TWI821827B - Electrostatic coating spray gun - Google Patents

Abstract

The electrostatic coating spray gun of the present invention is equipped with: a spray gun body (10); a nozzle (15A), which is located at the front end of the spray gun body (10); a pin-shaped discharge electrode (15D), which is used to cause the spray gun to flow from the nozzle (15A). ) is charged by the sprayed paint; and at least one electrode pin (61) causes an electric field to be generated between the discharge electrode (15D).

Description

Electrostatic coating spray gun

The present invention relates to electrostatic coating spray guns.

The electrostatic coating device disclosed in Patent Document 1 is equipped with: a nozzle that sprays paint toward a coating object connected to the ground; a corona electrode that charges the paint sprayed from the nozzle; and conductive electricity. ring, which generates an electric field between it and the corona electrode. The conductive ring system enables the electric field intensity of the corona electrode to be increased compared to the case without conductive rings. When the electric field intensity near the corona electrode is increased, a large amount of atmospheric ions can be generated to generate a large amount of charged paint. [Prior technical literature] [Patent Document]

Patent document 1: Japanese Patent Application Publication No. 2015-166073

(The problem that the invention wants to solve)

However, the above-mentioned electrostatic coating device is in the shape of a pin relative to the corona electrode, while the conductive ring is in the shape of a ring. Therefore, it is difficult to stabilize the electric field generated between the corona electrode and the conductive ring. As a result, there is a problem that it is difficult to obtain a stable electrostatic effect.

The present invention was completed based on the above-mentioned circumstances, and its object is to stabilize the electrostatic effect. (Technical means to solve problems)

The electrostatic coating spray gun of the present invention has: Spray gun body; A nozzle located at the front end of the above-mentioned spray gun body; Pin-shaped discharge electrodes used to charge the paint sprayed from the above-mentioned nozzles; and At least one electrode pin generates an electric field between the discharge electrode and the electrode pin. (Compare the effectiveness of previous technologies)

The electrostatic coating spray gun of the present invention generates an electric field between the pin-shaped discharge electrode and the electrode pin, thereby stabilizing the electric field. As a result, the electrostatic effect can be stabilized. This can reduce uneven coating.

The above-mentioned electrostatic coating spray gun preferably has an electric field control member installed on the above-mentioned spray gun body. The electric field control member preferably includes the electrode pin and a holding member that holds the electrode pin. According to this structure, it is not necessary to provide a structure for holding the electrode pin in the spray gun body, and the structure of the spray gun body can be simplified.

The electric field control member preferably has a resistance element provided on a path between the electrode pin and the ground terminal, and the resistance element is held by the holding member. According to this structure, compared with a structure without a resistive element, the output current of the discharge electrode becomes lower and the electric field intensity to the object to be painted is increased, so that the efficiency of coating the object to be coated with the charged paint can be improved. Furthermore, since the resistive element is held by the holding member and integrated as an electric field control member, the output current of the discharge electrode can be adjusted by attaching the electric field control member after adjusting the number or type of the resistive element to the spray gun body. .

The electric field control member preferably has a synthetic resin injection molded portion formed integrally with the holding member, and the resistive element is embedded in the injection molded portion. According to this structure, the insulation of the resistance element can be ensured.

Preferably, the outside of the spray gun body is provided with a variable resistor disposed on a path between the resistive element and the ground terminal. According to this structure, the output current of the discharge electrode can be adjusted not only by the resistance element but also by the variable resistor.

The electric field control member preferably has a synthetic resin injection-molded portion formed integrally with the holding member, and an electrode unit including the electrode pin is embedded in the injection-molded portion in a portion excluding the front end portion of the electrode pin. At least part of it. The "embedded" form includes: a form that is buried inside the injection molded part without exposing the outer surface of the injection molded part; and a form that is exposed from the outer surface of the injection molded part but does not protrude from the outer surface of the injection molded part. According to this configuration, at least part of the portion of the electrode pin excluding the front end portion of the electrode unit is embedded in the injection molded portion. In the injection molding step, since the synthetic resin material is in close contact with the electrode unit due to the injection pressure, no gap is generated between the injection molded part and the electrode unit. Thereby, when performing electrostatic coating, it is possible to prevent ground faults in parts of the electrode unit other than the electrode pins.

The holding member preferably covers only a portion of the outer peripheral surface of the spray gun body in the circumferential direction. According to this structure, compared with the form in which the holding member covers the entire outer circumferential surface of the spray gun body, the operability is improved due to the smaller size and lighter weight, and the material cost can be reduced.

The holding member preferably has an electrode holding portion for holding the electrode pin. According to this structure, in the injection molding step, it is possible to prevent the electrode pin from being displaced due to injection pressure.

The electrode unit preferably includes a resistance element, and the holding member is formed with a resistance holding portion for holding the resistance element in a positioned state. According to this structure, in the injection molding step, it is possible to prevent the resistor element from being displaced due to injection pressure.

Preferably, the electrode unit includes a grounding member connectable to a grounding elastic connection member provided on the spray gun body, and is provided on an outer surface of the injection molded portion to surround the exposure of the grounding member on an outer surface of the injection molded portion. Part of the sealing portion is integrally formed, and the sealing portion is in liquid-tight contact with the spray gun body. According to this structure, even if a sealing member separate from the injection molding part is not provided, it is possible to prevent the connection part between the elastic connection member and the grounding member from being covered with water.

The holding member preferably has a locking portion that is swingably fitted to the spray gun body, and a fixing portion that is fixed to the spray gun body by a fastening member. According to this structure, compared with the case where the holding member is attached to the spray gun body using a plurality of fastening members, the fixing part fixed by the fastening member can be made into only one location. Thereby, the workability when mounting the holding member to the spray gun body can be improved.

