Electrostatic powder spray gun with two degrees of freedom

Abstract

The application discloses a double-freedom electrostatic powder spray gun, comprising a double-freedom automatic rotating mechanism and a spray gun body. The double-freedom automatic rotating mechanism can be divided into a base, a second rotating body and a first rotating body. The second rotating body is controlled by a motor in the base and can rotate freely in a horizontal plane. The first rotating body is controlled by a motor in the second rotating body and can rotate freely in a vertical plane. The stepping motor can accurately control the rotating angle. Accordingly, the application proposes a double-bend powder conveying pipeline design with a built-in rectifier to match the double-freedom rotation and ensure uniform outlet flow rate distribution. The spray gun can safely improve the uniformity of powder coating coverage on the surface of a workpiece with a complex shape, effectively prevent metal corrosion and reduce powder coating consumption.

Description

TECHNICAL FIELD

[0001] The present invention relates to a powder spray gun, and more particularly to a powder spray gun for use in the powder spray industry, especially for use in spraying powder coating on parts in a narrow space, such as the back cavity of an automobile wheel. BACKGROUND

[0002] With the proposal of "carbon peak" and "carbon neutral", and the gradual tightening of domestic VOC policy, the standards and policies related to the painting industry are becoming more and more strict. The market share of solvent-based coatings is gradually declining. The mainstream of the corresponding alternative environmentally friendly products is powder coatings and water-based coatings. These two types of coatings have both competing fields and their own irreplaceable advantages. They will coexist and compete for a long time.

[0003] Compared with liquid coatings such as water-based paint, the utilization rate of powder coatings is very high, which can reach more than 95%. However, the problem of powder coating coverage is more prominent than that of liquid coatings, which can be reflected in the following three factors: (1) Due to poor leveling, the film thickness of the cured powder coating is basically determined by the thickness of the powder particles during spraying. This is particularly evident on the surface of complex-shaped workpieces. Liquid coatings have good leveling properties, and the coverage thickness after curing is relatively uniform; (2) During electrostatic spraying, the adsorption between the powder coating and the substrate basically relies on the action of the Coulomb force. For complex-shaped workpieces, due to uneven electric field distribution, the coverage of the powder coating on the substrate surface varies greatly. For example, in structures similar to recesses or grooves, if the process parameters of spraying (especially the angle parameters of spraying) are not appropriate, the powder coating coverage will be insufficient, and in severe cases, the problem of exposed substrate will occur, which is not conducive to metal corrosion protection. However, for liquid coatings, in addition to the action of the Coulomb force, the liquid also relies on surface tension to be adsorbed on the substrate, and the influence of the electric field is relatively weak at a long spraying distance; (3) The film thickness of powder spraying is much thicker than that of liquid spraying. This is both an advantage and a disadvantage. On the basis of the above two factors, and under the premise of ensuring that the workpiece does not leak the substrate, the unevenness of the film thickness of powder spraying is proportional to the degree of waste of powder coating. In the case of a groove structure, if the groove part is to be ensured not to expose the substrate, the method of increasing the powder output of the electrostatic powder spray gun will be used, which will greatly increase the film thickness around the groove structure, resulting in waste.

[0004] In summary, during electrostatic powder spraying, improving the uniformity of powder particle accumulation on the surface of the workpiece, especially for complex-shaped workpieces, not only benefits metal corrosion prevention, but also reduces powder coating waste, lowers powder spraying costs, and improves production capacity. Furthermore, from the perspective of "peak carbon" and "carbon neutralization", reducing powder coating consumption not only helps reduce carbon emissions during production (such as energy consumption for powder coating solidification and energy consumption for electrostatic generators), but also helps reduce overall carbon emissions in the coating industry. Currently, in industry, electrostatic powder for complex-shaped workpieces is still sprayed using a rough coating method. Traditional electrostatic powder spray guns are long and difficult to adjust the spraying angle flexibly for complex-shaped workpiece surfaces. It is difficult to obtain a uniform film thickness coverage with powder coatings.

