Coating method and coating system

Abstract

To provide a coating method and a coating system for the blade surface of a fan blade or a guide vane (blade), which can form a coated film having a desired width and a smooth surface at each part only with minor liquid dripping of paint.SOLUTION: In this method, a blade is held in a state where the span direction of the blade coincides with a horizontal direction and the blade turns about a pivot extending in the span direction, a spray gun that sprays paint downward toward the pivot is moved so as to form a coated film along a coating path on the coated surface of the blade, the coating path includes a plurality of coating sections separated from each other in the span direction to extend between the front edge and the rear eade of the blade, the blade is held in a state where a segment connecting intersection points of a line projecting a line constituting the coating sections on the coated surface and each of the front and rear edges is maintained horizontal, and the direction of the center axis of the spray gun is changed so as to be always perpendicular to the coated surface.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a painting method and a painting system, and in particular to a painting method and a painting system suitable for applying paint to the surfaces of the airfoils of fan blades and guide vanes of turbofan engines (hereinafter referred to as "airfoil surfaces"). [Background technology]

[0002] 2. Description of the Related Art A turbofan engine, which is a propulsion system for aircraft, is composed of a fan and a core engine that is arranged coaxially behind the fan and has a turbine for driving the fan.

[0003] The fan includes a generally cylindrical fan case, a generally cylindrical fan disk configured to rotate within the fan case, a plurality of fan blades attached to the outer periphery of the fan disk, and guide vanes attached to the inner periphery of the fan case aft of the fan blades. The fan disk is rotated by a turbine connected via a shaft.

[0004] During operation of a turbofan engine, the fan blades rotate together with the fan disk, drawing air into the fan. Some of the air flows into the core engine, where it generates high-temperature, high-pressure gas to drive the turbine, while the rest flows into a passage that bypasses the core engine, where it is straightened by guide vanes and then discharged from the rear, contributing to the generation of most of the thrust.

[0005] In order to reduce weight, the fan blades and guide vanes of a turbofan engine, including their airfoils, are manufactured from, for example, aluminum or FRP. When a turbofan engine is in operation, the air sucked into the fan may contain foreign objects such as sand grains, pebbles, and ice chips. Collisions with such foreign objects can cause damage (erosion) to the airfoils of the fan blades and guide vanes.

[0006] For this reason, in order to protect the leading edges of fan blades and guide vanes, which are most susceptible to collision with foreign objects, a sheath made of an abrasion-resistant material is bonded to cover the leading edges, and an erosion-resistant paint is applied to the entire surface except for the sheath.

[0007] When painting the blade surfaces of fan blades or guide vanes, the fan blades or guide vanes are usually fixed in the painting equipment by fixing their blade roots (the parts that are attached to adjacent parts such as fan disks and fan cases) to a jig. The jig has a groove with a shape complementary to the blade root, and the fan blades or guide vanes are fixed to the jig by inserting the blade roots into the groove and then restraining their movement in an appropriate manner. The blade roots of the fan blades or guide vanes are inserted into and removed from the grooves of the jig while the worker supports the blade roots with his or her hand. This is because supporting the blades with their hands may impair the surface smoothness of the paint film (hereinafter referred to as the "coat") formed on the blade surfaces immediately after painting is completed.

[0008] As described above, when an operator holds the root of a fan blade or guide vane with his or her hand, the fan blade or guide vane is usually in a vertical position (with the blade located above the root). This is because if the fan blade or guide vane is in a horizontal position (i.e., with the blade located to the side of the root), the weight of the blade must be cantilevered by the root located at one end of it, making handling difficult.

[0009] Considering these circumstances, painting of the blade surfaces of fan blades and guide vanes has conventionally been performed with the fan blades and guide vanes in a vertical position. In this position, the span direction of the blades of the fan blades and guide vanes (i.e., the direction that coincides with the radial direction of the fan when assembled with adjacent parts such as the fan disk and fan case) coincides with the vertical direction. In this position, the blade surface to be painted extends roughly along the vertical direction. Summary of the Invention [Problem to be solved by the invention]

[0010] As described above, when painting fan blades or guide vanes in a vertical position, paint is sprayed while moving the spray gun generally horizontally so that a coating is formed along the paint path on the surface of the fan blade or guide vane.

[0011] At this time, a large amount of paint is sprayed on the part of the blade surface where the thickness of the coating film needs to be increased. However, in this part, a phenomenon occurs in which part of the paint attached to the blade surface flows downward due to the action of gravity (dripping). Therefore, for the part where the thickness of the coating film needs to be increased as described above, a process of spraying a small amount of paint that does not cause dripping is conventionally repeated multiple times to form a coating film of the desired thickness by stacking thin coating films. However, this method has the problem that it takes a long time to paint, and it is difficult to obtain surface smoothness with a thin coating film, and the coating film obtained by stacking them also has poor surface smoothness.

