JPH0716505A - Spray gun - Google Patents

Abstract

PURPOSE:To facilitate maintenance of a paint valve structure of a spray gun and works accompanying the maintenance. CONSTITUTION:A needle valve 107 which is a valve for paint to open or close a paint supplying route and a valve operational structure to operate the valve corresponding to compressed air introduction or discharge are united into a unit and the unit is placed at a position deflected from the spraying axis of a spray gun, that is an axial line of a spraying axis in which the air cap 1 and a paint nozzle 2 are set, and the unit is enabled to be detached freely from a gun main body S. Consequently, maintenance of the structure contained in the unit becomes easy, and at the same time, even in the case the spray gun is used for an automatic sparying system such as a painting robot, the works to take the whole body of the gun out of the system or to install and adjust again the whole body of the gun are unnecessary.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a spray gun,
In particular, the paint valve mechanism of the automatic spray gun used in automatic painting systems such as painting robots and reciprocators has been improved.

[0002]

2. Description of the Related Art FIG. 1 is a side sectional view showing the structure of a conventional automatic spray gun. A substantially cylindrical spray gun body S made of injection-molded resin or the like has an air passage for receiving compressed air supplied from one end (not shown) and guiding it to the air cap 1 side. Passage is paint nozzle 2
It is configured to guide the compressed air to the center air hole 1C near the tip and the side air hole 1S provided in the cap 1. Here, the central air hole 1C has a function of creating a vacuum state for sucking up the paint, and is positioned concentrically with the tip of the paint nozzle 2. The side surface air holes 1S are provided on the inner side surfaces of a pair of corners projecting from the cap 1, respectively, and are provided for forming an elliptical pattern by the air ejected from the corners. Reference numeral 3P is an electrode pin projecting from the center of the tip of the paint nozzle 2 so as to face the grounded object to be coated, and a negative high voltage is applied via the high voltage cable 3. Reference numeral 20 denotes a nipple for attaching a paint hose 21, and the paint supplied from a paint pumping means such as a paint pump (not shown) via the paint hose 21 is a paint nozzle via an internal passage of the nipple 20 and a gun body internal passage 20A. Two
And is atomized by the injection of compressed air and charged by the application of a high voltage, and is used for coating work.

Reference numeral 7 is a needle valve set provided along the central axis of the gun body S, the tip of which is a paint nozzle 2
Is formed as a needle valve 7N capable of opening and closing the paint supply path leading to. 7E is a needle valve actuating portion provided at the other end of the needle valve set, and receives a spring 17 that biases the needle valve 7N in the closing direction (left direction in the drawing) of the paint supply passage. Further, a piston 25 is provided near the other end of the needle valve set 7, and the needle valve 7N can be moved in the opening direction of the paint supply passage (rightward in the figure) according to the operation thereof. That is, when compressed air is introduced from the air supply unit (not shown) into the chamber on the left side of the piston 25 in the drawing, the piston 25 moves to the right in the drawing against the biasing force of the return spring 15, and the needle valve The spring 1 is engaged with the operating portion 7E.
The needle valve set 7 is displaced against the biasing force of 7 and 15, and accordingly, the needle valve 7N is separated from the sheet 4 provided in the paint supply passage, and the paint can be sprayed. In addition, the introduction of the compressed air is cut off, and the chamber 25R
When the inside is exhausted, the piston 25 moves to the left in the figure by the biasing force of the return spring 15, while the needle valve 7N is displaced in the closing direction of the paint outlet by the biasing force of the spring 17 and seats on the seat 4. This stops the spray of paint. Reference numeral 18 denotes a paint adjustment guide in which knobs and the like (not shown) are combined, which is set to a desired position in the left-right direction in the drawing according to the operation of the knob, and defines the displacement amount of the needle valve 7N, that is, the opening area of the paint supply passage. And adjust the amount of paint supplied.

