JPH0580546U - Electrostatic coating device - Google Patents

Abstract

(57) [Abstract] [Purpose] Even if various devices are placed close to each other, it is possible to prevent the corona discharge from concentrating at specific parts of the devices, and thereby effectively avoid dielectric breakdown. To enable. [Arrangement] An arcuate chamfered portion 41a is provided at the upper end of a metal cylinder 41 which is in contact with a paint to which a high voltage is directly applied, and an arcuate chamfered portion is provided at a corner of a three-way switching valve 26 maintained at ground potential. 26a to 26d are formed. Therefore, even if a potential difference occurs between the metal cylinder 41 and the three-way switching valve 26, and corona discharge occurs between them,
Corona discharge is not concentrated on specific portions of the metal cylinder 41 and the three-way switching valve 26, and the corona discharge is dispersed to effectively prevent the occurrence of dielectric breakdown.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electrostatic coating device for performing electrostatic coating by directly applying a high voltage to conductive coating.

[0002]

[Prior Art]

 Conventionally, a paint color changing system disclosed in, for example, Japanese Patent Application Laid-Open No. 2-2885 is used as an electrostatic coating device for directly applying a high voltage to a conductive coating to electrostatically coat an object to be coated such as an automobile body. It has been known.

In this conventional technique, the conductive coating material is once introduced into an intermediate storage tank (reservoir) which is insulated from the ground potential, and then a high voltage is directly applied to the intermediate storage tank from which the object to be coated is coated. The electrostatic coating work is performed by being supplied.

In this case, in addition to an intermediate storage tank for temporarily storing the conductive paint, various switching valves for switching between the conductive paint and the cleaning liquid, air, etc. are used. This kind of equipment is made of a conductive material such as metal from the viewpoint of strength and cost. In order to make the whole system compact, the equipment is placed in a state where it cannot be insulated from each other through resin. It is conceivable to place them in close proximity.

[0005]

[Problems to be solved by the device]

 However, even if the above-mentioned devices are arranged apart from each other by a distance that can be insulated by the resin, a corona discharge will occur between these devices, albeit a minute amount. This corona discharge tends to concentrate on the corners of the equipment, which is a conductive material, and therefore, there is a problem that dielectric breakdown occurs between the corners and other equipment after long-term use. be pointed out.

Therefore, it is conceivable to set the thickness of the resin interposed between the devices to a sufficiently large value, but this leads to an increase in weight and cost, and dielectric breakdown is effective during long-term use. There is an inconvenience that it cannot be avoided.

The present invention solves this kind of problem, and even if various devices are arranged close to each other, it is possible to prevent corona discharge from concentrating at a specific part of the device. It is an object of the present invention to provide an electrostatic coating device capable of effectively avoiding dielectric breakdown.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a first member made of a conductive material such as a valve, an intermediate storage tank and a joint which is in contact with a conductive paint to which a high voltage is directly applied, and a conductive material at a ground potential. And a second member, and at least one of the first and second members is provided with an arcuate chamfered portion at a corner facing at least the other member side.

[0009]

[Action]

 In the electrostatic coating apparatus according to the present invention described above, the first member has a high potential, while the second member has the ground potential, so that a potential difference occurs between the first member and the second member, Corona discharge is likely to occur between the first member and the second member. At that time, since at least one of the first and second members has an arcuate chamfered portion at the corner facing at least the other member, corona discharge is not concentrated at the corner. .. Therefore, the dielectric breakdown between the first member and the second member can be effectively prevented, and the first member and the second member can be arranged as close to each other as possible.

[0010]

【Example】

 An electrostatic coating apparatus according to the present invention will be described below with reference to the accompanying drawings with reference to an embodiment.

In FIG. 2, reference numeral 10 indicates an electrostatic coating apparatus. The electrostatic coating apparatus 10 includes an intermediate storage tank 12 connected to a color change valve mechanism (not shown), and the intermediate storage tank 12 is provided. Is connected to a coating gun 16 via a four-way switching valve 14 and is fixed in a standing position by a holding device 18.

As shown in FIG. 1, the intermediate storage tank 12 has a manifold base 22 formed of an electrically insulating material and having a pipe body connecting portion 20 capable of piping a plurality of pipes from the outside, and the manifold. A storage portion (first member made of a conductive material) 24, which is integrally provided on the base 22 and in which the conductive coating material is temporarily stored, is separated from the storage portion 24 while ensuring a predetermined distance from each other. An insulating mechanism 30 having a pair of three-way switching valves 26, 28 arranged along the insulating mechanism 30, and an electrically insulating cover member 32a mounted on the manifold base 22 to cover devices including the insulating mechanism 30; 32b.