[0012] The present disclosure has been made in consideration of the above problems, and has an object to provide a painting method and painting system for the blade surfaces of fan blades and guide vanes, which can form a coating film having a desired thickness and a smooth surface in each area in a short period of time without causing paint dripping that would cause unacceptable changes to the coating thickness. [Means for solving the problem]

[0013] In order to solve the above problems, a first aspect of the present disclosure provides a coating method for coating the blade surface of a fan blade or guide vane of a turbofan engine, the fan blade or guide vane being held in a state in which its span direction coincides with the horizontal direction and in a state in which it can be rotated around a pivot extending in the span direction, a spray gun that sprays paint downward in the direction of its central axis being moved to form a coating film along a coating path on a surface to be coated located at the upper side of the blade surface, the coating path including a plurality of coating sections that are spaced apart from each other in the span direction and extend between a leading edge and a trailing edge of the fan blade or guide vane, while the spray gun moves to form the coating film along each of the coating sections, the fan blade or guide vane being held in a state in which line segments connecting intersections of lines constituting the coating sections projected vertically onto the surface to be coated and each of the leading edge and the trailing edge are maintained horizontal, and the direction of the central axis of the spray gun is changed so as to always be perpendicular to the surface to be coated.

[0014] In a painting method of a second aspect of the present disclosure, after the spray gun moves along one of the multiple painting sections and reaches its end point, while moving to the start point of the next painting section, the fan blade or guide vane is rotated about the pivot axis so that the line segment is maintained horizontal in the next painting section.

[0015] In a painting method of a third aspect of the present disclosure, the fan blade or guide vane is provided with a sheath covering the leading edge, and when the spray gun is in a spray gun forward inclination section of each of the painting sections where the intersection of the central axis and the surface to be painted is a distance measured rearward from the rear end face of the sheath that is less than or equal to the width of the spray pattern formed on the surface to be painted by the paint sprayed from the spray gun, the direction of the central axis of the spray gun is inclined toward the leading edge with respect to a direction perpendicular to the surface to be painted, and when the spray gun is in a section of each of the painting sections other than the spray gun forward inclination section, the direction of the central axis of the spray gun coincides with the direction perpendicular to the surface to be painted.

[0016] A painting system according to a first aspect of the present disclosure is for painting the blade surface of a fan blade or guide vane of a turbofan engine, and includes a painting robot, a paint supply device, a workpiece handling device having a workpiece holding unit, and a control device for controlling the operation of the painting robot, the paint supply device, and the workpiece handling device, wherein the painting robot moves a spray gun that sprays paint downward so that a coating film is formed along a painting path on a surface to be painted that is located on the upper side of the blade surface, and the workpiece holding unit rotates the fan blade or guide vane so that its span direction coincides with the horizontal direction and around a pivot axis extending in the span direction during painting. The painting path includes a plurality of painting sections spaced apart from one another in the span direction and extending between the leading edge and the trailing edge of the fan blade or guide vane, and the control device is configured to control the operation of the workpiece holding part so that, while the spray gun moves along each of the painting sections to form the coating film, the fan blade or guide vane is held in a state in which a line segment connecting the intersection points of a line constituting the painting section projected vertically onto the surface to be painted and each of the leading edge and the trailing edge is maintained horizontal, and to control the operation of the painting robot so that the direction of the central axis of the spray gun is always perpendicular to the surface to be painted.

[0017] In a painting system of a second aspect of the present disclosure, after the spray gun moves along one of the multiple painting sections and reaches its end point, while the spray gun moves to the start point of the next painting section, the workpiece holding unit rotates the fan blade or guide vane around the pivot axis so that the line segment is maintained horizontal even in the next painting section.

[0018] In the painting system according to the third aspect of the present disclosure, the object holder can also support the fan blade or guide vane so that its span direction coincides with the vertical direction. Effect of the Invention

[0019] According to the present disclosure, it is possible to obtain the excellent effect of forming a coating film having a desired thickness and a smooth surface in a short period of time on each portion of the blade surface of a fan blade or guide vane without causing paint dripping that would cause unacceptable changes to the thickness of the coating film. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a schematic explanatory diagram showing an example of a painting pass when painting the blade surface of a fan blade of a turbofan engine using the painting method of the present disclosure. [Diagram 2] 1 is a schematic explanatory diagram showing the attitude of a fan blade and the tilt of a spray gun when the spray gun is moved along one painting section of a painting pass when painting the positive pressure surface of a fan blade. FIG. [Diagram 3] 1 is a schematic explanatory diagram showing the attitude of a fan blade and the tilt of a spray gun when the spray gun is moved along one painting section of a painting pass when painting the negative pressure surface of a fan blade. FIG. [Figure 4] 2 is a schematic diagram showing how the spray from a spray gun flows along the surface of a fan blade. [Diagram 5]FIG. 1 is a schematic diagram showing the effect that the orientation of a spray gun has on the surface condition of a coating film formed on a blade surface near the rear of the sheath in a fan blade having a sheath on the leading edge. [Figure 6] This is a schematic explanatory diagram showing the posture of the fan blade and the inclination of the spray gun when moving the spray gun along one painting section of the painting pass when painting the positive pressure surface of a fan blade having a sheath on its leading edge. [Figure 7] This is a schematic explanatory diagram showing the posture of the fan blade and the inclination of the spray gun when moving the spray gun along one painting section of the painting pass when painting the negative pressure surface of a fan blade having a sheath on its leading edge. [Figure 8] FIG. 1 is a schematic diagram illustrating a coating system according to the present disclosure in the form of a state at each step of a coating method according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The coating method and coating system of the present disclosure will be described in detail below with reference to the drawings. Note that the coating method and coating system will be described below with reference to the drawings, taking as an example a case where an erosion-resistant paint is applied to the blade surface of a fan blade of a turbofan engine.

