JP2700271B2 - Paint on-off valve for coating equipment - Google Patents

Description

The present invention relates to a valve opening formed between an inflow chamber communicating with a paint supply source and an outflow chamber communicating with a paint discharge port, which is connected to and separated from the inflow chamber side. The valve body which opens and closes is fixed to the projecting end of the valve rod fitted into the guide hole into the inflow chamber, and the position near the opening of the guide hole to the inflow chamber, the outer periphery of the valve rod protruding into the inflow chamber, and The present invention relates to a paint opening / closing valve of a painting apparatus in which paint can be prevented from entering into a guide hole by an extendable bellows having both ends fixed to the paint chamber.

Problems to be Solved by the Related Art and the Invention Conventionally, bellows of a paint on-off valve of a coating apparatus as described above are independent from each other in that an outer circumferential groove that widens due to expansion and contraction extends in the length direction of the bellows. When cleaning the paint adhering to the outer periphery of the bellows using a solvent, the paint that has entered the inside of the groove is removed even when the solvent flows along the groove because it is composed of a plurality of grooves. Is difficult,
There is a drawback that a long time and a large amount of solvent are required for cleaning, and even if a lot of time and solvent are used, the paint cannot be completely removed, so that a plurality of paints having different colors are used. When performing color change, paint remaining in the groove without being removed even after washing mixes with other paint supplied after washing, and when using paint mixed with aggregates, Since the material accumulates in the groove, the stroke when the bellows contracts is shortened, and the opening of the valve opening at the time of opening the valve becomes small, so that there is a problem that the paint becomes difficult to flow.

Means for solving the problems The present invention, as means for solving the above problems,
The bellows was formed in a shape in which the outer peripheral groove that widened and narrowed as the bellows expanded and contracted formed a spiral shape.

Operation and Effect of the Invention The present invention is configured as described above, and when cleaning the outer periphery of the bellows, when the solvent flows along the groove on the outer periphery, the paint in the groove moves spirally in the groove together with the solvent. By flushing the bellows from one end of the groove to form a single flow path for allowing the paint in the groove to flow out of the groove by making the groove helical, the bellows can be washed. In a short time, there is an effect that can be performed with a small amount of solvent, and it is possible to completely remove the paint in the groove, and to perform color change using a plurality of paints of different colors In this case, it is possible to prevent the paint supplied earlier from remaining on the bellows and to mix into other paints supplied after washing, and to collect aggregates in the paint in the grooves. Shortening of the bellows contraction stroke is prevented This has the effect of keeping the opening of the valve opening large at the time of valve opening, and the use of a spiral groove makes it easier to remove the molded product from the mold. Can be manufactured by injection molding, the shape of the mold can be simplified, and the manufacturing cost can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

In the drawing, reference numeral 1 denotes a gun body having a nozzle 2 fixed to a front end thereof. When paint is supplied from a paint supply source (not shown) to a front end of the gun body 1 through a paint supply pipe 3, the paint will be described in detail later. The paint is sent to the nozzle 2 by passing through the paint on-off valve 5, and the paint outlet of the nozzle 2 is charged with a negative charge by the electrode 8 connected to a high voltage generator (not shown) via the filling metal 6 and the resistor 7. 9 is sprayed from the nozzle body 9 and atomized by the repelling action of the static electricity and the air jet spouting from the paint atomizing air jet port 11 of the nozzle 2 through the air pressure feeding path 10 in the gun main body 1, while the atomization of the gun main body 1 is performed. The air is ejected from the air outlet 13 for adjusting the pattern of the nozzle 2 through the air pressure supply passage 12 in the inside, and is adjusted to a predetermined elliptical shape so as to be applied to a positively charged workpiece (not shown). ing.

Next, the paint on-off valve 5 will be described.
Inside, an inflow chamber 15 having a paint supply hole 3a communicating with the paint supply pipe 3 opened at the rear end and an outflow chamber 16 communicating with the paint ejection port 9 of the nozzle 2 communicate with each other through a valve port 17. A valve rod is formed and fitted inside the inflow chamber 15 so as to be freely slidable in the front-rear direction in the guide hole 19 on the inner periphery of the support cylinder 18 and urged forward by a spring force (not shown). A front end portion of the valve rod 20 protrudes, and a valve body 21 that opens and closes a valve port 17 by moving a tapered portion 22 at the front end of the valve rod 20 in the front-rear direction is provided on the valve rod 20. Are screwed into female screw holes 25 on the front end face of the valve rod 20 so as to be integrally moved back and forth, and a trigger (not shown) connected to the rear end of the valve rod 20 resists an urging force. Then, when the pulling operation is performed, the valve port 17 is opened by moving the valve rod 20 and the valve element 21 backward, and When releasing the trigger pulling operation, by connexion valve rod 20 and valve rod 21 the biasing force is summer so the valve port 17 is closed by moving forward.

