JP2001137746A - Rotational atomization type coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify constitution, miniaturize and surely prevent condensation from being generated. SOLUTION: A coating valve 34 is provided with a casing part 40, a piston 42 freely slidably fitted in the axial direction in the casing part 40 and with a valve rod part 46 opening/closing a coating passage 30, the first air room 52 into which pilot air flows in the above described casing part 40, the second air room 56 opened outside through a hole part 54 and an exhaust air communication path 62 for exhausting a part of flowing exhaust air in the exhaust path 26 from the hole part 54 to the outside through the second air room 56.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary atomizing type coating apparatus which discharges paint from a rotary atomizing head to a workpiece to perform coating.

[0002]

2. Description of the Related Art In general, a coating apparatus for applying a high voltage to a coating material (liquid coating material) to apply an electrostatic coating to an object to be coated such as an automobile body is employed. For example, there is known a rotary atomizing type coating apparatus which discharges paint by the action of centrifugal force from the leading edge of the rotary atomizing head under the rotating action of the rotary atomizing head.

In this type of rotary atomizing type coating apparatus, a paint path for supplying paint to the rotary atomizing head is provided in the apparatus body, and this paint path is opened and closed via a paint valve. The supply and stop of the paint are performed. This paint valve usually includes a casing portion and a piston that is slidably fitted in the casing portion in the axial direction, and the piston protrudes toward the paint passage side to open and close the paint passage. A valve stem is provided.

In the casing, a first air chamber into which pilot air flows and a second air chamber (spring chamber) opened to the outside through a breathing hole (hole) correspond to both sides of the piston. It is provided. When painting is performed, the pilot air flows into the first air chamber, whereby the piston is moved to the second air chamber to open the paint path, thereby supplying paint to the rotary atomizing head. It is configured to be.

In this type of paint valve, pilot air is supplied to and exhausted from the first air chamber so that the piston slides in the axial direction to open and close the paint path. For this reason, it has been pointed out that the pressure increase and the pressure decrease are repeatedly performed in the first and second air chambers and dew condensation occurs due to adiabatic expansion.

Therefore, for example, Japanese Patent Application Laid-Open No. 7-251103
As disclosed in Japanese Unexamined Patent Application Publication No. H11-264, a proposal has been made to prevent water drops from accumulating and accumulating in an air chamber or the like of a paint valve. Specifically, as shown in FIG. 3, a hollow rotary shaft 3 is rotatably arranged in an electrostatic coating machine 1 via an air motor 2 and a rotary shaft (not shown) Atomizing head is connected. A paint discharge pipe 4 is disposed in the rotating shaft 3, and the paint discharge pipe 4 is provided with a paint valve 5.
It is opened and closed via.

[0007] In the casing 6 constituting the paint valve 5,
An air chamber 7 and a spring chamber 8 are formed via a piston 9, and the piston 9 is provided with a valve 9 a that can open and close the paint discharge pipe 4. The air chamber 7 has an air hole 7a.
The breathing hole 8a opened to the outside communicates with the spring chamber 8, and the air chamber 7 and the spring chamber 8 communicate with each other via a small-diameter communication passage 9b formed in the piston 9. are doing.

In such a configuration, when painting is performed, pilot air is supplied to the air chamber 7 from the air holes 7a. Therefore, the piston 9 is moved by the air pressure to the spring chamber 8.
Side, the valve element 9a is separated from the paint discharge pipe 4, and the paint is supplied to the rotary atomizing head (not shown). At this time, the pilot air supplied from the air hole 7a to the air chamber 7 slightly flows out to the spring chamber 8 side through the communication passage 9b,
Further, it is discharged from the spring chamber 8 to the outside through the breathing hole 8a. This prevents water droplets from accumulating and accumulating in the paint valve 5, and prevents high-voltage leakage for charging the paint.

[0009]

However, in the above-mentioned prior art, the air supplied to the air chamber 7 is
Since the air moves to the spring chamber 8 through the small-diameter communication passage 9b provided in the air passage, adiabatic expansion is easily caused in the air passing through the small-diameter communication passage 9b. As a result, a problem has been pointed out that the temperature of the air introduced into the spring chamber 8 decreases, and dew condensation occurs in the spring chamber 8. Therefore, if the communication passage 9b is set to have a large diameter, it is difficult to drive the piston 9. Even if the piston 9 can be driven, there is a problem that a considerably large amount of air is required and the opening operation of the paint valve 5 becomes unstable.