Preferably, the spray gun body is provided with an elastic connection member for grounding, and the holding member is provided with a grounding member connected to the elastic connection member in a state where the holding member is installed on the spray gun body. The grounding member is as follows: It is preferable to form a contact surface with which the elastic connecting member contacts the elastic connecting member in an elastically deformed state. According to this configuration, the elastic connecting member can be brought into contact with the grounding member simply by elastically deforming it while contacting the contact surface, so the workability is good.

The outer surface of the holding member is preferably formed with a continuous surface that is continuous with the outer peripheral surface of the spray gun body at an obtuse angle. According to this structure, it is difficult for paint to remain at the interface between the outer peripheral surface of the spray gun body and the outer surface of the holding member, and even if the paint remains at the interface between the outer peripheral surface of the spray gun body and the outer surface of the holding member, the paint can be easily removed Remove.

<Example 1> Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 16 . In addition, in the following description, regarding the front-to-back direction, the left side of FIGS. 1, 2, 4, 7, and 12 is defined as the front. Regarding the up and down directions, the directions shown in Figures 1, 3 to 6, 8, 9, 11, 13 to 15 are directly defined as upper and lower.

The electrostatic coating spray gun of Embodiment 1 is used when powder coating is used for electrostatic coating, that is, it is applied to a hand-held spray gun for operators to hold for painting. As shown in FIGS. 1 to 4 , the electrostatic coating spray gun is composed of a spray gun body 10 and an electric field control member 30 assembled. The spray gun body 10 has a longitudinally long handle 11 for the operator to hold, and a gun body 12 that is continuous with the upper end of the handle 11 and extends in the front-rear direction. The handle 11 is provided with a trigger 13 .

As shown in FIG. 4 , a high voltage generator 14 for generating high voltage is housed inside the gun body 12 . The high voltage generator 14 converts the AC voltage input from the side of the power supply 90 (see FIG. 16 ) into a high voltage DC voltage and outputs the converted AC voltage. The high voltage generator 14 has a transformer, a boost circuit, and an output resistor. The boost circuit is composed of, for example, a Kirkclough-Wharton type boost rectifier circuit. The boost circuit boosts and rectifies the AC voltage input from the transformer and converts it into a high DC voltage. The output side of the boost circuit is connected to the output resistor through a metal wire, for example.

As shown in FIG. 4 , a nozzle 15A, a nozzle cover 15B, a cover nut 15C, and a discharge electrode 15D are provided at the front end of the gun body 12 . The nozzle 15A sprays the paint supplied to the spray gun body 10 to the outside. The nozzle cover 15B is connected to the gun body 12 via the cover nut 15C, and covers the periphery of the front end side of the nozzle 15A. The discharge electrode 15D is made of metal, for example, and has a pin shape. Pin shape also includes needle shape. The output resistor of the high voltage generator 14 is connected to the discharge electrode 15D. The high voltage output from the high voltage generator 14 is applied to it, and a corona discharge is generated at the front end of the discharge electrode 15D, thereby generating the same high voltage as the applied one. Ions of the same polarity. The ions generated near the discharge electrode 15D charge the paint sprayed from the nozzle 15A.

As shown in FIG. 4 , a mounting portion 16 for mounting the electric field control member 30 is provided on the outer peripheral surface of the gun body 12 . The mounting portion 16 is disposed at the front-to-rear center portion of the lower surface side area of the gun body 12 . The front end side portion of the mounting portion 16 is a left-right symmetrical mounting recess 17 formed by recessing the half-circumferential area of the lower surface of the gun body 12 . The front end of the inner surface of the mounting recess 17 of the mounting portion 16 (mounting recess 17) in the outer circumferential surface of the gun body 12 functions as a stopper 18 that is perpendicular to the lower surface (outer circumferential surface) of the gun body 12. A laterally longer slit-shaped locking hole 19 is formed at the center portion of the stopper 18 in the circumferential direction (the lowermost end of the stopper 18 ). A female screw hole 20 with the axis facing up and down is formed at the rear end of the mounting portion 16 . The axis direction of the female screw hole 20 is perpendicular to the opening direction of the blocking hole 19 of the stopper 18 .

A square opening 21 is formed in the center of the mounting portion 16 in the front-rear direction (between the locking hole 19 and the female screw hole 20) to communicate the inside and outside of the gun body 12 (see FIG. 15). The opening portion 21 is opened in a region to the right of the center portion of the gun body 12 and the mounting portion 16 in the left-right direction. As shown in FIG. 15 , the elastic connecting member 22 provided in the gun body 12 is exposed in the opening 21 . The elastic connection member 22 is composed of a compression coil spring with its axis directed in the up and down direction. The elastic connection member 22 is connected to the ground portion (not shown) at the rear end of the spray gun body 10 (gun body 12) via the crimp terminal 23 and the electric wire 24. The grounding portion is made of a conductive resin material and is grounded via a grounding conductive path (not shown) in the handle 11 . The square area surrounding the opening 21 on the lower surface of the mounting portion 16 functions as a sealing surface 25 .

The electric field control member 30 integrates the housing 31 and the electrode unit 60 . The housing 31 is composed of a synthetic resin holding member 32 and an injection molded portion 55 that is integrated with the holding member 32 as a molded component by injection molding. As shown in FIGS. 7 to 9 , the holding member 32 has a curved portion 33 and a dish-shaped portion 40 protruding rearward from the curved portion 33 , and is formed as a single part. The holding member 32 is made of a synthetic resin material with high heat resistance.

When the holding member 32 is viewed from the front, the curved portion 33 has an arc shape that expands downward. When viewed from the front, the outer circumferential surface of the curved portion 33 is in a semicircular arc shape. The curvature radius of the outer circumferential surface of the curved portion 33 is slightly larger than the curvature radius of the front adjacent area 26 (see FIGS. 1 and 4 ) adjacent to the front end of the mounting portion 16 in the outer circumferential surface of the gun body 12 . A locking portion 34 protruding forward in a plate shape is formed at the lower end of the front surface of the curved portion 33 (the central portion of the curved portion 33 in the circumferential direction).