[0005] Automobile hubs are a typical example of complex-shaped metal workpieces that use a large amount of powder coating. The invention patent with publication number CN111218194A discloses a double-coating system composed entirely of powder coatings, which is specifically used for the surface of automobile hubs, and states that the current coating system for automobile hubs is mainly composed of powder coatings. Utility models with publication numbers CN208069286U and CN208021098U disclose an automobile hub design with a back cavity and weight-reducing recesses, respectively. Another utility model with publication number CN213768152U discloses a machining solution for the rim grooves of an automobile hub. From the above three patents, it can be seen that the design of recess structures in the back cavity of automobile hubs has become a popular trend to meet the demand for lightweight. This is the market driving force behind the complex design of automobile hub shapes.

[0006] Traditional electrostatic powder spray guns are too large in size due to the need for built-in DC high-voltage modules, making it difficult to adjust the spraying angle flexibly. The patent with publication number CN202160295U discloses a high-voltage package structure for a powder electrostatic spray gun and its packaging process. It is not difficult to see that the high-voltage module of the powder spray gun needs a certain length. The invention patent with publication number CN113856930A discloses a multi-spraying path electrostatic powder spray gun. It can be seen that the high-voltage module is generally built-in inside the powder spray gun and is parallelly packaged with the powder spraying pipeline. In addition to the nozzle and corona needle and other necessary parts, the overall length of a typical electrostatic powder spray gun is at least 20 centimeters. Currently, the outer diameter of automobile hubs on the market is generally 16 to 21 inches, and the width of the rim (J value) is generally 6 to 9 inches. For example, the overall length of a typical electrostatic powder spray gun is at least 20 centimeters, which is longer than the width of the rim (J value) of the automobile hub. Therefore, it is difficult to adjust the spraying angle flexibly for complex-shaped workpiece surfaces. Figure 1As shown, the conventional electrostatic powder spray gun is difficult to adjust the spray angle in the spray wheel hub back cavity. Due to the limited space of the hub back cavity and the interference of the center support, the spray gun nozzle can only face the back cavity weight reduction pocket, and cannot face the hub rim groove bottom. This causes the flow rate of the powder particles to be unable to overcome the electrostatic shielding effect of the groove, which is not conducive to the powdering of the rim groove structure. In view of this problem, the current commonly used solution in the industry is to increase the amount of powder coating used, and to ensure that the similar rim groove structure does not expose the metal base by increasing the overall film thickness coverage of the workpiece. This causes serious waste of powder coating. Therefore, for complex-shaped workpieces such as automobile wheels, if the spray gun can automatically and flexibly adjust the spray angle, it is beneficial to improve the film thickness coverage of the groove structure and reduce the overall powder coating coverage of the workpiece, thereby realizing lean production of electrostatic powder spraying.

[0007] The invalid invention with the application publication number CN106984457A discloses a kind of micro-hole injection electrostatic powder spray gun, and the purpose is to realize the flexible adjustment of powder spraying angle. The spray gun of the invalid invention has certain limitations in design, specifically as follows: (1) the driving device is designed in the powder spraying environment, which has safety hazards. Powder spraying needs to pay attention to powder explosion hazards, so the automatic equipment for controlling the spatial position of the spray gun is generally isolated from the powder environment; (2) the spray angle of the'spray ball' of the spray gun is limited. CN106984457A attempts to realize the flexible adjustment of the angle of the powder coating outlet by rotating the'spray ball'. However, to ensure that the'spray ball' is embedded in the spray gun head and does not come off under the impact of high-flow powder coating and compressed air, it is necessary to ensure that more than 50% of the volume of the'spray ball' is inside the spray gun. If the annular arc surface diameter of the embedded'spray ball' is equal to the diameter of the'spray ball' as described in the patent application of CN106984457A, only half of the'spray ball' is inside the spray gun head, and the'spray ball' cannot be strictly fixed on the spray gun and is easy to come off the spray gun body under the action of compressed air up to 8 bar. Secondly, the connecting structure of the connecting rod of the driving device and the'spray ball' is a spherical hinge type, and the angle it can rotate is necessarily less than 180°. (3) The'spray ball' and the powder conveying pipe must be flexibly connected. Considering practicality and safety, polytetrafluoroethylene is generally used as the pipe wall material for the powder conveying pipe, which is a rigid material and cannot be flexibly connected. Although the electrostatic powder spray gun described in CN106984457A has many limitations in design and is rejected, the design idea of flexibly adjusting the spray angle by controlling the spray gun head is more suitable for complex-shaped workpieces such as automobile wheels than the current method of controlling the whole spray gun by reciprocating machine or mechanical arm. SUMMARY

[0008] The invention is to provide a kind of electrostatic powder spray gun with double degrees of freedom, can be optimized by automated mechanical structure, spraying path.Especially, in the spraying of complex metal workpieces, the spray gun provided by the present application can flexibly adjust the spraying angle, so that the film thickness of powder coating on the workpiece surface is more uniform.