[0022] The greatest feature of the coating method of the present disclosure is that the surface to be coated is kept generally horizontal as a whole, and paint is sprayed vertically onto the surface from above.

[0023] More specifically, paint is sprayed while the direction of the central axis of the spray gun is constantly changed so that it is perpendicular to the surface to be painted, while the line segments connecting the intersections of the lines constituting the painting section projected vertically onto the wing surface (surface to be painted) and the leading and trailing edges of the wing portion are maintained horizontal as the spray gun moves along the painting section described below.

[0024] Here, painting is performed by moving the spray gun so that a paint film is formed along the painting path on the surface of the fan blade. Figure 1 shows an example of a painting path when painting the surface of a fan blade of a turbofan engine.

[0025] This figure shows the blade surface of a fan blade FB viewed from above in the vertical direction, with the span direction S of the blade portion coinciding with the horizontal direction. Here, the span direction S is the direction connecting the hub portion H and the tip portion T of the blade portion of the fan blade FB, and coincides with the radial direction of the fan (not shown) when assembled to a fan disk (not shown). The blade surface shown in this figure is located on the upper vertical side and is the surface to be painted, and will hereinafter be referred to as the surface to be painted.

[0026] In the illustrated example, the painting pass P includes a plurality of painting sections ZC spaced apart from one another in the span direction S of the fan blade FB. Each painting section ZC generally extends between a leading edge LE and a trailing edge TE in a direction perpendicular to the span direction S, i.e., along a chord direction C (hereinafter also referred to as the longitudinal direction).

[0027] In the illustrated example, all of the lines that make up the painting section ZC are (single) line segments, but they may also be formed by connecting two or more line segments of different directions (broken line) or curves, and further, they may be formed by connecting line segments or broken lines and curves in any manner.

[0028] The two painting sections ZC adjacent in the span direction S are connected to each other at their ends (points on the leading edge LE or the trailing edge TE) via transition sections ZT that are substantially U-shaped and set on imaginary planes in front of the leading edge LE and behind the trailing edge TE, respectively. As a result, the painting path P is formed in a zigzag shape as a whole.

[0029] Painting is performed by continuously moving the spray gun along the painting path P from the start point PS to the end point PE, and repeatedly spraying the erosion-resistant paint while moving through each painting section ZC. The movement of the spray gun along the painting path P can be performed using an industrial robot such as an articulated robot. The positions of the start point PS and the end point PE are not limited to those shown in the figure. For example, the start point PS may be located on the leading edge LE side rather than the trailing edge TE side as shown in the figure, and may also be located on the hub portion H side rather than the tip portion T side of the wing portion (the same applies to the end point PE).

[0030] The airfoil surface of the fan blade FB consists of a pressure surface SP and a suction surface SS, each of which extends from the leading edge LE to the trailing edge TE, and the intersection curves between the vertical plane including the lines constituting each coating zone ZC and the pressure surface SP and suction surface SS are concave curves CP and convex curves CS, respectively (see Figures 2 and 3). Here, the "vertical plane including the lines constituting the coating zone ZC" refers to the surface obtained as the trajectory of the line constituting the coating zone ZC when it is translated in the vertical direction (for example, if the line constituting the coating zone ZC is a line segment, then the vertical plane including that line segment).

[0031] On the other hand, in modern turbofan engines, both the pressure surface SP and the suction surface SS of the fan blade FB are configured as complexly curved three-dimensional surfaces. Therefore, the shapes of the curves CP and CS described above differ depending on the coating section ZC. In other words, the degree of inclination of the curves CP and CS relative to the horizontal as a whole differs depending on the coating section ZC.

[0032] Therefore, when the spray gun moves along the painting path P shown in Figure 1, if the posture of the fan blade FB remains the same, the degree of inclination of the blade surface directly below the spray gun relative to the horizontal will differ depending on the painting section ZC.

[0033] At this time, when the spray gun passes through the coating section ZC where the blade surface directly below has only a slight inclination with respect to the horizontal, the sprayed paint forms a uniform coating of the specified thickness on the blade surface without dripping that would cause unacceptable changes in the coating thickness.

[0034] On the other hand, when the spray gun passes through the coating zone ZC where the blade surface directly below is significantly inclined with respect to the horizontal direction, the sprayed paint first adheres to the blade surface and then flows down (drip) to lower parts of the blade surface due to the action of gravity, causing an unacceptable change in the thickness of the coating. Therefore, in such a case, it is not possible to form a coating film of a predetermined uniform thickness.

[0035] Therefore, in the coating method of the present disclosure, when the spray gun moves along the coating path P shown in Fig. 1, the fan blade FB is rotated about a pivot axis extending in the span direction S as necessary so that, for each coating section ZC, the line segments connecting the intersections of the lines formed by projecting the lines constituting the coating section ZC vertically onto the blade surface (surface to be coated) with the leading edge and the trailing edge of the blade are maintained horizontal. At the same time, while the spray gun moves along each coating section ZC, the direction of the central axis of the spray gun is changed so that the central axis is always perpendicular to the surface to be coated. This will be described below with reference to Figs. 2 and 3.