As shown in FIG. 8 , a box portion 35 is formed in the bent portion 33 . The box portion 35 is composed of a pair of left-right symmetrical side plate portions 36 standing upward from the inner peripheral surface of the curved portion 33, and a horizontal upper plate portion 37 connecting the upper end edges of the two side plate portions 36. The inside of the box portion 35 is opened at both front and rear end surfaces.

A pair of left-right symmetrical electrode holding portions 38 are formed at both ends of the curved portion 33 in the circumferential direction. The electrode holding portion 38 has a shape that protrudes radially outward (left-right direction) and extends in a rib-like shape along the front-rear direction. Electrode holding holes 39 are formed in the left and right electrode holding portions 38 so as to penetrate the electrode holding portions 38 in the front-rear direction. The spacing in the left-right direction between the left-right symmetrical pair of electrode holding holes 39 is larger than the diameter of the adjacent area 26 in the front of the gun body 12 .

When the holding member 32 is viewed from above, the dish-shaped portion 40 has a left-right symmetrical shape and a shovel shape with a sharp rear end. The maximum width dimension (dimension in the left-right direction) of the dish-shaped portion 40 is smaller than the width dimension of the curved portion 33 . As shown in FIG. 1 , the outer surface of the dish-shaped portion 40 is composed of a horizontal lower surface portion 41 , a pair of left-right and left-right symmetrical side continuous surfaces 42 , and a rear continuous surface 43 . The lower surface portion 41 is composed of a flat surface. constituted. When the back view of the holding member 32 is viewed from behind, the side continuous surfaces 42 extend obliquely upward and outward from both left and right edges of the lower surface portion 41 .

When the holding member 32 is viewed from the side, the rear continuous surface 43 is composed of a curved surface with a small curvature, and extends obliquely upward and rearward from the rear end of the lower surface portion 41 . The rear continuous surface 43 is connected to the rear edge of the lower surface portion 41 and the left and right side continuous surfaces 42 . When the holding member 32 is viewed from below, the rear continuous surface 43 (the rear end region of the dish-shaped portion 40 ) has a shape in which the width gradually becomes narrower toward the rear end.

A receiving recess 44 is formed at the front end of the dish-shaped portion 40 so that the upper surface of the dish-shaped portion 40 is recessed. In the front-rear direction, the accommodation recess 44 is formed only in a region further back than the rear end of the electrode holding hole 39 . The front wall of the receiving recess 44 is formed by the curved portion 33 . The rear wall of the accommodation recess 44 is composed of a partition wall 45 . The left and right walls of the accommodation recess 44 are composed of left and right side wall portions 46 having side continuous surfaces 42 .

A pair of left and right wire holding portions 47 are formed in the accommodation recessed portion 44 . The pair of conductor holding portions 47 are arranged at intervals in the left-right direction and stand upward in a wall shape from a position on the bottom surface of the accommodation recess 44 close to the rear surface of the curved portion 33 (the front surface of the accommodation recess 44).

A resistor holding portion 48 is formed in the housing recess 44 in a shape that projects upward from the bottom surface of the housing recess 44 . A plurality (four in this embodiment 1) of resistor holding grooves 49 are formed in the resistor holding portion 48 in an array along the left-right direction. The resistor holding groove 49 is opened on the upper surface and both the front and rear surfaces of the resistor holding portion 48 . The resistor holding groove 49 has an inner peripheral surface having an arcuate shape in front view.

A ground holding portion 50 protruding upward from the bottom surface of the accommodation recess 44 is formed in the accommodation recess 44 . The grounding holding portion 50 is composed of a pair of left-right symmetrical grounding holding protrusions 51 that are arcuate in plan view and arranged concentrically. Between the pair of ground holding protrusions 51 , a pair of front and rear cutout portions 52 are formed in a shape of being cut downward from the upper end of the ground holding portion 50 .

A cylindrical fixing part 53 is formed at the rear end of the dish-shaped part 40 with its axis directed in the up and down direction. A through-hole 54 is formed in the hollow of the fixing portion 53 so as to penetrate the dish-shaped portion 40 (holding member 32 ) in the up-down direction. The fixing part 53 is arranged at the rear end of the lower surface part 41 . The fixing part 53 and the locking part 34 are arranged in the center of the holding member 32 in the left-right direction. The fixing part 53 and the locking part 34 are arranged in a positional relationship spaced apart from each other in the front-rear direction.

The injection molded part 55 is provided for the purpose of ensuring the insulation of the electrode unit 60 , and is made of an insulating hot melt adhesive or a two-component resin. The injection molding part 55 has a first molding part 56 and a pair of left-right symmetrical second molding parts 57 . As shown in FIG. 5 , the first molded portion 56 is a portion of the injection molded portion 55 that is accommodated in the accommodation recessed portion 44 . The first molded portion 56 is filled to the entire accommodation recessed portion 44 . The upper surface of the first molded portion 56 is continuously flush with the upper surface of the upper plate portion 37 of the box portion 35 and the upper surface of the partition portion 45 at the same height. Inside the first molded portion 56, the entire conductor holding portion 47, the entire resistor holding portion 48, and the entire ground holding portion 50 are embedded.

A pair of left-right symmetrical sealing portions 58 are formed on the upper surface of the first forming portion 56 . The sealing portion 58 protrudes from the upper surface of the first forming portion 56 . The top view shape of the sealing portion 58 is a rectangular frame shape with the long side facing the front and rear directions. The sealing portion 58 on the right side is arranged to surround the grounding holding portion 50 in plan view. The pair of left and right second molded portions 57 have a form that rises upward from the rear end of the first molded portion 56 along the rear of the curved portion 33 .