[0009] The technical scheme adopted by the present application to solve the above technical problems is: an electrostatic powder spray gun comprising a double-degree-of-freedom automatic rotating mechanism, comprising a first rotating body, a second rotating body, a base and a spray gun body. The first rotating body comprises a nozzle. The first rotating body comprises a nozzle, and the first rotating body is connected to the side of the second rotating body by bearings and can be freely rotated to a fixed angle in the vertical plane. The second rotating body is connected to the top of the base by bearings and can be freely rotated to a fixed angle in the horizontal plane. The base is provided with a motor, which can drive and control the second rotating body through gear transmission. The second rotating body is provided with a motor, which can drive and control the first rotating body through gear transmission. The type of motor includes but is not limited to stepper motor.

[0010] Further, to cooperate with the first rotating body and the second rotating body to rotate in the vertical and horizontal planes respectively, the powder pipeline is arranged as follows: a bend is arranged in the powder conveying pipeline in the first rotating body and the powder conveying pipeline in the second rotating body respectively, the two bends have equal bending angles, and the bending angle is greater than or equal to 90 degrees. When the electrostatic powder spray gun is in the initial position, the lower part of the bend structure of the powder conveying pipeline in the base, the powder conveying pipeline in the spray gun body, the powder conveying pipeline in the second rotating body and the upper part of the bend structure of the powder conveying pipeline in the first rotating body are vertical pipes. The powder pipeline and the sealable connection can be connected relative to each other.

[0011] The powder conveying pipeline in the second rotating body and the powder conveying pipeline in the base can be connected relative to each other.

[0012] The powder conveying pipeline in the first rotating body, the powder conveying pipeline in the second rotating body, the powder conveying pipeline in the base and the powder conveying pipeline in the spray gun body constitute a powder transmission system with double bend structure.

[0013] Further, in order to cooperate with the first rotating body and the second rotating body to rotate in the vertical and horizontal planes respectively, the high-voltage circuit design scheme adopted is that: a second rotating body high-voltage conducting ring is arranged between the second rotating body high-voltage conducting line and the base high-voltage conducting line, and the base high-voltage conducting line keeps electrified with the second rotating body high-voltage conducting ring when the base high-voltage conducting line rotates relative to the second rotating body high-voltage conducting ring; a first rotating body high-voltage conducting ring is arranged between the first rotating body high-voltage line and the second rotating body high-voltage line, and the second rotating body high-voltage line keeps electrified with the first rotating body high-voltage conducting ring when the second rotating body high-voltage line rotates relative to the first rotating body high-voltage conducting ring; the first rotating body high-voltage conducting ring is located in the first rotating body shell, and the second rotating body high-voltage conducting ring is located in the second rotating body shell.

[0014] The corona needle, the second rotating body high-voltage conducting line, the base high-voltage conducting line, the high-voltage conducting line in the spray gun body, the first rotating body high-voltage conducting ring, the second rotating body high-voltage conducting ring and the voltage doubler block form a high-voltage circuit system of the spray gun.

[0015] Further, in order to cooperate with the first rotating body and the second rotating body to rotate in the vertical and horizontal planes respectively, the motor circuit design scheme adopted is that: the spray gun is provided with a built-in motor, a motor and a power and signal line. The power and signal line is arranged close to the second rotating body inner powder conveying pipeline, the base inner powder conveying pipeline and the spray gun body inner powder conveying pipeline. The first motor, the second motor and the power and signal line form a low-voltage circuit system of the spray gun.

