JP2005066410A - Electrostatic coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic coating apparatus which can rapidly actuate a high voltage safety device by rapidly raising and dropping high voltage. <P>SOLUTION: A housing 2 of the coating apparatus 1 is internally provided with an air motor 6, and a rotary atomizing head 7 is attached to the air motor 6. Also, a high voltage generator 13 which supplies high-voltage to the rotary atomizing head 7 through the air motor 6, or the like, is arranged within an arm section 5 of the housing 2 and a high voltage controller unit 17 consisting of a high voltage controller 18 and the high voltage safety device 21 is arranged adjacently to the high voltage generator 13. As a result, the raising and dropping of the high voltage can be rapidly executed by making the frequency of the driving voltage by the high voltage controller 18 higher and the transmission of the high voltage value Vm and high current value Im of the high voltage to the high voltage safety device 21 is made possible without delay and the high voltage safety device 21 can be rapidly actuated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrostatic coating apparatus that sprays paint with a high voltage applied to a coating machine.

  In general, as an electrostatic coating apparatus, a coating machine that sprays paint on an object to be coated, a high voltage generator that supplies a high voltage to the coating machine, a driving voltage that is supplied to the high voltage generator, and the high voltage is supplied. A device including a high voltage controller for controlling and a high voltage safety device for preventing occurrence of overvoltage and overcurrent using the voltage value and current value of the high voltage is known (for example, Patent Document 1). reference).

JP-A-2-298374

  In such an electrostatic coating apparatus according to the prior art, the coating machine is installed in the painting booth while attached to the painting robot. In order to facilitate the setting, a high voltage generator, a high voltage controller and a high voltage safety device were arranged outside the painting booth together with a painting robot control device for controlling the painting robot.

  In addition, as another conventional technique, a configuration in which a high voltage generator including a step-up transformer circuit and a multistage voltage doubler rectifier circuit (cockcroft circuit) is built in a coating machine (see, for example, Patent Document 2), a high voltage generator, A configuration in which a high voltage controller is built in a coating machine (for example, see Patent Document 3) is also known.

Japanese Utility Model Publication No. 60-151555 Japanese Utility Model Publication No. 58-108162

  By the way, in the electrostatic coating apparatus shown in patent document 1, while having separately arrange | positioned a coating machine and a high voltage generator, these were connected using the high voltage cable. For this reason, in addition to a large-diameter coaxial cable that can withstand a high voltage of, for example, −60 kV to −120 kV as a high-voltage cable, the high-voltage cable is used when the coating machine is attached to a painting robot or the like. There was a risk of damaging the insulation of the high-voltage cable by interfering with surrounding equipment.

  On the other hand, in the electrostatic coating apparatus shown in patent document 2, the high voltage cable is abolished by incorporating the high voltage generator in the coating machine. However, in this case, in order to operate the high-voltage safety device, the current value and voltage value of the high voltage generated by the high-voltage generator in the coating machine are detected, and this detection signal is transmitted through the signal cable and the like. It is necessary to transmit to the safety device.

  At this time, since the high-voltage safety device is arranged separately from the coating machine, for example, outside the painting booth, the length of the signal cable is 20 to 30 m, for example, and the resistance of the signal cable However, there is a problem that the transmission of the detection signal is likely to be delayed due to the influence of the capacity or the like, and the high voltage safeguard cannot be operated quickly.

  In addition, since such a long signal cable is easily affected by external noise, the high-voltage safety device tends to malfunction due to noise. For this reason, when, for example, a low-pass filter or the like is provided in order to remove noise, the filter cannot capture agile changes in the detection signal, and the operation of the high-voltage safety device is slow.

  In particular, in the electrostatic coating apparatus shown in Patent Document 2, a high voltage generator in the coating machine and an external high voltage controller are connected using a low voltage cable. Similarly, the length is about 20 to 30 m. For this reason, the resistance and stray capacitance of the low voltage cable are likely to increase, and if the frequency of the drive voltage is increased due to the influence of these resistance and stray capacitance, the high voltage generator cannot be driven. As a result, the high voltage controller can only increase the frequency of the drive voltage up to about 25 kHz, and it takes about 1 to 2 seconds to raise and lower the high voltage between 0 V and 100 kV. It was.

  For this reason, in the electrostatic coating apparatus shown in Patent Document 2, it is necessary to operate the high-voltage safety device in anticipation of the time required for raising and lowering the high voltage. The current value and the voltage value generated were set very low. As a result, the high voltage safety device immediately cuts off the high voltage when the coating machine approaches the object to be coated, so that the efficiency of the painting work has been reduced.

