JPH0560989B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a constant liquid solution that, when coating a workpiece, allows a coating tank containing a coating liquid to be raised and lowered relative to the workpiece, and enables optimal coating of the workpiece. It relates to a method of lifting and lowering a coating tank to secure the surface and a device for that purpose, and more specifically, it involves detecting the liquid level distance by an optical sensor in the pre-process of transporting the workpiece, and the post-process of detecting the liquid level distance. By transporting the workpiece and raising the coating tank, it is possible to detect the liquid level distance while minimizing the area of the opening at the liquid level part of the coating tank. The present invention relates to a method for lifting and lowering a coating tank, which can be made small, and which can easily suppress the amount of evaporation of the coating liquid as much as possible, and which is particularly suitable for coating a volatile coating liquid, and an apparatus therefor.

[Prior Art] As is well known, when coating a workpiece with a coating liquid, a coating tank containing the coating liquid is raised and lowered, and the workpiece is immersed in the coating liquid from the opening of the coating tank. It is.

The following conventional methods and devices for raising and lowering the coating tank are available.

That is, the workpiece is transported to the coating position, and the coating tank containing the coating liquid is driven by a drive source to move it up and down along the direction of gravity between the waiting position at the lower limit and the work position at the upper limit, and the coating is carried out. By detecting the liquid level distance between the liquid level and the optical sensor using the optical sensor, a constant liquid level that enables optimal coating of the workpiece at the work position is ensured. It is.

Here, the optimal coating for the above-mentioned workpiece means, for example, when coating the above-mentioned workpiece with a coating liquid such as paint or insulator, coating the above-mentioned paint or insulator to the optimum thickness according to the purpose. It is. The viscosity varies depending on the coating liquid such as the paint or the insulator. Therefore, the constant liquid level is appropriately determined depending on the workpiece, the purpose of the coating, and the variety of the coating liquid.

Since the coating liquid is coated on the workpiece, it is gradually consumed, and when the coating liquid is consumed to a certain extent, it is replenished into the coating tank. Therefore, since the position of the coating liquid level with respect to the coating tank is not constant, the conventional method of ensuring a constant liquid level at the working position is as follows.

That is, after transporting the workpiece to the coating position, while raising the coating tank, the distance between the liquid level of the coating liquid that is raised together with the coating tank and the optical sensor is measured by the optical sensor. By detecting this, the rising of the coating liquid is stopped when the liquid level of the coating liquid reaches the constant liquid level.

Here, the coating liquid is often volatile. More specifically, it is a paint or the like in which a pigment or the like is dissolved in a volatile solvent containing, for example, thinner or toluene. For this reason, it is desirable to make the opening of the coating tank as small as possible and to reduce the amount of evaporation of the coating liquid as much as possible.

[Problems to be Solved by the Invention] The above-mentioned conventional technology makes it possible to ensure a constant liquid level that enables optimal coating on the workpiece.

However, since the liquid level distance was detected and the coating tank was raised at the same time after the workpiece was transported, when the workpiece was positioned between the optical sensor and the liquid level, the liquid level distance could be It is impossible to detect. More specifically, for example, if the workpiece is made of an opaque material such as metal or resin, light will not pass through the workpiece, and if the workpiece is made of a transparent material such as glass, the light will be refracted. Therefore, it is impossible to detect the liquid level distance using the optical sensor. For this reason, if the area of the liquid surface at the opening of the coating tank is set to the minimum possible size that allows the workpiece to be immersed in the coating liquid, the liquid surface will be covered by the workpiece, and the liquid surface distance will be Therefore, it is impossible to ensure the above-mentioned constant liquid level.

Therefore, it is necessary to make the area of the liquid level part of the opening of the coating tank larger than the area that allows the workpiece to be immersed, so that the optical sensor can detect the liquid level distance. Therefore, it was difficult to reduce the area of the liquid level portion of the opening of the coating tank.

For this reason, when the coating liquid is volatile, it is difficult to reduce the amount of evaporation as much as possible, making it difficult to reduce the amount of the coating liquid, making it difficult to keep the cost of raw materials for the coating low. .