[0016] Further, in order to reduce the potential safety risk of the high-voltage circuit system and the low-voltage circuit system, the circuit design scheme adopted is that: the low-voltage system and the high-voltage system are completely separated by the powder conveying system and the spray gun shell, wherein the spray gun shell includes the second rotating body shell, the base shell and the spray gun body shell. The low-voltage circuit and the high-voltage circuit are respectively arranged on one side of the powder conveying system.

[0017] Further, in order to reduce the vortex caused by the powder pipeline elbow structure, the powder pipeline design scheme adopted is that: a rectifier is arranged in the powder pipeline. The rectifier is constructed as a multi-layer cylindrical grid structure, the installation point of which is the elbow fluid outlet, and the specific point is point 1. The installation attitude is that the cylindrical grid structure is coaxial with the powder pipeline. Under the influence of the inertial effect of the Coanda effect, the mixed fluid of the powder and the air is easy to generate vortex at the outlet of the elbow structure. The working principle of the rectifier is to eliminate the non-axial fluid flow velocity in the powder pipeline, increase the collision probability of the powder and the pipeline wall, so that the flow velocity distribution at the outlet of the spray gun is more uniform.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] (1) The electrostatic powder spray gun can accurately and flexibly adjust the spraying angle. The first motor, the second motor, the first transmission gear and the second transmission gear set provide two degrees of freedom in the horizontal and vertical directions for the electrostatic powder spray gun A1. Adjusting the spraying angle, the double-bend powder conveying pipeline shortens the distance of the required rotation of the pipeline. The conventional electrostatic powder spray gun must rotate the whole spray gun containing the high-voltage module, while the electrostatic powder spray gun of the present application does not need to rotate the spray gun body containing the high-voltage module, so that it can better adapt to workpieces with complex shapes.

[0020] (2) The corona needle 1-5 can always maintain a discharge state under different spraying angles. The high-voltage conductive circuit is provided with a first rotary body high-voltage conductive ring and a second rotary body high-voltage conductive ring. When the first rotary body and the second rotary body are rotated in the horizontal and vertical directions respectively, the high-voltage conductive circuit can always maintain a power-on state.

[0021] (3) The circuit safety is high. In the design, the powder conveying pipeline and the spray gun shell isolate the high-voltage circuit system and the low-voltage circuit system. Thus, the potential safety risk between the two is reduced.

[0022] (4) The electrostatic powder spray gun outlet flow rate distribution is uniform. First, when the first rotary body is in the vertical upward spraying state, the non-bend structure of the powder conveying pipeline in the base, the powder conveying pipeline in the spray gun body and the powder conveying pipeline in the first rotary body are in a parallel state. In this state, the flow rate unevenness caused by the two bend structures can offset each other. Second, whether the first rotary body is in the vertical upward spraying state or the horizontal spraying state, the rectifier in the pipeline at the outlet of the first bend can eliminate the vortex caused by the bend structure of the powder conveying pipeline in the first rotary body, so that the powder coating flow rate distribution at the nozzle is uniform.

[0023] (5) The powder coating can be more fully atomized in the powder conveying pipeline. The second bend, the first bend and the rectifier increase the collision probability of the powder coating in the pipeline, so that the powder coating is fully dispersed in the collision, achieving good atomization effect. BRIEF DESCRIPTION OF DRAWINGS

[0024] The present application will be described in further detail below with reference to the drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only simple schematic drawings drawn for the purpose of explaining the preferred embodiments, and therefore should not be considered as limiting the scope of the present application. In addition, unless specifically indicated, the drawings only schematically represent the composition or structure of the described objects and can include exaggerated displays, and the drawings are not necessarily drawn to scale.

[0025] Figure 1 It is a left view reference plane structure schematic diagram of the present application.

[0026] Figure 2 It is a schematic diagram of the decomposed structure of the right-view reference plane of the present invention.

[0027] Figure 3 This is a cross-sectional schematic diagram of the present invention spraying vertically upwards on the back cavity of an automobile wheel.

[0028] Figure 4 This is a cross-sectional schematic diagram of the horizontal spraying groove structure on the back cavity of an automobile wheel according to the present invention.

[0029] Figure 5 This is a cross-sectional diagram of a traditional electrostatic powder spray gun spraying on the back cavity of a car wheel.

[0030] Figure 6 This is an enlarged isometric diagram of the rectifier.

