JPH1046376A - Basin for liquid treating process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a basin wall-surface is fatigued by oscillatory waves and strength reduction and crack generation therein are caused by applying oscillatory waves to a liquid to improve treatment efficiency, etc., in a surface treatment in a pretreatment process of coating, etc. SOLUTION: An inside basin 52 made of a punching metal is arranged inside a basin 38 without contacting with the basin 38. A low frequency oscillation generator 50 and a car body 30 are located in the inside basin 52, thereby surface treatment of the car body 30 by the oscillatory wave can be improved. Meanwhile, since the oscillatory waves proceeding to the inwall surface of the basin 38 are attenuated at the inside basin 52, adverse influence thereof to the basin 38 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water tank for a liquid treatment step of performing a surface treatment using a liquid on a coating line of an object to be treated such as an automobile body, and more particularly, to a water tank using a vibration wave generator. The present invention relates to protection of a water tank that can perform processing at high speed.

[0002]

2. Description of the Related Art In a coating line for an object to be processed such as an automobile body, the object to be processed is suspended on an overhead hanger and continuously conveyed, and the object to be processed is pickled and degreased. Treatment, chemical conversion treatment, hydrophilic treatment,
A process such as water washing is performed. These treatments are surface treatments performed using a liquid such as an acid. Specifically, the treatments are performed by immersing an object to be treated in a water tank (tank) storing a liquid used for the treatment. The water tank is made of, for example, stainless steel for pickling and iron for alkali cleaning such as degreasing.

[0003] These surface treatments may be insufficient, for example, at a complicated part of the surface of the object to be treated, or the treatment may not progress easily only by immersion in a liquid. Therefore, conventionally, for example, it has been performed to generate a vibration wave in a liquid using a low-frequency vibration wave generator to promote a reaction process and a cleaning process on the surface of the workpiece. Thereby, there is an advantage that uniform processing on the surface can be completed in a short time.

[0004]

However, the vibration wave generated in the liquid by the low-frequency vibration wave generator or the like also acts on the water tank, and causes the wall surface of the water tank to fatigue over a long period of time, and the strength of the water tank is reduced. There was a problem that it was lowered or cracks were generated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a liquid treatment capable of successfully performing a surface treatment using a vibration wave generator and reducing an influence of a vibration wave on a water tank. It is an object to provide a process water tank.

[0006]

According to the present invention, there is provided a water tank for a liquid processing step according to the present invention, which stores a liquid to be subjected to a surface treatment on an object to be treated, and applies a vibration wave to the liquid to accelerate the surface treatment. And a damping material provided between the inner wall of the water tank and the vibration wave generator to attenuate the vibration wave reaching the inner wall.

According to the present invention, a liquid used for surface treatment of an object to be treated, such as pickling, degreasing, chemical conversion, hydrophilization, and water washing, is stored in the water tank. A vibration wave generator is arranged in the liquid inside. The vibration wave generator generates a vibration wave in a liquid, thereby causing the liquid to flow and the liquid concentration to be uniform, thereby facilitating the chemical or physical surface treatment of the liquid to be processed. The damping material scatters the vibration wave passing therethrough, or weakens the vibration wave by becoming a resistance to the vibration wave to reduce the force of the vibration wave exerted on the inner wall of the water tank,
This is for protecting the wall surface of the water tank, and is, for example, a perforated plate or a net. To protect the walls of the aquarium, the damping material is arranged between the inner wall of the aquarium and the vibration wave generator. The damping material may be installed so as to protect only the wall surface facing the vibration direction of the vibration wave, for example, or may be installed so as to particularly protect the entire inner wall of the water tank. In addition,
Since the object to be processed is placed in the vibration wave, it is located on the same side as the vibration wave generator with respect to the damping material.

[0008] In a preferred aspect of the present invention, the attenuating material constitutes an inner tub containing the area where the surface treatment is performed. In this aspect, in order to protect the entire wall surface of the water tank, an inner tank made of an attenuating material is arranged in the water tank, and the object to be processed and the vibration wave generator are arranged in this inner tank to perform surface treatment. .