  In addition, when electrostatic painting is performed on a painted surface having a complicated shape such as the inner surface of an engine room, trunk room, cabin, etc. of a car body using a painting robot, the rapid operation speed of the painting robot (for example, the highest speed) It is necessary to raise and lower the high voltage in accordance with 2200 mm / sec. Furthermore, when electrostatic coating is performed in a relatively narrow space surrounded by such a grounding body, it is not possible to secure a sufficient coating distance between the coating machine and the object to be coated. In order to continue the electrostatic coating, it is necessary to quickly raise and lower the high voltage according to the coating distance. However, the electrostatic coating apparatus shown in Patent Document 2 has a problem that it is difficult to efficiently raise and lower a high voltage in a short time, and it is difficult to efficiently coat a painted surface having a complicated shape.

  On the other hand, in the electrostatic coating apparatus shown in Patent Document 3, since the high voltage controller is also built in the coating machine in addition to the high voltage generator, the time required for raising and lowering the high voltage can be shortened. However, the electrostatic coating apparatus shown in Patent Document 3 has not been studied for a high-voltage safety device, and as in Patent Document 2, the high-voltage safety device can be quickly activated by delaying a high-voltage detection signal or the like. There is a problem that it cannot be activated.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an electrostatic coating apparatus capable of quickly raising and lowering a high voltage and quickly operating a high voltage safety device. It is in.

  In order to solve the above-described problems, the invention of claim 1 is directed to a coating machine that sprays paint on an object to be coated, a high voltage generator that supplies a high voltage to the coating machine, and a drive to the high voltage generator. Electrostatic coating comprising a high voltage controller for supplying voltage and controlling the high voltage, and a high voltage safeguard for preventing the occurrence of overvoltage and overcurrent using the voltage value and current value of the high voltage The apparatus is characterized in that the high voltage generator, the high voltage controller, and the high voltage safety device are arranged inside the coating machine.

  According to a second aspect of the present invention, the high voltage generator is provided with a voltage detector that detects a high voltage value and a current detector that detects a high voltage current value. The detector is connected to the high-voltage safety device through a filter that removes noise.

  According to a third aspect of the present invention, the high-voltage safety device has an absolute sensitivity circuit that stops the supply of the high voltage when the current value of the high voltage exceeds a predetermined maximum value.

  According to a fourth aspect of the present invention, the high-voltage safety device has a slope sensitivity circuit that stops the supply of the high voltage when the increase in the current value of the high voltage within a unit time exceeds a predetermined sensitivity setting value. Yes.

  In the invention of claim 5, the high-voltage safety device is configured to reduce the high-voltage voltage value so that the high-voltage current value becomes constant when the high-voltage current value becomes equal to or higher than a predetermined set value. The buffer circuit is included.

  In the invention of claim 6, the high voltage safety device has an overvoltage circuit that stops the supply of the high voltage when the voltage value of the high voltage exceeds a predetermined maximum value.

  In the seventh aspect of the invention, the high voltage controller includes a voltage setting circuit for setting the amplitude of the driving voltage, and a driving circuit for outputting an AC driving voltage having an amplitude by the voltage setting circuit. The generator includes a step-up transformer circuit that boosts the drive voltage of the drive circuit and a multistage voltage doubler rectifier circuit that generates a high voltage using the drive voltage boosted by the step-up transformer circuit.

  According to the invention of claim 1, since the high voltage generator, the high voltage controller, and the high voltage safety device are arranged in the interior of the coating machine, the high voltage generator and the high voltage safety device are brought close to each other. The voltage value and the current value of the high voltage can be transmitted without delay between them, and the high voltage safety device can be operated quickly. Further, since external noise can be reduced with respect to the high voltage value and current value, malfunction of the high voltage safety device can be prevented and the reliability of the coating apparatus can be improved.

  Furthermore, in addition to the high voltage generator and the high voltage safety device, the high voltage controller is also arranged inside the coating machine, so it is possible to arrange the high voltage generator and the high voltage controller close to each other. The frequency of the drive voltage supplied to the high voltage generator can be increased. For this reason, since the time required for raising and lowering the high voltage can be shortened, for example, when the rotary atomizing head abnormally approaches the object to be coated, the high voltage can be quickly lowered using the high voltage safety device. it can. As a result, the high voltage can be raised and lowered according to the operating speed of the painting robot that operates at high speed. Electrostatic coating can be performed in a state where a high voltage corresponding to the coating distance is applied, so that the coating efficiency can be increased and the safety of the coating apparatus can be improved.

  According to the second aspect of the present invention, since the voltage detector and the current detector are connected to the high voltage safety device via the filter, the detection value (voltage value, current value) of each detector is obtained using the filter. ) Can be removed, and malfunction of the high-voltage safety device can be prevented. Further, since the high voltage generator and the high voltage safety device can be arranged close to each other in the coating machine, noise mixed between each detector and the high voltage safety device can be reduced. For this reason, for example, when noise is removed using a low-pass filter, the cutoff frequency can be increased, so that an accurate high-voltage detection value can be transmitted to the high-voltage safety device without delay. The device can be operated quickly.