[0031] The specific descriptions of the reference numerals are as follows: 1. first rotating body; 1-1. first rotating body shell; 1-2. powder conveying pipe inside the first rotating body; 1-3. high-voltage conductive line inside the first rotating body; 1-4. high-voltage conductive ring of the first rotating body; 1-5. corona needle; 1-6. fan-shaped nozzle; 1-7. rectifier installation point; 2. second rotating body; 2-1. second rotating body shell; 2-2: powder conveying pipe inside the second rotating body; 2-3. high-voltage conductive line inside the second rotating body; 2-4. high-voltage conductive ring of the second rotating body Ring; 2-5, first transmission gear set; 2-6, first motor; 3, base; 3-1, base housing; 3-2, powder conveying pipeline in the base; 3-3, high-voltage conductive circuit in the base; 3-4, second transmission gear set; 3-5, second motor; 4, spray gun body; 4-1, spray gun body housing; 4-2, powder conveying pipeline in the spray gun body; 4-3, high-voltage conductive circuit in the spray gun body; 4-4, pressure multiplier block; 4-5, stepper motor power signal circuit, providing power and control signals for the first motor and the second motor. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to the accompanying drawings and embodiments, but the contents do not constitute a limitation of the present invention.

[0033] Figure 1 and Figure 2 The specific implementation scheme of the dual-degree-of-freedom electrostatic powder spray gun of the present invention includes a first rotating body 1, a second rotating body 2, a base 3 and a spray gun body 4.

[0034] like Figure 1 As shown, the first rotating body 1 is connected to the right side of the top of the second rotating body 2. A sleeve is provided at the end of the first rotating body shell 1-1, and the first rotating body 1 is connected to the powder conveying pipe 2-2 in the second rotating body through the sleeve by a bearing, and can be parallel to the front reference plane (the plane is Figure 2The device is free to rotate on a plane (the plane shown).

[0035] like Figure 3 As shown, the second rotating body 2 is connected to the base, and a sleeve is provided at the bottom right of the bottom cavity of the second rotating body. The sleeve can be inserted into the right side of the top cavity of the base. The second rotating body 2 is connected to the powder conveying pipe 3-2 in the base through the sleeve by a bearing. The second rotating body can be parallel to the upper reference plane (the plane can be Figure 1 and Figure 2 The center of rotation of the base is coincident with the center of the powder transmission line 3-2 in the base. Figure 2 As shown, the base 3 is fixed to the top of the spray gun body 4 and cannot rotate.

[0036] For the first rotating body 1, if Figure 3 As shown in the exploded structural diagram, the first rotating body housing 1-1 contains a first rotating body powder conveying pipe 1-2, a first rotating body high-voltage conductive line 1-3, a first rotating body high-voltage conductive ring 1-4, a corona needle 1-5, and a fan-shaped nozzle 1-6. The internal chamber of the first rotating body housing 1-1 can be divided into a top chamber and a bottom chamber.

[0037] For the second rotating body 2, if Figure 3 As shown in the exploded structural diagram, the second rotating body housing 2-1 contains the second rotating body powder conveying pipeline 2-2, the second rotating body high-voltage conductive line 2-3, the second rotating body high-voltage conductive ring 2-4, the first transmission gear set 2-5, and the first motor 2-6. The internal chamber of the second rotating body housing 2-1 can be divided into a top chamber and a bottom chamber.

[0038] For base 3, if Figure 3 As shown in the schematic diagram of the decomposed structure, the base shell 3-1 includes a base powder conveying pipeline 3-2, a base high-voltage conductive line 3-3, a first transmission gear set 2-5, and a first motor 2-6.

[0039] For the spray gun body 4, as Figure 3 As shown in the exploded structural diagram, the spray gun main body shell 4-1 includes a powder delivery pipeline 4-2, a high-voltage conductive line 4-3, a pressure multiplier block 4-4, a stepper motor power supply and a signal line 4-5.

[0040] The powder delivery pipeline of the present invention is composed of the powder delivery pipeline 1-2 in the first rotating body, the powder delivery pipeline 2-2 in the second rotating body, the powder delivery pipeline 3-2 and the powder delivery pipeline 4-2 in the spray gun body. A rectifier is set inside the powder delivery pipeline 1-2 in the first rotating body, and the rectifier is located at point 1-7. The rectifier structure is as follows Figure 6 In the powder conveying pipe 1-2 in the first rotating body, the cylinder of the rectifier grid structure is coaxial with the powder pipe.