[0004]

By the way, a spray gun may be subjected to maintenance work such as repair and cleaning in order to maintain desired performance or eliminate malfunction, and in particular, a needle valve set for opening and closing a paint path. In such a paint valve mechanism, there are many opportunities to solve problems such as piston malfunction and paint leakage. However, as is clear from FIG. 1, a needle valve set for opening and closing the paint outlet in the related art has a central axis of a substantially cylindrical gun body S made of resin, that is, an axis of an injection shaft on which an air cap and a paint nozzle are arranged. Since it was installed along
In order to carry out work such as repair and cleaning, the spray gun itself must first be removed from the assembly part of the automatic painting system such as the painting robot, and then the required disassembly must be carried out to carry out work such as repair and washing. Maintenance work was complicated. In addition, after such work, of course, the work of assembling and assembling to a painting robot or the like and a predetermined adjustment work are required. Furthermore, if the spray gun is attached to a painting robot,
Teaching has to be performed again, which imposes an excessive burden on the operator or maintenance worker. The present invention has been made in view of the above problems, and an object of the present invention is to facilitate the maintenance work of a spray gun or the work incidental thereto.

[0005]

To this end, the spray gun of the present invention is located on the paint supply path leading to the paint nozzle,
A paint valve mechanism having a valve that opens and closes the paint supply passage and a valve operating mechanism that opens and closes the valve depending on whether compressed air is introduced or not is biased from the axis of the spray shaft of the paint nozzle. It is characterized in that it is detachably attached to the spray gun body. Here, the valve projects into the opening of a sheet member having an opening that forms a part of the paint supply passage at the tip portion and sits down to close the paint supply passage and move backward. In the form of a needle valve having an extending shaft portion, the valve actuating mechanism is connected to the shaft portion, and the needle valve is displaced in a direction of opening the paint supply passage in response to introduction of compressed air. A piston and a spring for urging the piston in a direction in which the needle valve closes the paint supply passage can be provided.
Further, the paint valve mechanism is provided with means for regulating the amount of displacement of the piston to adjust the amount of paint to be supplied by adjusting the open area of the paint supply passage where the needle valve opens. it can. Further, the spray gun of the present invention comprises an electrode pin to which a high voltage is applied at the tip of the paint nozzle, and a cable or wiring member for supplying the high voltage to the electrode pin is arranged on the axis. It can be in the form of an electrostatic gun.

[0006]

According to the present invention, a needle valve, which is a paint valve for opening and closing the paint supply passage, and a valve actuating mechanism for actuating the needle valve according to the presence or absence of introduction of compressed air are unitized, and this unit is used as an injection shaft of a spray gun. That is, since it is provided at a position deviated from the axis of the injection shaft where the air cap and the paint nozzle are arranged and is detachable from the gun body, the maintenance of the mechanism included in the unit is easy and the spray gun is Even when used in an automatic painting system such as a painting robot, it is possible to simplify the work of removing or attaching the entire gun from the system and readjusting it.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. 2 to 4 show one embodiment of the spray gun of the present invention, FIG. 2 is a rear view thereof, and FIGS. 3 and 4 are side sectional views taken along lines AA and BB shown in FIG. 2, respectively. Is. In these drawings, a substantially cylindrical spray gun body S made of resin is supplied with compressed air from a compressor or the like (not shown) connected via air hoses attached to joints 32C and 32P.
It has an air passage configured to introduce compressed air into a central air hole 1C near the tip of the paint nozzle 2 and a side air hole 1S provided in the cap 1. Here, the central air hole 1C has a function of creating a vacuum state for sucking up the paint,
It is positioned concentrically with the tip of the paint nozzle 2. The side surface air holes 1S are provided on the inner side surfaces of a pair of corners projecting from the cap 1, respectively, and are provided for forming an elliptical pattern by the air ejected from the corners. Reference numeral 32O is a joint that receives compressed air from a compressor or the like (not shown) connected via an air hose, and the compressed air is supplied to a paint valve mechanism of a needle valve unit 100 described later via an air passage (not shown). Is guided to the valve actuation mechanism for opening and closing. A negative high voltage is applied via the high voltage cable 3 to the electrode pin 3P protruding from the center of the tip of the paint nozzle 2 so as to face the grounded object. The paint supplied from the paint pumping means such as a paint pump (not shown) through the paint hose 21 passes through the communication passage (not shown) from the internal passage of the nipple 20 and the needle valve unit 10
No. 0, the paint nozzle 2 is introduced into the paint supply passage 101, and further through the gap portion formed between the tip of the needle valve 107 and the seat 119 and the gun main body passage 20A.
And is atomized by the injection of compressed air and charged by the application of a high voltage, and is used for coating work.