[Objective] Therefore, the object of the present invention is to raise and lower a coating tank containing a coating liquid relative to the workpiece when coating the workpiece, and to maintain a constant liquid level that enables optimal coating of the workpiece. A method of raising and lowering a coating tank and a device therefor, in which the liquid level distance is detected by an optical sensor in a process before transporting the workpiece, and the distance of the liquid level is detected in a process after the liquid level is detected. By transporting the coating tank and raising the coating tank, it is possible to detect the liquid level distance, and at the same time, the area of the liquid level portion of the opening of the coating tank can be adjusted to allow the workpiece to be immersed. It is an object of the present invention to provide a coating tank lifting and lowering device which can minimize the amount of evaporation of the coating liquid and can easily suppress the amount of evaporation of the coating liquid to as low as possible.

[Means and effects for solving the problems] The present invention has the following technical means to solve the above problems. That is, to explain this using the reference numerals used in the attached drawings corresponding to the embodiments, the optical sensor 4 is used to detect the liquid level distance L between the liquid level W of the coating liquid 3 and the optical sensor 4. An analog / The digital conversion means 5 determines the number of pulses corresponding to the amount of rise H of the coating tank 2 based on the liquid level distance detection data and a predetermined constant pulse, and the amount of rise is formed by a pulse signal of the determined number of pulses. a rise amount determining means 6 for outputting data; a rise amount data/drive signal converting means 8 for converting the rise amount data into a drive signal for driving the drive source 7 and outputting the drive signal; By having the driving source 7 for causing the coating tank 2 to rise by the rising amount H with respect to the workpiece 1 transported to the coating position P by a signal, the liquid level determined by the optical sensor 4 can be adjusted. While making it possible to detect the distance L, the area of the opening 9 at the surface W of the coating liquid 3 in the coating tank 2 is made as small as possible to allow the workpiece 1 to be immersed in the coating liquid 3. This is a coating tank lifting device characterized by:

With the above configuration, when coating the workpiece 1, the liquid level of the coating liquid 3 in the coating tank 2, which is stationary at the standby position N, is detected by the optical sensor 4 in the pre-process of transporting the workpiece 1. The liquid level distance L between W and the optical sensor 4 is detected and a liquid level distance detection signal based on this liquid level distance L is output, and the liquid level distance detection signal is then converted into liquid level distance detection data consisting of a digital signal. Then, the number of pulses corresponding to the amount of rise H of the coating tank 2 is determined using the digital signal as the liquid level distance detection data and a predetermined constant pulse, and the pulse signal of the determined number of pulses is used. The coating bath 2 is driven by outputting the rising amount data, converting the rising amount data into a driving signal for driving the driving source 7, and driving the driving source 7 using the driving signal. By raising the workpiece 1 transported to the coating position P by the lifting amount H, the liquid level distance L can be detected in the process before the transport T of the workpiece 1, and the liquid level In the post-process of detecting the distance L, the workpiece 1 is transported to the coating position P, and the coating tank 2
This makes it possible to realize a coating tank raising method characterized in that the coating tank is raised S.

Therefore, it goes without saying that the coating tank 2 can be raised and lowered and the constant liquid level h can be ensured, and in particular, the liquid level distance L is detected in the process before the transport T of the workpiece 1.
When detecting the liquid level distance L, the work 1 does not exist between the optical sensor 4 and the liquid level W. Therefore, the liquid level distance L can be detected by the optical sensor 4. Since the transport T of the workpiece 1 and the raising S of the coating tank 2 are performed in the process subsequent to the detection of the liquid level distance L, there is no need to detect the liquid level distance L at this time. Therefore, the area of the liquid surface W portion of the opening 9 of the coating tank 2 can be minimized as much as possible to allow the workpiece 1 to be immersed. Therefore, the amount of evaporation of the coating liquid 3 can be easily suppressed. From the above, it is possible to detect the liquid level distance L while also easily reducing the amount of evaporation of the coating liquid 3.