[0041] The power required for the rotation of the second rotating body 2 is provided by the second motor 3-5. The rotating shaft of the second motor 3-5 drives the second gear set 3-4 to rotate. The sleeve surface at the bottom of the second rotating body shell 2-1 is provided with gears to transfer power to the sleeve of the shell 2-1, thereby driving the second rotating body 2 to rotate.

[0042] The power required for the rotation of the first rotating body 1 is provided by the first motor 2-6. The rotating shaft of the first motor 2-6 drives the first gear set 2-5 to rotate. The sleeve surface at the bottom of the first rotating body shell 1-1 is provided with gears to transfer power to the sleeve of the shell 1-1, thereby driving the first rotating body 1 to rotate.

[0043] The first motor 2-6 and the second motor 3-5 in this example are both step motors. As shown in Figure 3 , the power supply and signal lines 4-5 of the step motor are sealed inside the spray gun, and the first motor 2-6, the second motor 3-5, and their lines are located on the left side of the powder conveying pipeline 2-2 in the second rotating body, the powder conveying pipeline 3-2 in the base, and the powder conveying pipeline 4-2 in the spray gun body.

[0044] The built-in high-voltage circuit of the present application is composed of a voltage doubler 4-4, a high-voltage conductive circuit, a high-voltage conductive ring, and a corona needle 1-5. The high-voltage conductive circuit is composed of a first-rotating-body-internal high-voltage conductive circuit 1-3, a second-rotating-body-internal high-voltage conductive circuit 2-3, a base-internal high-voltage conductive circuit 3-3, and a spray-gun-body-internal high-voltage conductive circuit 4-3. The high-voltage conductive ring 1-4 is located inside the first rotating body shell 1-1. The high-voltage conductive ring 2-4 is located inside the sleeve structure of the second rotating body shell 2-1. The inner cylindrical surface and the outer cylindrical surface of the high-voltage conductive ring 2-4 are both wrapped by the shell 2-1 and physically isolated from the bottom cavity of the second rotating body 2. As shown in Figure Three , the second-rotating-body-internal high-voltage conductive circuit 2-3 is located on the right side of the powder conveying pipeline 2-2 in the second rotating body, and the second-rotating-body-internal high-voltage conductive circuit 2-3 is located on the right side of the powder conveying pipeline 3-2. The spray-gun-body-internal high-voltage conductive circuit 4-3 and the voltage doubler 4-4 are located on the right side of the powder conveying pipeline 4-2.

[0045] The motors and their lines and the voltage doubler and its lines in this example are located on one side of the powder conveying pipeline. The powder conveying pipeline and the corresponding shell part physically isolate the high-voltage circuit from the low-voltage circuit.

[0046] The application will be described in detail below in conjunction with the drawings, examples, and application examples, but the content described does not constitute a limitation on the application.

[0047] Figure 4 and Figure 5 , example A1 is Figure 1 , Figure 2 andFigure 3 The double-degree-of-freedom spray gun

[0048] With the automobile wheel as the construction object, the application effect of the embodiment A1 of the present application is as follows: (1) as shown in Figure 4 When spraying the back cavity of the automobile wheel, the first rotating body 1 of the embodiment A1 can be rotated to a near-horizontal state, so that the fan-shaped nozzle is directly opposite the back cavity groove structure for spraying; (2) as shown in Figure 5 When spraying the back cavity of the automobile wheel, the first rotating body 1 of the embodiment A1 can be rotated to a vertical state, so that the fan-shaped nozzle is directly opposite the back cavity groove structure for spraying.

[0049] Figure 6 Among them, the spray gun B1 is a traditional electrostatic powder spray gun. By comparing Figure 4 、 Figure 5 and Figure 6 , it is not difficult to conclude that the embodiment A1 of the present application can better spray the groove structure than the spray gun B1.

