Painting robot

Abstract

To provide a painting robot capable of reducing the effects of pressure fluctuations and ensuring a pressure range in which a pneumatic control valve can operate.SOLUTION: A painting robot 10 comprises: a painting head unit 50 including a plurality of nozzles 54 which eject droplets, and a painting head 53 having a piezoelectric substrate 62 for ejecting the droplets from the nozzles 54; a robot arm R1 for moving the painting head unit 50 to a desired position; and a paint supply mechanism 70 provided spanning the robot arm R1 and the painting head unit 50. Further, the paint supply mechanism 70 includes: a paint supply channel 72 for supplying a paint toward the painting head 53; a return flow channel 73 for recovering the paint that was not discharged from the nozzles 54; an air-operated paint regulator (AOPR) 92 provided in the paint supply channel 72 and capable of adjusting a valve opening degree in response to a controlled air pressure; and an orifice 96 provided on the downstream side of the paint supply channel 72 which is closer to the painting head side 53 than the AOPR 92.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a painting robot. [Background technology]

[0002] Robot painting using robots has become mainstream in painting lines for vehicles such as automobiles. As an example of a configuration related to this robot painting, for example, Patent Document 1 discloses a painting robot having a painting head (56) capable of discharging paint by the operation of a piezoelectric substrate (109), and a paint circulation device (51) that supplies paint to the painting head (56). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7203258 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the configuration of Patent Document 1, the effects of pressure fluctuations affect the stable discharge of paint from the coating head. For example, assuming that a pressure fluctuation of about ±1 kPa occurs due to the drive state of the gear pump (62) that supplies paint from the upstream side and the operation of the proportional valve (71) in response to an input pressure of 5 kPa, the influence of the pressure fluctuations would be, for example, 20%, and there is a risk that the discharge of paint would become unstable.

[0005] Furthermore, in vehicle painting environments, the use of AOPRs (air operated paint regulators), which are controlled by air pressure, rather than a proportional valve, which is an electrical device, is being considered for explosion-proofing purposes, etc. However, since the operable pressure range of an AOPR is higher than that of a proportional control valve, the configuration disclosed in Patent Document 1 does not allow the use of an AOPR.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a painting robot which is capable of reducing the effects of pressure fluctuations and setting an operable pressure range for an air pressure control valve. [Means for solving the problem]

[0007] In order to solve the above problems, according to a first aspect of the present invention, there is provided a painting robot for painting vehicles, comprising: a paint head unit having a paint head equipped with a plurality of nozzles for ejecting droplets and a piezoelectric substrate for pushing the droplets out of the nozzles when driven; a robot arm having the paint head unit attached to its tip and moving the paint head unit to a desired position; and a paint supply mechanism provided between the robot arm and the paint head unit, wherein the paint supply mechanism comprises: a paint supply path for supplying paint to the paint head; a return flow path connected to the paint discharge side of the paint head and for recovering paint that has not been ejected from the nozzles; an air pressure control valve provided in the paint supply path and capable of adjusting the valve opening in response to controlled air pressure; and a pressure boost mechanism provided in the paint supply path downstream of the air pressure control valve toward the paint head or upstream of the air pressure control valve, for increasing the pressure of the paint supplied to the air pressure control valve.

[0008] In the above-mentioned invention, it is preferable that the return flow passage is provided with an electrically operated valve whose valve opening degree can be adjusted by electrical operation.

[0009] In any of the above-mentioned inventions, it is preferable that the pressure boosting mechanism is an orifice in which the inner diameter of the paint supply passage is narrowed, and that the orifice is composed of a single hole or a plurality of holes.

[0010] In any one of the above-mentioned inventions or a combination thereof, it is preferable that the pressure boosting mechanism is a removal filter that removes foreign matter contained in the paint flowing through the paint supply passage.

[0011] In addition, in any of the above-mentioned inventions or combinations thereof, it is preferable that the paint supply mechanism is provided with a bypass flow path that connects the paint supply path and the return flow path and allows paint to circulate in parallel with the painting head, and that the pressure boosting mechanism is provided upstream of the paint supply path from the bypass flow path.

[0012] In any one of the above-mentioned inventions or a combination thereof, it is preferable that the orifice is capable of adjusting the opening degree of the flow path through which the paint flows. Effect of the Invention

[0013] According to the present invention, it is possible to provide a painting robot capable of reducing the influence of pressure fluctuations and setting an air pressure control valve within an operable pressure range. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing an overall configuration of a painting robot according to an embodiment of the present invention; [Diagram 2] 2 is a diagram showing a state in which a nozzle forming surface for discharging paint is seen from the front of the painting robot shown in FIG. 1. FIG. [Diagram 3] 2 is a diagram showing a state in which a plurality of painting heads are arranged in a staggered manner in the painting robot shown in FIG. 1. [Figure 4] 2 is a diagram showing a schematic configuration for supplying paint to each nozzle in the painting robot shown in FIG. 1. FIG. [Diagram 5] 5 is a cross-sectional view showing a configuration in the vicinity of a column-directional supply flow channel, a nozzle pressurizing chamber, and a column-directional discharge flow channel shown in FIG. 4. [Figure 6] 3 is a plan view showing the configuration of a nozzle forming surface of another paint head unit different from the paint head unit shown in FIG. 2. [Figure 7] 2 is a diagram showing a schematic configuration of a paint supply mechanism and the like provided in the painting robot shown in FIG. 1. [Figure 8] 8 is a diagram showing an example of the configuration of an orifice provided in the paint supply mechanism shown in FIG. 7. [Figure 9] FIG. 9 shows an orifice having an alternative configuration to the orifice shown in FIG. 8. [Figure 10] FIG. 10 shows an orifice of an alternative configuration to that shown in FIGS. 8 and 9. [Figure 11] FIG. 2 is a diagram showing an outline of a control configuration of the painting robot shown in FIG. [Figure 12] FIG. 8 is a diagram showing the experimental results of the relationship between the flow rate and the pressure loss when the inner diameter of the orifice provided in the paint supply mechanism shown in FIG. 7 is set to 0.75 mm, 1.0 mm, and 1.2 mm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The painting robot 10 according to each embodiment of the present invention will be described below with reference to the drawings. In the following description, as necessary, the X direction is the longitudinal direction of the nozzle forming surface 52 (painting head 53), the X1 side is the right side in Fig. 2, and the X2 side is the left side in Fig. 2. The Y direction is the lateral direction (width direction) of the nozzle forming surface 52 (painting head 53), the Y1 side is the upper side of the paper in Fig. 2, and the Y2 side is the lower side of the paper in Fig. 2.

