JP2001104849A - Relief valve and coating material supply device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material supply device using a relief valve capable of surely preventing the breakage of a coating material hose. SOLUTION: The coating material supply device is provided with a coating gun 4 for spraying a coating material sent from a coating material source to a material to be coated, a quantitative force feed pump 2 for quantitatively and forcibly sending the coating material to a coating gun through coating material supply pipes 5, 6, 7, the relief valve 10, arranged in the coating material supplying pipe, for discharging coating material pressure outside the system when the coating material pressure in the coating material supply pipe reaches equal to or above a prescribed pressure and a controller 12 for stopping the quantitative force feed pump after the coating material pressure is released outside the system by the relief valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relief valve which is preferably applied to a coating line of an automobile and a paint supply device using the same, and more particularly to a relief valve which can surely prevent breakage of a paint hose and uses the same. The present invention relates to a paint supply device.

[0002]

2. Description of the Related Art In a top coating line of an automobile body,
Since various paint colors are painted according to the paint color specifications of the vehicle, for example, a paint supply device as shown in FIG. 3 is employed. FIG. 3 is a piping circuit diagram showing an example of a conventional paint supply device, and includes a color change valve 1, a gear pump 2,
The trigger dump valve 3 and the paint gun 4 are connected by paint supply pipes 5, 6, and 7.

The color change valve 1 is a valve body 1
1 is a valve unit in which a large number of switching valves 12 are provided.
2 is supplied with a cleaning thinner and a cleaning air. The other switching valves 12 are supplied with paints of each paint color (A color, B color,..., Z color). The cleaning thinner and the paint A of each paint color are fed to the color change valve 1 by a paint feed pump (not shown).

The paint selected by the color change valve 1 is sent to a gear pump 2 via a paint supply pipe 5, and a certain amount of paint is supplied to the trigger dump valve 3 and the coating gun 4 by the gear pump 2.

The trigger dump valve 3 has a valve body 31.
A plurality of (here, four) switching valves 32 are provided, and cleaning thinner and cleaning air are supplied to the switching valves 32, 32 at the base end of the valve body 31. A paint supplied from the gear pump 2 is supplied to one of the other two switching valves 32, 32, and a paint pipe 9 for leading to the waste liquid tank 8 is connected to the other. The paint from the trigger dump valve 3 is applied to the paint pipe 7.
Is sent to the coating gun 4 via the.

[0006]

Since the trigger dump valve 3 is preferably provided as close to the coating gun 4 as possible, it is usually mounted on the main body of the coating machine. A flexible paint hose is used as the paint pipe 6 that connects the gear pump 2 and the trigger dump valve 3.

However, since the paint hose 6 is provided close to the automobile body, which is the object to be coated,
If the paint hose 6 is damaged due to a malfunction of the trigger dump valve 3 or a clogged nozzle, the paint adheres to the body and necessitates disposal or repainting. In addition, it takes a long time to repair and replace the damaged paint hose 6, during which a line stop is performed, and productivity is significantly reduced.

For this reason, a method of detecting the load current of the servomotor of the gear pump 2 and simulating the load current acting on the paint hose 6 has been studied. However, the load current of the servomotor can be set to an arbitrary value. The detection device is extremely expensive, and the threshold value of the load current does not directly specify the limit value of the paint pressure at which the paint hose 6 is damaged. It is necessary to check the relationship with the current.

[0009] Further, it has been examined whether the paint hose 6 cannot be replaced with a material having excellent breakage resistance. In fact, there are no good materials so far. Further, even if a paint hose having excellent breakage resistance exists, this is not a drastic measure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a relief valve capable of reliably preventing a paint hose from being damaged and a paint supply device using the same.

[0011]

According to a first aspect of the present invention, there is provided a relief valve provided in a paint supply pipe between a constant-pressure pump and a coating gun. A valve body, a first paint inlet formed in the valve body so that paint flowing down the paint supply pipe is introduced, and a valve body formed in communication with the first paint inlet. A paint passage, a paint outlet formed in the valve body so as to communicate with the paint passage, a valve body for opening and closing a valve opening formed in the first paint inlet, and a closing direction of the first paint inlet. And a resilient member for imparting an elastic force to the valve element.

[0012] In the present invention, at least detection means for detecting the open / closed state of the valve element, and control means for controlling the operation and stop of the constant-pressure pump based on the open / closed state of the valve element by the detection means. More preferably, it is further provided.

In this case, it is more preferable that the control means sends a stop signal to the constant-pressure pump when the valve element opens the valve port.

[0014] In the present invention, it is more preferable to further include a second paint inlet formed in the valve body so as to communicate with the paint outlet through the paint passage.