[0036] 2 and 3 are schematic diagrams showing the attitude of the fan blade FB as the spray gun G moves along a coating section when coating the pressure surface SP and suction surface SS (surface to be coated) of the fan blade FB, and the inclination of the spray gun G. Note that in these figures, the fan blade FB is shown as a cross section cut by a vertical plane including a line that constitutes the coating section, but here the cross section is simply shown as a curve (the curve CP that constitutes the pressure surface SP in Fig. 2, and the curve CS that constitutes the suction surface SS in Fig. 3).

[0037] The fan blade FB is attached to the fan blade holding part HA of the fan blade handling device HA, which will be described later. H 8), and while the spray gun G moves along one coating section, the fan blade FB is held in such an orientation that the line segment CL connecting the leading edge LE and the trailing edge TE of the curve CP or the curve CS is horizontal, as shown in Figs.

[0038] Then, while the spray gun G moves along the transition section to the start point of the next coating section after moving along the above-mentioned coating section, the above-mentioned jig rotates the fan blade FB about a rotation axis extending in the span direction S (the direction perpendicular to the paper in Figures 2 and 3) so that the line segment CL is horizontal in the next coating section as well. Note that, needless to say, if the directions of the line segment CL corresponding to the two above-mentioned coating sections are the same, there is no need to rotate the fan blade FB.

[0039] 2 and 3, the spray gun G is moved in the order of (a) → (b) → (c) → (d) (or vice versa). At each of the positions (a), (b), (c), and (d), the central axis G of the spray gun G is C and the intersection point X of the surface to be coated (positive pressure surface SP or negative pressure surface SS) a ~X d Tangent XT to curve CP or curve CS in a ~XT d are the central axis G of the spray gun G. C This is achieved by rotating a spray gun G held at the tip of an arm of a painting robot CR (see FIG. 8) described later, about a rotation axis extending in the span direction S according to the position of the spray gun G.

[0040] In addition, each of Figures 2 and 3 illustrates a case in which the spray gun G moves so that the distance between it and the surface to be painted (positive pressure surface SP or negative pressure surface SS) located directly below it is always approximately constant, but the distance may also be changed depending on the position along the painting section ZC.

[0041] Here, points to be noted in order to form a coating film of a desired thickness in the coating method of the present disclosure will be described below.

[0042] Figure 4 is a schematic diagram showing how the spray flow from the spray gun G (a flow consisting of paint and air for atomizing the paint (i.e., breaking it into tiny droplets)) flows along the blade surface (surface to be painted) of the fan blade FB, with Figure 4(a) showing the flow along the positive pressure surface SP and Figure 4(b) showing the flow along the negative pressure surface SS.

[0043] As shown in Figure 4(a), the spray flow from the spray gun G to the pressure surface SP forms a recirculation area on the outer periphery due to the concave curvature of the pressure surface SP. As a result, some of the paint in the spray flow does not adhere to the pressure surface SP immediately after collision but gets caught in the recirculation flow, and then adheres to and accumulates on the pressure surface SP after circulation.

[0044] On the other hand, as shown in Figure 4(b), the spray from the spray gun G to the suction surface SS flows away from the outer periphery due to the convex curvature of the suction surface SS. Therefore, unlike the case of the positive pressure surface SP, any paint in the spray that does not adhere to the suction surface SS immediately after collision flows away to the periphery and does not adhere or accumulate later.

[0045] Since the spray flow from the spray gun G to each of the positive pressure surface SP and the negative pressure surface SS exhibits the tendencies described above, when the state of the spray flow from the spray gun G is the same, the coating film formed on the positive pressure surface SP tends to be relatively thicker than the coating film formed on the negative pressure surface SS.

[0046] Furthermore, although not illustrated, when the state of the spray flow from the spray gun G is the same, the coating film formed when the spray gun G is moved slowly along the coating zone ZC has the characteristic of being relatively thicker than the coating film formed when the spray gun G is moved at high speed. This is because when the spray gun G is moved slowly, the amount of paint sprayed per unit length on the coating zone ZC is greater than when the spray gun G is moved at high speed.

[0047] When moving the spray gun G, the movement speed of the spray gun G can be adjusted taking into account the above-mentioned tendencies or characteristics, thereby forming a coating film of the desired thickness at each location in the coating zone ZC.

[0048] Incidentally, Figures 2 and 3 have described the posture of the fan blade FB and the inclination mode of the spray gun G when the spray gun G is moved along one painting section for a fan blade FB that does not have a sheath covering its leading edge (leading edge LE and its vicinity (positive pressure surface SP side and negative pressure surface SS side)).

[0049] However, it has been found that when a sheath is provided, the formation of a coating at the step between the blade surface and the sheath is significantly affected by the direction of the spray flow from the spray gun, as will be described below.

[0050] Fig. 5 is a schematic diagram for explaining the effect that the orientation of a spray gun G has on the surface condition of a coating film formed on the blade surface in the rear vicinity of a sheath SH of a fan blade FB having a sheath SH at its leading edge. Note that the figure illustrates an example in which painting is performed on a pressure surface SP. In addition, to make it easy to visually distinguish the difference between (a) and (b), the position of the fan blade FB (in the direction of rotation described above) is fixed, and the orientation of the spray gun G is changed.