  According to the invention of claim 3, since the high voltage safety device has an absolute sensitivity circuit, when the current value of the high voltage exceeds the maximum value, the supply of the high voltage is stopped using the absolute sensitivity circuit, The occurrence of sparks can be prevented. In addition, since the high voltage generator, high voltage controller, and high voltage safety device are arranged in the coating machine, they can be arranged close to each other, and the high voltage current value is accurately and accurately set to the absolute sensitivity circuit. It can be transmitted without delay, and the high voltage can be quickly raised and lowered using a high voltage controller. For this reason, since the supply of high voltage can be quickly stopped before overcurrent occurs, the predetermined maximum value can be brought close to the current value at which spark actually occurs, and the current value at which high voltage can be supplied The range can be expanded.

  According to the invention of claim 4, since the high voltage safety device has the slope sensitivity circuit, when the high voltage current suddenly increases, the supply of the high voltage is stopped using the slope sensitivity circuit, and the spark voltage is increased. Can be prevented. In addition, since the high voltage generator, high voltage controller, and high voltage safety device are disposed in the coating machine, they can be disposed close to each other, and the slope sensitivity circuit is capable of high voltage current within a unit time. The increment (increase rate) of the value can be accurately detected, and the high voltage can be raised and lowered quickly using the high voltage controller. For this reason, the slope sensitivity circuit can quickly stop the supply of the high voltage before an overcurrent occurs.

  According to the fifth aspect of the present invention, since the high voltage safeguard includes the current buffer circuit, the high voltage is lowered by using the current buffer circuit so that the current value is constant so that no overcurrent occurs. The electrostatic coating can be continued even when the coating machine approaches the workpiece. In addition, since the high voltage generator, high voltage controller and high voltage safety device are installed in the coating machine, they can be placed close to each other, and the high voltage can be raised and lowered by the current buffer circuit in a short time. Can do. For this reason, the current value at which the spark is generated can be brought close to the set value of the current at which the current buffer circuit operates, and even when the current buffer circuit operates, the voltage value of the high voltage is increased to improve the coating efficiency. be able to.

  According to the invention of claim 6, since the high voltage safety device has an overvoltage circuit, when the voltage value of the high voltage exceeds the maximum value, the supply of the high voltage is stopped using the overvoltage circuit, and the spark Occurrence can be prevented. Also, since the high voltage generator, high voltage controller and high voltage safety device are installed in the coating machine, they can be placed close to each other, and the accurate high voltage value is delayed with respect to the overvoltage circuit. The high voltage can be quickly raised and lowered using the high voltage controller, and the supply of the high voltage can be stopped quickly before the overvoltage occurs.

  According to the invention of claim 7, since the high voltage controller is constituted by the voltage setting circuit and the drive circuit, and the high voltage generator is constituted by the step-up transformer circuit and the multistage voltage doubler rectifier circuit, the step-up transformer circuit is driven. The AC drive voltage output from the circuit is boosted and supplied to the multistage voltage doubler rectifier circuit, and the multistage voltage doubler current circuit can raise and lower the high voltage according to the frequency of the drive voltage. And since the high voltage controller and the high voltage generator were arrange | positioned in the coating machine, these can be arrange | positioned close together and the frequency of a drive voltage can be raised. For this reason, the multistage voltage doubler rectifier circuit can raise and lower the high voltage in a short time, and the operating time of the high voltage safety device can be shortened.

  Hereinafter, a rotary atomizing head type coating apparatus will be described as an example of an electrostatic coating apparatus according to an embodiment of the present invention in detail with reference to the accompanying drawings.

  In the figure, reference numeral 101 denotes a painting robot serving as a painting machine, and the painting robot 101 executes a painting work using a painting machine 1 described later. The painting robot 101 includes a base 102, a vertical arm 103 that is rotatable and swingable on the base 102, and a horizontal arm that is swingably provided at the tip of the vertical arm 103. 104 and a wrist 105 provided at the tip of the horizontal arm 104 are roughly configured.

  Reference numeral 1 denotes a painting machine attached to a painting robot 101. The painting machine 1 is roughly constituted by a housing 2, an air motor 6, a rotary atomizing head 7, a cartridge 10 and the like which will be described later.

  Reference numeral 2 denotes a housing attached to the tip of the wrist 105 of the painting robot 101. The housing 2 is formed of an insulating resin material, and has a motor attachment portion 3 located on the front side, on the rear side. The cylinder mounting part 4 is formed. The housing 2 is formed with feed tube insertion holes 9 (described later) extending in the axial direction (front and rear directions) so as to pass through the center positions of the mounting portions 3 and 4. Further, the housing 2 is provided with an arm portion 5 that extends in the vertical direction from an intermediate position in the front and rear directions, and the arm portion 5 is connected to the wrist 105 of the painting robot 101.

  Reference numeral 6 denotes an air motor mounted in the motor mounting portion 3 of the housing 2. The air motor 6 includes a hollow rotary shaft 6B rotatably supported via a static pressure air bearing 6A, and a base end of the rotary shaft 6B. And an air turbine 6C fixed to the side. The air motor 6 rotates the rotating shaft 6B at a high speed of 3000 to 100,000 rpm, for example, by supplying air to the air turbine 6C through the air passage 2A of the housing 2.