The present invention has been made to solve this kind of problem, and provides a rotary atomizing type coating apparatus capable of simplifying and reducing the size of the structure and reliably preventing the occurrence of condensation. Aim.

[0011]

The rotary atomizing type coating apparatus according to the present invention includes a paint valve capable of opening and closing a paint path for supplying paint to the rotary atomizing head. Exhaust air exhaust of an air turbine that has a first air chamber that flows therein and a second air chamber that is opened to the outside through a hole, and wherein the second air chamber rotates a rotary atomizing head. It communicates with the path via an exhaust air communication passage.

For this reason, a part of the exhaust air flowing through the exhaust air discharge path is introduced into the second air chamber to which the pilot air is not supplied, and the exhaust air is supplied to the outside through a hole communicating with the second air chamber. Is discharged. Therefore, moisture does not stay in the second air chamber, and it is possible to reliably prevent the occurrence of dew condensation. In addition, there is no need to newly provide an air supply path communicating with the second air chamber, and the configuration is simplified, and the size of the entire paint valve is easily reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic internal structural explanatory view of a rotary atomizing type coating apparatus 10 according to an embodiment of the present invention.

The coating apparatus 10 has an apparatus main body 12, in which an air motor 14 is provided, and a cylindrical rotary shaft 18 is integrally formed with an air turbine 16 constituting the air motor 14. And a rotary atomizing head 20 is fixed to the tip of the rotary shaft 18.

The apparatus main body 12 has a turbine air supply path 22 for supplying turbine air for driving the air turbine 16 and a bearing air for supporting the rotating shaft 18 (because it is included in the turbine air, a turbine air Bearing air supply path 24 for supplying air).
An exhaust air discharge path 26 for discharging exhaust air from the air motor 14 to the outside is formed. In the center of the apparatus main body 12, a pipe member 28 is disposed inside the rotating shaft 18, and a paint path 30 and a cleaning liquid path 32 are formed in the pipe member 28. The tips of the paint path 30 and the cleaning liquid path 32 are open to the outside from the center side of the rotary atomizing head 20.

The paint path 30 is configured to be opened under the action of a paint valve 34 so that a predetermined paint can be discharged onto a work (not shown). The paint path 30 includes a discharge port 30a for discharging paint, a valve seat 36 provided inside the discharge port 30a, one end communicating with the valve seat 36, and the other end forming a paint valve 34. A housing section 38 communicating with a casing section 40 described later, and a paint introducing section 39 communicating with the housing section 38 at an angle to the other end side of the housing section 38 are provided.

The paint valve 34 includes a casing portion 40 fixed to the inside of the apparatus main body 12, and a piston 42 which is movable in the axial direction (direction of arrow A) by fluid pressure, for example, air pressure, in the casing portion 40. Is arranged. A rod portion 44 extends in the axial direction from an end portion of the piston 42, and a valve stem portion 46 is provided at a distal end portion of the rod portion 44.

The valve stem 46 is connected to the valve seat 36 of the paint path 30.
, The paint path 30 can be closed freely. A paint introduction chamber 48 is provided at the end of the housing 38 opposite to the valve seat 36 so as to have a larger diameter.
A tapered portion 50 is formed at a position corresponding to the paint introduction chamber 48 so as to decrease its diameter toward the valve seat portion 36.

As shown in FIG. 2, a first air chamber 5 provided on one end 42a side of a piston 42 into which pilot air flows is provided in a casing portion 40 constituting the paint valve 34.
2 and a second air chamber (spring chamber) 56 provided on the other end 42 b side of the piston 42 and opened to the outside through a hole (breathing hole) 54. , A spring 58 is disposed. First air chamber 52
, A pilot air path 60 communicates with the pilot air supply source (not shown). An exhaust air communication passage 62 for discharging a part of the exhaust air flowing from the air motor 14 through the exhaust passage 26 to the outside through the hole 54 through the second air chamber 56 communicates with the second air chamber 56. are doing.

The apparatus main body 12 accommodates a high voltage applying means (not shown) for charging the paint discharged from the rotary atomizing head 20 with static electricity.

The operation of the coating apparatus 10 configured as described above will be described below.

A paint is supplied to the paint path 30 from a paint supply source (not shown).
6 is seated on the valve seat portion 36, and the discharge of the paint is stopped. Then, the turbine air is supplied to the turbine air supply path 22 to rotate the air turbine 16 constituting the air motor 14 at high speed integrally with the rotary atomizing head 20, and the turbine air is supplied to the bearing air supply path 24. The rotating shaft 18 is supported.

