JPH0230035Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air spray gun that atomizes paint using compressed air and performs painting.

[Conventional technology]

Conventional spray guns provide pattern forming air by providing one or two pairs of auxiliary holes from the central atomizing air reservoir and colliding this auxiliary air with the air stream injected from the pattern forming air port. A wide jet of air from the mouth is applied to the paint spray to form a stable pattern.

However, in this case, when the injection pressure becomes high, the atomization of the paint spray flow is promoted, so it is susceptible to the influence of the air flow for pattern formation, and the same tendency occurs even if the paint spray amount decreases at high pressure. Generally speaking, the higher the spraying pressure, the thinner the center of the pattern, which is a so-called middle-splitting tendency, which is undesirable because the finished state of the coated surface becomes uneven.

In addition, recently, with the automation of painting, the spray pattern is controlled by separately controlling the central atomizing air and the pattern forming air as well as the amount of paint ejected, and in this case, the pattern control is more suitable for painting. When the center atomizing air is reduced, the air flow from the auxiliary holes is also reduced, and the effect of colliding the auxiliary air with the air jet from the pattern forming air port to form a wide jet is weakened, and the center of the paint spray flow is reduced. The particles collide with each other with force, and the center of the pattern becomes thinner and constricted at the center, resulting in a so-called split pattern, resulting in uneven coating film thickness and unfavorable spray control.

[Problem that the invention attempts to solve]

In view of the above-mentioned circumstances, the present invention aims to stabilize the pattern shape even when the injection pressure becomes high, and to obtain a spray gun with an air cap that does not cause a cracked pattern. The purpose is to always obtain an appropriate amount of auxiliary air depending on the air ratio for pattern formation by taking auxiliary air that was previously taken from a part of the air from the pattern forming air side. be.

[Means for solving problems]

The present invention takes auxiliary air, which was conventionally taken from a part of the central atomizing air, from the pattern forming air side, so that the amount of auxiliary air is always appropriate depending on the pattern forming air proportion. It was made so that it could be obtained. That is, a spray gun that atomizes paint using compressed air and performs painting, having an atomizing air port around the paint injection port and pattern forming air ports that spray compressed air from opposite positions on both sides with respect to the paint injection axis. An air reservoir is provided downstream of a valve that adjusts the amount of air to the pattern-forming air port, and communicates with the air reservoir to prevent the pattern-forming air flow from colliding with the paint jet axis before the jet flow from the pattern-forming air port collides with the paint jet axis. The above-mentioned problem is solved by providing an auxiliary air port which is opened so as to collide with the jet stream from the air port, and is located at a position opposite to the paint injection axis.

〔Example〕

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

FIG. 2 is a cross-sectional view of a known air spray gun, and 1 is a needle valve 5 inserted into a paint passage 4 in a paint nozzle 3 so as to be freely advanced and retracted by operating a trigger 2.
This is an air spray gun body with an atomizing air cap 7 installed at the tip that is inserted into the paint nozzle 3 with a cover 6. In addition, one or two pairs of auxiliary air ports 10 are formed around the paint injection port 9 on both sides of the central air hole 8, and a pattern forming hole is formed at the tip corner of the air cap 7. Air ports 11 are formed to face each other.

Here, FIG. 1 is a half-cut enlarged sectional view of the nozzle part showing an embodiment of the present invention, in which the air passage 12 of the spray gun body 1 is branched and the central air passage 13 is
The square air passage 14 is provided with an air reservoir 16 downstream of a valve 15 that adjusts the air flow rate to the pattern forming air port 11. Mouth 17
However, before the jet flow z from the auxiliary air port 17 collides with the jet flow y from the pattern forming air port 11 with the paint jet axis x, the pattern forming air port 11
The opening is opened at a position opposite to the paint jetting axis x so as to collide with the jetting flow y from the paint jetting axis x. The rest of the structure is similar to the known example shown in FIG. 2, and the same reference numerals are used.

In the above configuration, the operation of the present invention will be explained. First, compressed air is supplied to the air passage 12 from the compressed air inlet 19 in the handle part of the spray gun body 1, while paint is supplied from the paint inlet 20 to the paint nozzle. The paint passage 4 in the paint passage 3 is supplied. When the trigger 2 is pulled, the needle valve 5 moves back and the paint is injected from the paint injection port 9 at the tip of the nozzle 3, and the compressed air is released by the air valve 22 linked to the trigger 2 opening. Passing through the passage 12, it is divided into two parts: a central air passage 13 for paint atomization and a corner air passage 14 for pattern formation. The injected paint is atomized, and the other is ejected from the pattern forming air port 11 to form an atomized spray stream into a spray pattern suitable for painting. The above is the function of a known air spray gun, but in the present invention, the air passage 12 is divided into two, with a central air passage 13 communicating with the central air hole 8 and a corner communicating with the pattern forming air opening 11. By forming an air passage 14, an air reservoir 16 is provided in the corner air passage 14, and an auxiliary air port 17 communicates with the air reservoir 16.
The compressed air divided into two parts from the air passage 12 and guided to the square air passage 14 passes through the air reservoir 16 and enters the auxiliary air port 17.
At the same time, it is injected from the pattern forming air port 11, and before the jet flow y from the pattern forming air port 11 collides with the paint jet axis x, the jet flow z from the auxiliary air port 17 collide. That is, by colliding the air flow jetting out from the pattern forming air port 11 with the air flow jetting out from the auxiliary air port 17, the jet flow from the pattern forming air port 11 is made into a wide jet and collides with the paint spray flow, making it stable. It forms a spray pattern with a clear spray pattern.

[Effect of idea]

As mentioned above, the present invention allows the amount of auxiliary air to be always appropriate depending on the air ratio for pattern formation by communicating the auxiliary air port with the pattern forming air port through the air reservoir from the corner air passage. The airflow from the auxiliary air port increases and decreases as the pattern-forming air increases and decreases, and always collides with the pattern-forming airflow in the best condition, reducing the force of the jet, and maintaining that state. Since the coating material is exposed to the paint spray flow passing through the central part, the pattern can be formed suitably and stably without causing the tendency of the central part of the pattern to become thinner in the middle during high-pressure spraying as in the past.

Moreover, in the present invention, since the auxiliary air port is provided from the pattern forming air port side, a sufficient central atomization air flow rate can be ensured, and the atomization efficiency can be improved.

Furthermore, the present invention is highly effective in spray guns in which air for central atomization and air for pattern formation are controlled separately.

[Brief explanation of the drawing]

FIG. 1 is an enlarged half-cut sectional view of a nozzle portion showing an embodiment of the present invention, and FIG. 2 is a sectional view of a known spray gun. 1...Spray gun body, 3...Paint nozzle, 7...
Air cap, 8...Center air hole, 11...Air port for pattern formation, 12...Air passage, 13...Center air passage, 14...Corner air passage, 15...Valve, 16...Air reservoir, 17...Auxiliary air port, x ...Paint injection axis.

Claims (1)

[Scope of utility model registration request] In a spray gun that atomizes paint with compressed air and performs painting, the spray gun has an atomizing air port around the paint injection port and a pattern forming air port that sprays compressed air from opposite positions on both sides with respect to the paint injection axis. An air reservoir is provided downstream of a valve that adjusts the flow rate of air to the pattern-forming air port, and communicates with the air reservoir to form a pattern before the jet flow from the pattern-forming air port collides with the paint jet axis. An air spray gun comprising: an auxiliary air port that is opened to collide with the jet stream from the main air port, and is provided at a position opposite to the paint injection axis.