  Reference numeral 7 denotes a rotary atomizing head attached to a rotary shaft 6B of the air motor 6. The rotary atomizing head 7 is formed of, for example, a metal material or a conductive resin material, and is rotated at a high speed by the air motor 6. When the coating material is supplied through the feed tube 12 described later in a state where the rotary atomizing head 7 is rotated at a high speed, the coating material is centrifugally atomized to be atomized and sprayed toward the object to be grounded. . A high voltage generator 13 (described later) is connected to the rotary atomizing head 7 via an air motor 6 or the like, and a high voltage is applied to the entire rotary atomizing head 7. Thereby, when performing electrostatic coating, the rotary atomizing head 7 charges the coating material which flows on the surface directly to a high voltage.

  Reference numeral 8 denotes a shaping air ring provided on the front end side of the housing 2 so as to surround the rotary atomizing head 7. The shaping air ring 8 has a plurality of air discharge holes 8A, and the air discharge holes 8A. Jets shaping air toward the paint sprayed from the rotary atomizing head 7.

  Reference numeral 9 denotes a feed tube insertion hole extending from the central portion of the cylinder mounting portion 4 into the rotary shaft 6B of the air motor 6. The feed tube insertion hole 9 is removably inserted into a feed tube 12 of a cartridge 10 to be described later. Is done.

  Reference numeral 10 denotes a coating cartridge for supplying paint toward the rotary atomizing head 7. The cartridge 10 includes a cylinder 11 formed as a cylindrical body (cylinder) extending in the front and rear directions, and an axial direction from the cylinder 11. And a piston (both not shown) that define the inside of the cylinder 11 as a paint storage chamber and an extrusion thinner storage chamber.

  The cartridge 10 is attached to the cylinder attachment portion 4 of the housing 2 in a state where the feed tube 12 is inserted through the feed tube insertion hole 9. At the time of painting, the piston is slid and displaced by supplying thinner to the extrusion thinner housing chamber through the thinner passage 2B of the housing 2, and the paint in the cylinder 11 is discharged toward the rotary atomizing head 7 through the feed tube 12. To do. At the time of filling the paint, the cartridge 10 is removed from the cylinder mounting portion 4 and attached to a paint filling device (not shown), and the paint is filled into the paint containing chamber of the cylinder 11 through the feed tube 12.

  Reference numeral 13 denotes a high voltage generator built in the arm portion 5 of the housing 2, and the high voltage generator 13 boosts a drive voltage by a high voltage controller 18 described later, and the boost transformer circuit 14. And a multi-stage voltage doubler rectifier circuit 15 (so-called cockcroft circuit) composed of a plurality of capacitors and diodes (all not shown) that generate a high voltage using the boosted drive voltage.

  Here, the input side of the step-up transformer circuit 14 is connected to a high voltage controller 17 described later, and the output side is connected to the multistage voltage doubler rectifier circuit 15. The output side of the multistage voltage doubler rectifier circuit 15 is connected to the air motor 6 via a high resistance 16 of about several hundred MΩ for preventing sparks. The high voltage generator 13 generates a high voltage of, for example, −30 to −120 kV, and charges the paint directly to a high voltage through the air motor 6 and the rotary atomizing head 7.

  Reference numeral 17 denotes a high voltage control device provided in the housing 2 of the coating machine 1 in a state of being connected to the high voltage generator 13, and the high voltage control device 17 includes a high voltage controller 18 and a high voltage safety device which will be described later. 21.

  Reference numeral 18 denotes a high voltage controller that supplies a drive voltage to the high voltage generator 13 to control the high voltage. The high voltage controller 18 includes a processing unit (CPU) and the like, and sets the amplitude of the drive voltage. A processing circuit 19 as a voltage setting circuit and a driving circuit 20 that outputs an alternating driving voltage that vibrates with an amplitude set by the processing circuit 19 are configured. Further, the drive circuit 20 is supplied with, for example, a 24V DC voltage (DC24V) through a coating control device 32 described later on the input side, and is connected to the step-up transformer circuit 14 of the high voltage generator 13 on the output side.

  Here, the drive circuit 20 includes two FETs (field effect transistors) that convert a DC voltage into an AC drive voltage, and an NPN-type power transistor (none of which is shown) that sets the amplitude of the drive voltage. It consists of A DC voltage is supplied to the collector of the power transistor, and the emitter is connected to the input side of the step-up transformer circuit 14. In the drive circuit 20, the base voltage of the power transistor is set by the processing circuit 19, and the emitter voltage value (input voltage value of the step-up transformer circuit 14) is set according to the base voltage.

  Two FETs are also connected to the input side of the step-up transformer circuit 14, and these FETs are alternately closed and opened (ON, OFF) according to the drive signal from the processing circuit 19. As a result, the drive circuit 20 converts the DC voltage set by the power transistor into an AC drive voltage that vibrates at a frequency of about 250 kHz, for example.