[0009] In a preferred aspect of the present invention, the inner tub is supported in non-contact with the water tub. In this aspect, the inner tub is supported so as not to contact the water tub, and thereby the vibration of the inner tub caused by the vibration wave is prevented from being transmitted to the water tub, so that the deterioration of the strength of the water tub is suppressed.

In a preferred aspect of the present invention, the damping material is a perforated plate. In this embodiment,
The damping material is a perforated plate having a large number of holes, for example, a punching metal, a wire mesh, or the like. Since these have resistance to the passage of the liquid, the fluctuation of the pressure of the liquid after the passage is more suppressed than that before the passage, so that the force acting on the wall surface of the water tank is reduced.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an example of a flowchart of a pretreatment process in a coating line for an automobile body in which the present invention is implemented. A vehicle body manufactured at a vehicle body factory is subjected to a hot water washing process 2 and a water washing process 4 sequentially by a spray method, and then subjected to a degreasing process 6 by a dip method. Next, after receiving two water washing treatments 8 and 10 by a spray method, a dip method
A surface adjustment treatment 12 and a film conversion treatment 14 are performed. Then, the vehicle body is subjected to a water-washing process 16 by spraying, a water-washing process 18 by dipping, and a pure water washing process 20 by spraying, and then dried (step 22) and passed to an undercoating step including processing such as electrodeposition coating. .

Here, the dip method means a water tank (tank).
In this method, a liquid used for processing is stored, and a body to be processed is immersed in the liquid to perform processing.

FIG. 2 is a schematic view showing an image of the pretreatment step. In the figure, the degreasing process 6 to the film forming process 14
Are shown. The vehicle body 30 is transported between each process by a trolley-type continuous conveyor system 32. In this continuous conveyor, a hanger 36 suspended from a rail 34 provided on the ceiling side of a factory moves using a chain (not shown) running along the rail 34 as power. Therefore, the body 30 to be processed is
Moves while being supported by the hanger 36. The hanger 36 includes a type in which an upper portion of the vehicle body, for example, a window frame portion is hooked, and a type in which the vehicle body 30 is mounted and carried.

A water tank 38 used in the dipping process stores a liquid 40 used in the process. The rail of the continuous conveyor system 32 is provided at a lower position on the water tank 38 than at other places. The high and low positions of the rail are connected by an inclined rail. Therefore, when approaching the water tank 38, the vehicle body 30 slowly descends into the water tank 38 together with the hanger 36, and the liquid 4
0. Then, the vehicle body 30 receives the processing with the liquid 40 while slowly moving in the water tank 38.

After moving to the end of the water tank 38, it is slowly pulled up from the liquid surface.

The liquid 40 used in the degreasing treatment 6 is an alkaline degreasing agent, which is treated, for example, at about 50 ° C. for about one minute. Thus, the oil attached to the surface of the vehicle body 30 is removed. When the alkaline degreasing agent is sufficiently washed away by the water washing processes 8 and 10, the surface conditioning process 12 is performed. The surface conditioning treatment 12 is a treatment in which the vehicle body 30 is immersed in the surface conditioning agent for, for example, several tens of seconds, whereby the formation of a chemical conversion film in the subsequent film conversion treatment 14 is performed well. Film conversion treatment 1
Reference numeral 4 denotes a process that is a main process of the pretreatment process. In the coating conversion treatment 14, a conversion coating such as zinc phosphate is formed on the surface of the vehicle body 30 made of iron for the purpose of rust prevention. This chemical conversion film is an inorganic poor electric conductor, and densely coats an iron base material to prevent electrochemical corrosion. Further, the chemical conversion coating forms an appropriate rough surface and significantly improves the adhesion of the paint. Since the paint is less likely to be peeled off, the appearance of the vehicle body 30 is maintained and corrosion prevention can be achieved. In the film formation treatment 14, the vehicle body 30 is immersed in a film formation agent such as a zinc phosphate at about 50 ° C. for about 2 minutes.

The above surface treatments such as the degreasing treatment and the film conversion treatment can be performed by a spray method, but a dip method has recently been adopted to improve the rust prevention effect. Since the degreasing treatment 6 uses an alkali as a treatment liquid, an iron water tank is used, and the other water tank is made of stainless steel here.

