JPH02298375A - Paint quantitative supply apparatus - Google Patents

Abstract

PURPOSE:To prevent the reduction of an emitting amount by mounting a control means outputting a signal increasing and decreasing the flow rate of air on the basis of a moving time detection means. CONSTITUTION:The paint sucked in a paint chamber 14 from a suction port 18 by moving a follower piston 17 in a direction expanding the volume in the paint chamber 14 is emitted from an emitting port 19 and flows in a gun 11 to be applied. An air access port 16 is connected to an air feeder 32 by an air flow passage 33 through a solenoid valve 30 and a voltage converter 31. The first proximity sensor 41 and the second proximity sensor 42 positioned at the respective moving ends of a drive piston 15 to be arranged to a pump 12 and turned ON when the drive piston 15 is moved to the respective moving ends are connected to the control apparatus 40 controlling the voltage converter 31 and the solenoid valve 30 to make it possible to measure a time. The pressure of the air supplied to an air chamber 13 is controlled by a voltage converter 31 so as to obtain a predetermined moving time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a coating device used in an automobile painting process, etc., and in particular, the present invention automatically applies a constant amount of paint to an optimal amount even in response to fluctuations in coating conditions. This invention relates to a paint quantitative supply device that can be supplied with

(Prior art) The painting process in the automobile production process is different from pressing processes, welding processes, parts assembly processes, etc. in that most of the processes involve handling paint, so the characteristics of this paint must be taken into consideration. It is necessary to carry out process design or equipment design.

Paints differ somewhat depending on their materials and the compositions they contain, but the viscosity of paints has the characteristic of decreasing as the temperature rises. Therefore, even if the amount of paint discharged from the paint gun is adjusted to a constant level, if the temperature of the paint increases, the amount of paint discharged will increase, and this will cause damage to the surface of the car body, which is the object to be painted. The amount of paint film that adheres increases, causing so-called "sagging". Conversely, there are cases where the paint temperature drops from the state where the discharge amount is set to a predetermined amount, making it impossible to form a coating film with a predetermined film thickness on the surface of the object to be coated.

Therefore, conventionally, there is a coating device that takes such temperature conditions etc. into account and manually sets the amount of paint discharged according to the object to be coated.
For example, there is one shown in FIG.

This figure shows a pump 3 that supplies paint from a paint tank 1 containing paint to a gun 2 that is operated by an operator or the like and sprays paint onto an object to be painted. The compressed air supplied by the supply device 4 is transferred to the solenoid valve 5.
The air is sucked in through the pump 3, and this air operates a piston installed inside the pump 3 so as to be able to move forward and backward, and the paint is sucked in and discharged according to the movement of the piston.

Further, this pump 3 is provided with a position sensor 6 that detects the position of the piston, and this position sensor 6 is connected to a control device 7 that controls the operation of the pump 3. The electromagnetic valves 5 are operated alternately based on the sensor 6 to continuously supply paint to the gun 2.

Further, the air supplied to the pump 3 is provided in the air flow path between the air inlet and outlet of the pump 3 and the solenoid valve 5, as shown in the figure, to adjust the flow rate of the air supplied to the pump 3. The flow rate is adjusted by operating the speed controller 8 by the operator, making it possible to adjust the amount of paint supplied to the gun 2.

Then, the operator can apply the paint to the object to be coated using the gun 2 by adjusting the speed controller 8 and the discharge amount of the pump 3 in advance.

(Problem to be solved by the invention) However, in such a conventional coating device,
Even if you set the pump discharge amount to an appropriate amount at the start of painting work, if the temperature of the paint drops during the work, the viscosity of the paint will increase, and the pump that is supplied with the specified air port will Depending on this viscosity, the moving speed of the internal piston may decrease, and the discharge amount may decrease. For this reason, for example, when using two sets of such pumps and mixing two colors of paint with a gun for painting, the rate of change in viscosity with respect to temperature of each paint is different, so it is difficult to mix. There was a risk that the ratio would change and the paint color would change.