It also converts the liquid level distance detection signal from the optical sensor 4 into the liquid level distance detection data consisting of pulse signals. Since the pulse signal is based only on ON/OFF of an electrical signal, it is easy to simplify the electric circuit for transmitting the signal.

Further, when detecting the liquid level distance L, the coating tank 2 is kept stationary at the standby position N. Therefore, it is easier to detect the liquid level distance L compared to the prior art, which detects the liquid level distance when the coating tank is raised.

[Example] Next, an example of the present invention will be described in detail with reference to the accompanying drawings.

In this embodiment, the present invention is applied to a method of lifting and lowering a coating tank and an apparatus therefor when coating a substantially cylindrical workpiece 1 with the coating liquid 3.

The work 1 is pivotally supported by a conveyor 10 on a rail 11, and together with the conveyor 10, the work 1 is supported by a conveyor 10 on a rail 11.
1 and is rotated around the central axis while being immersed in the coating liquid 3 at the coating position P to be coated.

A coating tank 2 is provided below the coating position P in the direction of gravity. The coating liquid 3 is placed in the coating tank 2, and a slider 12 is disposed at the bottom of the coating tank 2. A drive source 7 is provided below the coating tank 2 . The drive shaft 17 of the drive source 7 is provided with a ball screw, extends from below to above in the direction of gravity, and is screwed onto the slider 12. Therefore, the coating tank 2 can be raised and lowered by driving the drive source 7.

Then, in order to enable the immersion, the coating tank 2 containing the coating liquid 3 is raised S from below in the direction of gravity with respect to the workpiece 1 at the coating position P, and The workpiece 1 is immersed in the coating liquid 3 through the opening 9.

In order to ensure a constant liquid level h at the work position M, the liquid level distance L between the liquid level W and the optical sensor 4 is detected by the optical sensor 4, and the driving source 7 is activated. This is to control the stoppage.

The above are the same parts as the prior art, and in order to solve the above-mentioned problems, this embodiment of the present invention is as follows.

That is, the coating tank lifting device of this example includes, in addition to the optical sensor 4 and the drive source 7, analog/digital conversion means 5, lifting amount determining means 6, and lifting amount data/drive signal converting means 8. It is made up of

The optical sensor 4 is located above the coating position P in the direction of gravity, and detects the liquid level distance L between the optical sensor 4 and the liquid level W of the coating liquid 3, and also detects the detection signal/detection signal. This is for outputting a liquid level distance detection signal to the data conversion means 5.

As the drive source 7, a pulse motor 7 is used in this example.

The analog/digital conversion means 5 converts the liquid level distance detection signal from the optical sensor 4 into a digital signal representing the liquid level distance L, and converts the liquid level distance detection data into liquid level distance detection data, and converts the liquid level distance detection data into a digital signal representing the liquid level distance L. It is output to the quantity determining means 6. Incidentally, since the electric circuit as the analog/digital conversion means 5 is well known, detailed description and illustration thereof will be omitted.

The rise amount determining means 6 outputs a pulse signal corresponding to the rise amount H based on the liquid level distance detection data as a digital signal representing the liquid level distance L and a constant pulse. Here, when the coating tank 2 is raised by the liquid level distance L, the liquid level W rises S to the position of the optical sensor 4. Therefore, the rise amount determination means 6 in this example determines the rise distance H by subtracting the distance between the constant liquid level h and the optical sensor 4 from the liquid level distance L. In this example, the increase amount determining means 6 is realized by the central processing unit 14 of the microcomputer 13. Then, in this central processing unit 14, an amount of rise H is determined according to (L→H) using a digital signal representing the liquid level distance L, and this amount of rise H is determined as a pulse per unit length l. The constant pulse is calculated according to (H×a/l=×), and a pulse signal of × pulses corresponding to the above-mentioned increase amount H is determined. The above calculation formulas (L→H), (H×a/l=×), etc. are written for ease of understanding, and in reality, the above calculation formulas and constant pulses, etc. are written in the programming language. This format is converted into the format and stored in the computer 13. Since various types of program languages and programs based on the program languages are considered, a detailed description thereof will be omitted. Further, the constant pulses are stored in advance in the storage device 15 of the microcomputer 13 in the format of the program language. It goes without saying that the microcomputer 13 is provided with an input/output device 16 for inputting and outputting signals.