In the manifold base 22, the outer wall portion 34 of the storage portion 24 and the device mounting portions 36a to 36d are integrally molded in addition to the pipe body connecting portion 20, and the pipe body connecting portion 20 is formed. Screws 38a and 38b for fixing the cover members 32a and 32b are formed at both ends of the. Three-way switching valves 26, 28 constituting an insulating mechanism 30 are fixed to the device mounting portions 36a, 36b, and an insulating tube having a length capable of insulating a predetermined high voltage between the three-way switching valves 26, 28. 40 is arranged. Arc-shaped chamfered portions 26a to 26d are provided at respective corners of the three-way switching valve 26 which is the second member made of a conductive material.

The storage section 24 includes a metal cylinder 41, and an arcuate chamfered portion 41 a is provided at least at an upper end portion of the metal cylinder 41, and slides along an inner wall surface of the metal cylinder 41. A first cylinder chamber 44 for injecting the paint and the cleaning liquid and a second cylinder chamber 46 for supplying air are dividedly formed through the displacing piston 42. The piston 42 is provided with a cylindrical detection rod 48 extending to the outside of the storage portion 24, and a tank 50 for storing the cleaning fluid is provided above the detection rod 48. The dog member 52 is fixed to a predetermined position of the detection rod 48, and the dog portion 53 is formed in the tank 50. The dog member 52 and the dog portion 53 engage with the detection means 54.

The detection means 54 includes open / close valves 56 a and 56 b that are engaged with the dog member 52 and the dog portion 53 to be switched and driven, and the open / close valves 56 a and 56 b are connected to the manifold base via a mounting member 58. It is fixed to the equipment mounting portion 36c of the table 22. A flow rate control valve 60 that communicates with the first cylinder chamber 44 of the storage section 24 and adjusts the discharge amount of the paint is fixed to the equipment mounting portion 36d of the manifold base 22.

The pipe connection portion 20 formed at the end of the manifold base 22 has a first port 62 for supplying conductive paint to the three-way switching valve 26, and a cleaning liquid for the three-way switching valve 26. Of the three-way switching valve 28, a third port 66 for communicating one outlet side of the three-way switching valve 28 with a waste liquid tank (not shown) through a discharge path 65, and a first port through a delivery path 68. A fourth port 70 for communicating the cylinder chamber 44 with the four-way switching valve 14, a drive fluid port (not shown) for the piston 42 and the on-off valves 56a, 56b, and the like are provided (FIGS. 1 and 2). reference). The manifold base 22 is provided with a paint passage 72 for communicating the other outlet side of the three-way switching valve 28 with the first cylinder chamber 44 of the storage section 24.

The holding device 18 includes bolt members 86 a and 86 b provided on the outer wall of the intermediate storage tank 12, a frame body 88 having a shape corresponding to the outer shape of the intermediate storage tank 12, and the frame body. 88, which are provided with groove portions 90a and 90b for engaging the bolt members 86a and 86b to hold the intermediate storage tank 12 in an upright state, and the frame body 88 is a wall surface (not shown) in the workplace. Fixed).

Next, the operation of the electrostatic coating device 10 thus configured will be described.

First, when a paint of a predetermined color is pressure-fed to the first port 62 from a color changing valve mechanism (not shown), the paint is supplied from the three-way switching valve 26 through the insulating pipe 40 to the three-way switching valve 28. The first cylinder chamber 44 of the reservoir 24 is filled from the paint flow path 72. The paint with which the first cylinder chamber 44 is filled is sent from the flow rate control valve 60 to the four-way switching valve 14 through the fourth port 70 and the sending path 68, and then the paint gun 16 is filled. At that time, the piston 42 rises and the dog member 52 engages with the on-off valve 56a, so that the filling of the coating material can be automatically detected.

Next, driving air is supplied from an air supply source (not shown), and the switching operation of the three-way switching valves 26, 28 constituting the insulating mechanism 30 is performed. Therefore, the cleaning liquid supplied from the cleaning valve is discharged from the second port 64 to the waste liquid tank through the three-way switching valve 26, the insulating pipe 40, the three-way switching valve 28 and the discharge passage 65 and the third port 66. It Then, the insulating mechanism 30 is dried, so that the color change valve mechanism and the intermediate storage tank 12 are electrically insulated.