In addition, when dealing with such a problem, if the setting work is performed manually as in the past, there is a problem that the setting takes a lot of time and furthermore, the work becomes extremely complicated.

Furthermore, if the flow rate of air supplied to the pump is adjusted by manual operation, the pump discharge amount will increase, so it is possible to deal with viscosity, but the amount of air being adjusted is small. If it increases excessively, the paint discharged from the gun will pulsate, and there is a risk that the paint will not be properly applied to the object to be coated.The occurrence of such pulsations varies depending on the type of paint. , to appropriately adjust the air volume to such an extent that such pulsation does not occur,
The problem was extremely difficult.

The present invention has been made in order to solve these conventional problems, and provides a paint quantitative supply device that can automatically supply a constant, optimal amount of paint in response to fluctuations in coating conditions. The purpose is to

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a container in which a piston is provided so as to be able to move forward and backward, and the piston is driven by supplying air into the container from the outside. , a pump that sucks in and discharges paint by movement of the piston, a flow rate adjusting means that adjusts the flow rate of air supplied to the pump, a moving time detecting means that detects the moving time of the piston, and a moving time detecting means. Based on this, if the travel time is longer than a predetermined time required to discharge a preset optimum amount of the paint, an increase signal is sent to the flow rate adjusting means to increase the flow rate of the air. and control means for outputting a reduction signal for reducing the flow rate of the air to the flow rate adjustment means when the travel time is shorter than the predetermined time.

(Function) The present invention configured as described above functions as follows.

The moving time detection means detects the moving time of the piston and outputs it to the control means.

Then, the control means compares the travel time with a predetermined time required to discharge a preset optimum amount of paint, and if the travel time is longer than the predetermined time, the control means controls the pump. It is determined that the discharge amount of the paint has been reduced, and in order to discharge the optimal amount of paint from the pump, an increase signal is output to the flow rate adjusting means to increase the air flow m supplied to the pump, and the movement time is If the time is shorter than the predetermined time, a reduction signal for reducing the amount of air is output to the flow rate adjusting means.

Then, the flow rate adjusting means manually inputting this increase signal or decrease signal increases or decreases the amount of air supplied to the pump,
Adjust the speed at which the piston moves to optimize the pump's discharge volume.

Therefore, even if the viscosity of the paint changes and the pump discharge rate changes, the pump discharge rate is automatically adjusted to an optimal constant amount, and the pump can stably supply paint. can.

(Example) Below, the paint quantitative supply device according to the present invention will be explained in detail based on the drawings.

FIG. 1 is a schematic diagram of the paint chamber m supply device according to the present invention. A paint dispensing device is shown, which allows for a constant rate of paint dispensing.

The illustrated paint quantitative supply device is actually designed to supply paint to multiple guns in order to paint multiple colors, but since the explanation will be repeated here, such multiple This is an example of a paint quantitative supply device that supplies paint to one of the guns.

As shown in the figure, this paint quantitative supply device is equipped with a pump 12 that supplies paint from a paint tank 10 containing paint to a gun 11, similar to the painting device described in the conventional art. The paint supplied to the gun 11 by the gun 12 is so designed that the operator can apply the appropriate amount of paint to the object by adjusting the trigger of the gun 11.

The pump 12 that supplies paint to the gun 11 has an air chamber 13 formed in the center for storing air supplied from the outside, and a paint tank 10 on both sides of the air chamber 13.
At the same time, this inhaled paint is transferred to gun 1.
1 are respectively formed.

A drive piston 15 that slides on the inner wall surface is movably arranged in the air chamber 13, and the drive piston 15 is connected to an air inlet/outlet 16 formed in the air chamber 13.
The compressed air supplied from the air chamber 13 is moved back and forth within the air chamber 13. Further, a driven piston 17 is connected to the driving piston 15, which is similarly arranged to be movable in the respective paint chambers 14 and slides on the inner wall surface of the paint chamber 14. , similarly reciprocate within the paint chamber 14 in accordance with the reciprocating movement of the drive piston 15.