In this case, the second paint inlet and the paint outlet are always in communication irrespective of the open / close state of the valve body, and the valve body is in contact with the paint flowing down from the second paint inlet to the paint outlet. More preferably, it is a non-resistance shape.

(2) In order to achieve the above object, according to a second aspect of the present invention, there is provided a coating gun for spraying a coating material supplied from a coating source onto an object to be coated, and the coating gun through a coating material supply pipe. A quantitative pump for quantitatively pumping the paint to a gun,
A relief valve provided in the paint supply pipe, for discharging the paint pressure to the outside of the system when the paint pressure in the paint supply pipe is equal to or higher than a predetermined pressure, and when the relief valve discharges the paint pressure to the outside of the system. Control means for stopping the constant-pressure pump,
A paint supply device provided with:

In this case, the relief valve communicates with the valve body, a first paint inlet formed in the valve body so that paint flowing down the paint supply pipe is introduced, and the first paint inlet. A paint passage formed in the valve body, a paint outlet formed in the valve body so as to communicate with the paint passage, and a valve body that opens and closes a valve opening formed in the first paint inlet. An elastic body that applies elastic force to the valve body in a closing direction of the first paint inlet;
More preferably, when the paint pressure reaches a predetermined pressure, the valve body opens the valve port against the elastic force of the elastic body.

(3) In the above invention, when the paint is supplied from the constant-pressure pump to the coating gun, the valve body of the relief valve operates according to the balance between the paint pressure and the force between the elastic body and the valve port. Opens, allowing the paint pressure to escape to the outside of the system.
The damage can be prevented.

At the same time, since the operation of the relief valve is detected and the constant-pressure pump is stopped, it is possible to more effectively prevent the paint hose and the like from being damaged.

[0020]

According to the first and sixth aspects of the present invention,
Even if the paint pressure supplied from the metering pump is abnormally increased, the paint pressure is released outside the system by the relief valve. Damage can be prevented.

In addition, according to the present invention, the operation of the relief valve is detected and the constant-pressure pump is stopped. It can be effectively prevented and the waste paint is minimized.

According to the fourth, fifth or eighth aspect of the present invention, the waste paint pipe of the coating gun and the waste paint pipe of the relief valve can be shared, so that the number of pipes is reduced and the cost is reduced. The space is also improved.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a piping circuit diagram showing an embodiment of a paint supply device of the present invention, and FIG. 2 is a sectional view showing an embodiment of a relief valve of the present invention.

First, the relief valve 10 of the present embodiment shown in FIG. 2 will be described.
The valve body 101 includes a first paint inlet 102, a second paint inlet 103, and a paint outlet 104. The first paint inlet 102, the second paint inlet 103, and the paint outlet 104 communicate with each other through a paint passage 105 formed in the valve body 101, and a needle valve 106 described below (corresponding to a valve body of the present invention). But the valve port 107
Is closed, the second paint inlet 103 and the paint outlet 10
However, when the needle valve 106 opens the valve port 107, the first paint inlet 102 and the second paint inlet 10 communicate with each other.
3 and paint outlet 104 communicate with each other.

However, since the paint is fed under a predetermined pressure, even if the needle valve 106 opens the valve port 107, the paint from the first paint inlet 102 to the paint outlet 104 and the second paint
Only the paint flowing from the paint inlet 103 to the paint outlet 104 is present.

A needle valve 106 is provided in the paint passage 105 so as to be vertically movable in FIG. The distal end of the needle valve 106 is formed in a needle shape so that a valve port 107 formed in the valve body member 101d can be opened and closed, and a piston 108 is fixed to the proximal end of the needle valve 106. The needle valve 106 according to the present embodiment is formed in a substantially cylindrical shape so as not to obstruct the flow of the paint in the paint passage 105.

The piston 108 is connected to the valve body member 10.
1a is slidable in the cylinder 109,
The coil spring 110 (corresponding to the elastic body of the present invention) constantly urges the spring downward. That is, the needle valve 106 is pressed against the valve port 107 by the coil spring 110 with a predetermined load.

The needle valve 106 is provided so as to be slidable with respect to the valve body member 101e. By providing the U-packing 111 and the O-rings 112 and 113, the paint in the paint passage 105 can be moved to the cylinder 109 side or the like. Leakage is prevented. Also, the valve body member 101
The leakage of the paint in the paint passage 105 is also prevented by the packing 114 and the O-ring 115 provided at d.