As shown in FIGS. 10 and 11 , the electrode unit 60 includes a pair of left-right symmetrical electrode pins 61 , a plurality (four in this embodiment 1) of resistance elements 63 , a grounding member 64 , and a metal Long size wire 68. The electrode pin 61 is a metal part having an elongated shape in the front-rear direction. The electrode pin 61 has a pin shape. Pin shape also includes needle shape. The front end of the electrode pin 61 is arranged rearward of the front end of the discharge electrode 15D. A circular large-diameter portion 62 whose diameter is increased is formed at the rear end of the electrode pin 61 . The resistive element 63 has a cylindrical shape with its axis facing the front and rear direction. The grounding member 64 is a cylindrical metal part with its axis facing up and down. A circular enlarged diameter portion 65 with an enlarged diameter is formed on the upper end of the grounding member 64 . The upper surface of the enlarged diameter portion 65 functions as a contact surface 66 .

Each resistive element 63 has a pair of short-sized conductors 67 extending in the front-rear direction from both front and rear ends thereof. The ground member 64 has a short wire 67 extending radially outward. Both the long wire 68 and the short wire 67 are plastically deformable, and have shape retention properties such that the rigidity of the wires 67 and 68 maintains a fixed shape.

In the state before the electrode unit 60 is integrated with the case 31, as shown in FIG. 10 , the pair of electrode units 60 are arranged at intervals along the left and right in a state facing the front and back direction. The rear ends (large-diameter portions 62 ) of the two electrode pins 61 are connected to each other via a conductive path, and the conductive path is composed of a linear long wire 68 . The plurality of resistive elements 63 are arranged in series along the front-rear direction behind the electrode pin 61 . The ground member 64 is arranged behind the rearmost resistive element 63 and arranged in the row of the resistive elements 63 .

The pair of electrode pins 61 and the frontmost resistive element 63 are connected via a conductive path in which the long wire 68 and the short wire 67 of the frontmost resistive element 63 are fixed in a T-shape through a welding portion 69 . Adjacent resistive elements 63 are connected to each other via a conductive path, and the conductive path is formed by fixing the short wires 67 of the adjacent resistive elements 63 to each other in a straight line through the welding portion 69 . The resistive element 63 and the ground member 64 at the final end are connected through a conductive path, and the conductive path fixes the short conductor 67 of the resistor 63 and the short conductor 67 of the ground member 64 in a straight line through the welding portion 69 .

Next, the steps of integrating the electrode unit 60 and the case 31 will be described. Before the electrode unit 60 is mounted on the holding member 32 , the long wire 68 and the short wire 67 are bent into a predetermined shape. Thereby, as shown in FIG. 11 , the electrode pin 61 , the resistor element 63 , and the ground member 64 are arranged in positions corresponding to the electrode holding portion 38 , the resistance holding portion 48 , and the ground holding portion 50 . Specifically, the pair of electrode pins 61 are arranged in parallel with each other along the left and right intervals. The plurality of resistive elements 63 are arranged side by side in the left-right direction with the short wires 67 extending in the front-rear direction. A plurality of resistive elements 63 arranged side by side are arranged obliquely downward and behind the pair of electrode pins 61 and between the pair of electrode pins 61 in the left-right direction. The ground member 64 is arranged near the right side of the row of resistive elements 63 .

A pair of arc-shaped portions 68A are formed at both ends of the long wire 68 . The pair of arc-shaped portions 68A are connected to the electrode pin 61 by plastically deforming the arc-shaped portions 68A along the curved portion 33 . The area between the pair of arcuate portions 68A in the long conductor 68 becomes a linear portion 68L. The conductive path (short-sized wire 67) connecting the resistive elements 63 is plastically deformed into a "U-shape" when viewed from above. In FIG. 10 , the conductive path (short-sized wire 67 ) connecting the resistance element 63 at the rearmost end and the ground member 64 is plastically deformed into an "L-shape".

Next, the electrode unit 60 deformed into the above-mentioned form is temporarily assembled to the holding member 32 as shown in FIGS. 12 to 14 . At this time, the electrode pin 61 is inserted from the rear of the electrode holding portion 38 to penetrate the electrode holding hole 39 , and the large-diameter portion 62 is brought into contact with the front surface of the curved portion 33 . Thereby, the electrode pin 61 is positioned in the up-down direction and the left-right direction with respect to the holding member 32, and is positioned so that it may not be relatively displaced toward the front. Only the front end portion of the electrode pin 61 protrudes from the front of the electrode holding portion 38 .

The arcuate portion 68A of the long wire 68 is arranged along the rear surface of the curved portion 33 . The proximal end portion of the arcuate portion 68A of the long wire 68 that is continuous with the straight portion 68L is accommodated in the accommodation recess 44 . The entire linear portion 68L is also accommodated in the accommodation recess 44 . The left and right ends of the linear portion 68L are sandwiched in the front-rear direction between the rear surface of the curved portion 33 and the lead wire holding portion 47 .

The plurality of resistance elements 63 are individually pressed into the plurality of resistance holding grooves 49 from above the resistance holding portion 48 . Thereby, the resistance element 63 is positioned in the up-down direction, the left-right direction, and the front-back direction with respect to the holding member 32. The grounding member 64 is pressed between the pair of grounding holding protrusions 51 from above the grounding holding portion 50 so that the enlarged diameter portion 65 comes into contact with the upper end of the grounding holding protrusions 51 . Thereby, the grounding member 64 is positioned in the up-down direction, the left-right direction, and the front-back direction with respect to the holding member 32. The plurality of short wires 67 are arranged in front or behind the resistor holding portion 48 . The resistor element 63 , the ground member 64 , and the plurality of short wires 67 are accommodated in the accommodation recess 44 .