[0051] As shown in the upper diagram of FIG. 1(a), the spray gun G is rotated along its central axis G CWhen the sheath SH is tilted backward (to the right in the figure) with respect to a straight line N perpendicular to a tangent (not shown) to the curve CP at the intersection X between the sheath SH and the blade surface (pressure surface SP) (see arrow RWD), a flow is generated behind the sheath SH that erodes the surface of the coating film being formed there. For this reason, when paint is sprayed with the spray gun G tilted backward as described above, the coating film that is formed will have a recess RS on its surface, as shown in the lower diagram in Figure (a). As a result, the formed coating film FS (the surface is indicated in the figure) is smaller than the designed coating film FS D (Similarly, the figure indicates the surface) and as a result will have thicker and thinner parts.

[0052] In contrast, as shown in the upper diagram of FIG. 1(b), the spray gun G is rotated along its central axis G C If the sheath SH is tilted forward (leftward in the figure) with respect to the straight line N perpendicular to the tangent (not shown) of the curve CP at the intersection X between the sheath SH and the blade surface (pressure surface SP) (see arrow FWD), no flow will be generated behind the sheath SH that will erode the surface of the coating film being formed there. For this reason, if paint is sprayed with the spray gun G tilted forward as described above, the designed coating film FS D It is possible to form a coating film FS having a smooth surface that generally corresponds to the surface roughness of the coating film FS.

[0053] In view of the above, for a fan blade FB having a sheath SH on its leading edge, it is desirable to tilt the spray gun G in a manner similar to that described with reference to Figures 2 and 3 when moving the spray gun G along one coating section, and to tilt the spray gun G forward compared to the manner described with reference to Figures 2 and 3 when forming a coating film on the blade surface in the rear vicinity of the sheath SH. Such a manner of tilting the spray gun G will be described below with reference to Figures 6 and 7.

[0054] 6 and 7 are schematic diagrams showing the attitude of a fan blade FB and the inclination of a spray gun G as the spray gun G moves along a coating section when coating the pressure surface SP and suction surface SS (surface to be coated) of a fan blade FB having a sheath SH provided on its leading edge. Note that in these figures, as in Figures 2 and 3, the fan blade FB is simply shown as a curve CP (Figure 6) constituting the pressure surface SP or a curve CS (Figure 7) constituting the suction surface SS.

[0055] The fan blade FB is attached to the fan blade holding part HA of the fan blade handling device HA, which will be described later. H 8), and while the spray gun G moves along one coating section, the fan blade FB is held in an attitude such that the line segment CL connecting the leading edge LE of the sheath SH and the trailing edge TE of the curve CP or the curve CS is horizontal, as shown in Figures 6 and 7, respectively.

[0056] Then, after the spray gun G moves along the above-mentioned coating section and reaches its end point, while it moves along the transition section to the start point of the next coating section, the above-mentioned jig rotates the fan blade FB about a rotation axis extending in the span direction S (the direction perpendicular to the paper in Figures 6 and 7) so that the line segment CL is horizontal in the next coating section as well. It goes without saying that if the directions of the line segment CL corresponding to the above-mentioned two coating sections are the same, there is no need to rotate the fan blade FB.

[0057] In each of Figures 6 and 7, the spray gun G is moved in the order of (a) -> (b) -> (c) -> (d) -> (e) (or vice versa).

[0058] In each of the positions (a), (c), (d), and (e) other than (b), the central axis G of the spray gun G CThe tangent of the curve CP or the curve CS (the curve constituting the surface of the sheath SH in (a)) at the intersection of the curve CP and the surface to be coated (the positive pressure surface SP or the negative pressure surface SS) (the surface of the sheath SH in (a)) is the central axis G of the spray gun G. C (In order to avoid complicating the drawing due to the inclusion of the sheath SH, the intersections and tangents are omitted.) This is also achieved by rotating the spray gun G held at the tip of the arm of a painting robot CR (see FIG. 8), which will be described later, around a rotation axis extending in the span direction S according to the position of the spray gun G.

[0059] On the other hand, as shown in (b), when the spray gun G is in a position to form a coating film on the surface to be coated near the rear of the sheath SH, the central axis G of the spray gun G C is the central axis G C and the intersection point X of the surface to be coated (positive pressure surface SP or negative pressure surface SS) b In the figure, the spray gun G is inclined forward (to the left in the figure) with respect to a straight line N perpendicular to a tangent to the curve CP or the curve CS (not shown for the same reason as above). The spray gun G is tilted by a robot that holds it (a painting robot CR, described later; see FIG. 8).

[0060] Strictly speaking, the forward tilt of the spray gun G is C and the intersection point X of the surface to be coated (positive pressure surface SP or negative pressure surface SS) b However, the spray gun forward tilt section ZC F This is done when the spray gun is in the forward tilt zone (ZC). F is the rear end surface SH of the sheath SH R This is the section where the distance measured from the tip to the rear is equal to or less than the width of the spray pattern formed on the surface to be coated by the paint sprayed from the spray gun G. In addition, it is desirable that the forward inclination angle θ of the spray gun G is 0<θ≦45°.