[0016] (1. Overview of the Inkjet Painting Robot 10) The painting robot 10 of this embodiment "paints" objects to be painted, such as vehicles or vehicle parts (hereinafter, vehicle parts that are part of a vehicle will also be described as vehicles) located on a painting line in an automobile manufacturing factory, and aims to form a paint film on the surface of the object to be painted to protect the surface and provide a beautiful appearance. Therefore, it is necessary to paint vehicles that move along the painting line at predetermined intervals within a certain time with the desired painting quality.

[0017] Furthermore, the painting robot 10 of this embodiment is capable of forming not only the above-mentioned coating film but also various designs and images on objects to be painted, such as vehicles and vehicle parts. Note that the objects to be painted are not limited to vehicles and vehicle parts, and may be any parts other than automobiles (for example, exterior parts of airplanes and trains) that require painting.

[0018] (1-1. Overall configuration of the inkjet painting robot 10) Fig. 1 is a schematic diagram showing the overall configuration of a painting robot 10 according to a first embodiment of the present invention. As shown in Fig. 1, the painting robot 10 mainly includes a robot body 20 and a painting head unit 50. The painting robot 10 shown in Fig. 1 is a six-axis vertical articulated robot as an example, but the painting robot 10 may be any type of robot, such as a vertical articulated type other than six axes, a horizontal articulated type, or an Cartesian robot.

[0019] (1-2. About the robot body) 1, the robot body 20 mainly comprises a base 21, first to sixth rotating shafts 22a to 22f, legs 23, a first rotating arm 24, a second rotating arm 25, a rotating arm 26, a wrist 27, and a motor (not shown) for driving these. Note that the portion from the legs 23 to the wrist 27 corresponds to the robot arm R1, but other portions such as the base 21 may also correspond to the robot arm R1.

[0020] Of these, the base 21 is a part that is installed on an installation site such as a floor surface, but the base 21 may be movable relative to the installation site. The legs 23 are parts that stand upward from the base 21, and are provided rotatable relative to the base 21 via a first rotating shaft 22a by driving a motor (first motor) not shown. The legs 23 may be configured not to rotate relative to the base 21.

[0021] A first rotating arm 24 is provided on the upper end of leg 23 so as to be rotatable via second rotating shaft 22b by driving a motor (second motor) not shown. Furthermore, a second rotating arm 25 is provided on the tip side of first rotating arm 24 so as to be rotatable via third rotating shaft 22c by driving a motor (third motor) not shown.

[0022] A rotating arm 26 is provided at the tip of the second rotating arm 25 so as to be rotatable around the central axis of the second rotating arm 25. The rotating arm 26 is rotatable via a fourth rotating shaft 22d by driving a motor (fourth motor) not shown. A wrist section 27 is provided at the tip of the rotating arm 26. The wrist section 27 is capable of rotating around a plurality of (for example, two) shaft sections in different directions. In FIG. 1, the rotating shafts capable of the rotating movement are the fifth rotating shaft 22e and the sixth rotating shaft 22f, respectively. This makes it possible to control the orientation of the painting head unit 50 with high precision. The number of shaft sections may be any number equal to or greater than two.

[0023] Further, a painting head unit 50 is attached to the wrist portion 27, but this painting head unit 50 may be provided so as to be detachable from the wrist portion 27.

[0024] (1-3. About the painting head unit) Next, the paint head unit 50 will be described. FIG. 2 is a diagram showing a front view of the nozzle forming surface 52 of the paint head unit 50 from which paint is ejected. As shown in FIG. 2, the paint head unit 50 includes a head cover (not shown), and various components are built into the head cover. As shown in FIG. 2, the nozzle forming surface 52 includes a plurality of nozzle rows 55 in which the nozzles 54 are aligned in a direction inclined with respect to the longitudinal direction of the paint head unit 50. In this embodiment, the nozzle rows 55 include a first nozzle row 55A on one side (Y2 side) of the main scanning direction (Y direction) and a second nozzle row 55B on the other side (Y1 side) of the main scanning direction.

[0025] When discharging paint, the drive timing of each nozzle 54 is controlled so that droplets discharged from nozzles 54 in the second nozzle row 55B land between droplets discharged from adjacent nozzles 54 in the first nozzle row 55A, thereby improving the dot density during coating.

[0026] As shown in Fig. 2, a single paint head 53 is present on the nozzle forming surface 52. However, the nozzle forming surface 52 may have a head group made up of a plurality of paint heads 53. In this case, as an example, a configuration in which the plurality of paint heads 53 are aligned and arranged in a staggered pattern as shown in Fig. 3 can be given, but the arrangement of the paint heads 53 in the head group does not have to be staggered.

[0027] Fig. 4 is a diagram showing a schematic configuration for supplying paint to each nozzle 54. Fig. 5 is a cross-sectional view showing the configuration near the column-direction supply flow passage 58, the nozzle pressurizing chamber 59, and the column-direction discharge flow passage 60. As shown in Figs. 4 and 5, the coating head 53 includes a supply-side large flow passage 57, a column-direction supply flow passage 58, the nozzle pressurizing chamber 59, the column-direction discharge flow passage 60, and a discharge-side large flow passage 61. The supply-side large flow passage 57 is a flow passage to which paint is supplied from a paint supply passage 72 of the paint supply mechanism 70, which will be described later. The column-direction supply flow passage 58 is a flow passage to which paint in the supply-side large flow passage 57 is diverted.

[0028] Furthermore, the nozzle pressurizing chamber 59 is connected to the column-directional supply flow passage 58 via a nozzle supply flow passage 59a. As a result, paint is supplied to the nozzle pressurizing chamber 59 from the column-directional supply flow passage 58. The nozzle pressurizing chambers 59 are provided in a number corresponding to the number of nozzles 54, and the paint inside can be ejected from the nozzles 54 using a piezoelectric substrate 62 described later.

[0029] Furthermore, the nozzle pressurizing chamber 59 is connected to the column-directional discharge flow path 60 via the nozzle discharge flow path 59b. Therefore, paint not ejected from the nozzle 54 is discharged from the nozzle pressurizing chamber 59 to the column-directional discharge flow path 60 via the nozzle discharge flow path 59b. Furthermore, the column-directional discharge flow path 60 is connected to a discharge-side large flow path 61. The discharge-side large flow path 61 is a flow path where the paint discharged from each column-directional discharge flow path 60 joins together. This discharge-side large flow path 61 is connected to a return flow path 73 of the paint supply mechanism 70, which will be described later.