Here, the piston 42 is displaced to the side of the first cylinder chamber 44 by the driving air supplied from the air supply source, and the discharge amount of the paint is adjusted by the flow rate control valve 60, and at the same time, It is supplied from the coating gun 16 to a work (not shown) while the voltage is directly applied. At this time, the piston 42 moves toward the first cylinder chamber 44 side and the dog portion 53 engages with the on-off valve 56b, whereby the movement information of the piston 42 is automatically detected.

By the way, in the state in which the color change valve mechanism and the intermediate storage tank 12 are electrically insulated as described above, the storage in contact with the paint to which the high voltage is directly applied is inside the intermediate storage tank 12. While the metal cylinder 41 of the portion 24 is maintained at a high voltage, the three-way switching valve 26 made of a conductive material and forming the insulating mechanism 30 is maintained at the ground potential. For this reason, a potential difference is generated between the metal cylinder 41 and the three-way switching valve 26, and corona discharge is likely to occur between them. Particularly, as shown in FIG. Corona discharge concentrates on one corner 94 of the switching valve 26, and a dielectric breakdown portion 96 is generated between the upper corner 92 and the corner 94.

However, in this embodiment, as shown in FIG. 3B, an arcuate chamfered portion 41a is provided at the upper end of the metal cylinder 41, and the three-way switching valve 26 has the upper end of the metal cylinder 41. An arcuate chamfered portion 26a is formed at a corner portion facing to, and an arcuate chamfered portion 26b is provided at a corner portion facing the outer peripheral portion of the metal cylinder 41. Therefore, the corona discharge does not concentrate at the specific portions of the metal cylinder 41 and the three-way switching valve 26, and the corona discharge is dispersed to effectively prevent the occurrence of dielectric breakdown. Is obtained. As a result, the distance L (see FIG. 3b) between the metal cylinder 41 and the three-way switching valve 26 can be made smaller than the distance at which the high voltage directly applied to the paint can be insulated by air, and this three-way switching is performed. It is possible to effectively reduce the thickness of the resin manifold base 22 that is interposed between the valve 26 and the metal cylinder 41. Therefore, there is an advantage that the total weight of the manifold base 22 can be reduced, the manufacturing cost of the intermediate storage tank 12 as a whole can be reduced, and the durability can be improved all at once.

In the present embodiment, the metal cylinder 41 of the storage section 24 and the three-way switching valve 26 constituting the insulating mechanism 30 have been described, but the present invention is not limited to this, and a high voltage is directly applied. The structure of the present invention can be used as long as it is a member made of a conductive material that is in contact with the paint in the fixed state and a member made of a conductive material in a grounded state (insulated state).

[0025]

[Effect of the device]

 According to the electrostatic coating device of the present invention, the following effects can be obtained.

Even if corona discharge occurs between the first member that is brought to a high potential state by contacting the conductive coating material to which the high voltage is directly applied and the second member that is at the ground potential, the first member Also, corona discharge does not concentrate on a specific portion of the second member. Therefore, the dielectric breakdown between the first member and the second member can be effectively prevented, and the first member and the second member can be arranged as close to each other as possible. There are advantages that the overall weight of the coating equipment can be reduced and the manufacturing cost can be easily reduced, and the durability is excellent.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional explanatory view of an intermediate storage tank constituting an electrostatic coating device according to the present invention.

FIG. 2 is a schematic perspective view of the electrostatic coating device and the holding device.

FIG. 3 is a partially enlarged explanatory view of a conventional intermediate storage tank and the intermediate storage tank of the present embodiment.

[Explanation of symbols]

 10 ... Electrostatic coating device 12 ... Intermediate storage tank 16 ... Coating gun 18 ... Holding device 20 ... Pipe connection part 22 ... Manifold base 24 ... Storage part 26, 28 ... Three-way switching valve 26a-26d ... Chamfer part 30 ... Insulation Mechanisms 36a to 36d ... Equipment mounting portion 40 ... Insulation pipe 41 ... Metal cylinder 41a ... Chamfering portion 42 ... Piston 44, 46 ... Cylinder chamber 60 ... Flow control valve 62, 64, 66, 70 ... Port

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Motohashi 1-10-1 Shin-Sayama, Sayama-shi, Saitama Prefecture Honda Engineering Co., Ltd. (72) Akifumi Murai 1-10-1 Shin-sayama, Sayama-shi, Saitama Prefecture Inside Honda Engineering Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A first member made of a conductive material, such as a valve, an intermediate storage tank and a joint, which comes into contact with a conductive paint to which a high voltage is directly applied, and a second member made of a conductive material at a ground potential. At least one of the first and second members is provided with an arc-shaped chamfered portion at a corner facing at least the other member side.