The rise amount data/drive signal conversion means 8 converts the rise amount data from the rise amount determination means 6 into a drive signal for driving the drive means 7, and outputs the drive signal to the drive means 7. In this example, the pulse motor 7 is used as the drive means 7, so the rise amount data/drive signal conversion means 8 is an excitation circuit, so-called driver 8, for driving the pulse motor 7. It is being

With the above configuration, the procedure of coating the workpiece 1 according to this embodiment will be explained below with reference to the step chart shown in FIG. First, in a pre-process of transporting the work 1 to the coating position P in step S2, a liquid level distance L between the optical sensor 4 and the liquid level W of the coating liquid 3 is detected. (See FIG. 1A and FIG. 2) At this time, since this is a pre-process of transporting T of the work 1, the work 1 does not exist between the optical sensor 4 and the liquid surface W. Therefore, the liquid level distance L can be detected. Further, at this time, since the coating tank 2 is kept stationary at the standby position N, it is easy to detect the liquid level distance L. Next, in step S3, the above work 1
is transported T to the coating position P.

Then, in step S4, the analog/digital conversion means 5 converts the liquid level detection signal from the optical sensor 4 into a digital signal representing the liquid level distance L, and converts this digital signal into liquid level distance detection data. is output as Next, in step S5, in the microcomputer 14, the central processing unit 14 serving as the increase amount determining means 6 reads out the constant pulse from the storage device 15. Then in step S6,
In the central processing unit 15, the liquid level distance L
The number of pulses corresponding to the amount of rise H is calculated using the liquid level distance detection data representing , and the constant pulse, and the amount of rise data consisting of pulse signals of this number of pulses is output. Next, in step S7, the increase amount data is converted by the driver 8 into a drive signal for driving the pulse motor 7.
Next, in step S8, the pulse motor 7 is driven by the drive signal to rotate the drive shaft 17 on which the ball screw is carved. (See Figure 3)
Next, in step S9, the coating tank 2 is raised S. At this time, the pulse motor 7 is driven to raise the coating bath 2 by the drive signal converted from the rise data, so the coating bath 2 is moved from the standby position N to the work position M by the amount of rise. It is possible to raise S by H. (See Figure 1B)
At this time, the work 1 is transferred to step S3.
It has already been transported T to the coating device P. Therefore, the workpiece 1 is immersed in the coating liquid 3 by the raising S of the coating tank 2, and the liquid level W of the coating liquid 3 at the work position M of the coating tank 2 is lowered.
can be positioned at the constant liquid level h. Next, in step S10, the work 1 is rotated and coated. At this time, since the liquid level W of the coating liquid 3 is positioned at the constant liquid level h, the workpiece 1 can be coated optimally. Next, when the coating is completed, the coating bath 2 is lowered in step S11. Next, in step S12, the workpiece 1 is carried out from the coating position P, and returns to the state shown in FIG.
Next, in step S13, if there is a workpiece 1 to be coated next, the process returns to step S2 as shown by arrow Y, and the above procedure is repeated. Then, in step S13, if there is no workpiece 1 to be coated next, as shown by arrow N, the coating operation is completed.