[0061] In addition, each of Figures 6 and 7 illustrates a case in which the spray gun G moves so that the distance between it and the surface to be painted (positive pressure surface SP or negative pressure surface SS) located directly below it is always approximately constant, but the distance may also be changed depending on the position along the painting section ZC.

[0062] In addition, for a fan blade FB having a sheath SH at its leading edge, when the erosion-resistant paint is applied to the entire blade surface including the sheath SH by the above-mentioned method, the thickness of the coating film formed on the surface of the sheath SH is made as thin as possible. This is because the sheath SH, which is made of an abrasion-resistant material, does not need to be covered with erosion-resistant paint in practice, and the coating film formed on its surface is removed by a method such as grinding after painting is completed in order to reduce the weight of the fan blade FB. In this way, after the coating film once formed on the surface of the sheath SH is removed, the surface of the sheath SH and the surface of the coating film formed on the blade surface excluding the sheath SH are flush with each other in the fan blade FB. This makes it possible to avoid a decrease in the aerodynamic performance of the fan blade FB due to steps remaining on the surface of the blade portion.

[0063] Next, a coating system for carrying out the coating method of the present disclosure described above will be described below with reference to FIG.

[0064] 8 is a schematic diagram showing the coating system of the present disclosure in each step of the coating method of the present disclosure described above. Note that, again, the coating of erosion-resistant paint on the blade surface of a fan blade of a turbofan engine will be described as an example.

[0065] The painting system CE includes a painting robot CR, a fan blade handling device HA (painted object handling device), a control device (not shown) that controls the operation of the painting robot CR and the fan blade handling device HA, and a paint supply device (not shown).

[0066] The painting robot CR is, for example, an industrial robot such as an articulated robot, and a spray gun G for spraying erosion-resistant paint onto the blade surface of the fan blade FB is attached to the tip of the arm.

[0067] The fan blade handling device HA is a device for handling the fan blades FB1 and FB2, and has a support part HA S And arm part HA A And arm part HA A The fan blade holding parts HA are provided at both ends of the H (Workpiece holding portion).

[0068] Support part HA S Arm part HA A (During painting, the fan blade holders HA on both ends H The fan support FB1 includes fan blades FB1 and FB2 held by the support FB1 and FB2, and has built-in servo motors and the like (not shown) for generating motions of the various parts described below.

[0069] Arm section HA A HA is the support part S 8A, the fan blade detachment position is configured to be slidable in the longitudinal direction between a reference position and a fan blade attachment / detachment position (see the arrow in FIG. 8A).

[0070] The reference position is the position when painting is performed, and is the arm part HA A The center of the longitudinal direction is the support part HA S In this position, the arm HA A HA is the support part S The actuator can rotate around its longitudinal center located directly above the actuator (see the arrow in FIG. 8(e)).

[0071] On the other hand, the fan blade attachment / detachment position is set by the worker W at the arm part HA A The fan blade holding portion HA at one end of the H This is the position when attaching or detaching the fan blade FB1 or FB2, and the arm section HAA is offset to the opposite side of the painting robot CR.

[0072] Fan blade holding part HA H is a portion for holding the fan blades FB1, FB2, and is provided with a groove (not shown) of a shape complementary to the blade roots of the fan blades FB1, FB2. After the blade roots of the fan blades FB1, FB2 are inserted into this groove, the fan blades FB1, FB2 are restrained from moving in an appropriate manner, so that the fan blades FB1, FB2 are held by the fan blade holding portion HA. H is fixed at.

[0073] In addition, the fan blade holding part HA H is configured to perform two types of rotational motion using the above-mentioned servo motor as a drive source.

[0074] The first rotational movement is the rotation of the support HA S The rotational motion is centered on an axis extending in the tangent direction of a circle centered at and is performed between the fan blade attachment / detachment position and the painting position.

[0075] The fan blade attachment and detachment position is the fan blade holding part HA. H When the fan blade holding portion HA holds the fan blades FB1, FB2, the span direction S of the fan blades FB1, FB2 coincides with the vertical direction. The painting position is a position where the span direction S of the fan blades FB1, FB2 coincides with the horizontal direction. H When the fan blade holding portion HA is in the fan blade attachment / detachment position, the fan blade FB1 or FB2 is attached or detached by the operator W (see FIG. 8(a)). H When the coating is in the coating position, coating is performed (see Fig. 8 (c), (d), and (f)).

[0076] The second rotational movement is the support HA S The rotational motion is centered on a rotation axis extending in the radial direction of a circle centered on the fan blade holding portion HA. HThis is a rotational motion around a pivot axis extending in the span direction S of the fan blades FB1, FB2 when the fan blades FB1, FB2 are held by the rotor 21 (see FIGS. 8(c), (d), and (f)).

[0077] The second rotational motion described above, as explained with reference to Figures 2 and 3, and Figures 6 and 7, rotates the fan blade FB in accordance with the position of the spray gun G in the coating zone. H The second rotational motion of the spray gun G is performed in conjunction with the motion of the painting robot CR which moves the spray gun G along the painting path P as described with reference to FIG. 1. Therefore, the position of the spray gun G moved by the painting robot CR and the position of the fan blade holding part HA of the fan blade handling device HA are H The relationship between the rotation angle of the paint robot CR and the fan blade holding unit HA is taught to the control device in advance, and during painting, the painting robot CR and the fan blade holding unit HA are controlled by the control device based on the teaching result. H The operation of is controlled.