[0030] With this configuration, paint supplied from a paint supply passage 72 of a paint supply mechanism 70 (described later) passes through the supply-side large flow passage 57, the column-direction supply flow passage 58, the nozzle supply flow passage 59a, and the nozzle pressurizing chamber 59, before being discharged from the nozzle 54. Furthermore, paint that has not been discharged from the nozzle 54 passes from the nozzle pressurizing chamber 59 through the nozzle discharge flow passage 59b, the column-direction discharge flow passage 60, and the discharge-side large flow passage 61, and is returned to a return flow passage 73 of the paint supply mechanism 70 (described later).

[0031] 4, one column-directional discharge flow path 60 is arranged to correspond to one column-directional supply flow path 58. However, a plurality of (for example, two) column-directional discharge flow paths 60 may be arranged to correspond to one column-directional supply flow path 58. Also, a plurality of column-directional supply flow paths 58 may be arranged to correspond to one column-directional discharge flow path 60.

[0032] 5, a piezoelectric substrate 62 is disposed on the top surface of the nozzle pressurizing chamber 59 (the surface opposite to the nozzle 54). The piezoelectric substrate 62 includes two piezoelectric ceramic layers 63a and 63b, which are piezoelectric bodies, and further includes a common electrode 64 and an individual electrode 65. The piezoelectric ceramic layers 63a and 63b are members that can expand and contract when a voltage is applied from the outside. For such piezoelectric ceramic layers 63a and 63b, ceramic materials having ferroelectricity, such as lead zirconate titanate (PZT)-based, NaNbO3-based, BaTiO3-based, (BiNa)NbO3-based, and BiNaNb5O15-based materials, can be used.

[0033] 5, the common electrode 64 is disposed between the piezoelectric ceramic layer 63a and the piezoelectric ceramic layer 63b. A surface electrode (not shown) for the common electrode is formed on the upper surface of the piezoelectric substrate 62. The common electrode 64 and the surface electrode for the common electrode are electrically connected through a through conductor (not shown) present in the piezoelectric ceramic layer 63a. The individual electrodes 65 are disposed in the portions facing the nozzle pressurizing chamber 59. The portion of the piezoelectric ceramic layer 63a sandwiched between the common electrode 64 and the individual electrodes 65 is polarized in the thickness direction. Therefore, when a voltage is applied to the individual electrodes 65, the piezoelectric ceramic layer 63a is distorted by the piezoelectric effect. Therefore, when a predetermined drive signal is applied to the individual electrodes 65, the piezoelectric ceramic layer 63b is relatively displaced so as to reduce the volume of the nozzle pressurizing chamber 59, thereby discharging the paint.

[0034] 5, the common electrode 64 is disposed on the ceiling surface of the nozzle pressurizing chamber 59, but the common electrode 64 is not limited to the configuration in which it is disposed on the ceiling surface of the nozzle pressurizing chamber 59 as shown in Fig. 5. For example, the common electrode 64 may be disposed on the side surface of the nozzle pressurizing chamber 59 (a surface perpendicular or nearly perpendicular to the above-mentioned ceiling surface), or any other configuration may be adopted as long as the paint can be discharged satisfactorily from the nozzle 54.

[0035] (1-4. Other configurations of the painting head unit) Next, another configuration of the paint head unit 50 will be described. FIG. 6 is a plan view showing the configuration of the nozzle forming surface 52 of another paint head unit 50. As shown in FIG. 6, a nozzle row 55 may be configured by arranging a plurality of nozzles 54 along the short side direction (width direction; Y direction) of the paint head 53. In the configuration shown in FIG. 6, a plurality of nozzles 54 are arranged in the short side direction (width direction; main scanning direction) of the paint head 53 to form the nozzle row 55, but a configuration in which only one (single) nozzle 54 is arranged in the short side direction (width direction; main scanning direction) of the paint head 53 may also be used. In other words, the nozzle row 55 may be configured by one nozzle 54.

[0036] Furthermore, when painting a vehicle using a paint head 53 as shown in Fig. 6, painting may be performed with the longitudinal direction of the paint head 53 slightly tilted with respect to the main scanning direction of the paint head 53. For example, in the configuration of the paint head 53 shown in Fig. 2, if the nozzle row 55 is tilted at an angle α with respect to the main scanning direction, the longitudinal direction of the paint head 53 may be tilted at the angle α with respect to the main scanning direction of the paint head 53. When tilted in this manner, painting equivalent to that of the paint head 53 shown in Fig. 2 can be achieved simply by adjusting the timing of paint ejection from each nozzle 54.

[0037] (1-5. Paint supply mechanism) Next, the paint supply mechanism 70 and the air bubble removing member and flow meter provided in the paint supply mechanism 70 will be described.

[0038] 7 is a diagram showing a schematic configuration of the paint supply mechanism 70, etc. The paint supply mechanism 70 has, as its main components, a paint circulation path 71, an external supply path 75, an air bubble removing member 76, a supply pump 90, a suction pump 91, an air operated paint regulator (AOPR) 92, a secondary proportional control valve 93, a degassing module 94, a removal filter 95, an orifice 96, pressure sensors S1 to S8, a first flow meter FM1, and a second flow meter FM2.

[0039] The paint circulation path 71 is a flow path for circulating the paint, and has a paint supply path 72, a return path 73, and a bypass path 74. The paint supply path 72 is a flow path for supplying paint that has been supplied from an external supply path 75 or returned from the return path 73 toward the painting head 53, and is connected to the supply-side large path 57 described above.

[0040] The return flow passage 73 is connected to the large discharge flow passage 61 of the coating head 53, and is a flow passage for returning paint that has not been discharged from the coating head 53 to the air bubble removing member 76.

[0041] The bypass flow path 74 is a flow path that connects the paint supply path 72 and the return flow path 73. In other words, the bypass flow path 74 is provided in parallel with the paint head 53, and when paint is not being ejected from the paint head 53, the operation of a three-way valve 77, which will be described later, is switched so that paint flows into this bypass flow path 74.

[0042] The external supply passage 75 is a pipe for supplying paint supplied from a paint storage portion such as a circulation tank to the inside of the tank body of the air bubble removing member 76 .

[0043] The air bubble removal member 76 is a member for removing air bubbles contained in paint. The air bubble removal member 76 is provided at a stable position outside the robot arm R1 where the posture does not change. The air bubble removal member 76 is connected to the paint supply path 72 so as to be able to supply paint, and is also connected to the return flow path 73 so as to be supplied with paint from the return flow path 73. The air bubble removal member 76 has a tank body that can be sealed from the outside, and the tank body is provided with an outlet for discharging gas caused by air bubbles that have accumulated inside.