In this example, a high voltage cable is arranged in a cavity extending from the rear surface of the gun body (see FIG. 2) toward the paint nozzle 2 along the central axis of the gun body S having a substantially cylindrical shape. , The electrode pin 3P located at the tip of the nozzle
The electrical wiring is provided along the central axis as it is. When the gun body is formed using the injection-molded cylindrical resin base material, the resin curing during the injection molding of the cylindrical base material proceeds from the peripheral surface that contacts the cooled mold. In addition, voids are likely to collect near the central axis. When the voids remain, not only the mechanical strength of the gun body is lowered, but also in electrostatic coating as in this example, discharge breakdown may occur with the application of a high voltage. Therefore, conventionally, a hole was cut along the center axis of the base material to hollow out the resin part where the void exists and the needle valve set was placed in that part, whereas in this example, the high voltage Wiring members are arranged for cables or electrode pins. According to this example, since the wiring portion from the high voltage cable 3 to the electrode pin 3P can be formed in a substantially straight line shape, the high voltage cable is received on an axis line eccentric from the central axis, that is, it is located on the central axis line. As compared with the case where the wiring portion bent toward the electrode pin is formed, the structure of the electrical contact portion can be simplified and its reliability can be improved. Further, in this example, the paint valve mechanism, which was conventionally arranged along the central axis, is arranged at a position that is outwardly biased with respect to the central axis,
A needle valve unit 100 including a needle valve 107, a valve actuating mechanism which will be described later, and a paint seal 120 is configured to be attachable to and detachable from the gun body S in a direction indicated by an arrow in the figure. That is, the needle valve unit 100 of this example
Is a cylinder portion 12 that receives sliding of the needle valve 107.
It is attached by screwing a male screw 121A engraved in 1 onto a female screw 121B provided on the gun body, and removing the dirt prevention cover 5 of the gun body or an opening provided at a predetermined portion of the cover 5. A tool such as a wrench is engaged with a predetermined engaging portion 105 via the
The male screw 121A and the female screw 121B are screwed together,
Alternatively, it can be attached and detached by releasing it.

Therefore, according to the present embodiment, it is not necessary to remove the spray gun itself from the assembly portion of the automatic coating system such as the coating robot in the work such as repair and cleaning of the needle valve and its operating mechanism, and the needle valve unit 100 It suffices to remove only the main body from the spray gun main body S and perform the required work, and after that work, assemble the spray gun main body. Therefore, also when the spray gun is attached to a painting robot, teaching is unnecessary again. Further, in this embodiment, the valve operating mechanism incorporated is improved in order to facilitate the disassembly, repair or cleaning and assembly work when the needle valve unit 100 itself is subjected to maintenance. The needle valve unit 100 of this example, particularly the valve actuation mechanism, will be described in detail with reference to FIG.