[0078] Next, with reference to FIG. 8, the procedure for performing painting according to the disclosed method using the painting system CE will be described below.

[0079] First, as shown in FIG. 8(a), the arm part HA of the fan blade handling device HA is A The arm part HA is set at the fan blade attachment / detachment position offset to the opposite side of the painting robot CR (the right side in the figure), A The fan blade holding part HA at one end (the right end in the figure) H In this state, the fan blade FB1, whose blade root is supported by the worker W, is held vertically (i.e., its span direction S is aligned with the vertical direction) by the fan blade holding portion HA. H Although not shown in the figure, the arm portion HA A The arm part HA rotates around the center of the longitudinal direction. AThe other end (the left end in the figure) of the fan blade holding part HA H The fan blade FB2 is also fixed to the arm portion HA A The fan blade holding parts HA are provided on both ends of the H By fixing the fan blades FB1 and FB2 to each of the fan blades, as described below, the erosion-resistant paint can be applied to the blade surfaces of the two fan blades in succession.

[0080] Next, as shown in FIG. 8(b), the arm portion HA of the fan blade handling device HA is A With the arm part HA set to the reference position, A The fan blade holding parts HA are provided on both ends of the H Each of the is rotated 90 degrees (first rotational motion) and set in the painting position.

[0081] 8(c)-(d), while moving the spray gun G by the painting robot CR along the painting path P as described with reference to FIG. 1, for each painting section ZC, the fan blade FB1 is held by the fan blade holding part HA as necessary so that the line segments connecting the intersections of the lines constituting the painting section ZC projected vertically onto the blade surface (surface to be painted) with the leading edge and the trailing edge of the blade are kept horizontal. H At the same time, while the spray gun moves along each painting section ZC, the painting robot CR rotates the spray gun G so that the direction of the central axis of the spray gun is always perpendicular to the surface to be painted, while spraying the erosion-resistant paint from the spray gun G to form a coating of the erosion-resistant paint on the surface of the fan blade FB1.

[0082] When painting of one of the pressure surface SP and the suction surface SS of the fan blade FB1 is completed, as shown in FIG. 8(e), the arm portion HA of the fan blade handling device HA is A , Support part HA SThe arm is rotated 180 degrees around the center of the longitudinal direction located directly above the arm. A The fan blade holding part HA at the opposite end of the H The fan blade FB2 held by the paint roller 1 is positioned on the side of the painting robot CR. In this state, painting is started on one of the positive pressure surface SP and the negative pressure surface SS of the fan blade FB2, as shown in Fig. 8(f). The painting of this fan blade FB2 is performed in the same manner as the painting of the fan blade FB1 shown in Figs. 8(c) to (d).

[0083] In FIG. 8(f), while painting is being performed on one of the pressure surface SP and the suction surface SS of the fan blade FB2, the fan blade FB1, which has already been painted on one of the pressure surface SP and the suction surface SS, is being moved to the arm portion HA. A During this time, the coating film formed on the blade surface of the fan blade FB1 can be dried.

[0084] In this way, when painting of one of the positive pressure surface SP and the negative pressure surface SS of the fan blade FB2 is completed, the arm part HA of the fan blade handling device HA is moved in the same manner as in FIG. A , Support part HA S The fan blade FB1 is then rotated 180 degrees around the longitudinal center portion located directly above the painting robot CR, and the fan blade FB1 is again positioned on the painting robot CR side, where painting is performed on the other of the positive pressure surface SP and negative pressure surface SS. Then, when painting of the other of the positive pressure surface SP and negative pressure surface SS of the fan blade FB1 is completed, the arm portion HA of the fan blade handling device HA is rotated in the same manner as in FIG. 8(e). A , Support part HA S The fan blade FB2 is then rotated 180 degrees around its longitudinal center located directly above the fan blade FB2, and again positioned on the painting robot CR side, and painting is performed on the other of the positive pressure surface SP and the negative pressure surface SS.

[0085] In the above description, the case has been described in which painting is performed in the order of one of the pressure surface SP and the negative pressure surface SS of the fan blade FB1, one of the pressure surface SP and the negative pressure surface SS of the fan blade FB2, the other of the pressure surface SP and the negative pressure surface SS of the fan blade FB1, and the other of the pressure surface SP and the negative pressure surface SS of the fan blade FB2, but the order of painting is not limited to this. That is, painting may be performed in the order of one of the pressure surface SP and the negative pressure surface SS of the fan blade FB1, the other of the pressure surface SP and the negative pressure surface SS of the fan blade FB1, one of the pressure surface SP and the negative pressure surface SS of the fan blade FB2, and the other of the pressure surface SP and the negative pressure surface SS of the fan blade FB2.

[0086] In this way, when the painting of the fan blades FB1 and FB2 is completed and further drying is completed, the arm part HA of the fan blade handling device HA is moved in the same manner as in FIG. 8(a). A Set the arm part HA to the fan blade attachment / detachment position. A The fan blade holding part HA at one end (the right end in the figure) H In this state, the fan blade FB1 (or FB2) is first removed while the blade root is supported by the worker W. Next, the arm portion HA A After rotating the fan blade FB2 (or FB1) 180 degrees around its longitudinal center, the fan blade FB2 (or FB1) is removed while being supported by the worker W at its blade root.