The holding member 32 to which the electrode unit 60 is temporarily assembled is provided in a mold for injection molding (not shown). In the mold, a mold groove (not shown) formed by the receiving recessed portion 44, a mold groove (not shown) formed between the bending portion 33 and the mold, and an internal space of the box portion 35 are ensured. mold slot (picture omitted). In these mold cavities, molten insulating hot melt adhesive or two-pack resin is injected under pressure.

The hot melt adhesive or two-component resin injected in a pressurized state is filled between the holding member 32 and the components 61, 62, 63, 64, and 67 constituting the electrode unit 60 by the injection pressure, and It is in close contact with the entire components constituting the electrode unit 60 without gaps. Hot melt adhesive or two-component resin hardens in a short time. When the hot melt adhesive or the two-component resin hardens, the housing 31 (the holding member 32 and the injection molded part 55 ) is connected to the electrode unit 60 while the injection molded part 55 and the holding member 32 are integrated. Be integrated. Thereby, the manufacturing of the electric field control member 30 is completed.

In a state where the injection molded part 55 and the holding member 32 are integrated, most of the electrode unit 60 is buried in the injection molded part 55 . Regarding the electrode pin 61 , only the large diameter portion 62 is embedded in the injection molded portion 55 , but most of the electrode pin 61 ahead of the large diameter portion 62 is located outside the injection molded portion 55 . Regarding the ground member 64 , the upper surface (contact surface 66 ) of the expanded diameter portion 65 is exposed on the upper surface of the injection molded portion 55 , but the entire ground member 64 including the expanded diameter portion 65 is buried inside the injection molded portion 55 . The front ends of the left and right electrode pins 61 protrude forward toward the front of the electrode holding hole 39 (electrode holding portion 38).

Since the hot melt adhesive or the two-component resin is injected under pressure, there is a concern that the electrode unit 60 may be displaced due to the injection pressure. However, since the electrode pin 61 is inserted into the electrode holding hole 39 and the large diameter portion 62 is in contact with the rear surface of the curved portion 33 , there is no positional deviation of the electrode pin 61 relative to the holding member 32 . Since the long conductor 68 is sandwiched between the rear surface of the bent portion 33 and the conductor holding portion 47 , there is no positional deviation in the front-rear direction with respect to the holding member 32 . Since the resistance element 63 is pressed into the resistance holding groove 49, there is no positional deviation with respect to the holding member 32. Since the grounding member 64 is elastically sandwiched between the grounding holding protrusions 51 , there is no positional deviation with respect to the holding member 32 .

The electric field control member 30 manufactured as described above is installed on the spray gun body 10 . During installation, the posture of the electric field control member 30 is tilted so that the upper surface of the injection molded portion 55 becomes lower toward the rear, and the locking portion 34 at the front end of the holding member 32 is inserted into the locking position of the spray gun body 10 from the lower back. Hole 19. The electric field control member 30 is swingable in the up and down direction relative to the spray gun body 10 with the locking portion between the locking portion 34 and the locking hole 19 as a fulcrum. In a state where the front end of the bent portion 33 is in contact with the stopper 18 of the mounting portion 16, the fitting portion of the locking portion 34 and the locking hole 19 (the upper edge of the opening edge of the locking hole 19) is fulcrum to lift the electric field control member 30 . During this period, the enlarged diameter portion 65 of the grounding member 64 is brought into contact with the lower end of the elastic connecting member 22, and the elastic connecting member 22 is pushed up by the contact surface 66 (upper surface) of the enlarged diameter portion 65 to make it elastic in the up and down direction. shrink. Since the outer diameter of the enlarged diameter portion 65 is larger than the outer diameter of the elastic connecting member 22 , it can reliably bring the expanded diameter portion 65 into contact with the elastic connecting member 22 .

The ground member 64 is connected to the ground terminal 91 via the elastic connection member 22 (see FIG. 16 ). That is, as shown in FIG. 16 , the above-mentioned resistive element 63 is provided between the electrode pin 61 and the ground terminal 91 . By disposing the resistive element 63 between the electrode pin 61 and the ground terminal 91, compared with the structure without the resistive element 63, the output current of the discharge electrode 15D becomes lower, and the electric field intensity to the painting object becomes higher. . Therefore, it can improve the coating efficiency of the charged paint on the coating object. Furthermore, since the resistive elements 63 are held by the holding member 32 and integrated into the electric field control member 30, the discharge can be adjusted by installing the electric field control member 30 with the number and type of the resistive elements 63 adjusted on the spray gun body 10 The output current of electrode 15D.

When the left and right sealing parts 58 touch the lower surface of the mounting part 16 of the spray gun body 10 , the through hole 54 of the fixing part 53 becomes vertically opposed to the female screw hole 20 of the spray gun body 10 . Thereafter, the screw 70 is inserted into the through hole 54 from below the holding member 32 and screwed into the female screw hole 20 of the spray gun body 10 . When the screw 70 is tightened, the sealing portion 58 is in liquid-tight contact with the sealing surface 25 in an elastically deformed state. Since the opening 21 of the spray gun body 10 is sealed by the sealing portion 58 on the right side, foreign matter (powder paint) can be prevented from entering into the spray gun body 10 through the opening 21 . Since the sealing portion 58 is formed to be symmetrical, the left sealing portion 58 is in close contact with the lower surface of the mounting portion 16 of the spray gun body 10, thereby preventing the holding member 32 (electric field control member 30) from tilting left and right relative to the spray gun body 10. .