  Further, the processing circuit 19 is connected to a voltage sensor 26 and a current sensor 27, which will be described later, on the input side, and from the high voltage generator 13 using a high voltage value Vm and a current value Im by these sensors 26 and 27. The high voltage that is output is feedback controlled.

  Reference numeral 21 denotes a high voltage safeguard that prevents the occurrence of overvoltage and overcurrent using a high voltage value Vm and a current value Im. The high voltage safeguard 21 includes an absolute sensitivity circuit 22 and a slope sensitivity circuit 23 described later. The input side is connected to the voltage sensor 26 and the current sensor 27, and the output side is connected to the processing circuit 19 of the high voltage controller 18.

  Reference numeral 22 denotes an absolute sensitivity circuit that stops the supply of high voltage when the current value Im of the high voltage exceeds a predetermined maximum value Imax. The absolute sensitivity circuit 22 is connected to the current sensor 27 on its input side, The output side is connected to the processing circuit 19. The absolute sensitivity circuit 22 outputs a stop signal for stopping the supply of the high voltage to the processing circuit 19 when the current value Im by the current sensor 27 exceeds the maximum value Imax of about 150 μA, for example. Thereby, the processing circuit 19 sets the driving voltage by the driving circuit 20 to OV and stops the supply of the high voltage.

  Reference numeral 23 denotes a slope sensitivity circuit that stops the supply of high voltage when the increment ΔIm of the high voltage current value Im within a unit time exceeds a predetermined sensitivity setting value ΔImax. The output side is connected to the processing circuit 19 while being connected to the current sensor 27. When the increase ΔIm of the current value Im by the current sensor 27 exceeds the sensitivity setting value ΔImax within a unit time of, for example, about several milliseconds to several tens of milliseconds, the slope sensitivity circuit 23 performs processing similar to the absolute sensitivity circuit 22. A stop signal for stopping the supply of the high voltage is output to the circuit 19, and the supply of the high voltage is stopped using the processing circuit 19.

  Reference numeral 24 denotes a current buffer circuit for reducing the high voltage value Vm so that the high voltage current value Im becomes constant at the set value Im0 when the high voltage current value Im becomes equal to or higher than a predetermined set value Im0. The current buffer circuit 24 has an input side connected to the voltage sensor 26 and the current sensor 27, and an output side connected to the processing circuit 19. The current buffer circuit 24 outputs a step-down signal for reducing the high voltage value Vm to the processing circuit 19 when the current value Im by the current sensor 27 becomes equal to or greater than the set value Im0. As a result, the processing circuit 19 lowers the drive voltage by the drive circuit 20 and steps down the high voltage.

  The set value Im0 of the current buffer circuit 24 is set to, for example, about 155 μA as a value (Im0> Imax) larger than the maximum value Imax of the absolute sensitivity circuit 22. As a result, the current buffer circuit 24 functions as a backup for the absolute sensitivity circuit 22. Further, the current buffer circuit 24 stops the supply of the high voltage using the processing circuit 19 when the voltage value Vm falls below a predetermined minimum value Vmin due to the step-down of the high voltage.

  Reference numeral 25 denotes an overvoltage circuit which stops the supply of high voltage when the voltage value Vm of the high voltage exceeds a predetermined maximum value Vmax. The overvoltage circuit 25 has an input side connected to the voltage sensor 26 and an output side It is connected to the processing circuit 19. When the voltage value Vm by the voltage sensor 26 exceeds the maximum value Vmax, the overvoltage circuit 25 outputs a stop signal for stopping the supply of the high voltage to the processing circuit 19, as in the absolute sensitivity circuit 22. Then, the supply of the high voltage is stopped using the processing circuit 19.

  Reference numeral 26 denotes a voltage sensor (voltage detector) connected to the output side of the multistage voltage doubler rectifier circuit 15. The voltage sensor 26 is connected between the high resistance 16 and the multistage voltage doubler rectifier circuit 15. The high voltage applied to the rotary atomizing head 7 is divided and detected, and this voltage detection value is output to the high voltage safety device 21 as the voltage value Vm.

  Reference numeral 27 denotes a current sensor (current detector) connected to the input side of the multistage voltage doubler rectifier circuit 15. The current sensor 27 detects a current flowing in the high voltage generation path including the multistage voltage doubler rectifier circuit 15, This detected current value is output to the high voltage safety device 21 as the current value Im.

  Note that the current sensor 27 is not limited to the input side of the multistage voltage doubler rectifier circuit 15, and may be configured to detect a current flowing on the output side of the multistage voltage doubler rectifier circuit 15, for example.

  Reference numerals 28 and 29 denote filters provided between the voltage sensor 26 and the current sensor 27 and the high-voltage safety device 21, respectively. Each of the filters 28 and 29 is constituted by, for example, a low-pass filter or the like, and has a voltage value Vm, Noise mixed from the outside into the current value Im is removed.