As described above, it is of course possible to raise and lower the coating tank 2 and ensure the constant liquid level h, and in particular, the detection of the liquid level distance L can be carried out in the process before the transport T of the workpiece 1, that is, as shown in FIG. Since the workpiece 1 is not present between the optical sensor 4 and the liquid level W when the liquid level distance L is detected. Therefore, the optical sensor 4 can be positioned above the coating position P, and the liquid level distance L can be detected by the optical sensor 4. And the above work 1
Since the transport T and the raising S of the coating tank 2 are performed in the process after the detection of the liquid level distance L, there is no need to detect the liquid level distance L at this time. Therefore, as shown by the one-dot chain line in FIG. 2, the coating tank 2
When the workpiece 1 is immersed in the coating liquid 3, the area of the liquid surface W of the opening 9 of the coating tank 2 is
Even if the immersion is made as small as possible,
There is no problem in detecting the liquid level distance L mentioned above. Therefore, the area of the liquid surface W of the opening 9 of the coating tank 2 can be made as small as possible to allow the workpiece 1 to be immersed, so that the amount of evaporation of the coating liquid 3 can be minimized. It is easy to keep it to a minimum. From the above, it is possible to detect the liquid level distance L while also easily reducing the amount of evaporation of the coating liquid 3.

It also converts the liquid level distance detection signal from the optical sensor 4 into the liquid level distance detection data consisting of pulse signals. Since the pulse signal is based only on ON/OFF of an electrical signal, it is easy to simplify the electric circuit for transmitting the signal. In addition, in this example, since the pulse motor 7 is used as the drive source 7, the rise amount data consisting of the pulse signal is converted into the drive signal consisting of the pulse signal by the driver 8, thereby generating the pulse motor 7. The motor 7 can be easily driven.

Further, when detecting the liquid level distance L, the coating tank 2 is kept stationary at the standby position N. Therefore, it is easier to detect the liquid level distance L compared to the prior art, which detects the liquid level distance while raising the coating tank.
In this example, the substantially cylindrical workpiece 1 is used as an example of the workpiece 1, but it goes without saying that the present invention is not limited to this example and can be applied to coating a wide variety of different types of workpieces 1. Also,
In this example, the conveyor 10 is used to transport the workpiece 1, but various means can be considered as the means for transporting the workpiece T.

Further, in this example, the optical sensor 4 detects the liquid level distance L and outputs a liquid level detection signal according to this liquid level distance L, but the present invention is not limited to this. A detection signal corresponding to the rise amount H obtained by subtracting the distance between the constant liquid level h and the optical sensor 4 from the liquid level distance L may be output as the liquid level distance detection signal. can. That is, it can also be detected as (L=H). In this case, the number of pulses corresponding to the rise H can be easily calculated in the rise determining means 6 using the liquid level distance detection data and the constant pulse, so the program to be input to the microcomputer 13 is simplified. Easy to do.

[Effects] As detailed above, the present invention has the following effects.

According to the invention of claim 1, when coating the workpiece, the coating tank containing the coating liquid can be moved up and down with respect to the workpiece, and a constant liquid level is maintained to enable optimal coating of the workpiece. Of course, this can be ensured, especially by having the optical sensor detect the liquid level distance in the process before transporting the workpiece, since the workpiece does not exist between the optical sensor and the liquid surface at the time of detection. It is possible to detect the above liquid level distance using an optical sensor,
Moreover, since the workpiece is transported and the coating tank is raised in the process after detecting the liquid level distance, there is no need to detect the liquid level distance when the workpiece is immersed in the coating liquid. Therefore, even if the area of the liquid surface at the opening of the coating bath is made as small as possible to allow the workpiece to be immersed, there is no problem in detecting the liquid level distance. and,
By making the area of the liquid surface portion of the opening of the coating tank as small as possible, the amount of evaporation of the coating liquid can be kept as small as possible.

As described above, it is possible to provide a method for lifting and lowering a coating tank, which allows the detection of the liquid level distance and also easily suppresses the amount of evaporation of the coating liquid.

Further, since the liquid level distance detection signal from the optical sensor is converted into the liquid level distance detection data consisting of a pulse signal, it is easy to simplify the electric circuit for transmitting the signal.

Furthermore, since the coating tank is made to stand still at the standby position when detecting the liquid level distance, it is easy to detect the liquid level distance.

According to the second aspect of the invention, it is possible to provide a coating tank lifting device suitable for realizing the coating tank lifting method according to the first claim.