[0044] Furthermore, the paint supply passage 72 is connected to a three-way valve 77 downstream of an AOPR 92, which will be described later. This three-way valve 77 is connected to a midway portion of the paint supply passage 72, and is also connected to a bypass passage 74. Therefore, during painting, the upstream and downstream sides of the three-way valve 77 of the paint supply passage 72 are open, and paint is supplied to the painting head 53. On the other hand, when painting is not being performed, paint flows from the paint supply passage 72 to the bypass passage 74, but is switched so that paint is not supplied to the downstream side of the paint supply passage 72 (the painting head 53 side).

[0045] Further, an on-off valve 78 is provided in the middle of the bypass flow passage 74. By operating this on-off valve 78 to open, the paint can flow through the bypass flow passage 74.

[0046] Furthermore, a three-way valve 79 is connected downstream of the on-off valve 78 in the bypass flow passage 74, and this three-way valve 79 is further connected to the upstream side (i.e., the paint head 53 side of the return flow passage 73) and the downstream side (i.e., the suction pump 91 side of the return flow passage 73 described later). Therefore, when painting is performed, the upstream side and downstream side of the return flow passage 73 from the three-way valve 79 are opened, and paint that has not been discharged from the paint head 53 flows to the downstream side of the return flow passage 73. On the other hand, when painting is not performed, the three-way valve 79 is switched so that the paint flowing through the bypass flow passage 74 flows to the downstream side of the return flow passage 73 (the suction pump 91 side).

[0047] In addition, a switching valve 80 is disposed downstream of a suction pump 91, which will be described later, in the return flow passage 73. This switching valve 80 is also a three-way valve, and is connected to a discharge passage 81 in addition to the upstream and downstream sides of the return flow passage 73. In a normal state, this switching valve 80 is in a state in which paint flows between the upstream and downstream sides of the return flow passage 73. However, for example, when a cleaning liquid flows from the paint supply passage 72 to the return flow passage 73 via the coating head 53 or the bypass passage 74, the operation of the switching valve 80 is switched, and the above-mentioned cleaning liquid (waste liquid) is discharged via the discharge passage 81.

[0048] The return flow path 73 is connected to the above-mentioned air bubble removing member 76 downstream of the switching valve 80 .

[0049] A supply pump 90 is connected to the middle of the paint supply passage 72. The supply pump 90 corresponds to the paint transfer means and the paint supply means. The supply pump 90 is a means for applying a positive pressure to the paint flowing through the paint supply passage 72 toward the downstream side of the supply pump 90. It is preferable to use a gear pump as the supply pump 90, which can control the amount of paint supplied by controlling the rotation speed. However, a pump other than a gear pump may be used as the supply pump 90. The operation of the supply pump 90 is controlled by a control unit 100, which will be described later. Thereby, the operation of the supply pump 90 can be controlled to a predetermined pressure setting value.

[0050] A suction pump 91 is connected to the middle of the return flow passage 73. The suction pump 91 corresponds to the paint transfer means and the paint recovery means. The suction pump 91 is a means for applying negative pressure to the paint flowing through the return flow passage 73 on the upstream side of the suction pump 91. As with the above-mentioned supply pump 90, it is preferable to use a gear pump as the suction pump 91, which can control the amount of paint supplied by controlling the rotation speed. However, the suction pump 91 may be a pump other than a gear pump. The operation of the suction pump 91 is also controlled by the control unit 100, which will be described later. Thereby, the operation of the suction pump 91 can be controlled so that the downstream side is at a predetermined pressure setting value.

[0051] Further, in paint supply passage 72, AOPR 92 is disposed downstream of supply pump 90. AOPR 92 is a paint regulator for controlling (maintaining constant) the pressure of paint supplied from AOPR 92 in accordance with the input air pressure. That is, AOPR 92 is provided to control (maintain) the pressure of paint supplied from AOPR 92 at a predetermined ratio, for example, 1 / 20 to 2 times the input air pressure. In this way, AOPR 92 is controlled by air pressure and not electrically, and therefore can be used even in explosion-proof environments where it is difficult to use electrical equipment.

[0052] The opening degree of the AOPR 92 can be adjusted according to the control air pressure under the control of the control unit 100 described later. This makes it possible to control the pressure on the downstream side of the AOPR 92 to a predetermined pressure setting value in response to the pressure on the upstream side of the AOPR 92.

[0053] Further, a secondary proportional control valve 93 is disposed in the return flow path 73 upstream of the suction pump 91. The secondary proportional control valve 93 reduces pulsation in the suction pump 91 and sucks in paint at a constant pressure (negative pressure). This secondary proportional control valve 93 is also capable of adjusting its opening in response to the control air pressure and electric signals under the control of the control unit 100, which will be described later. As a result, the pressure upstream of the secondary proportional control valve 93 can be controlled to a predetermined pressure set value in response to the pressure downstream of the secondary proportional control valve 93.

[0054] In this embodiment, the AOPR 92 is disposed upstream of the paint head 53, and the paint supply pressure is controlled by this AOPR 92. Therefore, compared to a case where an electrically controlled proportional control valve is used instead of the AOPR 92, the secondary proportional control valve 93 can keep pressure fluctuations of the paint supplied low. This makes it easier to control the pressure of the secondary proportional control valve 93 based on the control unit 100.

[0055] Further, in the paint supply passage 72, a degassing module 94 is disposed downstream of the supply pump 90 and upstream of the AOPR 92. The degassing module 94 is disposed downstream of the paint supply passage 72 from a removal filter 95 (described later), and is a member for removing (degassing) dissolved gases dissolved in the paint.

[0056] Further, in the paint supply passage 72, a removal filter 95 is disposed upstream of the deaeration module 94 and downstream of the supply pump 90. The removal filter 95 removes foreign matter contained in the paint flowing through the paint supply passage 72. The removal filter 95 ensures that the paint head 53 can continue to operate normally by reliably removing coarse foreign matter and pigment aggregates from paint that contains, for example, pigment.

[0057] A removal filter similar to the above removal filter 95 may be additionally provided between the degassing module 94 and the AOPR 92. In this case, the additional removal filter corresponds to the pressure boosting mechanism, but a removal filter 95 different from the additional removal filter may correspond to the pressure boosting mechanism, or both the additional removal filter and the removal filter 95 may correspond to the pressure boosting mechanism. Also, a removal filter may be provided between the degassing module 94 and the AOPR 92 without providing the removal filter 95 upstream of the degassing module 94.