FIGS. 3 and 4 are schematic cross-sectional views showing the configuration of a water tank used in each of the above-mentioned dipping type liquid processing steps in the present embodiment. FIG. 3 is a cross-sectional view taken along the transport direction. Is a cross-sectional view perpendicular to the transport direction. Low-frequency vibration generators 50 supported by columns (not shown) are provided at both ends of the water tank 38 in the transport direction.

Between the low frequency vibration generator 50 and the water tank 38, there is provided an inner tank 52 made of punched metal. The vehicle body 30 and the low-frequency vibration generator 50 are located in the inner tank 52.

A shaft 56 projects from the motor section 54 of the low-frequency vibration generator 50, and a diaphragm 58 is attached to a portion of the shaft 56 that is inserted into the liquid. By vibrating the diaphragm 58 by the motor 54,
A low frequency, for example, a vibration wave of 30 to 50 Hz is generated in the liquid in the water tank 38. Due to this vibration wave, for example, degreasing treatment 6
In the chemical conversion treatment 14, the body 3
Liquid flow occurs at the interface between 0 and the chemical conversion agent to promote the chemical conversion reaction.

The thickness of the iron plate or stainless steel plate constituting the wall of the water tank 38 depends on the size of the water tank 38 and the weight of the stored liquid. When low-frequency vibration acts on the water tank 38 for a long period of time, the wall surface causes metal fatigue due to microvibration, and the strength is reduced. The inner tank 52 peculiar to the present invention is for preventing this. The punching metal 70 constituting the inner tank 52 is an iron plate or a stainless plate in which a large number of circular holes are arranged in an arrangement based on, for example, an equilateral triangle.

FIG. 5 is a perspective view showing an image of the punching metal 70 constituting the inner tank 52. The material of the punching metal 70 is selected according to the use of the water tank 38, and is usually the same as the material forming the wall surface of the water tank 38. The pressure fluctuation caused by the low frequency vibration wave is attenuated by the inner tank 52, and the pressure fluctuation in the water tank 38 is reduced.
This has something in common with the principle of an automobile muffler and a silencer. It is conceivable that the inner tank 52 itself is also affected by the low-frequency vibration wave and the strength is deteriorated.
Since there is no need to worry about liquid leakage even if cracks occur, the restriction on the service life is less strict than the water tank 38. The shape of the hole in the punching metal 70 is considered to be most preferable in the case of a circular shape as in the present embodiment from the viewpoint of the life of the inner tank 52 without stress concentration, but from the viewpoint of the protection effect of the water tank 38. Other shapes may be used. In the above-mentioned water tank, the punching metal 70 is joined by welding,
An inner tank 52 that is resistant to vibration is configured.

As shown in FIG. 4, in the water tank for the liquid treatment step of the present embodiment, the low-frequency vibration generator 50 is mounted on an arm 80 which is horizontally protruded above the water tank 38. Further, the inner tank 52 is attached to the water tank 38 by a column 82 with vibration damping means such as a damper (not shown) interposed. With this configuration, since the vibration of the inner tank 52 due to the low frequency vibration wave is not transmitted to the water tank 38, the vibration does not cause the water tank 38 to deteriorate in strength. The arm 80 is supported by a column 84 outside the water tank 38.

In the water tank 38, the water tank 3 for low frequency vibration waves is used.
In order to reduce the influence on the water tank 8, the inner tank 52 in which the punching metal 70 has a cage shape is used, but the water tank wall face in the vibration direction of the low frequency vibration wave and the water tank in which the intensity distribution of the low frequency vibration wave becomes strong. Perforated metal 70 only on the front of the wall
A corresponding effect can be obtained even with a simple configuration in which is arranged.

Further, instead of the punching metal 70, another porous plate can be used. Another porous plate is, for example, a net. Further, if it is an attenuating material that attenuates low-frequency vibration waves heading toward the inner wall surface of the water tank 38, it is not necessary to be in a plate shape. For example, a number of rods may be arranged on the front surface of the inner wall surface of the water tank.