  Reference numeral 30 denotes an electrostatic coating control device arranged outside the coating booth. The electrostatic coating control device 30 includes a coating robot control device 31 and a coating control device 32, and is connected to a commercial power source 33. Are connected to the painting robot 101 and the painting machine 1 via cables 34 and 35, respectively. The painting robot control device 31 controls the operation of the painting robot 101 at the time of painting or filling the paint.

  On the other hand, the painting control device 32 converts the AC voltage of the commercial power supply 33 into a DC voltage of, for example, about 24V using a power conversion circuit or the like and supplies it to the drive circuit 20 of the high voltage controller 18, and also the high voltage controller. Eighteen processing circuits 19 are used to control the high voltage value Vm and the like.

  The rotary atomizing head type coating apparatus according to the present embodiment has the above-described configuration. Next, the operation of the coating apparatus will be described.

  When the object to be coated is arranged in the vicinity of the painting robot 101 using a conveyor device or the like, the painting robot control device 31 operates the painting robot 101 based on the teaching operation stored in advance, and is close to the object to be coated. The painting machine 1 is moved to.

  At this time, the coating machine 1 rotates the rotary atomizing head 7 at high speed by the air motor 6 and supplies the coating material to the rotary atomizing head 7 through the feed tube 12 in this state. Thereby, the coating machine 1 atomizes the paint by the centrifugal force when the rotary atomizing head 7 rotates and sprays the paint, while supplying the shaping air through the shaping air ring 8 while controlling the spray pattern. The particles are applied to an object connected to earth.

  Further, a high voltage by a high voltage generator 13 is applied to the rotary atomizing head 7 via an air motor 6. As a result, the paint particles are directly charged to a high voltage through the rotary atomizing head 7 and fly along the electrostatic field formed between the rotary atomizing head 7 and the object to be coated. Apply to the workpiece.

  Here, for example, when the rotary atomizing head 7 abnormally approaches an object to be grounded, the current flowing in the high voltage generation path including the high voltage generator 13 can cause dielectric breakdown (spark). May increase to a degree. At this time, since the current value Im by the current sensor 27 becomes larger than the maximum value Imax set in advance by the coating control device 32 or the like, the absolute sensitivity circuit 22 stops supplying high voltage to the processing circuit 19. The stop signal is output and the supply of high voltage is stopped. Thereby, it is possible to prevent a spark from occurring between the rotary atomizing head 7 and the object to be coated.

  Further, when the absolute sensitivity circuit 22 does not operate even though the current value Im exceeds the maximum value Imax due to a failure of the absolute sensitivity circuit 22, the current value Im becomes equal to or higher than the set value Im0 of the current buffer circuit 24. For this reason, the current buffer circuit 24 outputs a step-down signal for reducing the high voltage value Vm to the processing circuit 19, and the high voltage step-down so that the current value Im is constant at the set value Im0. Let As a result, the absolute sensitivity circuit 22 can be backed up using the current buffer circuit 24.

  Further, for example, the current value Im may increase rapidly as the rotary atomizing head 7 abnormally approaches the workpiece. At this time, since the increment ΔIm of the current value Im by the current sensor 27 exceeds the sensitivity setting value ΔImax within the unit time, the slope sensitivity circuit 23 is a stop signal for stopping the supply of the high voltage to the processing circuit 19. And the supply of the high voltage is stopped using the processing circuit 19. As a result, it is possible to prevent a spark from occurring as the current value Im increases rapidly.

  Further, when the high voltage value Vm exceeds the predetermined maximum value Vmax, the overvoltage circuit 25 outputs a stop signal for stopping the supply of the high voltage to the processing circuit 19, Use to stop supplying high voltage.

  However, in the present embodiment, the high voltage generator 13, the high voltage controller 18, and the high voltage safety device 21 are arranged inside the coating machine 1, so that the high voltage generator 13 and the high voltage safety device are arranged. 21 can be placed close to each other. For this reason, since the long signal cable which connects between the high voltage generator 13 and the high voltage safeguard 21 like a prior art can be abolished, an external noise can be excluded easily and malfunctioning is carried out. This can improve the reliability of the coating equipment. In addition, since the high voltage generator 13 and the high voltage safety device 21 can be arranged close to each other, the high voltage value Vm and the current value Im can be transmitted between them without delay, and the high voltage safety can be achieved. The device 21 can be activated quickly.

  In addition to the high voltage generator 13 and the high voltage safety device 21, the high voltage controller 18 is also arranged inside the coating machine 1, so that the high voltage generator 21 and the high voltage controller 18 are connected to each other. The frequency of the drive voltage supplied to the high voltage generator 21 can be increased. For this reason, since the time required for raising and lowering the high voltage can be shortened, for example, when the rotary atomizing head 7 abnormally approaches the object to be grounded, the high voltage safety device 21 is used promptly. High voltage can be stepped down.