[0087] In the above, the arm part HA A is a straight member, and has fan blade holding parts HA on both ends. H However, the present invention is not limited to this. A Each end is supported by a support part HA S The fan blade support portion HA is formed of, for example, three or more straight members connected directly above the fan blade support portion HA. H (a total of three or more).

[0088] According to the painting method of the present disclosure described above, the paint sprayed from the spray gun adheres to the surface to be painted, which is kept in a generally horizontal state, so that no dripping occurs that would cause unacceptable changes to the thickness of the coating, and a coating of the desired thickness can be formed in each part of the fan blade surface in a short period of time.

[0089] Furthermore, according to the coating method of the present disclosure, a relatively thick coating film can be formed in a single coating pass (one coat), making it possible to make the surface of the coating film smoother compared to a case in which a thick coating film is formed by layering thin coating films. can be done.

[0090] Furthermore, in the coating method disclosed herein, paint is basically sprayed vertically downward from the spray gun, but for fan blades that have a sheath covering the leading edge, paint is sprayed with the spray gun tilted forward only when a coating is to be formed on the surface to be coated near the rear of the sheath. This prevents the coating thickness from becoming uneven due to the step between the sheath and the blade surface, and makes it possible to form a coating of the desired thickness over the entire blade surface. [Explanation of symbols]

[0091] CE Painting System CL Line segment connecting leading edge and trailing edge (of fan blade) CR Painting robot FB Fan Blade G Spray Gun Gc Spray gun central axis HA Fan blade handling device (handling device for coated objects) HA H Fan blade holder (workpiece holder) LE (leading edge of fan blade) P Paint pass S span direction SH sheath TE (trailing edge of fan blade) ZC Painting section

Claims

1. A method for painting a surface of a fan blade or guide vane of a turbofan engine, comprising the steps of: The fan blade or guide vane is held in a state in which its span direction coincides with the horizontal direction and can be rotated about a rotation axis extending in the span direction, A spray gun that sprays paint downward in the direction of the central axis is moved along a painting path so as to form a coating film on a surface to be painted that is located on the upper side of the blade surface, the paint pass includes a plurality of paint sections spaced apart in the spanwise direction and extending between leading and trailing edges of the fan blades or guide vanes; While the spray gun moves along each of the coating sections to form the coating, The fan blade or guide vane is held in a state in which the line segments connecting the intersections of the leading edge and the trailing edge with the lines formed by projecting the lines constituting the coating section vertically onto the surface to be coated are maintained horizontal, and The method of claim 1, wherein the central axis of the spray gun is always redirected perpendicular to the surface being coated.

2. 2. The method of claim 1, wherein, after the spray gun moves along one of the plurality of painting sections to an end thereof and then moves to a start of a next painting section, the fan blade or guide vane is pivoted about the pivot axis so that the line segment remains horizontal in the next painting section.

3. The fan blade or guide vane is provided with a sheath covering the leading edge, when the spray gun is in a spray gun forward tilt section of each of the coating sections where the distance measured rearward from the rear end surface of the sheath at an intersection of the central axis and the surface to be coated is equal to or less than the width of a spray pattern formed on the surface to be coated by paint sprayed from the spray gun, the direction of the central axis of the spray gun is inclined toward the leading edge side with respect to a direction perpendicular to the surface to be coated, The method according to claim 1 , wherein when the spray gun is in a section other than the spray gun forward tilt section among the respective painting sections, the direction of the central axis of the spray gun coincides with a direction perpendicular to the surface to be painted.

4. 1. A coating system for a surface of a fan blade of a turbofan engine, comprising: Painting robots and A paint supply device; A coating workpiece handling device having a coating workpiece holding portion; a control device for controlling the operations of the painting robot, the paint supply device, and the workpiece handling device; Equipped with the painting robot moves a spray gun that sprays paint downward so that a paint film is formed along a painting path on a surface to be painted that is located on the upper side of the wing surface; the coating object holding unit holds the fan blade or guide vane during coating so that its span direction coincides with the horizontal direction and in a state in which the fan blade or guide vane can be rotated about a rotation axis extending in the span direction; the paint pass includes a plurality of paint sections spaced apart in the spanwise direction and extending between leading and trailing edges of the fan blades or guide vanes; The control device controls the spray gun to move along each of the coating sections to form the coating film. The operation of the workpiece holding unit is controlled so that the fan blade or guide vane is held in a state in which the line segments connecting the intersections of the leading edge and the trailing edge with the lines formed by projecting the lines constituting the painting section vertically onto the surface to be painted are maintained horizontal, and The system is configured to control the movement of the painting robot so that the direction of the central axis of the spray gun is always perpendicular to the surface to be painted.

5. 5. The painting system according to claim 4, wherein, while the spray gun moves along one of the plurality of painting sections and reaches its end point, and then moves to the start point of the next painting section, the workpiece holding unit rotates the fan blade or guide vane about the pivot axis so that the line segment is maintained horizontal even in the next painting section.

6. The coating system according to claim 5 , wherein the coating object holder can also support the fan blade or guide vane such that its span direction coincides with the vertical direction.

Images