When the sealing portion 58 is in close contact with the lower surface of the mounting portion 16 of the spray gun body 10 , the dish-shaped portion 40 covers the rear end area of the mounting portion 16 of the spray gun body 10 , and the curved portion 33 is fitted into the mounting recess 17 . If the locking of the screws 70 is completed, the installation step of the electric field control member 30 to the spray gun body 10 is completed. The electric field control member 30 is installed in the gun body 12 at a position further behind the nozzle 15A (in the opposite direction to the discharge direction of the powder coating material from the nozzle 15A). When the electric field control member 30 is attached to the spray gun body 10, the front ends of the pair of left and right electrode pins 61 protrude (expose) toward the front of the holding member 32 (electrode holding portion 38) behind the nozzle 15A. condition. In front view and plan view, the pair of electrode pins 61 is located near the outer peripheral surface of the spray gun body 10 and is arranged to sandwich the spray gun body 10 from the left and right sides.

When electrostatic coating is performed, the powder paint supplied to the spray gun body 10 is discharged forward from the nozzle 15A while being charged by the high voltage generator 14 . The powder coating material discharged from the nozzle 15A is applied to the surface to be coated by the electric field generated between the nozzle 15A and the surface to be coated (illustration omitted).

During electrostatic coating, the electric field control member 30 generates an electric field for absorbing free ions between the nozzle 15A and the electrode pin 61 . The electric field generated by the electric field control component 30 can reduce the number of free ions in the powder layer of the powder coating applied to the surface to be coated. This can suppress the reverse ionization phenomenon (electrostatic repulsion) caused by free ions remaining in the powder layer and maintain the smoothness of the coating film.

The electrostatic coating spray gun of this embodiment 1 includes a spray gun body 10 and an electric field control member 30 . A nozzle 15A for discharging powder paint forward is provided at the front end of the spray gun body 10 . The electric field control member 30 is installed on the outer peripheral surface of the spray gun body 10 at a position further behind the nozzle 15A. The electric field control member 30 includes a plurality of electrode pins 61 that generate an electric field with the nozzle 15A, and a holding member 32 that holds the plurality of electrode pins 61 in a state of being arranged at intervals along the circumferential direction.

The holding member 32 holding the plurality of electrode pins 61 is formed to cover only a portion of the outer circumferential surface of the spray gun body 10 in the circumferential direction. Compared with the annular holding member (not shown) that covers the entire outer circumference of the spray gun body, the holding member 32 (electric field control member 30) of the first embodiment can be miniaturized. Since the only component that holds the electrode pin 61 is the holding member 32 , a smaller number of parts is required compared to the case where two components are used to hold the electrode pin 61 .

The electric field control member 30 has a synthetic resin injection molded portion 55 formed integrally with the holding member 32 . The electrode unit 60 includes electrode pins 61 . At least a part of the portion of the electrode unit 60 excluding the front end portion of the electrode pin 61 is embedded in the injection molded portion 55 . Here, the “embedded” form includes a form that is embedded inside the injection molded part 55 and is not exposed from the outer surface of the injection molded part 55 , and a form that is exposed from the outer surface of the injection molded part 55 but is not exposed from the injection molded part 55 . Protruding form on the outer surface.

In the first embodiment, at least a part of the portion of the electrode unit 60 excluding the tip portion of the electrode pin 61 (a portion excluding the electrode pin 61 ) is embedded in the injection molded portion 55 . According to this configuration, in the injection molding step, since the synthetic resin material (hot melt adhesive or two-component resin) is in close contact with the electrode unit 60 due to the injection pressure, there is no gap between the injection molded part 55 and the electrode unit 60 . Gaps will occur. Thereby, during electrostatic coating, it is possible to prevent erroneous grounding to parts other than the electrode pins 61 in the electrode unit 60 .

The electrode unit 60 includes an electrode pin 61 , a resistance element 63 , and a ground member 64 . Since the holding member 32 is formed with the electrode holding portion 38 for holding the electrode pin 61, it is possible to prevent the electrode pin 61 from being displaced due to the injection pressure during the injection molding step. Since the holding member 32 is formed with the resistance holding portion 48 for holding the resistance element 63 in a positioned state, it is possible to prevent the resistance element 63 from being displaced due to the injection pressure during the injection molding step. Since the holding member 32 is formed with the grounding holding portion 50 that holds the grounding member 64 in a positioned state, it is possible to prevent the grounding member 64 from being displaced due to injection pressure during the injection molding step.

The electrode unit 60 includes a grounding member 64 connectable to a grounding elastic connection member 22 provided on the spray gun body 10 . The contact surface 66 of the grounding member 64 is exposed on the outer surface of the injection molded part 55 . A sealing portion 58 surrounding the exposed portion (contact surface 66 ) of the ground member 64 on the outer surface of the injection molded portion 55 is integrally formed on the outer surface of the injection molded portion 55 . The sealing portion 58 is in liquid-tight contact with the spray gun body 10 . According to this configuration, even if the sealing portion 58 separate from the injection molding portion 55 is not provided, the connecting portion of the elastic connecting member 22 and the grounding member 64 can be prevented from being wetted by water or foreign matter from entering the spray gun body 10 .

The holding member 32 has a locking portion 34 that is swingably fitted to the spray gun body 10 and a fixing portion 53 that is fixed to the spray gun body 10 by a fastening member (screw 70). According to this configuration, compared to the case where the holding member 32 is attached to the spray gun body 10 using a plurality of fastening members, it is possible to provide only one fixing part 53 fixed by the fastening member (screw 70 ). parts. Thereby, the workability when attaching the holding member 32 to the spray gun body 10 can be improved.

The spray gun body 10 is provided with an elastic connecting member 22 for grounding. The holding member 32 is provided with a grounding member 64 connected to the elastic connection member 22 in a state where the holding member 32 is attached to the spray gun body 10 . The grounding member 64 is formed with a contact surface 66 for contacting the elastic connection member 22 in a state of elastic deformation. The outer diameter of the contact surface 66 is larger than the outer diameter of the elastic connection member 22 . According to this configuration, the elastic connection member 22 can be brought into contact with the grounding member 64 simply by elastically deforming the elastic connection member 22 while bringing the elastic connection member 22 into contact with the contact surface 66 , so the workability is good.