At the upper end of the piston 108, a convex portion 116 is formed.
1a. Then, as the piston 108 moves up and down, that is, the needle valve 106 moves up and down, the convex portion 116
01a will appear. A limit switch 11 (corresponding to a detecting means of the present invention) is provided at a position where the convex portion 116 appears and disappears. A detection ON / OFF signal by the limit switch 11 is supplied to a controller (control of the present invention) described later. Means). Specifically, when the needle valve 106 opens the valve port 107, the convex portion 116 of the piston 108
01a, the limit switch 11 is turned ON (or OFF). By sending this ON signal (or OFF signal) to the controller, the valve port 107 is opened, that is, the paint pressure in the paint hose 6 is increased. Is detected to be higher than a predetermined value.

Next, an embodiment in which the above-described relief valve 10 is applied to a paint supply device will be described with reference to FIG. FIG. 1 is a piping circuit diagram showing a paint supply device of the present embodiment, and includes a color change valve 1, a gear pump 2, a relief valve 10, a trigger dump valve 3, and a coating gun 4.
Are connected by paint supply pipes 5, 6, 7 and 9.

The color change valve 1 is a valve body 1
1 is a valve unit in which a large number of switching valves 12 are provided.
2 is supplied with a cleaning thinner and a cleaning air. The other switching valves 12 are supplied with paints of each paint color (A color, B color,..., Z color). The cleaning thinner and the paint A of each paint color are fed to the color change valve 1 by a paint feed pump (not shown).

The paint selected by the color change valve 1 is sent to a gear pump 2 via a paint supply pipe 5, and the gear pump 2 supplies a fixed amount of paint via a relief valve 10 to a trigger dump valve 3 and a coating gun 4. Supplied to

The trigger dump valve 3 has a valve body 31
A plurality of (here, four) switching valves 32 are provided, and cleaning thinner and cleaning air are supplied to the switching valves 32, 32 at the base end of the valve body 31. A paint supplied from the gear pump 2 is supplied to one of the other two switching valves 32, 32, and a paint pipe 9 for leading to the waste liquid tank 8 via a relief valve 10 is connected to the other. The paint from the trigger dump valve 3 is sent to the paint gun 4 via the paint pipe 7.

The paint hose 6 is connected to the first paint inlet 102 of the relief valve 10 of the present embodiment, so that the paint pressure of the paint passing through the paint hose 6 always acts on the tip of the needle valve 106. Become. Further, the paint hose 9 connected to the switching valve 32 of the trigger dump valve 3
The other end is connected to a second paint inlet 103 of the relief valve 10, and a paint hose 9 is connected to a paint outlet 104. The tip of the paint hose 9 is connected to the waste liquid tank 8.

A controller 12 is provided for taking in a detection signal from a limit switch 11 provided in the relief valve 10 and controlling the operation and stop of the gear pump 2 based on the detection signal. When the controller 12 determines from the limit switch 11 that the needle valve 106 of the relief valve 10 has opened the valve port 107, the controller 12 sends a signal to stop the gear pump 2 to the gear pump 2.

Next, the operation will be described. For example, the next car is A
When painting a color, first, the switching valve 12 of the color change valve 1 is controlled to supply the A color paint to the gear pump 2 via the paint pipe 5. The gear pump 2 sends a constant amount of the paint supplied from the color change valve 1 to the downstream side, whereby a constant amount of the A color paint is supplied to the trigger dump valve 3 via the paint hose 6.

The A color paint supplied to the trigger dump valve 3 in a normal state is supplied to the coating gun 4 and applied to an object to be coated.

At this time, the color A paint in the paint hose 6 is
It also flows into the first paint inlet 102 of the relief valve 10 to apply paint pressure to the tip of the needle valve 106. Until the paint pressure overcomes the load of the coil spring 110, the valve port 107 is kept closed. However, the paint pressure in the paint hose 6 increases due to a malfunction of the trigger dump valve 3 and the like, and the needle valve 106 When the load of the coil spring 110 acting on the needle valve 10 exceeds
6 rises to open the valve port 107. Thus, the paint in the paint hose 6 flows into the paint passage 105 through the first paint inlet 102 and the valve port 107, and is further guided from the paint outlet 104 to the waste liquid tank 8 through the paint hose 9. When the needle valve 106 rises, the convex portion 116 of the piston 108 operates the limit switch 11, and a detection signal thereof is sent to the controller 12. The controller 12 receives the detection signal from the limit switch 11 and sends a stop signal to the gear pump 2. As a result, the gear pump 2 stops and the supply of the paint further stops, and the paint in the paint hose 6 is removed from the waste tank 8.
Is released to the side and the paint pressure drops, so the paint hose 6
Is prevented from being damaged.