  As a result, the high voltage can be raised and lowered according to the operating speed of the coating robot 101 that operates at a high speed. Therefore, even if the coating surface has a complicated shape, it is possible to reliably prevent the occurrence of sparks. Electrostatic coating can be performed in a state where a high voltage according to the coating distance is applied, and the coating efficiency can be increased and the safety of the coating apparatus can be improved.

  Further, since the voltage sensor 26 and the current sensor 27 are connected to the high voltage safety device 21 via the filters 28 and 29, the detection values (voltage values) of the voltage sensor 26 and the current sensor 27 using the filters 28 and 29 are used. Vm, current value Im) can be removed, and malfunction of the high voltage safeguard 21 can be prevented. Moreover, since the high voltage generator 13 and the high voltage safeguard 21 can be disposed close to each other in the coating machine 1, noise mixed between the sensors 26 and 27 and the high voltage safeguard 21 is reduced. be able to. For this reason, when noise is removed by using, for example, a low-pass filter as the filters 26 and 27, the cutoff frequency can be increased, so that the accurate high voltage voltage value Vm and current value Im can be safely increased without delay. The high voltage safety device 21 can be activated quickly.

  Further, since the high voltage safety device 21 has the absolute sensitivity circuit 22, when the current value Im exceeds the maximum value Imax, the supply of high voltage is stopped using the absolute sensitivity circuit 22 to prevent the occurrence of sparks. can do. Further, since the high voltage generator 13, the high voltage controller 18 and the high voltage safety device 21 are disposed in the coating machine 1, they can be disposed close to each other, and a high voltage is applied to the absolute sensitivity circuit 22. Current value Im can be transmitted accurately and without delay, and the high voltage can be quickly raised and lowered using the high voltage controller 18. For this reason, since the supply of the high voltage can be quickly stopped before the overcurrent occurs, the predetermined maximum value Imax can be brought close to the current value Is at which the spark is actually generated, and the current capable of supplying the high voltage The range of the value Im can be expanded.

  In addition, since the high voltage safety device 21 has the slope sensitivity circuit 23, when the high voltage current increases rapidly, the supply of the high voltage is stopped using the slope sensitivity circuit 23 to prevent the occurrence of sparks. can do. In addition, since the high voltage generator 13, the high voltage controller 18 and the high voltage safety device 21 are disposed in the coating machine 1, they can be disposed close to each other, and the slope sensitivity circuit 23 is provided with a high voltage current. The increment ΔIm of the value Im can be accurately detected, and the high voltage can be quickly raised and lowered using the high voltage controller 18. For this reason, the slope sensitivity circuit 23 can quickly stop the supply of the high voltage before the overcurrent occurs.

  Further, since the high voltage safety device 21 has the current buffer circuit 24, the high voltage is lowered so that the current value Im becomes constant at the set value Im0 so that no overcurrent is generated by using the current buffer circuit 24. Electrostatic coating can be continued even when the coating machine 1 approaches the workpiece. Further, since the high voltage generator 13, the high voltage controller 18 and the high voltage safety device 21 are arranged in the coating machine 1, they can be arranged close to each other, and the current buffer circuit 24 raises and lowers the high voltage. Can be performed in a short time. For this reason, the current setting value Im0 at which the current buffer circuit 24 operates can be brought close to the current value Is at which sparking actually occurs, and even when the current buffer circuit 24 is operated, the high voltage value is increased and applied. Efficiency can be improved.

  Further, since the high voltage safety device 21 has the configuration including the overvoltage circuit 25, when the high voltage value Vm exceeds the maximum value Vmax, the overvoltage circuit 25 is used to stop the supply of the high voltage and to generate a spark. Can be prevented. Further, since the high voltage generator 13, the high voltage controller 18 and the high voltage safety device 21 are disposed in the coating machine 1, they can be disposed close to each other, and the high voltage generator 25 can be accurately connected to the overvoltage circuit 25. The voltage value Vm of the voltage can be transmitted without delay, and the high voltage can be quickly raised and lowered using the high voltage controller 18, and the supply of the high voltage can be quickly stopped before an overvoltage occurs. it can.

  Further, since the high voltage controller 18 is constituted by the processing circuit 19 and the drive circuit 20, and the high voltage generator 13 is constituted by the step-up transformer circuit 14 and the multistage voltage doubler rectifier circuit 15, the step-up transformer circuit 14 is composed of the drive circuit. The AC drive voltage output from 20 is boosted and supplied to the multistage voltage doubler rectifier circuit 15, and the multistage voltage doubler rectifier circuit 15 can raise and lower the high voltage according to the frequency of the drive voltage. And since the high voltage controller 18 and the high voltage generator 13 were arrange | positioned in the coating machine 1, these can be arrange | positioned close together and the frequency of a drive voltage can be raised. For this reason, the multistage voltage doubler rectifier circuit 15 can raise and lower the high voltage in a short time, and the operating time of the high voltage safety device 21 can be shortened.