On the outer surface of the holding member 32, there are formed side continuous surfaces 42 and rear continuous surfaces 43 that are continuous at an obtuse angle with respect to the outer peripheral surface of the spray gun body 10. The side continuous surface 42 is continuous to the side area of the outer peripheral surface of the gun body 12 without intervening through grooves, gaps, recesses, etc. The rear continuous surface 43 is continuous to the bottom surface area of the outer peripheral surface of the gun body 12 without intervening through grooves, gaps, recesses, etc. According to this structure, powder paint is less likely to remain at the interface between the outer peripheral surface of the spray gun body 10 and the outer surface of the holding member 32 (the side continuous surface 42 and the rear continuous surface 43). Even if powder paint remains at the interface between the outer peripheral surface of the spray gun body 10 and the outer surface of the holding member 32 (the side continuous surface 42 and the rear continuous surface 43), the paint can be easily removed and has excellent cleanability. .

<Example 2> The electric field control member is not limited to the shape of the above-mentioned Embodiment 1. In this Embodiment 2, an example in which the electric field control member is in a ring shape will be described. Hereinafter, Example 2 will be described with reference to FIGS. 17 to 19 . In addition, in the following description, the same components as those in Embodiment 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIG. 17 , the electrostatic coating spray gun of Embodiment 2 has a spray gun body 210 . The spray gun body 210 has a handle 11 and a gun body 212 . Inside the gun body 212, similarly to the gun body 12 of Embodiment 1, a high voltage generator 14, a discharge electrode 15D, and the like are provided. An electric field control member 230 is installed on the outer periphery of the gun body 212.

As shown in FIGS. 18 and 19 , the electric field control member 230 has a holding member 232 , a pair of left and right electrode pins 261 , a resistance element 263 , a ground member 264 , and a lead wire 268 . A pair of electrode pins 261 is spaced apart from one end of the conductor 268, a grounding member 264 is provided on the other end of the conductor 268, and a resistive element is provided between the pair of electrode pins 261 and the grounding member 264 on the conductor 268. 263. The ground member 264 is connected to the ground terminal 91 (see FIG. 16 ). That is, the resistance element 263 is provided between the electrode pin 261 and the ground terminal 91 .

The holding member 232 is made of synthetic resin and has an annular shape, specifically an annular shape. The holding member 232 has an annular inner member 281 and an annular outer member 282 arranged outside the inner member 281 . The inner member 281 has an annular portion 283 and a flange portion 284 extending radially outward from one axial end of the annular portion 283 . The outer member 282 is fitted from the other axial end side of the inner member 281 and is screwed to the flange portion 284 .

Between the inner member 281 and the outer member 282 in the radial direction, a pair of left and right electrode pins 261 excluding the front end parts and a resistive element 263 are arranged. In this state, the left and right pair of electrode pins 261 and the resistive element 263 are arranged. held by the holding member 232. As shown in FIGS. 17 and 18 , the front ends of the pair of left and right electrode pins 261 are exposed outside the holding member 232 .

As shown in FIGS. 18 and 19 , a resin injection port 285 is formed in the outer member 282 outside the holding member 232 . When resin is injected from the resin injection port 285, a resin molded portion (not shown) is formed in the holding member 232. The resistive element 263 and the electrode pin 261 are embedded in the resin molded portion except for the front end portion. As shown in FIG. 17 , the holding member 232 is installed on the spray gun body 210 .

<Example 3> In this Embodiment 3, the structure provided with the variable resistor 71 is demonstrated with reference to FIG. 20. In addition, in the following description, the same components as those in Embodiment 1 are denoted by the same reference numerals, and detailed descriptions are omitted.

As shown in FIG. 20 , a variable resistor 71 is provided between the resistive element 63 and the ground terminal 91 . According to this structure, not only the resistance element 63 but also the variable resistor 71 can adjust the output current of the discharge electrode 15D.

<Other Examples> The present invention is not limited by the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In the above-mentioned Embodiment 1, the sealing part is integrally formed in the injection molding part as a means of preventing the connection part between the elastic connection member and the grounding member from being wetted by water, but a sealing member separate from the injection molding part may also be used. , to prevent the connection part between the elastic connecting member and the grounding member from being wetted by water. In the above-mentioned Embodiment 1, although the holding member is installed on the spray gun body through one locking part and one fixing part, as a means of installing the holding member on the spray gun body, a plurality of locking parts may be used, or a plurality of locking parts may be provided. Multiple fixed parts. In the above-mentioned Embodiment 1, although it is assumed that the installation of the holding member to the spray gun body and the connection of the grounding member to the elastic connection member can be performed by one action, different operations can also be used to install the holding member to the spray gun body. , and the connection of the grounding component to the elastic connecting component. In the above-mentioned Embodiments 1 and 2, although there are two electrode pins, the number of electrode pins may be one or more than three. In the above-mentioned Embodiments 1 to 3, although the electrostatic coating spray gun used for the hand-held spray gun held by the operator for painting has been described, the present invention can also be applied to an automatic coating device ( Reciprocator) or robotic automatic spray gun.