By the way, the operation in the case of applying the other paint color, for example, the B color paint after applying the A color paint will be described. First, the supply of the A color paint is stopped at the color change valve 1 until then. And switching valve 1
1 is switched to cleaning air, and the A-color paint remaining in the valve body 11, the paint pipe 5, the gear pump 2, the paint hose 6, the first paint inlet of the relief valve 10, and the switching valve 32 of the trigger dump valve 3 is pushed out. This residual paint
Switching valve 32 of trigger dump valve 3, paint hose 9
Through the waste liquid tank 8.

At this time, the waste liquid paint may be directly led to the waste liquid tank 8 without passing through the relief valve 10, but the paint hose 9 for guiding the waste liquid is passed through the relief valve 10 as in the present embodiment. The paint hose 9 from the relief valve 10 to the waste liquid tank 8 can be shared.

When the extrusion of the residual paint by the cleaning air is completed, the switching valve 11 of the color change valve 1 is turned off.
Is supplied to the valve body 11, the paint pipe 5, the gear pump 2, the paint hose 6, the first paint inlet of the relief valve 10, and the switching valve 32 of the trigger dump valve 3 to clean them. I do. When this is completed, the switching valve 11 of the color change valve 1 is again switched to the cleaning air, and the cleaning thinner up to that time is pushed out. After repeating these operations a plurality of times, the switching valve 11 of the color change valve 1 is switched to the next color B paint, and the coating gun 4
To supply.

The trigger dump valve 3 and the coating gun 4
The A color paint remaining between the above and the cleaning air supplied to the trigger dump valve 3 and the cleaning thinner are used.
The color change is performed according to the procedure described above.

The embodiments described above have been described in order to facilitate understanding of the present invention, but not to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a piping circuit diagram showing an embodiment of a paint supply device of the present invention.

FIG. 2 is a sectional view showing an embodiment of the relief valve of the present invention.

FIG. 3 is a piping circuit diagram showing a conventional paint supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Color change valve 2 ... Gear pump (fixed pressure pump) 3 ... Trigger dump valve 4 ... Coating gun 5,6,7,9 ... Paint pipe 8 ... Waste liquid tank 10 ... Relief valve 11 ... Limit switch (detection means) 12 ... Controller (control means)

Claims (8)

[Claims] 1. A relief valve provided in a paint supply pipe between a constant-pressure pump and a coating gun, wherein the valve is formed in the valve body so that paint flowing down the paint supply pipe is introduced. A first paint inlet, a paint passage formed in the valve body so as to communicate with the first paint inlet, a paint outlet formed in the valve body so as to communicate with the paint passage, (1) A relief valve for a paint supply device, comprising: a valve body that opens and closes a valve port formed at a paint inlet; and an elastic body that applies an elastic force to the valve body in a closing direction of the first paint inlet. 2. The apparatus further comprises: detecting means for detecting at least the open / closed state of the valve element; and control means for controlling the operation and stop of the constant-pressure pump based on the open / closed state of the valve element by the detecting means. The relief valve for supplying paint according to claim 1. 3. The relief valve for a paint supply device according to claim 2, wherein said control means sends a stop signal to said constant-pressure pump when said valve body opens said valve port. 4. The paint supply relief valve according to claim 1, further comprising a second paint inlet formed in said valve body so as to communicate with said paint outlet via said paint passage. 5. The second paint inlet and the paint outlet are always in communication irrespective of the open / close state of the valve, and the valve is adapted to prevent paint flowing down from the second paint inlet to the paint outlet. The paint supply relief valve according to claim 4, wherein the relief valve has a non-resistance shape. 6. A paint gun for spraying a paint sent from a paint source onto an object to be coated, a constant-pressure pump for quantitatively pumping the paint to the paint gun via a paint supply pipe, A relief valve that is provided to discharge the paint pressure out of the system when the paint pressure in the paint supply pipe is equal to or higher than a predetermined pressure; and that the constant-pressure pump is released when the relief valve discharges the paint pressure out of the system. A paint supply device comprising: a control unit for stopping the paint supply device. 7. The relief valve communicates with a valve body, a first paint inlet formed in the valve body so that paint flowing down the paint supply pipe is introduced, and the first paint inlet. A paint passage formed in the valve body, a paint outlet formed in the valve body so as to communicate with the paint passage, a valve body that opens and closes a valve opening formed in the first paint inlet, An elastic body that applies elastic force to the valve body in the closing direction of the first paint inlet, wherein the valve body opposes the elastic force of the elastic body when the paint pressure reaches a predetermined pressure. The paint supply device according to claim 6, wherein the valve port is opened. 8. A trigger paint valve is further provided between the relief valve and the coating gun, and a waste paint pipe of the trigger dump valve is connected to a second paint inlet of the relief valve. Paint supply equipment.