  In the embodiment, the high voltage safeguard 21 is provided separately from the processing circuit 19 including the processing device (CPU) and the like. For example, the operation similar to that of the high voltage safeguard 21 is performed using the processing circuit 19. It is good also as a structure which operates the program which performs.

  Moreover, in the said embodiment, it was set as the structure using the cartridge type coating machine 1 which supplies a coating material using the cartridge 10 which can be attached or detached to the housing 2. FIG. However, the present invention is not limited to this. For example, the feed tube may be connected to a paint source such as a color change valve device, and a coating machine that supplies paint from the paint source may be used.

  Moreover, in the said embodiment, the rotary atomization head 7 is formed with a metal material or a conductive resin material, and the direct charging type rotation in which the paint is directly charged to a high voltage via the rotary atomization head 7. The atomizing head type coating apparatus has been described as an example. However, the present invention is not limited to this. For example, an external electrode is provided on the outer peripheral side of the cover of the rotary atomizing head type coating apparatus, and the rotary atomizing head is provided by this external electrode. The present invention may be applied to an indirect charging type rotary atomizing head type coating device that indirectly charges a paint sprayed from a high voltage.

  In the above embodiment, the wrist 105 is provided in the painting robot 101, and the high voltage generator 13 and the high voltage control device 17 are disposed in the housing 2 of the painting machine 1 attached to the wrist 105. did. However, the present invention is not limited to this. For example, when a coating machine is configured including a wrist separate from or integrated with the housing, a high voltage generator is disposed in the housing and a high voltage is generated in the wrist. It is good also as a structure which arrange | positions a control apparatus and connects these. Specifically, since an actuator for swinging and rotating the coating machine is disposed in the wrist, a high voltage control device can be disposed together with these actuators.

  Furthermore, in the above-described embodiment, the case where the electrostatic spraying device is applied to a rotary atomizing head type coating device that sprays paint using the rotary atomizing head 7 is described as an example, but the paint is sprayed from the nozzle tip. It may be applied to a spray gun type coating apparatus.

It is a front view which shows the rotary atomization head type coating device by embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the coating machine in FIG. It is a block diagram which shows the coating machine in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating machine 2 Housing 5 Arm part 6 Air motor 7 Rotating atomizing head 10 Cartridge 13 High voltage generator 14 Step-up transformer circuit 15 Multistage voltage doubler rectifier circuit 17 High voltage controller 18 High voltage controller 19 Processing circuit (voltage setting circuit)
20 drive circuit 21 high voltage safety device 22 absolute sensitivity circuit 23 slope sensitivity circuit 24 current buffer circuit 25 overvoltage circuit 26 voltage sensor (voltage detector)
27 Current sensor (current detector)
28, 29 filters

Claims (7)

  A coating machine for spraying paint on the object to be coated, a high voltage generator for supplying a high voltage to the coating machine, a high voltage controller for supplying a driving voltage to the high voltage generator and controlling the high voltage, In the electrostatic coating apparatus comprising a high voltage safeguard that prevents the occurrence of overvoltage and overcurrent using the voltage value and current value of the high voltage, the high voltage generator, the high voltage controller, and the high voltage An electrostatic coating apparatus characterized in that the safety device is arranged inside the coating machine.   The high voltage generator is provided with a voltage detector that detects the voltage value of the high voltage and a current detector that detects the current value of the high voltage, and the voltage detector and the current detector are The electrostatic coating apparatus according to claim 1, wherein the electrostatic coating apparatus is configured to be connected to the high-voltage safety device through a filter for removing noise.   The electrostatic coating according to claim 1, wherein the high-voltage safety device includes an absolute sensitivity circuit that stops the supply of the high voltage when a current value of the high voltage exceeds a predetermined maximum value. apparatus.   The high-voltage safety device includes a slope sensitivity circuit that stops the supply of the high voltage when an increase in the current value of the high voltage within a unit time exceeds a predetermined sensitivity setting value. , 2 or 3 electrostatic coating apparatus.   The high-voltage safety device includes a current buffer circuit that reduces the high-voltage voltage value so that the high-voltage current value is constant when the high-voltage current value is equal to or higher than a predetermined set value. The electrostatic coating apparatus according to claim 1, 2, 3, or 4.   6. The high-voltage safety device according to claim 1, 2, 3, 4, or 5, further comprising an overvoltage circuit that stops the supply of the high voltage when the voltage value of the high voltage exceeds a predetermined maximum value. The electrostatic coating apparatus described. The high voltage controller includes a voltage setting circuit that sets an amplitude of the driving voltage, and a driving circuit that outputs an AC driving voltage having an amplitude by the voltage setting circuit,
The high voltage generator includes a step-up transformer circuit that boosts the drive voltage by the drive circuit, and a multistage voltage doubler rectifier circuit that generates a high voltage using the drive voltage boosted by the step-up transformer circuit. The electrostatic coating apparatus according to claim 1, 2, 3, 4, 5 or 6.

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