Further, each paint chamber 14 is formed with a suction port 18 for sucking paint into the paint chamber 14 by the reciprocating movement of the driven piston 17, and a discharge port 19 for discharging the sucked paint. The port 18 is connected to the paint tank 10 by a paint flow path 21 via a check valve 20 that regulates the flow of paint from the paint tank 10 to the pump 12, while the discharge port 19 restricts the flow of paint from the pump 12. A similar paint flow path 21 is connected to the gun 11 via a check valve 20 regulating the gun 11.
connected by. Although not shown, pump 1
In the middle of the paint flow path 21 between the gun 11 and the gun 11, a so-called regulator is provided to prevent the flow rate of paint supplied to the gun 11 from becoming excessive in order to prevent the above-mentioned pulsation.

By moving the driven piston 17 in the direction of expanding the internal volume of the paint chamber 14, the paint chamber 1 is opened from the suction port 18.
When the driven piston 17 moves in the direction of compressing the internal volume of the paint chamber 14, the paint sucked into the check valve 20
Therefore, the water does not flow back from the suction port 18 to the paint tank 10,
Even if the driven piston 17 moves in the direction of expanding the internal volume of the paint chamber 14, the paint discharged from the discharge port 19, flowing into the gun 11, and supplied to the gun 11 is also discharged from the paint chamber by the check valve 20. The paint does not flow back into the gun 14 and is applied to the object to be coated from the gun 11.

Further, each air inlet/outlet 16 of the air chamber 13 is connected to the air flow path 3.
3 is connected to an air supply device 32 via a solenoid valve 30 and an electro-pneumatic converter 31, and this air supply device 32 generates compressed air at a predetermined pressure to drive the drive piston 15, and It is designed to be supplied to an electro-pneumatic converter 31. The electro-pneumatic converter 31 that sucks this compressed air can adjust the flow rate of the air by adjusting the pressure of the air supplied to the air chamber 13 in accordance with a control current from a control device to be described later. The air whose flow rate is regulated by the electro-pneumatic converter 31 is passed through the solenoid valves 3 which are alternately operated by the control device.
0, the air chambers 13 are alternately connected from the respective air inlets and outlets 16.
The driving piston 15 is configured to reciprocate within the air chamber 13 in accordance with the operation of the solenoid valve 30.

That is, the electro-pneumatic converter 31 adjusts the moving speed of the driving piston 15 by adjusting the flow m of air supplied into the air chamber 13, and this adjustment causes the movement of the driven piston 17 connected to the driving piston 15. The discharge amount determined by the amount will be adjusted. That is, the electropneumatic converter 31
By adjusting the flow rate of air supplied to the air chamber 13, the discharge amount of the pump 12 can be adjusted.

Further, the air supply device 32 is configured to supply compressed air to the gun 11, and the gun 11 can spray the paint supplied from the pump 12 using this compressed air.

A control device 40 for controlling the electro-pneumatic converter 31 and the electromagnetic valve 30 is disposed in the pump 12 at each moving end of the driving piston 15, and the driving piston 15 is moved to each moving end. The first proximity sensor 4 turns on when
The first and second proximity sensors 42 are connected, and the control device 40 can measure the time during which these proximity sensors are turned on.

Further, as described above, this control device 40 includes an in-use switch 43 for detecting which gun 11 is being used by the operator among the plurality of guns 11 provided according to a plurality of paint colors. are electrically connected, and this in-use switch 43 corresponds to each gun 11 and connects the gun 11 and pump 12.
It is arranged in the paint passage of the pump 12 and turns on when paint flows from the pump 12 to the gun 11.
0 is the gun 11 corresponding to the switch 43 in use that is turned on.
It is now possible for workers to recognize that they are using the system.