In FIG. 5, 130 is the needle valve 107.
Is a shaft portion connected to the first piston 1 and extending in the direction of the central axis of the actuating mechanism.
25A and the second piston 125B are fixed.
Chamber parts 161L and 163L on the left side of these pistons in the figure
The compressed air for operation can be introduced and exhausted through the air passage 50 on the gun body side, the gap 51 between the gun body and the needle valve actuation portion, and the air inlet ports 133A and 133B of the needle valve actuation portion. The pistons 125A and 125B are movable in the rightward and leftward directions in the drawing, respectively, in response to the introduction and the exhaust. Reference numeral 135 denotes a partition wall inserted between the first piston 125 and the second piston 125, which can receive the sliding movement of the shaft portion 130.
In addition, it is slidably attached to the inner wall of the needle valve unit body forming the cylinder. 153 is a V provided on the outer peripheral portions of the first and second pistons 125A and 125B.
A packing, 155 is an O-ring provided on the sliding portion between the partition wall 135 and the shaft portion 130, 157 is an O-ring provided on the sliding portion between the partition wall 135 and the inner wall of the unit body forming the cylinder, 1
Reference numeral 59 is a member for setting the position of the second piston 125B with respect to the shaft portion 130. 140 is the needle valve 10
1, a shaft portion 130, a first piston 125A, a second piston 125B and a partition wall 135 is an operating member used for attaching and detaching the valve operating portion assembly to and from the needle valve unit body. The bore portion 141 is formed, and the shaft end portion of the shaft portion 130 is screwed to hold the valve operating portion assembly. When the valve operating portion assembly is attached to the needle valve unit body, the valve operating portion assembly may be pushed rightward in the drawing with respect to the needle valve unit body with the paint adjusting guide 128 removed. On the other hand, at the time of removal, for example, a bolt or the like may be screwed into the bore portion 141 and then pulled out rightward in the drawing. The first piston 125A abuts on the partition wall 135 in association with the pushing operation at the time of mounting, and the corner portion of the partition wall is not locked by the locking portion 151 of the unit body depending on the pushing operation, and the partition wall 135 is positioned. However, the partition wall 135 is separated from the first piston 125A by the introduction of the compressed air for operation when the gun is used, and the partition wall 135 comes into contact with the locking portion 151 to position the partition wall 135. In addition, a predetermined space is secured on the left side of the first piston 125A. The paint adjustment guide 128 in which the knob portion 128A shown in FIG.
It is set to a desired position in the left-right direction in the drawing according to the operation of the knob 128A, and the engagement position between the end portion of the operation member 140 and the convex portion 128B provided so as to be opposed thereto, that is, the displacement amount of the needle valve 107. To regulate the amount of paint supplied. 127 is the paint adjustment guide 128 and the first piston 12
5A is a compression spring provided between the first piston 12 and
The needle valve 107 is urged to the left in the figure via 5A or the valve operating portion assembly. The piston chamber portion 1 formed by the first piston A and the paint adjusting guide 128
61R is a vent port 128 provided in the paint adjustment guide 128.
Piston chamber portion 163R communicating with the atmosphere through C and formed by the second piston 125B and the partition wall 130
Is a passage 130A in the shaft portion 130 formed by connecting the opening facing the space with the shaft end portion, that is, the opening facing the space 161.
Is provided to communicate with the atmosphere. Therefore, the pistons 125A and 125B are smoothly displaced rightward or leftward in the drawing due to the introduction of the compressed air for operation or the action of the biasing force of the spring 127.

In the above structure, the air passage 50 on the gun body side from the air supply portion (not shown), the gap 51 between the gun body and the needle valve operating portion, and the air inlet ports 133A and 133B of the needle valve operating portion are provided. When compressed air is introduced into the chambers on the left side of the first and second pistons 125A and 125B in FIG. 5 via the shafts 130, the shaft portion 130 to which these pistons are fixed resists the urging force of the return spring 127 and the right side in the figure. The needle valve 107 tip end is separated from the seat 119 provided in the paint supply path, and the paint can be sprayed. Further, if the introduction of the compressed air is cut off and the chamber on the left side of the piston is exhausted, the piston 125A,
125B is moved leftward in the figure by the urging force of the return spring 127, the needle valve 107 is displaced in the closing direction of the paint outlet, and is seated on the seat 119, so that the spraying of paint is stopped. In this example, since the spring 127 is pushed in by the total pressure of the compressed air that acts on the total pressure receiving area of the first and second pistons 125A and 125B, the pressure receiving area does not have to be large even if the piston diameter is increased. That is, a stable and highly responsive opening operation of the needle valve can be obtained, and the piston diameter or valve operating mechanism, and consequently the needle valve unit and the spray gun to which it is applied can be downsized and the needle valve can be operated at a low pressure. . This structure basically employs the structure proposed by the applicant in Japanese Utility Model Laid-Open No. 63-46957. However, in this proposal, since the partition wall that pneumatically seals between the first and second pistons is fixed to the inner wall of the main body that houses the valve operating mechanism, it is necessary to remove the valve operating mechanism. The first piston, the partition wall, the predetermined spring, and the second piston must be removed or assembled in order, there is a problem in operability during maintenance or replacement, and care must be taken not to lose the removed parts. Met.