The above embodiment relates to the water tank for the liquid treatment step used for the surface treatment in the pretreatment step in the coating line of the automobile, but the use of the water tank for the liquid treatment step according to the present invention is limited to this. Absent. In other words, applying the vibration wave to promote the surface treatment is also performed in the processing of other products, and the water tank for the liquid treatment step according to the present invention is also used for such a liquid treatment step, For example, ED (electrodeposition) is another example in the automobile manufacturing process.
The invention can also be applied to a water tank for storing paint.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The dimensions of the water tank are different depending on the object to be treated. As an example, the specifications of an experimentally created water tank for the liquid treatment process are described. FIG. 6 is a schematic perspective view of this experimental water tank. The water tank 138 has a cubic shape with a width, depth and height of about 0.5 m each, and a volume of about 0.15 cubic meters. The water tank 138 is made of an iron plate having a thickness of about 3.2 mm. Inner tub 152 is sized to have a spacing of approximately 50 mm between water tub 138. The inner tank 152 is made of iron punching metal having a thickness of about 2.2 mm. A large number of circular holes having a diameter of about 6 mm are formed in the punching metal.
The ratio of the opening area of the circular holes, that is, the ratio of the total area of the holes to the plate area is about 20%. One low-frequency vibration generator 150 having an output of about 0.2 kW and a frequency of 40 Hz was arranged inside the inner tank 152. The low-frequency vibration generator 150 is attached to a beam 180, and the beam 180 is supported on both sides by columns 184.

Under the above conditions, a value of 0.6 m / s ² was obtained as the wall vibration acceleration data of the water tank 138.
On the other hand, the value when the inner tank 152 is not provided is 5.6 m / s ^{2. In} this case, the influence of the vibration wave on the wall surface of the water tank 138 is reduced to about 1/10 by the inner tank 152.

The dimensions and the like described above are the same as those described above.
If the size of 38 changes depending on the application, it naturally changes. In addition, an appropriate value should be selected in consideration of the influence of the number, output, frequency, arrangement position, and the like of the low-frequency vibration generators 150.

[0030]

According to the water tank for the liquid treatment step of the present invention, the damping material for attenuating the vibration wave is arranged on the front surface of the inner wall surface of the water tank, so that the vibration wave from the vibration wave generator toward the wall surface of the water tank is attenuated. Thus, the effect of reducing the strength or cracking of the water tank wall surface due to the vibration wave is suppressed, and the effect of improving the life of the water tank is obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart of a pretreatment process in an automobile body painting line according to an embodiment of the present invention.

FIG. 2 is a schematic view showing an image of a pretreatment step.

FIG. 3 is a schematic cross-sectional view parallel to a transport direction showing a configuration of a water tank for a liquid processing step.

FIG. 4 is a schematic cross-sectional view perpendicular to a transport direction showing a configuration of a water tank for a liquid treatment process.

FIG. 5 is a perspective view showing an image of a punching metal constituting the inner tank.

FIG. 6 is a schematic perspective view of an experimental water tank.

[Explanation of symbols]

6 Degreasing treatment, 14 Film conversion treatment, 18 Rinsing treatment,
30 vehicle body, 32 continuous conveyor system, 38 water tank, 40 liquid, 50 low frequency vibration generator, 52 inner tank, 70 punching metal, 72 circular hole, 80 arm, 82 column.

Claims (4)

[Claims] 1. A water tank for storing a liquid for performing a surface treatment on an object to be processed, a vibration wave generator for applying a vibration wave to the liquid to promote the surface treatment, and an inner wall of the water tank and a vibration wave generation. An attenuating material provided between the vessel and the vessel to attenuate the vibration wave reaching the inner wall. 2. The water tank for a liquid treatment step according to claim 1, wherein the attenuating material forms an inner tank containing an area where the surface treatment is performed. 3. The water tank for a liquid treatment step according to claim 2, wherein the inner tank is supported in non-contact with the water tank. 4. The water tank for a liquid treatment process according to claim 1, wherein the damping material is a perforated plate.