[Brief explanation of the drawing]

The attached drawings show an embodiment of the present invention, and FIG. 1A is a configuration diagram when liquid level distance is detected, FIG. 1B is a configuration diagram when a workpiece is immersed, and FIG. 2 is a side view of the coating tank lifting device. , FIG. 3 is a step chart showing the coating procedure. In the figure, 1... workpiece, 2... coating tank, 3... coating liquid, 4... optical sensor,
5... Analog/digital conversion means, 6... Increase amount determining means, 7... Drive source, 8... Increase amount data/drive signal conversion means, 9... Opening, 13...
Microcomputer, W...liquid level, position h...
Constant liquid level, arrow M...work position, arrow N...standby position, arrow L...liquid level distance, arrow H...rise amount, arrow P...coating position, arrow S... The rising of the workpiece, and the arrow T...indicate the conveyance of the workpiece, respectively.

Claims (1)

[Claims] 1. When a workpiece is transported to a coating position and coated by immersing it in a coating liquid, the coating tank containing the coating liquid is driven by a drive source to move the workpiece to a standby position at the lower limit and a standby position at the upper limit. By raising and lowering the coating liquid along the direction of gravity between the work positions and detecting the distance between the liquid level of the coating liquid and the optical sensor using the optical sensor, the optimum position for the workpiece at the work position is determined. In the method of raising and lowering the coating tank to ensure a constant liquid level of the coating liquid that enables coating; In the coating tank that is stopped at the standby position by the optical sensor in the pre-process of transporting the workpiece. Detects the liquid level distance between the coating liquid level and the optical sensor, and outputs a liquid level distance detection signal based on this liquid level distance, and then converts the liquid level distance detection signal into a liquid level signal consisting of a digital signal. The data is converted into distance detection data, and then the number of pulses corresponding to the amount of rise of the coating tank is determined using a digital signal as the liquid level distance detection data and a predetermined constant pulse, and a pulse signal of the determined number of pulses is generated. outputting rising amount data consisting of the above, converting the rising amount data into a driving signal for driving the driving source, and driving the driving source using the driving signal to cause the coating bath to be coated. By raising the workpiece conveyed to the position by the amount of rise described above, the liquid level distance can be detected in the process before transporting the workpiece, and the liquid level distance can be detected in the process after detecting the liquid level distance. A method for raising and lowering a coating tank, characterized in that the workpiece is transported to the coating position and the coating tank is also raised. 2. A coating tank having an opening for receiving the coating liquid and immersing the workpiece in the coating liquid, for coating the workpiece transported to the coating position by immersing it in the coating liquid; and the coating liquid. and a driving source for raising and lowering the coating tank between a lower limit standby position and a higher limit work position, In the coating tank elevating device for ensuring a constant liquid level of the coating liquid that enables optimal coating of the workpiece at the work position; at the standby position N in the pre-process of the transport T of the workpiece 1; The liquid level W of the coating liquid 3 in the coating tank 2 in a stationary state and the optical sensor 4
In order to detect the liquid level distance L between the positions, the optical sensor 4 is positioned above the coating position P in the direction of gravity, and the liquid level distance detection signal based on the liquid level distance L from the optical sensor 4 is converted into a digital signal. an analog/digital conversion means 5 for converting and outputting the liquid level distance detection data, and a pulse number corresponding to the rising amount H of the coating tank 2 using the liquid level distance detection data and a predetermined constant pulse; and a rise amount determining means 6 for outputting rise amount data consisting of a pulse signal of the determined number of pulses, and a rise amount determining means 6 for converting the rise amount data into a drive signal for driving the drive source 7. Lift amount data/drive signal converting means 8 for outputting, and drive signal for causing the coating tank 2 to rise by the lifting amount H with respect to the workpiece 1 transported T to the coating position P. By having the drive source 7, it is possible to detect the liquid level distance L by the optical sensor 4, and also to reduce the area of the opening 9 of the liquid surface W portion of the coating liquid 3 in the coating tank 2 as described above. A coating tank lifting device characterized in that the workpiece 1 is immersed in the coating liquid 3 to the minimum possible extent.