JP2506374Y2 - Liquid supply device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for drawing a liquid such as paint by a gear pump and supplying the liquid to a discharge device through a supply passage.

2. Description of the Related Art A liquid supply device using a gear pump is used, for example, as a paint supply to a spray gun in a coating device because a stable supply flow rate can be obtained. If the supply of the paint is not stopped when the nozzle to the spray gun is closed, the inside of the supply pipe may be damaged by high pressure, and it is necessary to take measures against it. Therefore, conventionally, the gear pump is always driven by an ordinary motor to continuously supply the paint from the gear pump, while a three-way valve that is switched in conjunction with opening and closing of the nozzle is provided in front of the spray gun. Then, when the nozzle is closed, the paint is returned to the original tank side without supplying the paint to the spray gun by switching the three-way valve.

DISCLOSURE OF THE INVENTION Problems to be Solved By the way, while reciprocating the spray gun up and down by a reciprocator, the spray gun is sprayed in the range corresponding to the shape of the object to be transferred successively on the front surface of the object. When performing automatic painting, especially when the object to be coated has a large number of window holes, the nozzle is opened and closed every few seconds, and the three-way valve is frequently switched accordingly. The durability of the three-way valve was a problem.

Means for Solving the Problems The liquid supply device of the present invention has been devised mainly against the above-mentioned circumstances, in which the drive source of the gear pump is a servo motor and the switching control of the servo motor is a discharge device. The configuration is performed in conjunction with the opening / closing operation of the discharge port.

The operation and effect of the present invention With the above configuration, when the discharge port of the discharge operation is opened, the servo motor is activated in conjunction with this and the gear pump is driven to supply the liquid, and when the discharge port is closed, the servo is activated. Immediately after the motor stops and the gear pump stops, the liquid supply is stopped.

That is, in the present invention, the servomotor is used as the drive source of the gear pump, and the drive and stop of the gear pump itself are switched in conjunction with the opening and closing of the discharge port to control the supply and stop of the liquid. Even when switching between opening and closing is performed frequently, it is possible to control the supply and stop of the liquid with good response accordingly, and since the conventional three-way valve, which has a problem with durability, is not used, The liquid supply switching operation can be reliably performed over a long period of time.
Further, since the liquid return passage can be eliminated, the flow passage system can be simplified.

Embodiment An embodiment in which the present invention is applied to a paint supply operation will be described below with reference to FIG.

In the figure, a paint tank 1 and a spray gun 2 are connected by a paint supply path 3, a gear pump 5 for pressure-feeding the paint is provided in the middle of the paint tank, and the spray gun 2 has an electromagnetic opening / closing valve 6 By alternately switching the supply of air from the trigger air supply source 7 and stopping it, the needle valve 9 is driven backward or forward to open / close the valve port 11 communicating with the nozzle 10, The spraying of paint from 10 and its stop can be switched. Further, in the present embodiment, particularly, the gear pump 5 described above is used.
A servo motor 13 is used as a drive source of the electromagnetic open / close valve 6 and the electromagnetic open / close valve 6 is connected to the servo motor 13.
The servo motor 13 is switched between ON and OFF in conjunction with the switching of opening and closing of.

This embodiment has such a structure. When the electromagnetic on-off valve 6 is opened and the nozzle 10 of the spray gun 2 is opened, the servo motor 13 is activated in conjunction with this, the gear pump 5 is driven, and the paint a is removed. When it is supplied to the spray gun 2 and ejected from the nozzle 10, the electromagnetic opening / closing valve 6 is opened and the nozzle 10 is closed, at the same time, the servo motor 13 is stopped and the gear pump 5 is stopped, so that the paint a Supply stops.

That is, in this embodiment, the drive source of the gear pump 5 is the servo motor 13, and the servo motor 13 is turned ON / OFF in conjunction with the opening / closing of the nozzle 10 to switch the drive and stop of the gear pump 5 to supply the paint a. Therefore, even if the opening / closing switching of the nozzle 10 is frequently performed, it is possible to control the supply and the stop of the coating material a with good response, and there is a problem in the conventional durability. Since a certain three-way valve is not used, the switching operation of the paint supply can be reliably performed over a long period of time. Also, paint a
Since the passage for returning the liquid to the tank 1 side can be eliminated, the paint system is simplified.

FIG. 2 shows another embodiment applied to a paint supply device having a color changing function. On the suction side of the gear pump 5, a paint tank 21 that specially stores two kinds of paints A and B,
22 is connected in parallel via on-off valves 23 and 24 for color change, and further, a pump 26 for pressure feeding the cleaning thinner T and a supply source 27 of cleaning air are connected via on-off valves 28 and 29 in parallel. The system from the discharge side of the gear pump 5 to the spray gun 2 is the same as that of the above embodiment.

Then, in a state in which the color-changing on-off valve 23 is opened and the on-off valve 24 is closed, the paint A is supplied to the spray gun 2 by the gear pump 5 to apply the paint A, and the on-off valve 23 is closed to perform cleaning. After cleaning the inside of the spray gun 2 from the gear pump 5 with thinner T and cleaning air, when the opening / closing valve 24 is opened, the color is changed to the paint B and the coating is performed.
While coating with paint A or B respectively,
When the nozzle 10 is opened / closed, the servo motor 13 is turned on / off in conjunction with the opening / closing operation to switch the drive and stop of the gear pump 5 and the supply and stop of the paint A or B are controlled. .

That is, in the conventional color change coating apparatus of this type, each paint can be constantly pumped up by a special gear pump and supplied to the spray gun, while a return passage to the tank is provided by interposing a three-way valve. Since each 3-way valve was used for color changeover switching, and was also functioning as a paint supply / stop control in conjunction with the nozzle opening / closing operation, the durability of the 3-way valve was a problem. However, in the present embodiment, as described above, the open / close valves 23 and 24 are only opened / closed at the time of color change, and are not operated in conjunction with the opening / closing of the nozzle 10. It never happens.
Further, as compared with the conventional apparatus, the gear pump 5 can be shared by both paints A and B, and only one gear pump 5 is required. Also, since the paint return passage is not required, the structure of the entire paint system can be simplified.

The present invention is not limited to the paint supply device shown in the above embodiment, but can be widely applied to all other liquid supply devices using a gear pump.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of another embodiment. a, A, B: Paint, 1, 21, 22: Paint tank, 2: Spray gun, 3: Paint supply path, 5: Gear pump, 6: Electromagnetic on-off valve, 7:
Air supply source for trigger, 9: Needle valve, 10: Nozzle, 13:
Servomotor

Claims (1)

(57) [Scope of utility model registration request] 1. A liquid supply device for drawing a liquid such as paint by a gear pump and supplying it to a discharge device via a supply path, wherein a drive source of the gear pump is a servo motor, and the switching control of the servo motor is the discharge control. A liquid supply device characterized in that the liquid supply device is configured to operate in conjunction with the opening / closing operation of the discharge port of the device.