[0058] Furthermore, an orifice 96 corresponding to the pressure boosting mechanism is provided in the paint supply passage 72 downstream of the AOPR 92. This orifice 96 is a portion where the inner diameter of the paint supply passage 72 is narrower (smaller) than other portions of the paint supply passage 72, and has a predetermined length. However, the orifice 96 may be configured to have a short length, for example, by providing an orifice plate.

[0059] Also, various types of orifices can be used as the orifice 96. For example, the orifice 96 may be of a type in which the inner diameter of the central portion of the paint supply passage 72 is narrowed by a predetermined length as shown in Fig. 8. In this case, the orifice 96 may be of a type in which the inner diameter of the central portion of the paint supply passage 72 is narrowed by a predetermined length L that is sufficiently longer than the configuration shown in Fig. 8 as shown in Fig. 9. The orifice 96 may also be of a type that is composed of a plurality of small diameter holes as shown in Fig. 10. The orifice 96 may also be a variable orifice whose opening area varies under air pressure control or electrical control.

[0060] One example of the dimensions of the paint supply passage 72 and orifice 96 is that, when the inner diameter of the paint supply passage 72 other than the orifice 96 is 2.5 to 8 mm, the inner diameter of the orifice 96 is 0.1 to 5 mm and the length of the orifice 96 is 0.1 to 5 mm. However, other than these dimensions, any appropriate dimensions can be adopted.

[0061] Due to the presence of the orifice 96, pressure loss occurs due to the viscosity of the paint upstream of the orifice 96 in the paint supply passage 72. This causes a pressure rise in the AOPR 92. Here, the minimum pressure value of the operable pressure range of the AOPR 92 is higher than that of an electrically controlled proportional control valve. Also, the AOPR 92 has the characteristic that pressure adjustment (pressure control) is possible with a smaller error on the side where the input air pressure is high compared to the side where the air pressure is low.

[0062] As an example of the control of the AOPR 92, which has been confirmed through experiments, etc., when paint is to be supplied at a predetermined flow rate, if there is no orifice 96 in the paint supply passage 72, the air pressure that needs to be input to the AOPR 92 is 5 KPa. In this case, if the air pressure that needs to be input varies by ±1 KPa from 5 KPa, the pressure will vary by approximately 20%. On the other hand, if a predetermined orifice 96 is provided in the paint supply passage 72, the air pressure that needs to be input to the AOPR 92 is 17 KPa. In this case, even if the air pressure that needs to be input varies by ±1 KPa from 17 KPa, the pressure variation will be approximately 5.9%, making it possible to reduce the effect of the pressure variation.

[0063] As another example of control of the AOPR 92, one confirmed by experiment etc. is that when paint is at a predetermined flow rate, if there is no orifice 96 in the paint supply passage 72, the air pressure that needs to be input to the AOPR 92 is 15 KPa. In this case, if the air pressure that needs to be input varies by ±1 KPa from 15 KPa, the pressure will vary by approximately 6.7%. On the other hand, if a predetermined orifice 96 is provided in the paint supply passage 72, the air pressure that needs to be input to the AOPR 92 is 39 KPa. In this case, even if the air pressure that needs to be input varies by ±1 KPa from 39 KPa, the pressure variation will be approximately 2.6%, making it possible to reduce the effect of the pressure variation.

[0064] Next, the pressure sensors S1 to S8 and the flow meters FM1, FM2 will be described. In the paint supply path 72, a pressure sensor S1 is disposed upstream of the supply pump 90. In addition, in the paint supply path 72, a pressure sensor S2 is disposed downstream of the supply pump 90 and upstream of the removal filter 95. The pressure sensor S1 measures the supply pressure of the paint to the supply pump 90 and transmits the measurement result to the control unit 100. In addition, the pressure sensor S2 measures the pressure of the paint discharged from the supply pump 90 and transmits the measurement result to the control unit 100.

[0065] In this way, by measuring the paint pressure upstream and downstream of the supply pump 90 using the pressure sensors S1 and S2, it is possible to accurately measure the estimated pressure of the supply pump 90. The estimated pressure of the supply pump 90 may be the average value of the pressure value of the pressure sensor S1 and the pressure sensor S2, or it may be the pressure value of either one of them. The estimated pressure is used to calculate the head pressure and the head pressure difference.

[0066] Further, a vacuum pump 98 is connected to the above-mentioned degassing module 94 via a suction pipe 97. As described above, the vacuum pump 98 is a device for reducing the pressure inside the housing (inside the hollow fiber membrane) of the degassing module 94. This reduction in pressure removes (degasses) dissolved gas dissolved in the paint supplied inside the housing.

[0067] Moreover, the pressure sensor S3 measures the pressure in the suction line 97 between the vacuum pump 98 and the degassing module 94.

[0068] A first flow meter FM1 is disposed in the paint supply passage 72 downstream of the degassing module 94 and upstream of the AOPR 92. The first flow meter FM1 measures the flow rate of paint fed to the AOPR 92 and transmits the measurement result to the control unit 100. This first flow meter FM1 is a non-contact type flow meter that has no moving parts, such as an ultrasonic type, optical type, electromagnetic type, or thermal type, and therefore the first flow meter FM1 is disposed outside the paint supply passage 72. The first flow meter FM1 may be a flow meter that has moving parts.

[0069] Here, if the first flow meter FM1 is an optical type, at least the portion of the paint supply passage 72 where the flow rate is measured by the first flow meter FM1 is provided to be transparent. However, if the first flow meter FM1 is an ultrasonic type other than the optical type, at least the portion of the paint supply passage 72 where the flow rate is measured by the first flow meter FM1 does not need to be provided to be transparent.

[0070] Furthermore, a pressure sensor S4 is disposed in paint supply passage 72 downstream of first flow meter FM1 and upstream of AOPR 92. Furthermore, a pressure sensor S5 is disposed in paint supply passage 72 downstream of AOPR 92 and upstream of three-way valve 77 and orifice 96. Pressure sensor S4 measures the supply pressure of paint to AOPR 92 and transmits the measurement result to control unit 100. Furthermore, pressure sensor S5 measures the pressure of paint discharged from AOPR 92 and transmits the measurement result to control unit 100.

[0071] In this way, it is possible to accurately measure the estimated pressure of the AOPR 92 by using the pressure sensors S4 and S5 to measure the paint pressure on the upstream and downstream sides of the AOPR 92. The estimated pressure of the AOPR 92 may be the average value of the pressure value of the pressure sensor S4 and the pressure sensor S5, or it may be the pressure value of either one of them.