[0050] The following table compares the powder coating film thickness coverage of the groove structure when the spray gun B1 and the embodiment A1 spray the back cavity of the wheel. The samples are two identical automobile wheels, and the five groups of data are respectively:

[0051]

[0052]

[0053] From the above table, it is not difficult to conclude that the corresponding example A1 of the present application can make the powder coating of the groove structure of the back cavity of the wheel more uniform, thereby reducing the amount of powder coating.

Claims

1. An electrostatic powder spray gun with two degrees of freedom, characterized by: The invention comprises a first rotating body (1), a second rotating body (2), a base (3) and a spray gun body (4), wherein the first rotating body (1), the second rotating body (2) and the base (3), the first rotating body comprises a nozzle (1-6), the first rotating body (1) is connected to the side of the second rotating body (2) by a bearing and can be freely rotated to a fixed angle on a vertical plane, and the second rotating body (2) is connected to the top of the base (3) by a bearing and can be freely rotated to a fixed angle on a horizontal plane; The first rotating body powder conveying pipe (1-2) and the second rotating body powder conveying pipe (2-2) each have an elbow, and the bending angles of the two elbows are equal and greater than or equal to ninety degrees. The base powder conveying pipe (3-2), the spray gun body powder conveying pipe (4-2), the portion below the elbow structure of the second rotating body powder conveying pipe (2-2), and the portion above the elbow structure of the first rotating body powder conveying pipe (1-2) are all vertical pipes. The end of the first rotating body powder conveying pipe (1-2) is equipped with a corona needle (1-5) and a fan-shaped nozzle (1-6). Stepper motors are respectively built into the second rotating body (2) and the base (3); the first motor (2-6) in the second rotating body (2) is located directly below the powder pipelines of the two elbows, and the initial position of the second motor (3-5) in the base (3) is directly below the first motor (2-6); A second rotating body high-voltage conductive ring (2-4) is provided between the second rotating body high-voltage conductive circuit (2-3) and the base high-voltage conductive circuit (3-3). When the base high-voltage conductive circuit (3-3) rotates relative to the second rotating body high-voltage conductive ring (2-4), the second rotating body high-voltage conductive ring (2-4) remains energized. A first rotating body high-voltage conductive ring (1-4) is provided between the first rotating body high-voltage conductive circuit (1-3) and the second rotating body high-voltage conductive circuit (2-3). When the second rotating body high-voltage conductive circuit (2-3) rotates relative to the first rotating body high-voltage conductive ring (1-4), the first rotating body high-voltage conductive ring (1-4) remains energized. The first rotating body high-voltage conductive ring (1-4) is located in the first rotating body housing (1-1), and the second rotating body high-voltage conductive ring (2-4) is located in the second rotating body housing (2-1).

2. The electrostatic powder spray gun with two degrees of freedom according to claim 1, characterized in that: The first rotating body shell (1-1), the second rotating body shell (2-1), the base shell (3-1) and the spray gun main body shell (4-1) are connected in sequence.

3. The electrostatic powder spray gun with two degrees of freedom according to claim 1, characterized in that: The powder conveying pipe (1-2) in the first rotating body has a built-in rectifier, which is constructed as a multi-layer cylindrical grid structure. The installation point is at the elbow fluid outlet, and the installation posture is that the cylindrical grid structure and the powder conveying pipe (1-2) in the first rotating body are coaxial.

4. The electrostatic powder spray gun with two degrees of freedom according to claim 1, characterized in that: The stepper motor power signal circuit (4-5) is arranged close to the powder conveying pipe (4-2) in the spray gun body, the powder conveying pipe (3-2) in the base, and the powder conveying pipe (2-2) in the second rotating body.

5. The electrostatic powder spray gun with two degrees of freedom according to claim 1, characterized in that: The first motor (2-6), the second motor (3-5) and the stepper motor power signal circuit (4-5) constitute a low-voltage system of the spray gun, and the corona needle (1-5), the high-voltage conductive circuit (2-3) in the second rotating body, the high-voltage conductive circuit (3-3) in the base, the high-voltage conductive circuit (4-3) in the spray gun body, the first rotating body high-voltage conductive ring (1-4), the second rotating body high-voltage conductive ring (2-4), and the pressure multiplier block (4-4) constitute a high-voltage system of the spray gun, which is isolated and separated by the powder transmission system and the spray gun housing.

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