Then, the control device 40 determines that this in-use switch 43 is turned off.
If N, the first proximity sensor 41 and the second proximity sensor 42
The moving time of the driving piston 15 is measured, and this moving time is stored in an internal memory in advance and is compared with a predetermined moving time of the driving piston 15 required to optimize the amount of paint supplied to the gun 11. , if the measured travel time is longer than this predetermined travel time, that is, if the current discharge n is less than the optimum discharge amount of the pump 1.2, the pneumatic converter 3
1 outputs a pressure increasing current that increases the pressure in air chamber 1.
The pressure of the air supplied to gun 3 is increased to increase the flow rate of air there, and the discharge rate of pump 12 is increased to its optimum discharge rate, thereby making the supply rate of paint supplied to gun 11 the optimum supply rate. It looks like this. On the other hand, if the measured travel time is shorter than the predetermined travel time, that is, if the current discharge amount is greater than the optimum discharge amount of the pump 12, the pneumatic converter 31
outputs a pressure reduction current that reduces the pressure in the air chamber 13.
The pressure of the air supplied to the gun 11 is reduced to reduce the flow rate of that air, and the discharge amount of the pump 12 is reduced to its optimum discharge amount, thereby making the amount of paint supplied to the gun 11 the optimum supply amount. ing. That is, the control device 40 measures the travel time of the drive piston 15, and adjusts this travel time to the pressure of the air supplied to the air chamber 13 so that it becomes a predetermined travel time corresponding to an optimal discharge amount set in advance. The electro-pneumatic converter 3
1.

The manner in which the paint quantitative supply device configured as described above adjusts the paint supplied to the gun 11 will be described based on the operation flowchart shown in FIG.

In the figure, a control device 40 measures the travel time of the drive piston 15 using a first proximity sensor 41 and a second proximity sensor 42, and based on this travel time, an electro-pneumatic converter 31 causes the pump 12 to discharge. It is shown how the amount is adjusted to the optimum discharge amount.

First, the control device 40 sets one of the in-use switches 43 to ON and waits until the operator paints with one of the guns 11 (step 1), and this in-use switch 4
3 is turned on, ONL reads out the optimum travel time of the drive piston 15 corresponding to the optimum discharge amount of paint corresponding to the in-use switch 43 from the internal memory (step 2).
.

Then, in order to repeatedly and accurately measure the travel time of the drive piston 15, the control device 40 sets a flag in the memory for counting this repetition to 0 (Step 3), so that the drive piston 15 It waits until it reaches the original position, which is the reference for this measurement, that is, the moving end where the second proximity sensor 42 is turned on (step 4).

When the second proximity sensor 42 is ON and the drive piston 15 is at its original position, the control device 40 activates an internal timer to move the drive piston 15 to the other end, that is, to the position where the first proximity sensor 41 is ON. Measure the travel time until the end (Step Knob 5.6).

Then, the first proximity sensor 41 is ONL, the drive piston 1
5 moves to the other end, the control device 40 stores this movement time in the internal memory (step 7) and activates the timer again, so that the drive piston 15 is in its original position, that is, the second proximity sensor 42 is The travel time until moving to the ON position is measured (step 8.9).

Further, the second proximity sensor 42 is ONL, the drive piston 1
5 moves to the original position, the control device 40 stores this movement time in the internal memory (step 10), adds 1 to the flag, and repeats the operations from step 4 to step 10 until the flag reaches 10. Step 11.12)
, by repeating this operation 10 times, the average moving time for 10 times is calculated (step 13). Note that this number of times may be 10 times or more.

First, it is determined whether this average travel time is the same as the optimal travel time read in step 2, and if it is, it is determined that the current discharge amount of the pump 12 is optimal, and the process is terminated. (Step 14).

On the other hand, if they are not the same, it is determined whether the average travel time is greater than the optimum travel time (step 15). If it is, an increased current is output to the electro-pneumatic converter 31 and supplied to the air chamber 13. The discharge amount of the pump 12 is increased by increasing the flow rate of air and the moving speed of the drive piston 15 (step knob 16), and the process is completed.