[0072] It is preferable that the paint supply mechanism 70 is provided with the pressure sensor S4, but a configuration in which the pressure sensor S4 is omitted may be adopted. The pressure sensor S4 may be provided on the paint head unit 50 side, or on the second rotating arm 25 side (robot arm R1 side). The pressure sensor S4 may be provided upstream of the first flow meter FM1.

[0073] In addition, a pressure sensor S6 is disposed in the return flow path 73 downstream of the three-way valve 79 and upstream of the secondary proportional control valve 93. In addition, in the return flow path 73, a pressure sensor S7 is disposed further downstream of a flow meter FM2 (described later) downstream of the secondary proportional control valve 93. The pressure sensor S6 measures the supply pressure of paint to the secondary proportional control valve 93 and transmits the measurement result to the control unit 100. In addition, the pressure sensor S7 measures the pressure of the paint discharged from the secondary proportional control valve 93 (i.e., the supply pressure of paint to the suction pump 91) and transmits the measurement result to the control unit 100.

[0074] In this way, by using the pressure sensors S6 and S7 to measure the paint pressure upstream and downstream of the secondary proportional control valve 93, it is possible to accurately measure the estimated pressure of the secondary proportional control valve 93. The estimated pressure of the secondary proportional control valve 93 may be the average value of the pressure value of the pressure sensor S6 and the pressure value of the pressure sensor S7, or it may be the pressure value of either one of them.

[0075] It should be noted that a pressure sensor may be disposed in the return flow passage 73 downstream of the secondary proportional control valve 93 and upstream of the flow meter FM2.

[0076] A second flow meter FM2 is disposed in the return flow passage 73 downstream of the secondary proportional control valve 93. The second flow meter FM2 measures the flow rate of the paint fed to the suction pump 91 and transmits the measurement result to the control unit 100. Like the above-mentioned first flow meter FM1, this second flow meter FM2 is also a non-contact type flow meter that has no moving parts, such as an ultrasonic type, optical type, electromagnetic type, or thermal type, and therefore a detailed description thereof will be omitted. Note that the second flow meter FM2 may also be a flow meter that has moving parts.

[0077] In addition, a pressure sensor S8 is disposed in the return flow path 73 downstream of the suction pump 91 and upstream of the switching valve 80. The pressure sensor S8 measures the pressure of the paint discharged from the suction pump 91 and transmits the measurement result to the control unit 100.

[0078] In this way, by using pressure sensors S7 and S8 to measure the paint pressure upstream and downstream of the suction pump 91, it is possible to accurately measure the estimated pressure of the suction pump 91. The estimated pressure of the suction pump 91 may be the average value of the pressure value of the pressure sensor S7 and the pressure sensor S8, or it may be the pressure value of either one of them.

[0079] (1-8. Schematic configuration of the control unit)

[0080] Next, a schematic configuration of the control unit 100 for controlling the operation of the painting robot 10 will be described. Fig. 11 is a diagram showing a schematic control configuration centered on the control unit 100 of the painting robot 10. As shown in Fig. 11, the control unit 100 mainly includes a main control unit 110, an arm control unit 120, a head control unit 130, a paint supply control unit 140, a control memory 150, a position sensor 300, and an inclination sensor 310. The painting robot 10 is connected to an image processing device 200 to form a painting robot system.

[0081] The main control unit 110, arm control unit 120, head control unit 130, paint supply control unit 140, and image processing unit 210 described later are composed of a CPU (Central Processing Unit), memory 220 such as a storage unit (ROM (Read Only Memory), RAM (Random Access Memory), non-volatile memory, etc.), and other elements. The image processing unit 210 may use a GPU (Graphics Processing Unit) together with a CPU with excellent image processing performance, or instead of the CPU.

[0082] Of the above control configurations, the main control unit 110 is a part that transmits predetermined control signals to the arm control unit 120, head control unit 130 and paint supply control unit 140 described above so that each motor (first to sixth motors) of the robot arm R1, each operating unit of the paint supply mechanism 70, and the piezoelectric substrate 62 work together to paint the object to be painted.

[0083] The arm control unit 120 is a unit that controls the driving of each motor (first to sixth motors) of the robot arm R1 described above. The arm control unit 120 includes an arm memory 121, which stores data on the trajectory of the paint head 53 (trajectory data) and posture data on the posture of the paint head 53, such as the inclination, that are created by robot teaching in consideration of the paint width that can be painted by the paint head 53.

[0084] The arm control unit 120 controls the driving of each motor (first to sixth motors) of the robot arm R1 based on the trajectory data and posture data stored in the arm memory 121 and image processing by the image processing unit 210 described later. This control allows the painting head 53 to pass a desired position for painting at a desired speed and to stop at a predetermined position. The arm memory 121 may be provided in the painting robot 10, but it may also be possible for the arm memory 121 to exist outside the painting robot 10 and for information to be sent and received to the arm memory 121 via wired or wireless communication means.

[0085] The head control unit 130 is a part that controls the operation of the piezoelectric substrate 62 in the paint head unit 50 based on image processing by the image processing device 200. When the head control unit 130 reaches a predetermined position in the trajectory data using means for detecting the position, such as a position sensor 300 and an inclination sensor 310 described below, it controls the discharge of paint based on the divided paint data corresponding to that position. In this case, the drive frequency of the piezoelectric substrate 62 is controlled to control the number of dots (number of droplets) discharged from the nozzle 54, and the voltage applied to the piezoelectric substrate 62 is controlled to control the size of the droplets discharged from the nozzle 54, so that the film thickness on the vehicle is uniform.

[0086] The paint supply control unit 140 is a part that controls the supply of paint to the painting head 53, and specifically controls the operation of each operating part in the paint supply mechanism 70, such as the supply pump 90, suction pump 91, AOPR 92, secondary proportional control valve 93, vacuum pump 98, three-way valves 77, 79, on-off valve 78, and changeover valve 80. At this time, it is preferable that the paint supply control unit 140 controls the operation of the operating parts such as the pumps and valves so that paint is supplied to the painting head 53 at a constant pressure. However, the paint supply control unit 140 may be capable of controlling the operation of the operating parts such as the pumps and valves so that paint is supplied to the painting head 53 at a constant flow rate.

[0087] Here, the paint supply control unit 140 is capable of accessing the control memory 150, and by such access, it is possible to read out an appropriate pressure setting value stored in the control memory 150.

