheral surface being 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 between the rear surface of the hub member and the paint receiving surface of the bell cup. A paint reservoir that is defined and stores the paint or solvent supplied to the paint receiving surface from the nozzle provided in the main body of the coating machine, and the paint or solvent that is provided in the hub member and supplied from the nozzle to the paint reservoir. In a rotary atomizing head consisting of a plurality of paint outflow holes that flow out to the paint thinning surface of the bell cup, the inlet is located on the inner peripheral surface of the bell cup and
A plurality of paint outlets that open at the paint receiving surface at positions deeper than the paint outflow holes and have an outlet opening at the outer peripheral surface of the bell cup are provided to connect the paint reservoir and the outer peripheral surface of the bell cup. A solvent passage, an annular guide that surrounds the bell cup in a state where there is a gap with the outer peripheral surface of the bell cup, and that guides the solvent flowing out from the outlet of each solvent passage; A rotary atomizing head, comprising a solvent diffusion chamber which is formed over the entire circumference between a peripheral surface and the outer peripheral surface of the bell cup and which diffuses the solvent supplied from the solvent passage. 2. Inside the solvent diffusion chamber, the solvent flowing between the inner circumferential surface of the annular guide and the outer circumferential surface of the bell cup is diffused over the entire circumference of the bell cup. The rotary atomizing head according to claim 1, further comprising an annular ridge portion. 3. An annular projecting portion projecting toward the outer peripheral surface of the bell cup is provided on the inner peripheral surface of the annular guide, and an annular throttle passage is provided between the annular projecting portion and the outer peripheral surface of the bell cup. The rotary atomizing head according to claim 1, wherein the rotary atomizing head is formed. 4. An outer peripheral surface of the bell cup is provided with an annular protruding portion projecting toward an inner peripheral surface of the annular guide, and an annular throttle passage is provided between the annular protruding portion and the outer peripheral surface of the bell cup. The rotary atomizing head according to claim 1, which is formed. 5. The rotary atomizing head according to claim 1, wherein each of the solvent passages is configured to incline in a rotation direction of the bell cup from an inflow port toward an outflow port. 6. The rotary atomizing head according to claim 1, wherein the solvent passages are inclined toward the rear side of the bell cup from the inlet to the outlet.