10:Spray gun body 11: Grip 12: Gun body 13: Trigger 14:High voltage generator 15A:Nozzle 15B:Nozzle cover 15C: Cover nut 15D: discharge electrode 16:Installation Department 17:Installation recess 18: Stopper 19:Latching hole 20:Female screw hole 21:Opening part 22: Elastic connection components 23: Crimp terminal 24:Wire 25:Sealing surface 26: Adjacent area ahead 30: Electric field control components 31: Shell 32: Maintain components 33:Bending part 34:Latching part 35: Box Department 36: Side panel part 37: Upper plate part 38: Electrode holding part 39: Holding hole for electrode 40: dish 41: Lower surface 42: Side continuous surface (continuous surface) 43: Rear continuous surface (continuous surface) 44:Containment recess 45: Next door 46: Left and right side walls 47: Holding part for wire 48: Holding part for resistor 49:Retaining groove for resistor 50: Holding part for grounding 51:Retaining protrusion for grounding 52:Resection part 53: Fixed part 54:Through hole 55: Injection molding department 56: First forming department 57: Second forming section 58:Sealing part 60:Electrode unit 61:Electrode pin 62: Large diameter part 63:Resistance element 64: Grounding component 65: Expanded diameter part 66:Contact surface 67:Short size wire 68:Long size wire 68A:Arc-shaped part 68L: Linear part 69:Welding Department 70: Screws (fastening components) 71:Variable resistor 90:Power supply 91: Ground terminal 210:Spray gun body 212: Gun body 230: Electric field control components 232:Keep components 261:Electrode pin 263:Resistance element 264:Grounding components 268:Wire 281:Inside member 282:Outside member 283: Annular part 284:Flange part 285:Resin injection port

FIG. 1 is a perspective view of the electrostatic coating spray gun of Embodiment 1 viewed obliquely from the front. Figure 2 is a top view of the electrostatic coating spray gun. Figure 3 is a partially enlarged front view of the electrostatic coating spray gun. Figure 4 is a partially cutaway side view of the electrostatic coating spray gun. FIG. 5 is a perspective view of the electric field control member viewed obliquely from the front. Figure 6 is a front view of the electric field control component. Figure 7 is a top view of the holding member. Fig. 8 is a perspective view of the holding member viewed obliquely from the front. Fig. 9 is a perspective view of the holding member viewed obliquely from above and from the rear. FIG. 10 is a plan view showing the state of the electrode unit during manufacture. FIG. 11 is a perspective view of the electrode unit to be attached to the holding member when viewed obliquely from above and from the rear. Fig. 12 is a plan view of the electrode unit attached to the holding member. FIG. 13 is a perspective view of a state in which the electrode unit is mounted on the holding member, viewed obliquely from the front. FIG. 14 is a perspective view of a state in which the electrode unit is mounted on the holding member, viewed obliquely from above and from behind. 15 is a partially enlarged side sectional view showing the connection structure between the elastic connection member of the spray gun body and the ground member of the electric field control member. FIG. 16 is an explanatory diagram showing the electrical structure of the electrostatic coating spray gun. FIG. 17 is a perspective view of the electrostatic coating spray gun according to the second embodiment of the present invention viewed obliquely from the upper front. Fig. 18 is a top view of the holding member of the second embodiment. Fig. 19 is an exploded perspective view of the holding member of the second embodiment. FIG. 20 is an explanatory diagram showing the electrical structure of the electrostatic coating spray gun according to the third embodiment.

10:Spray gun body

11: Grip

12: Gun body

13: Trigger

15B:Nozzle cover

15C: Cover nut

16:Installation Department

17:Installation recess

26: Adjacent area ahead

30: Electric field control components

38: Electrode holding part

40: dish

41: Lower surface

42: Side continuous surface (continuous surface)

43: Rear continuous surface (continuous surface)

61:Electrode pin

70: Screws (fastening components)

Claims (11)

An electrostatic coating spray gun is provided with: a spray gun body; a nozzle located at the front end of the spray gun body; a handle extending downward from the rear end of the spray gun body; and a pin-shaped discharge electrode for The paint sprayed from the nozzle is charged; at least one electrode pin generates an electric field between the discharge electrode and the electric field control member; the electric field control member is installed on the spray gun body; the electric field control member has the electrode pin, and a holding member for holding the electrode pin, wherein the holding member covers only a portion of the outer peripheral surface of the spray gun body in the circumferential direction and spans the lower surface of the spray gun body. The electrostatic coating spray gun of Claim 1, wherein the electric field control member has a resistive element provided on a path between the electrode pin and the ground terminal, and the resistive element is held by the holding member. The electrostatic coating spray gun according to claim 2, wherein the electric field control member has a synthetic resin injection molded portion formed integrally with the holding member, and the resistive element is embedded in the injection molded portion. The electrostatic coating spray gun of claim 2 or 3, wherein a variable resistor is provided on the outside of the spray gun body and is provided on a path between the resistive element and the ground terminal. The electrostatic coating spray gun according to claim 1 or 2, wherein the electric field control member has a synthetic resin injection molded portion formed integrally with the holding member, and an electrode including the electrode pin is embedded in the injection molded portion. At least part of the portion of the electrode pin in the unit except the front end portion. The electrostatic coating spray gun according to claim 1, wherein the holding member is formed with an electrode holding portion capable of holding the electrode pin. The electrostatic coating spray gun according to claim 1, wherein the electrode unit includes a resistance element, and the holding member is formed with a resistance holding portion for holding the resistance element in a positioned state. The electrostatic coating spray gun of claim 5, wherein the electrode unit includes a grounding member that can be connected to a grounding elastic connection member provided on the spray gun body, and is located on the outer surface of the injection molding part and surrounds the outside of the injection molding part. The sealing portion of the exposed portion of the ground member on the surface is integrally formed, and the sealing portion is in liquid-tight contact with the spray gun body. The electrostatic coating spray gun of claim 1, wherein the holding member has: a locking portion that is swingably fitted into the spray gun body; and a fixing portion that is fixed to the spray gun body by a fastening member. Such as the electrostatic coating spray gun of claim 1, wherein, The spray gun body is provided with an elastic connection member for grounding, the holding member is provided with a grounding member connected to the elastic connection member in a state where the holding member is installed on the spray gun body, and a grounding member is formed on the grounding member. A contact surface for the above-mentioned elastic connecting member to contact in a state of elastic deformation. The electrostatic coating spray gun of claim 1, wherein a continuous surface extending at an obtuse angle from the outer peripheral surface of the spray gun body is formed on the outer surface of the holding member.