If the current is not large, a reduced current is output to the electro-pneumatic converter 31, the flow rate of air supplied to the air chamber 13 is reduced, and the moving speed of the drive piston 15 is reduced.
The discharge amount of step 2 is decreased (step 17), and the process is ended.

Note that there are cases where the operator operates the trigger of the gun 11 to apply a very small amount of paint, so when increasing the discharge amount of the pump 12 in step 16, a predetermined amount corresponding to such a painting operation is applied. If the travel time is set and the average travel time exceeds the predetermined travel time, the pump 12
The discharge amount may not be changed.

Therefore, the control device 40 measures the travel time of the drive piston 15 using the first proximity sensor 41 and the second proximity sensor 42, and if this travel time is not the optimal travel time for the optimal discharge amount depending on the paint, Since the flow rate of the air that drives the drive piston 15 is adjusted by the electro-pneumatic converter 31 to achieve the optimum travel time, and the discharge amount of the pump 12 is set to the optimum discharge amount, for example, the viscosity of the paint changes depending on the temperature. As a result, even if the moving speed of the drive piston 15 changes and the discharge amount of the pump 12 changes, the control device 40 sets the discharge amount of the pump 12 to its optimum discharge amount, so that the pump 12 always outputs An optimal constant amount of paint will be supplied to the gun 11.

In this embodiment, the pump 12 is illustrated as having two driven pistons 17 connected opposite to the driving piston 15, but the invention is not limited to this. Of course, it is also possible to use one in which two driven pistons 17 are provided.

(Effects of the Invention) As is clear from the explanation below, the present invention has the following effects.

The control means compares the piston movement time detected by the movement time detection means with a predetermined time required to discharge an optimal amount of paint, and determines that the movement time is longer than the predetermined time. In this case, in order to discharge the optimal amount of paint from the pump, an increase signal is output to the flow Hk:J3 section means to increase the flow rate of air supplied to the pump, and the movement time is shorter than this predetermined time. If it is the time, output a reduction signal to reduce the flow rate of the air supplied to the pump to the flow rate regulating means in order to discharge the optimum amount of paint from the pump, and the flow rate to which these increase or decrease signals are input. The adjustment means can increase or decrease the amount of air supplied to the pump and adjust the discharge amount of the pump to its optimum amount, and even if the viscosity of the paint changes due to temperature changes, it can be automatically adjusted. The amount of air supplied to the pump is adjusted accordingly, and the discharge amount of the pump becomes a preset optimum amount, making it possible for the pump to always discharge an optimum constant amount of paint.

Also, since the pump can always discharge a fixed amount of paint, if you use such a pump for painting, you can stably apply the paint to the object to be painted, and the painting will be done more neatly. becomes possible.

Furthermore, by detecting the movement time of the piston, it is possible to accurately detect the pump discharge amount, so it is also possible to easily detect the amount of paint consumed. Painting work can be done systematically and efficiently.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a paint quantitative supply device according to the present invention;
FIG. 2 is an operation flowchart of the paint quantitative supply device according to the present invention, and FIG. 3 is an explanatory diagram of a conventional coating device. DESCRIPTION OF SYMBOLS 12... Pump, 31... Electro-pneumatic converter (flow rate adjustment means), 40... Control device (control means), 41... First proximity sensor (travel time detection means), 42... a second proximity sensor (travel time detection means);

Claims (1)

[Claims] A piston is installed inside the container so that it can move forward and backward, and the piston is driven by supplying air into the container from the outside, and a pump that sucks in and discharges paint by movement of the piston, and supplies the paint to the pump. A flow rate adjusting means for adjusting the flow rate of air, a moving time detecting means for detecting a moving time of the piston, and an optimum amount of the paint whose moving time is set in advance based on the moving time detecting means. outputting an increase signal to the flow rate adjusting means to increase the flow rate of the air if the travel time is longer than the predetermined time required for the movement; and if the travel time is shorter than the predetermined time; . A paint quantitative supply device comprising: a control means for outputting a reduction signal for reducing the flow rate of the air to the flow rate adjustment means.