[0088] Moreover, the position sensor 300 is a sensor that detects the current position of the paint head 53. As the position sensor 300, various sensors such as a rotary encoder, a resolver, a laser sensor, etc. can be used. Furthermore, the tilt sensor 310 is a sensor that detects the tilt angle of the paint head 53, and corresponds to the angle detection means. As the tilt sensor 310, various sensors such as a gyro sensor, an acceleration sensor, an inclination sensor, etc. can be used.

[0089] (2. About the Experimental Results) The experimental results for the case where the orifice 96 is provided in the paint supply passage 72 as described above will be described with reference to FIG.

[0090] Fig. 12 is a diagram showing the experimental results of the relationship between the flow rate and the pressure loss when the inner diameter of the orifice 96 is 0.75 mm, 1.0 mm, and 1.2 mm. In Fig. 12, for example, when the flow rate of the paint supply passage 72 is 50 cc / min, the pressure loss is 10 KPa in the first experiment and 11 KPa in the second experiment when the inner diameter of the orifice 96 is 0.75 mm. Moreover, under the same conditions, when the inner diameter of the orifice 96 is 1.0 mm, the result of the first experiment is 3 KPa and the result of the second experiment is 2 KPa. Moreover, under the same conditions, when the inner diameter of the orifice 96 is 1.2 mm, the result of the first experiment is 2 KPa and the result of the second experiment is 2 KPa.

[0091] When the inner diameter of the orifice 96 is 0.75 mm, the pressure loss at the flow rate of the paint supply passage 72 is 27 KPa in the first experiment and 27 KPa in the second experiment. When the inner diameter of the orifice 96 is 1.0 mm under the same conditions, the pressure loss is 10 KPa in the first experiment and 9 KPa in the second experiment. When the inner diameter of the orifice 96 is 1.2 mm under the same conditions, the pressure loss is 5 KPa in the first experiment and 6 KPa in the second experiment.

[0092] When the inner diameter of the orifice 96 was 0.75 mm, the pressure loss at the flow rate of the paint supply passage 72 was 48 KPa in the first experiment and 48 KPa in the second experiment. When the inner diameter of the orifice 96 was 1.0 mm under the same conditions, the pressure loss was 17 KPa in the first experiment and 17 KPa in the second experiment. When the inner diameter of the orifice 96 was 1.2 mm under the same conditions, the pressure loss was 9 KPa in the first experiment and 9 KPa in the second experiment.

[0093] (3. About the effects) The painting robot 10 configured as described above comprises a painting head unit 50 having a plurality of nozzles 54 that eject droplets, a painting head 53 having a piezoelectric substrate 62 that is driven to push the droplets out of the nozzles 54, a robot arm R1 having the painting head unit 50 attached to its tip and moving the painting head unit 50 to a desired position, and a paint supply mechanism 70 provided between the robot arm R1 and the painting head unit 50. The paint supply mechanism 70 includes a paint supply passage 72 that supplies paint toward the paint head 53, a return flow passage 73 that is connected to the paint discharge side of the paint head 53 and collects paint that has not been ejected from the nozzle 54, an AOPR 92 (air pressure control valve) that is provided in the paint supply passage 72 and can adjust the valve opening degree according to the controlled air pressure, and an orifice 96 (pressure boost mechanism) that is provided in the paint supply passage 72 downstream toward the paint head 53 from the AOPR 92 (air pressure control valve) or upstream of the AOPR 92 (air pressure control valve) and increases the pressure of the paint supplied to the AOPR 92 (air pressure control valve).

[0094] With this configuration, the paint flowing through the paint supply passage 72 can experience a large pressure loss when it flows through the orifice 96 (pressure boosting mechanism). Therefore, the paint supply pressure can be increased upstream of the orifice 96 (pressure boosting mechanism) in the paint supply passage 72. This makes it possible to reduce the ratio of pressure fluctuation to the pressure value input to the paint upstream of the orifice 96 (pressure boosting mechanism).

[0095] That is, without the orifice 96 (pressure boosting mechanism), even a slight fluctuation in pressure would change the paint flow rate, which could result in a decrease in coating quality due to variations in the amount of paint discharged from the nozzle 54. However, as described above, the presence of the orifice 96 (pressure boosting mechanism) makes it possible to converge the pressure fluctuations within a range that does not affect coating quality, even if some pressure fluctuations occur upstream of the orifice 96 (pressure boosting mechanism) in the paint supply passage 72, and as a result, coating quality can be improved.

[0096] Furthermore, since the paint supply pressure can be increased upstream of the orifice 96 (pressure boosting mechanism) in the paint supply passage 72, it is possible to use the AOPR 92 (pneumatic valve) which has a higher operable pressure range than a proportional control valve, which is an electrical device. This eliminates the need to use a proportional control valve, which is an electrical device. This allows the painting robot 10 to be configured in a manner suitable for an explosion-proof environment.

[0097] In addition, by using the AOPR92 (pneumatic valve), it is possible to widen the operable pressure range for the pressure set by the user, compared to the case where a proportional control valve, which is an electrical device, is used.

[0098] In this embodiment, the return flow path 73 is provided with a secondary proportional control valve 93 (electrically operated valve) whose valve opening can be adjusted by electrical operation. When configured in this manner, the AOPR 92 (air pressure control valve) is disposed upstream of the secondary proportional control valve 93 (electrically operated valve) in the paint circulation path 71. This makes it possible to stabilize the pressure on the input side (upstream side; primary side) of the secondary proportional control valve 93 (electrically operated valve), thereby facilitating pressure control on the output side (downstream side; secondary side) of the secondary proportional control valve 93 (electrically operated valve).

[0099] In this embodiment, the pressure boosting mechanism is an orifice 96 in which the inner diameter of the paint supply passage 72 is narrowed, and the orifice 96 may be composed of a single hole as shown in FIG. 8 or FIG. 9, or may be composed of multiple holes as shown in FIG. 10. In this configuration, when the paint passes through the orifice 96, it passes through a single hole or multiple holes. Therefore, it is possible to apply shear stress to the paint during the passage, and it is possible to reduce the viscosity of the paint. Therefore, the paint after passing through the orifice 96 can be discharged from the nozzle 54 with good results, and the fluidity of the paint that has not been discharged from the nozzle 54 can be increased when it is returned through the return passage 73.

[0100] In this embodiment, the pressure boosting mechanism can be a removal filter that removes foreign matter contained in the paint flowing through the paint supply passage 72. When configured in this manner, the paint passes through a number of holes in the removal filter. As a result, shear stress can be applied to the paint as it passes through, making it possible to reduce the viscosity of the paint. As a result, the paint that has passed through the removal filter can be smoothly ejected from the nozzle 54, and the fluidity of the paint that has not been ejected from the nozzle 54 can be increased when it is returned through the return passage 73.