On the other hand, in the paint valve 34, pilot air is supplied to the first air chamber 52 via the pilot air path 60, and the piston 42 moves in the direction of arrow A1 against the elastic force of the spring 58. Therefore, the valve stem 46 connected to the piston 42 is separated from the valve seat 36, and the paint supplied to the paint path 30 is discharged from the discharge port 30a to the rotary atomizing head 20, and is shown in FIG. A high voltage is applied to this paint via a high voltage applying means that does not. Accordingly, the paint charged with static electricity is released in an atomized state, and a desired electrostatic painting operation is performed on a work (not shown).

In this case, in this embodiment, the air motor 1
4 is exhausted through the exhaust path 26, and a part of the exhausted turbine air is introduced into the second air chamber 56 through the exhaust air communication passage 62, Is discharged to the outside.

As a result, a part of the turbine air is discharged to the outside from the hole 54 via the second air chamber 56, so that an air flow is always generated in the second air chamber 56. For this reason, even if the paint valve 34 repeatedly performs the opening / closing operation, an effect is obtained that the dew formation in the second air chamber 56 can be reliably prevented.

In addition, it is only necessary to connect the exhaust path 26 of the turbine air to be exhausted to the second air chamber 56 through the exhaust air communication passage 62, and a new air supply path is connected to the second air chamber 56. There is no need to provide, and the configuration is effectively simplified. Further, even when the opening diameter of the exhaust air communication passage 62 is formed to be relatively large, for example, about
The whole is not enlarged. Accordingly, the opening diameter of the exhaust air communication passage 62 can be set large, and the exhaust air introduced into the second air chamber 56 does not cause adiabatic expansion, thereby simplifying the configuration and miniaturizing the configuration. This has the advantage that the occurrence of condensation can be prevented as much as possible.

[0027]

According to the rotary atomizing type coating apparatus according to the present invention,
A paint valve that opens and closes a paint path has a first air chamber into which pilot air flows, and a second air chamber that opens to the outside through a hole.
An air chamber, and the second air chamber communicates with an exhaust air discharge path of an air turbine that rotates a rotary atomizing head through an exhaust air communication passage. For this reason, a part of the exhaust air flowing through the exhaust air discharge path is discharged to the outside from the hole through the second air chamber, and it is possible to reliably prevent the occurrence of dew condensation in the second air chamber. Can be. In addition, it is not necessary to provide a new air supply path in communication with the second air chamber, so that the configuration is simplified and the overall size of the apparatus can be easily reduced.

[Brief description of the drawings]

FIG. 1 is a schematic internal configuration explanatory view of a coating apparatus according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view of a paint valve constituting the coating apparatus.

FIG. 3 is a partially sectional explanatory view of a coating apparatus according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Coating apparatus 12 ... Device main body 14 ... Air motor 16 ... Air turbine 18 ... Rotating shaft 20 ... Rotary atomizing head 22 ... Turbine air supply path 24 ... Bearing air supply path 26 ... Discharge path 30 ... Paint path 32 ... Cleaning liquid path 36 … Valve seat part 38… accommodation part 39… paint introduction part 40… casing part 42… piston 46… valve rod part 50… taper part 52, 56… air chamber 54… hole part 58… spring 60… pilot air path 62… exhaust Air communication passage

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Osamu Kageyama 1-10-1 Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd. F-term (reference) 4D075 AA10 AA71 4F033 AA01 GA02 PB16 4F034 AA04 BA22 BA26 BB02 BB04 BB07

Claims (1)

[Claims] An apparatus main body that houses a rotary atomizing head capable of discharging paint to a work, an air turbine that rotates the rotary atomizing head, and a discharge path for exhaust air of the air turbine. A paint path provided in the apparatus body and supplying paint to the rotary atomizing head; and a paint valve provided in the apparatus body and capable of discharging paint to a workpiece by opening the paint path. A coating device, comprising: a casing portion; and a casing portion, which is fitted slidably in the axial direction in the casing portion, and protrudes from the casing portion into the paint path. A piston having a valve stem for opening and closing the paint passage; a first air chamber provided at one end of the piston in the casing and into which pilot air flows; Provided on the other side of the piston, it communicates with the second air chamber which is open to the outside, and the second air chamber and the exhaust air eject path through the holes,
A part of the exhaust air flowing through the exhaust air discharge path is
A rotary atomization type coating apparatus, comprising: an exhaust air communication passage for discharging the air to the outside from the hole through an air chamber.