In the inflow chamber 15, a front-rear stretchable bellows 26 made of a synthetic resin material having elasticity has an inward flange 17 on the front end inner periphery and a rear end face of the valve body 21 and a front end face of the valve rod 20. Between the support cylinder and the outward flange 28 on the outer periphery of the rear end.
The valve rod 20 is mounted so as to cover the outer periphery of the valve rod 20 by being sandwiched between the front end surface of the valve 18 and the enlarged diameter step 29 at the rear of the inflow chamber 15. The paint inside is prevented from entering the gap between the inner periphery of the guide hole 19 and the outer periphery of the valve rod 20.

As shown in FIG. 2, the bellows 26 has a shape in which a plurality of triangular portions 31 are continuous in a longitudinal direction in a longitudinal section, and the adjacent triangular portions 31 , 31 form a single groove 32 in a spiral shape, the rear end of the spiral groove 32 reaches the front end surface of the outward flange 28, and the front end of the groove 32 is formed by the bellows 26. The bellows 26 has reached the front end face, and as the valve rod 20 advances and retracts, the bellows 26 expands while the width of the groove 32 increases, and the bellows 26 contracts while the width of the groove 32 is sandwiched.

This embodiment has the above-described structure, and when cleaning the inside of the flow path of the paint, when the solvent is pressure-fed into the inflow chamber 15 through the paint supply pipe 3 with the paint on-off valve 5 opened, the bellows 2 expands and contracts. At the position corresponding to the rear end of the portion 30, the solvent that has flowed into the inflow chamber 15 flows forward through the inflow chamber 15 and is opened.
As the paint is ejected from the paint outlet 9 through the outlet 17 and the outflow chamber 16, the paint in the flow path is washed away by the solvent and is ejected from the paint outlet 9.

Here, when the solvent flows forward in the inflow chamber 15, a spiral flow along the groove 32 occurs near the outer periphery of the bellows 26, and the paint adhered to the outer periphery of the bellows 26 due to the flow of the solvent, The bellows 26
While rotating the outer periphery of the bellows, it gradually moves forward and is pushed out from the front end surface of the bellows 26, and is completely removed without remaining in the groove 32.

Therefore, when performing the color change painting using a plurality of paints of different colors, there is no possibility that the paint used previously will be mixed in the paint supplied after washing, and also, the aggregate is mixed. When the paint is used, the aggregate can be completely removed from the groove 32, so that the contraction of the bellows 26 at the time of contraction of the bellows 26 due to accumulation of the aggregate in the groove 32 is prevented, and the aggregate is opened. The opening of the valve port 17 at the time of valve opening can be made sufficiently large to maintain a good flow of the paint.

In manufacturing the bellows 26, the expansion and contraction portion 30 has a spiral shape and can be easily removed from the mold by rotating the molded product in the mold. Can be used, whereby the manufacturing cost can be kept low.

In addition, the present invention is not limited to the paint on-off valve built into the spray gun, the paint on-off valve of another coating device, such as a paint on-off valve provided in the supply path from the paint pressure supply source to the spray gun in the color changing device Can also be applied.

[Brief description of the drawings]

The accompanying drawings show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is a partially cutaway side view of a bellows. 5: Paint on / off valve, 9: Paint outlet, 15: Inflow chamber, 16: Outflow chamber,
17: Valve port, 19: Guide hole, 20: Valve rod, 21: Valve body, 26: Bellows, 32: Groove

Claims (1)

(57) [Claims] 1. A valve body, which opens and closes a valve opening formed between an inflow chamber communicating with a paint supply source and an outflow chamber communicating with a paint discharge port by contacting and separating from the inflow chamber side, is provided in a guide hole. The guide rod is fixed to a protruding end of the valve rod into the inflow chamber, and both ends are fixed to a position near the opening of the guide hole to the inflow chamber and an outer periphery of a protruding portion of the valve rod to the inflow chamber. A paint opening / closing valve of a coating apparatus in which a paint in the inflow chamber is prevented from entering into the guide hole by an extendable bellows, wherein an outer peripheral groove that widens and narrows the bellows as the bellows expands and contracts. Characterized in that it is formed in a spiral shape.