[0101] In addition, in this embodiment, the paint supply mechanism 70 is provided with a bypass flow path 74 that connects the paint supply path 72 and the return flow path 73 and circulates paint in parallel with the painting head 53, and the orifice 96 (pressure boosting mechanism) is provided upstream of the bypass flow path 74 in the paint supply path 72.

[0102] When configured in this manner, the orifice 96 (pressure boosting mechanism) is provided upstream of the bypass flow path 74 in the paint supply path 72, so that paint not ejected from the paint head 53 also passes through the orifice 96 (pressure boosting mechanism). This makes it possible to reduce the viscosity of the paint as it passes through the orifice 96 (pressure boosting mechanism). Therefore, by circulating the paint not ejected from the paint head 53 via the bypass flow path 74 and passing through the orifice 96 (pressure boosting mechanism), it becomes possible to satisfactorily reduce the viscosity of the paint.

[0103] In this embodiment, the orifice 96 can be configured to adjust the opening of the flow path through which the paint flows. In such a configuration, the orifice 96 can adjust the opening of the flow path, so that when cleaning the paint supply path 72, etc., the opening of the orifice 96 can be increased to improve cleaning performance. Also, by adjusting the opening of the orifice 96, it is possible to adjust the operability of the AOPR 92 (air pressure control valve) to a good range.

[0104] (4. Modifications) Although one embodiment of the present invention has been described above, the present invention can be modified in various ways in addition to the above embodiment. Modifications will be described below.

[0105] In the above-described embodiment, a configuration including pressure sensors S1 to S8, a first flow meter FM1, and a second flow meter FM2 is adopted. However, when the first flow meter FM1 and the second flow meter FM2 are provided, at least one of the pressure sensors S1 to S8 may be omitted, and when the pressure sensors S1 to S8 are provided, at least one of the first flow meter FM1 and the second flow meter FM2 may be omitted.

[0106] In the embodiment described above, the orifice 96 is provided in the paint supply passage 72 upstream of the three-way valve 77. However, the orifice 96 may be provided in the paint supply passage 72 downstream of the three-way valve 77 and upstream of the paint head 53.

[0107] In the above embodiment, the orifice 96 is provided downstream of the AOPR 92 in the paint supply passage 72. However, if the pressure range of the AOPR 92 is not significantly higher than that of the secondary proportional control valve 93 or if there is a portion other than the orifice 96 that causes pressure loss, a configuration in which the orifice 96 is omitted may be adopted. [Explanation of symbols]

[0108] 10...painting robot, 20...robot body, 21...base, 22a...first rotating shaft, 22b...second rotating shaft, 22c...third rotating shaft, 22d...fourth rotating shaft, 22e...fifth rotating shaft, 22f...sixth rotating shaft, 24...first rotating arm, 25...second rotating arm, 26...rotating arm, 27...wrist portion, 50...painting head unit, 52...nozzle forming surface, 53...painting head, 54...nozzle, 55...nozzle row, 55A...first nozzle row, 55B...second nozzle row, 57...supply side large flow path, 58...row-direction supply flow path, 59...nozzle pressurizing chamber, 59a...nozzle supply flow path, 59b...nozzle discharge flow path, 60...row-direction discharge flow path, 61...discharge side large flow path, 62...piezoelectric substrate, 63a...piezoelectric ceramic layer, 63b...piezoelectric ceramic layer, 64...common electrode, 65...individual electrode, 70...paint supply mechanism, 71...paint circulation path, 72...paint supply path, 73...return flow path, 74...bypass flow path, 75...External supply path, 76...Air bubble removal member, 77...Three-way valve, 78...Opening and closing valve, 79...Three-way valve, 80...Switching valve, 81...Drain path, 90...Supply pump (corresponding to paint supply means), 91...Suction pump (corresponding to paint recovery means), 92...AOPR (corresponding to air pressure control valve), 93...Secondary proportional control valve (corresponding to electrically operated valve), 94...Degassing module, 95...Removal filter, 96...Orifice (corresponding to pressure boosting mechanism), 97...Suction line, 9 8...vacuum pump, 100...control unit, 110...main control unit, 120...arm control unit, 121...arm memory, 130...head control unit, 140...paint supply control unit, 150...control memory, 200...image processing device, 210...image processing unit, 220...memory, 300...position sensor, 310...tilt sensor (corresponding to angle detection means), FM1...first flow meter, FM2...second flow meter, R1...robot arm, S1 to S8...pressure sensors

Claims

1. A painting robot for painting a vehicle, a coating head unit including a coating head having a plurality of nozzles for ejecting droplets and a piezoelectric substrate for driving the coating head to push out the droplets from the nozzles; a robot arm having a tip end to which the painting head unit is attached and which moves the painting head unit to a desired position; a paint supply mechanism provided between the robot arm and the paint head unit, The paint supply mechanism includes: A paint supply passage for supplying paint toward the painting head; a return flow passage connected to a paint discharge side of the painting head and configured to recover the paint that has not been discharged from the nozzle; an air pressure control valve provided in the paint supply passage and capable of adjusting a valve opening degree in response to the controlled air pressure; a pressure boosting mechanism that is provided in the paint supply passage downstream of the air pressure control valve toward the paint head or upstream of the air pressure control valve and that increases the pressure of the paint supplied to the air pressure control valve; A painting robot comprising:

2. The painting robot according to claim 1, The return flow path is provided with an electrically operated valve whose valve opening degree can be adjusted by electrical operation. A painting robot characterized by the above.

3. The painting robot according to claim 1, The pressure boosting mechanism is an orifice having a narrowed inner diameter in the paint supply passage, The orifice is composed of a single hole or multiple holes. A painting robot characterized by the above.

4. The painting robot according to claim 1, The pressure boosting mechanism is a removal filter that removes foreign matter contained in the paint flowing through the paint supply passage. A painting robot characterized by the above.

5. The painting robot according to claim 1, the paint supply mechanism is provided with a bypass flow path that connects the paint supply path and the return flow path and that allows the paint to flow in parallel with the paint head, The pressure boosting mechanism is provided upstream of the paint supply passage from the bypass passage. A painting robot characterized by the above.

6. 4. The painting robot according to claim 3, The orifice is capable of adjusting the opening degree of a flow path through which the paint flows. A painting robot characterized by the above.

Images