On the other hand, in the valve actuating mechanism according to the present embodiment, the seal having a degree of freedom in the sliding direction with respect to the inner wall of the unit main body is provided on the outer peripheral portion of the partition wall for airtightly sealing the first and second pistons. Since the structure is adopted, the needle valve 107, the shaft portion 130, the first piston 125A, the second piston 125B.
The valve actuating portion assembly including the partition wall 135 and the like can be integrally attached to and detached from the needle valve unit main body, and such a problem can be solved. In the above embodiments, the case where the present invention is applied to an automatic spray gun in the form of an electrostatic gun has been described, but it goes without saying that the application target of the present invention is not limited to the electrostatic gun. In addition to automatic guns used in automatic painting systems such as painting robots, compressed air was introduced from the outside to operate the paint valves in order to reduce operator fatigue, and in response to this. The present invention can be effectively applied to a handgun having a valve actuating mechanism that operates. Further, in the above-mentioned embodiment, two piston portions of the valve actuating mechanism are provided. However, the magnitude of the actuating pressure, the dimensional tolerance of the valve actuating mechanism or the needle valve unit or the gun body, the sliding resistance of the piston, etc. It goes without saying that an appropriate number of pistons can be provided in consideration of the elements. In the above example, the spray gun body is provided with three joints for introducing compressed air for spraying, spray pattern adjustment, and piston actuation, but at least two of these joints are made common, and an air passage in the main body or corresponding The configuration of each part can be appropriately determined.

[0013]

As described above, according to the present invention,
A needle valve, which is a paint valve that opens and closes the paint supply path, and a valve actuation mechanism that operates this in response to the introduction and exhaust of compressed air are integrated into a unit, and this unit is installed with the spray shaft of the spray gun, that is, the air cap and paint nozzle. It is installed at a position deviated from the axis of the injection axis and is detachable from the gun body, so the mechanism included in that unit is easy to maintain and the spray gun is used in automatic coating systems such as painting robots. In this case, it is possible to simplify the work of removing the entire gun from the system, or mounting and re-adjusting it.

[0014]

[Brief description of drawings]

FIG. 1 is a side sectional view showing a configuration of a conventional automatic spray gun.

FIG. 2 is a rear view showing an embodiment of the spray gun of the present invention.

FIG. 3 is a side sectional view taken along line AA shown in FIG. 2, showing an embodiment of the spray gun of the present invention.

FIG. 4 is a side sectional view taken along line BB shown in FIG. 2, showing an embodiment of the spray gun of the present invention.

5 is an enlarged view of a valve operating mechanism in the needle valve unit shown in FIG.

[0015]

[Explanation of symbols]

 1 Air Cap 2 Paint Nozzle 3 High Voltage Cable 3P Electrode Pin 7 Needle Valve Set 7N, 107 Needle Valve 7E Needle Valve Actuator 15, 17, 127 Spring 4, 119 Seat 18, 118 Paint Adjustment Guide 32C, 32P, 32O Joint 50 Working compressed air passage 100 Needle valve unit 101 Paint supply passage 121 Cylinder portion 125A, 125B Piston 130 Shaft portion 135 Partition wall 140 Operating member 152 Locking portion S Spray gun body

Claims (4)

[Claims] 1. A paint valve having a valve located on a paint supply path leading to a paint nozzle for opening and closing the paint supply path, and a valve operating mechanism for opening and closing the valve depending on whether compressed air is introduced or not. A spray gun, wherein the mechanism is provided so as to be detachable from the spray gun main body by deviating from the axis of the spray shaft of the paint nozzle. 2. The valve closes the paint supply passage while being seated by projecting into and seating in a seat member having an opening which forms a part of the paint supply passage at a front end thereof. In the form of a needle valve having a shaft portion extending toward, the valve actuating mechanism is connected to the shaft portion, and in the direction in which the needle valve opens the paint supply passage in response to the introduction of compressed air. The spray gun according to claim 1, further comprising a piston that is displaced, and a spring that biases the piston in a direction in which the needle valve closes the paint supply passage. 3. The paint valve mechanism has means for adjusting the amount of paint to be supplied by regulating the amount of displacement of the piston and adjusting the open area of the paint supply passage where the needle valve opens. The spray gun according to claim 2, wherein: 4. An electrode pin to which a high voltage is applied is provided at the tip of the paint nozzle, and a cable or wiring member for supplying the high voltage to the electrode pin is arranged on the axis. The spray gun according to any one of claims 1 to 3, wherein: