JP2016036771A

JP2016036771A - Bell cup of rotary atomization type coating apparatus

Info

Publication number: JP2016036771A
Application number: JP2014161134A
Authority: JP
Inventors: 重徳風間; Shigenori Kazama
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2014-08-07
Filing date: 2014-08-07
Publication date: 2016-03-22
Anticipated expiration: 2034-08-07
Also published as: JP6314735B2

Abstract

PROBLEM TO BE SOLVED: To provide a bell cup of a rotary atomization type coating apparatus capable of suppressing wear of a bell cup surface without forming a wear-resistant coated film or the like.SOLUTION: A bell cup 3 includes: a bell cup main body 30 which is fit to a top end part of a rotation shaft 13 of a rotary atomization type coating apparatus 1, having a feed tube 15 inserted to a center of the rotation shaft and allows coating material to be ejected from the feed tube to a coating material diffusion surface 31 on an inner surface thereof; and a bell hub which is fit to a base end center of the bell cup main body, allows the coating material to be ejected from the feed tube to the inner surface thereof, and guides the coating material to a base end part of the coating material diffusion surface 31 of the bell cup main body via a plurality of through-holes 41 disposed on an outer circumferential part thereof. Therein, a first range 31A of the base end part side of the bell cup main body, of the coating material diffusion surface 31 is constituted with a first coating material diffusion surface of which an angle with the rotation shaft is larger than 0° and is smaller than 5° and continues to the first coating material diffusion surface, and a second range 31B up to a top end edge of the bell cup main body is constituted with a convex curved surface proceeding to the rotation shaft.SELECTED DRAWING: Figure 1

Description

本発明は、回転霧化式塗装装置のベルカップに関するものである。 The present invention relates to a bell cup of a rotary atomizing coating apparatus.

回転霧化式塗装装置において、塗料に含まれるアルミフレークや雲母フレークなどの光輝性顔料がベルカップ表面を摩耗させる傾向がある。そのため、ベルカップの表面に珪素ドープ非晶質炭素被膜などの耐摩耗被膜を形成することが行われている（特許文献１）。 In the rotary atomizing coating apparatus, glitter pigments such as aluminum flakes and mica flakes contained in the paint tend to wear the bell cup surface. Therefore, an abrasion-resistant film such as a silicon-doped amorphous carbon film is formed on the surface of the bell cup (Patent Document 1).

特開２００１−３５３４５５号公報JP 2001-353455 A

しかしながら、ベルカップの表面に耐摩耗被膜を形成すると、耐摩耗被膜のメッキ工程などベルカップの製造工程が増加し、コストアップにつながるという問題がある。 However, when a wear-resistant coating is formed on the surface of the bell cup, there is a problem that the manufacturing process of the bell cup such as a plating process of the wear-resistant coating increases, leading to an increase in cost.

本発明が解決しようとする課題は、耐摩耗被膜などを形成することなくベルカップ表面の摩耗を抑制できる回転霧化式塗装装置のベルカップを提供することである。 The problem to be solved by the present invention is to provide a bell cup of a rotary atomizing coating apparatus that can suppress wear on the surface of the bell cup without forming a wear-resistant film or the like.

本発明は、ベルカップ本体の塗料拡散面のうち基端部側の第１範囲を、回転軸とのなす角度が０°を超え５°未満の第１塗料拡散面で構成し、第１塗料拡散面に連続し、ベルカップ本体の先端縁までの第２範囲を、回転軸に向かう凸状の曲面で構成することによって上記課題を解決する。 According to the present invention, the first range on the base end portion side of the paint diffusing surface of the bell cup body is constituted by a first paint diffusing surface whose angle with the rotation axis is more than 0 ° and less than 5 °, The above-described problem is solved by configuring the second range that is continuous with the diffusion surface and extends to the tip edge of the bell cup body with a convex curved surface that faces the rotation axis.

本発明に係るベルカップは、フィードチューブから塗料が吐出される第１塗料拡散面が回転軸に対して０°を超え５°未満の角度とされているので、当該第１塗料拡散面に沿う遠心力成分が著しく小さい。このため、第１塗料拡散面に塗料の液溜りが生じ、これにより塗料に含まれる光輝性顔料が第１塗料拡散面に衝突したり擦れたりすることでベルカップ表面が摩耗するのを抑制することができる。 In the bell cup according to the present invention, the first paint diffusing surface from which the paint is discharged from the feed tube has an angle of more than 0 ° and less than 5 ° with respect to the rotation axis. The centrifugal force component is extremely small. For this reason, the liquid pool of a paint arises on the 1st paint diffusion surface, and this suppresses abrasion of the bell cup surface by the glittering pigment contained in the paint colliding with or rubbing the first paint diffusion surface. be able to.

本発明に係るベルカップの一実施の形態を適用した回転霧化式静電塗装装置の先端部を示す断面図である。It is sectional drawing which shows the front-end | tip part of the rotary atomization type electrostatic coating apparatus to which one Embodiment of the bell cup which concerns on this invention is applied. 図１のベルカップ本体を示す断面図である。It is sectional drawing which shows the bell cup main body of FIG. 図１のベルハブ及びスペーサを示す断面図である。It is sectional drawing which shows the bell hub and spacer of FIG. 図３のＩＶ部の拡大断面図である。It is an expanded sectional view of the IV section of FIG. 本発明に係るベルカップの他の実施の形態を適用した回転霧化式静電塗装装置の先端部を示す断面図である。It is sectional drawing which shows the front-end | tip part of the rotary atomization type electrostatic coating apparatus to which other embodiment of the bell cup which concerns on this invention is applied. 図５のリング部材を示す斜視図である。It is a perspective view which shows the ring member of FIG. 図５のＶＩＩ部の拡大断面図である。It is an expanded sectional view of the VII part of FIG.

以下、本発明の一実施の形態を図面に基づいて説明する。図１は、本発明に係るベルカップ３の一実施の形態を適用した回転霧化式塗装装置１の先端部を示す断面図、図２はベルカップ本体３０を示す断面図、図３はベルハブ４０及びスペーサ５０を示す断面図、図４は図３のＩＶ部の拡大断面図である。以下において、ベルカップ本体３０、ベルハブ４０及びスペーサ５０を含めてベルカップ３と総称する。回転霧化式塗装装置に用いられるベルカップ３は、霧化頭又は噴霧頭とも称されるが、本明細書ではベルカップ３という。最初に図１を参照して回転霧化式塗装装置１の一例を説明する。また、ベルカップ３の基端側とは、回転霧化式塗装装置１の中空シャフト１３側をいい、これに対してベルカップ３の先端側とは被塗物側をいうものとする。なお、本発明に係るベルカップ３は、以下に説明する構造の回転霧化式塗装装置１にのみ限定されず、その他の構造の回転霧化式塗装装置にも適用することができる。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a cross-sectional view showing a tip portion of a rotary atomizing coating apparatus 1 to which an embodiment of a bell cup 3 according to the present invention is applied, FIG. 2 is a cross-sectional view showing a bell cup body 30, and FIG. 3 is a bell hub. 40 is a cross-sectional view showing the spacer 40 and FIG. 4, and FIG. 4 is an enlarged cross-sectional view of a portion IV in FIG. Hereinafter, the bell cup body 30, the bell hub 40 and the spacer 50 are collectively referred to as the bell cup 3. The bell cup 3 used in the rotary atomizing coating apparatus is also referred to as an atomizing head or a spray head, but is referred to as a bell cup 3 in this specification. First, an example of the rotary atomizing coating apparatus 1 will be described with reference to FIG. Further, the base end side of the bell cup 3 refers to the hollow shaft 13 side of the rotary atomizing coating apparatus 1, while the tip end side of the bell cup 3 refers to the object to be coated. The bell cup 3 according to the present invention is not limited to the rotary atomizing coating apparatus 1 having a structure described below, and can be applied to a rotary atomizing coating apparatus having another structure.

図１に示す回転霧化式塗装装置１は、静電印加式塗装装置であって、電気絶縁性材料から形成されたハウジング１１と、このハウジング１１内に設けられた、エアーモータ１２によって回転する中空シャフト１３とを有する。中空シャフト１３の先端には、塗料を噴霧するベルカップ３が、そのねじ部３５（図２参照）を図１に示す中空シャフト１３のねじ部２１にねじ締結することにより固定され、中空シャフト１３とともに回転駆動する。また、中空シャフト１３の中心孔には、塗料供給装置１４から供給される塗料や洗浄シンナーをベルカップ３へ供給する非回転の中空状のフィードチューブ１５が配置されている。なおベルカップ３の背面外周は、ハウジング１１の先端によって覆われている。 A rotary atomizing coating apparatus 1 shown in FIG. 1 is an electrostatic application type coating apparatus, and is rotated by a housing 11 made of an electrically insulating material and an air motor 12 provided in the housing 11. And a hollow shaft 13. The bell cup 3 for spraying paint is fixed to the tip of the hollow shaft 13 by screwing the screw portion 35 (see FIG. 2) to the screw portion 21 of the hollow shaft 13 shown in FIG. And rotationally drive together. In addition, a non-rotating hollow feed tube 15 that supplies paint or cleaning thinner supplied from the paint supply device 14 to the bell cup 3 is disposed in the center hole of the hollow shaft 13. Note that the outer periphery of the back surface of the bell cup 3 is covered by the tip of the housing 11.

回転霧化式塗装装置１は、高圧電源１６からの印加によって帯電した塗料粒子を、被塗物との間に形成された静電界に沿って飛行させて当該被塗物に塗着させるものである。被塗物は、図１の左側に所定のガン距離を隔てて存在し、塗装台車や塗装ハンガを介して接地されている。高圧印加方式としては、図１に示すように高圧電源１６をハウジング１１内に設け、導電性材料で構成された中空シャフト１３を介して、同じく導電性材料で構成されたベルカップ本体３０に印加する内部印加型を採用することができる。またこれに代えて、ベルカップ本体３０を電気絶縁性材料で構成した場合は、高圧電源が接続された放電電極をベルカップ３０の周囲に設け、ベルカップ本体３０から飛び出した塗粒に印加する外部印加型の回転霧化式静電塗装装置も採用することができる。 The rotary atomizing coating apparatus 1 is a device for applying paint particles charged by application from a high-voltage power supply 16 along a static electric field formed between the paint particles and the object to be coated. is there. The object to be coated exists on the left side of FIG. 1 at a predetermined gun distance, and is grounded via a coating carriage or a coating hanger. As a high voltage application method, as shown in FIG. 1, a high voltage power supply 16 is provided in a housing 11 and applied to a bell cup body 30 also made of a conductive material through a hollow shaft 13 made of a conductive material. An internal application type can be employed. Alternatively, when the bell cup main body 30 is made of an electrically insulating material, a discharge electrode connected to a high voltage power source is provided around the bell cup 30 and applied to the coating particles protruding from the bell cup main body 30. An externally applied rotary atomizing electrostatic coating apparatus can also be employed.

また回転霧化式塗装装置１は、ベルカップ本体３０の背面側からシェーピングエアーと称される空気流をエアー吐出口１７から吐出し、ベルカップ本体３０により微粒化された塗料粒子を、ベルカップ本体３０の前方に位置する被塗物に向かう方向に偏向させる。このため、ハウジング１１の一部に、エアー供給装置１８に接続されたエアー通路１９が形成されるとともに、ハウジング１１の先端に当該エアー通路１９が連通する環状のエアー通路２０が形成されている。そして、環状のエアー通路２０に連通するエアー吐出口１７が、ハウジング１１の先端円周面に沿って所定間隔で複数個形成されている。このエアー吐出口１７から吹き出されるシェーピングエアーの流量や吹き出し角度を調節することにより、ベルカップ本体３０の先端から接線方向に飛び出した塗料粒子の飛行方向、すなわち塗装パターンを制御することができる。また、塗料粒子には上述した静電界による力以外にも、このシェーピングエアーによる運動量が与えられることになる。なお、図１に示すシェーピングエアーのエアー吹出口１７は環状に一列設けたが、シェーピングエアーの吹き出し角度を調整するために複数列設けてもよい。 Further, the rotary atomizing coating apparatus 1 discharges an air flow called shaping air from the back side of the bell cup body 30 from the air discharge port 17, and the paint particles atomized by the bell cup body 30 are discharged to the bell cup. It is deflected in a direction toward the object to be coated located in front of the main body 30. Therefore, an air passage 19 connected to the air supply device 18 is formed in a part of the housing 11, and an annular air passage 20 that communicates with the air passage 19 is formed at the tip of the housing 11. A plurality of air discharge ports 17 communicating with the annular air passage 20 are formed at predetermined intervals along the circumferential surface of the front end of the housing 11. By adjusting the flow rate and the blowing angle of the shaping air blown out from the air discharge port 17, the flight direction of the paint particles that are blown out tangentially from the tip of the bell cup body 30, that is, the coating pattern can be controlled. In addition to the force caused by the electrostatic field, the paint particles are given momentum by the shaping air. Although the shaping air air outlets 17 shown in FIG. 1 are provided in a row, a plurality of rows may be provided to adjust the blowing angle of the shaping air.

フィードチューブ１５の先端は、中空シャフト１３の先端から露出し、ベルカップ本体３０の内面に向けて延在している。このフィードチューブ１５には、塗料供給装置１４から塗料又は洗浄シンナーが供給され、その先端からベルカップ本体３０の塗料拡散面３１へ供給される。なお、洗浄シンナーは、ベルカップ本体３０の塗料拡散面３１及び後述するベルハブ４０を洗浄するための洗浄液（有機溶剤系塗料の場合には有機溶剤、水系塗料の場合は水）であり、本例の回転霧化式塗装装置１を、色替え操作を必要とする上塗り塗装工程や中塗り塗装工程に適用した場合に、塗料の色替え時の洗浄用として供給されるものである。したがって、色替え操作が不要な塗装工程、たとえば単一種の中塗り塗料のみを塗装する中塗り塗装工程などにあっては、塗料のみがフィードチューブ１５に供給されることもある。色替え操作は、塗料供給装置１４に含まれる図示しないカラーチェンジバルブなどの色替弁ユニットにより行われる。 The distal end of the feed tube 15 is exposed from the distal end of the hollow shaft 13 and extends toward the inner surface of the bell cup body 30. The feed tube 15 is supplied with paint or cleaning thinner from the paint supply device 14, and is supplied from the tip thereof to the paint diffusion surface 31 of the bell cup body 30. The cleaning thinner is a cleaning liquid for cleaning the paint diffusing surface 31 of the bell cup body 30 and the bell hub 40 described later (an organic solvent in the case of an organic solvent-based paint, and water in the case of a water-based paint). When the rotary atomization type coating apparatus 1 is applied to a top coating process or an intermediate coating process that requires a color change operation, it is supplied for cleaning when changing the color of the paint. Accordingly, only a paint may be supplied to the feed tube 15 in a painting process that does not require a color change operation, such as an intermediate coating process in which only a single type of intermediate coating is applied. The color change operation is performed by a color change valve unit such as a color change valve (not shown) included in the paint supply device 14.

本例のベルカップ本体３０は、導電性材料、たとえばアルミニウム、アルミニウム合金、ステンレス合金その他の金属材料で構成されている。ただし、上述した外部印加型の回転霧化式静電塗装装置に適用されるベルカップ本体３０においては、硬質の樹脂材料から構成してもよい。本例のベルカップ本体３０は、略カップ形状をなし、カップ状の内面の塗料拡散面３１、カップ状の外面３２と、内面の先端に位置する塗料が放出される先端縁３３と、を有する。塗料拡散面３１の構成については後述する。 The bell cup body 30 of this example is made of a conductive material such as aluminum, an aluminum alloy, a stainless alloy, or other metal materials. However, the bell cup body 30 applied to the externally applied rotary atomizing electrostatic coating apparatus described above may be made of a hard resin material. The bell cup body 30 of the present example has a substantially cup shape, and has a cup-shaped inner surface paint diffusing surface 31, a cup-shaped outer surface 32, and a tip edge 33 from which the paint located at the front end of the inner surface is discharged. . The configuration of the paint diffusing surface 31 will be described later.

ベルカップ本体３０の基端側の中央であって、フィードチューブ１５の先端近傍には、ベルハブ４０が取り付けられている。このベルハブ４０は、金属などの導電性材料でも樹脂などの電気絶縁性材料でも構成することができるが、樹脂材料で構成することがより好ましい。本例のベルハブ４０は、図３に示すねじ部４６を図２に示すベルカップ本体３０の基端内面に形成されたねじ部３４にネジ締結することで固定され、ベルカップ本体３０及び中空シャフト１３とともに回転する。ただし、ベルハブ４０を中空シャフト１４の先端に装着してもよいし、フィードチューブ１５の先端に装着して非回転に構成してもよい。 A bell hub 40 is attached to the center of the base end side of the bell cup body 30 and in the vicinity of the tip of the feed tube 15. The bell hub 40 can be made of a conductive material such as a metal or an electrically insulating material such as a resin, but is preferably made of a resin material. The bell hub 40 of this example is fixed by screwing the screw portion 46 shown in FIG. 3 to the screw portion 34 formed on the base end inner surface of the bell cup main body 30 shown in FIG. 13 and rotate. However, the bell hub 40 may be attached to the tip of the hollow shaft 14, or may be attached to the tip of the feed tube 15 so as not to rotate.

また、ベルカップ本体３０が正面視において回転中心軸ＣＬを中心とする円形であることから、ベルハブ４０も正面視において円形とされている。そして、ベルハブ４０の外周部には所定間隔をもって複数の通孔４１が形成され、フィードチューブ１５の先端から供給された塗料又は洗浄シンナーは、ベルハブ４０の通孔４１を通過してベルカップ本体３０の塗料拡散面３１へ導かれ、先端縁３３の全周から飛散することになる。 Further, since the bell cup body 30 is circular with the rotation center axis CL as the center in the front view, the bell hub 40 is also circular in the front view. A plurality of through holes 41 are formed at predetermined intervals on the outer periphery of the bell hub 40, and the paint or cleaning thinner supplied from the tip of the feed tube 15 passes through the through holes 41 of the bell hub 40 and the bell cup body 30. To the paint diffusing surface 31 and scattered from the entire periphery of the tip edge 33.

本例のベルハブ４０は、スペーサ５０を介在させた状態でベルカップ本体３０の基端部にネジ締結により固定される。スペーサ５０は、図３に示すように環状凸部５１を有し、この環状凸部５１がベルカップ本体３０の基端部に形成された環状凸部３６に当接することで、スペーサ５０はベルハブ４０とベルカップ本体３０の基端部との間に挟持される。なお、スペーサ５０は、金属などの導電性材料でも樹脂などの電気絶縁性材料でも構成することができる。また、スペーサ５０は、必要に応じて省略してもよい。 The bell hub 40 of this example is fixed to the base end portion of the bell cup body 30 by screw fastening with the spacer 50 interposed. As shown in FIG. 3, the spacer 50 has an annular convex portion 51, and the annular convex portion 51 abuts on an annular convex portion 36 formed at the base end portion of the bell cup body 30, so that the spacer 50 is a bell hub. 40 and the base end portion of the bell cup body 30. The spacer 50 can be made of a conductive material such as metal or an electrically insulating material such as resin. Further, the spacer 50 may be omitted as necessary.

次に、本例のベルカップ本体３０の塗料拡散面３１とベルハブ４０の構成について説明する。
図２は、図１に示すベルカップ本体３０の単体の拡大断面図であり、本例のベルカップ本体３０は、中空シャフト１３の回転中心軸ＣＬ廻りに回転対称とされた塗料拡散面３１を有する。この塗料拡散面３１は、ベルカップ本体３０の内面の基端側、具体的には塗料が吐出する通孔４１が対面する位置を始点とし、ベルカップ本体３０の内面の先端縁３３の位置を終点とする連続した曲面で構成されている。なお、これら始点および終点なる用語は、フィードチューブ１５から吐出される塗料の流動方向に沿って表現した趣旨であり、塗料拡散面３１の両端が、通孔４１の位置とベルカップ本体３０の内面の先端縁３３とで定義される意味である。 Next, the structure of the paint diffusion surface 31 and the bell hub 40 of the bell cup body 30 of this example will be described.
FIG. 2 is an enlarged cross-sectional view of a single body of the bell cup body 30 shown in FIG. 1. The bell cup body 30 of this example has a paint diffusing surface 31 that is rotationally symmetric about the rotation center axis CL of the hollow shaft 13. Have. The paint diffusing surface 31 starts from the base end side of the inner surface of the bell cup body 30, specifically, the position where the through hole 41 through which the paint discharges faces, and the position of the tip edge 33 on the inner surface of the bell cup body 30. It consists of a continuous curved surface as the end point. The terms “start point” and “end point” are expressed along the flow direction of the paint discharged from the feed tube 15, and both ends of the paint diffusion surface 31 are located at the positions of the through holes 41 and the inner surface of the bell cup body 30. It is the meaning defined by the front-end edge 33.

特に本例の塗料拡散面３１は、通孔４１に対面する始点を含む基端部までの第１範囲３１Ａは、回転中心軸ＣＬに対して０°を超え５°未満の曲面で構成される一方で、この第１範囲３１Ａに連続する、ベルカップ本体３０の先端縁３３までの第２範囲３１Ｂは、回転中心軸ＣＬに向かう凸状の曲面で構成されている。第１範囲３１Ａの塗料拡散面を第１塗料拡散面３１Ａ、第２範囲３１Ｂの塗料拡散面を第２塗料拡散面３１Ｂともいう。第１範囲の第１塗料拡散面３１Ａの曲面は、図２に示すように中空シャフト１４の回転中心軸ＣＬを含む任意平面の断面において、第１塗料拡散面３１Ａを通る直線Ｌ１と回転中心軸ＣＬとのなす角度αが、０°＜α＜５°となる、先端側に向かって拡開する円錐台の側面形状と成されている。 In particular, in the paint diffusing surface 31 of the present example, the first range 31A up to the base end including the starting point facing the through hole 41 is configured by a curved surface that is greater than 0 ° and less than 5 ° with respect to the rotation center axis CL. On the other hand, the 2nd range 31B which continues to this 1st range 31A to the front-end edge 33 of the bell cup main body 30 is comprised by the convex curved surface which goes to the rotation center axis | shaft CL. The paint diffusion surface in the first range 31A is also referred to as a first paint diffusion surface 31A, and the paint diffusion surface in the second range 31B is also referred to as a second paint diffusion surface 31B. The curved surface of the first paint diffusion surface 31A in the first range is a straight line L1 passing through the first paint diffusion surface 31A and the rotation center axis in a cross section of an arbitrary plane including the rotation center axis CL of the hollow shaft 14 as shown in FIG. An angle α formed with CL is 0 ° <α <5 °, which is a side shape of a truncated cone that expands toward the tip side.

なお、第１塗料拡散面３１Ａを通る直線Ｌ１と回転中心軸ＣＬとのなす角度αが０°であると、第１塗料拡散面３１Ａに吐出された塗料や洗浄用シンナがベルカップ本体３０の回転による遠心力によって第２塗料拡散面３１Ｂへ流れ難い。また、第１塗料拡散面３１Ａを通る直線Ｌ１と回転中心軸ＣＬとのなす角度αが０°未満であると、すなわち、基端側に向かって拡開する円錐台の側面形状であると、第１塗料拡散面３１Ａに吐出された塗料や洗浄用シンナがベルカップ３０の回転による遠心力によってベルカップ本体３０の基端部に向かって逆に流れることになる。一方、第１塗料拡散面３１Ａを通る直線Ｌ１と回転中心軸ＣＬとのなす角度αが５°以上であると、以下に説明する塗料溜りの効果が得難い。したがって、第１塗料拡散面３１Ａを通る直線Ｌ１と回転中心軸ＣＬとのなす角度αは０°＜α＜５°であることが好ましい。 If the angle α formed by the straight line L1 passing through the first paint diffusion surface 31A and the rotation center axis CL is 0 °, the paint and the cleaning thinner discharged to the first paint diffusion surface 31A are It is difficult to flow to the second paint diffusing surface 31B by centrifugal force due to rotation. Further, when the angle α formed by the straight line L1 passing through the first paint diffusion surface 31A and the rotation center axis CL is less than 0 °, that is, the side surface shape of the truncated cone expanding toward the base end side, The paint and cleaning thinner discharged to the first paint diffusing surface 31 </ b> A flow reversely toward the base end portion of the bell cup body 30 due to the centrifugal force caused by the rotation of the bell cup 30. On the other hand, when the angle α formed by the straight line L1 passing through the first paint diffusion surface 31A and the rotation center axis CL is 5 ° or more, it is difficult to obtain the effect of paint accumulation described below. Therefore, the angle α formed by the straight line L1 passing through the first paint diffusion surface 31A and the rotation center axis CL is preferably 0 ° <α <5 °.

第２範囲の第２塗料拡散面３１Ｂの曲面は、回転中心軸ＣＬに向かう凸状の曲面であって、回転中心軸ＣＬとその接線とのなす角度が、ベルカップ本体３０の先端縁３３に向かうにしたがって徐々に大きくなる曲面とされている。なお、第１塗料拡散面３１Ａと第２塗料拡散面３１Ｂとの境界部分は滑らかに変化する曲面とされている。 The curved surface of the second paint diffusing surface 31B in the second range is a convex curved surface toward the rotation center axis CL, and the angle formed between the rotation center axis CL and its tangent is at the tip edge 33 of the bell cup body 30. It is a curved surface that gradually increases as you go. The boundary portion between the first paint diffusion surface 31A and the second paint diffusion surface 31B is a curved surface that changes smoothly.

一方、ベルハブ４０は、図３に示すように各通孔４１の出口である先端部に、当該通孔４１から第１塗料拡散面３１Ａに向かって滑らかに漸近するスカート部４２が形成されている。このスカート部４２によって通孔４１から吐出する塗料が第１塗料拡散面３１Ａに衝突するのを緩和する。また、ベルハブ４０の内面のうち、回転中心軸ＣＬを含む、フィードチューブ１５の先端に対面する中央部の内面は、ベルカップ本体３０の基端方向に向かう凹状曲面４３とされている。一方、ベルハブ４０の内面のうち外周部は、この凹状曲面４３に連続し、ベルカップ本体３０の基端方向に向かう凸状曲面４４とされている。この凹状曲面４３及び凸状曲面４４により、フィードチューブ１５から吐出した塗料の流れ方向が変わることで減速することになる。これにより、通孔４１に達した際の塗料の流速が制限され、第１塗料拡散面３１Ａに衝突するエネルギが小さくなる。 On the other hand, as shown in FIG. 3, the bell hub 40 is formed with a skirt portion 42 that smoothly and gradually approaches from the through hole 41 toward the first paint diffusion surface 31 </ b> A at the tip end that is the outlet of each through hole 41. . The skirt portion 42 reduces the collision of the paint discharged from the through hole 41 with the first paint diffusion surface 31A. Further, among the inner surfaces of the bell hub 40, the inner surface of the central portion that faces the distal end of the feed tube 15, including the rotation center axis CL, is a concave curved surface 43 that faces the proximal direction of the bell cup body 30. On the other hand, the outer peripheral portion of the inner surface of the bell hub 40 is a convex curved surface 44 that continues to the concave curved surface 43 and extends toward the proximal end of the bell cup body 30. Due to the concave curved surface 43 and the convex curved surface 44, the flow direction of the paint discharged from the feed tube 15 is changed to reduce the speed. Thereby, the flow velocity of the paint when reaching the through hole 41 is limited, and the energy that collides with the first paint diffusion surface 31A is reduced.

なお、ベルハブ４０の中央には複数の洗浄孔４５が形成されている。この洗浄孔４５は、ベルハブ４０の内面に複数の開口を有し、ベルハブ４０の外面において一つの開口とされている。すなわち、各洗浄孔４５は回転中心軸ＣＬに向かって傾斜する孔、換言すればベルカップ３の先端に向かって縮径方向に傾斜する孔とされている。本例の洗浄孔４５は、ベルカップ本体３０及びベルハブ４０の外面を洗浄用シンナにより洗浄する際に用いられ、ベルカップ３の回転速度を低速とした状態でフィードチューブ１５から洗浄用シンナを供給すると、ベルハブ４０の内面に吐出された洗浄用シンナには大きな遠心力が作用しない。このため、当該洗浄用シンナの一部は洗浄孔４５を介してベルハブ４０の外面に至り、当該ベルハブ４０の外面を洗浄することができる。ただし、塗料を塗布する際のようにベルカップ３を高速で回転させると、その遠心力と洗浄孔４５の逆傾斜により、ベルハブ４０の内面に吐出された塗料が洗浄孔４５からベルハブ４０の外面に至ることはない。 A plurality of cleaning holes 45 are formed in the center of the bell hub 40. The cleaning hole 45 has a plurality of openings on the inner surface of the bell hub 40, and is a single opening on the outer surface of the bell hub 40. That is, each cleaning hole 45 is a hole inclined toward the rotation center axis CL, in other words, a hole inclined in the diameter reducing direction toward the tip of the bell cup 3. The cleaning hole 45 of this example is used when the outer surfaces of the bell cup body 30 and the bell hub 40 are cleaned by the cleaning thinner, and the cleaning thinner is supplied from the feed tube 15 with the rotation speed of the bell cup 3 being low. Then, a large centrifugal force does not act on the cleaning thinner discharged on the inner surface of the bell hub 40. For this reason, a part of the cleaning thinner reaches the outer surface of the bell hub 40 through the cleaning hole 45, and the outer surface of the bell hub 40 can be cleaned. However, when the bell cup 3 is rotated at a high speed as in the case of applying the paint, the paint discharged to the inner surface of the bell hub 40 from the washing hole 45 due to the centrifugal force and the reverse inclination of the washing hole 45 is applied to the outer surface of the bell hub 40. It will not lead to.

次に作用を説明する。
図１に示す状態でエアーモータ１２を駆動して中空シャフト１３を、たとえば４０，０００ｒｐｍの高速回転させながらフィードチューブ１５から塗料を供給すると、この塗料はベルハブ４０の内面の中央に吐出されたのち、ベルカップ本体３０の高速回転による遠心力によって、凹状曲面４３から凸状曲面４４に沿って流れたのち複数の通孔４１に至る。この凹状曲面４３及び凸状曲面４４により、フィードチューブ１５から吐出した塗料の流れ方向が変わり塗料の流れが減速する。これにより、通孔４１に達した際の塗料の流速が制限され、第１塗料拡散面３１Ａに衝突するエネルギが小さくなる。 Next, the operation will be described.
When the air motor 12 is driven in the state shown in FIG. 1 and the paint is supplied from the feed tube 15 while rotating the hollow shaft 13 at a high speed of 40,000 rpm, for example, the paint is discharged to the center of the inner surface of the bell hub 40. The bell cup body 30 flows from the concave curved surface 43 along the convex curved surface 44 by the centrifugal force generated by the high-speed rotation of the bell cup body 30 and then reaches the plurality of through holes 41. The concave curved surface 43 and the convex curved surface 44 change the flow direction of the paint discharged from the feed tube 15 and decelerate the flow of the paint. Thereby, the flow velocity of the paint when reaching the through hole 41 is limited, and the energy that collides with the first paint diffusion surface 31A is reduced.

各通孔４１に至った塗料は、通孔４１を通過したのち、スカート部４２によってベルカップ本体３０の第１塗料拡散面３１Ａに滑らかに流れる。これにより、アルミフレークや雲母フレークなどの光輝性顔料を含む塗料がベルカップ本体３０の第１塗料拡散面３１Ａへ大きなエネルギをもって衝突することが抑制される。 After passing through the through holes 41, the paint reaching each through hole 41 flows smoothly to the first paint diffusing surface 31 </ b> A of the bell cup body 30 by the skirt portion 42. Thereby, it is suppressed that the coating material containing luster pigments, such as aluminum flakes and mica flakes, collides with the 1st coating material diffusion surface 31A of the bell cup main body 30 with big energy.

また、第１塗料拡散面３１Ａは、回転中心軸ＣＬに対して５°未満といった略平行の円錐台側面で構成されているので、第１塗料拡散面３１Ａに至った塗料に作用する遠心力のうち、ベルカップ３の先端方向に向かう速度成分（すなわち第１塗料拡散面３１Ａに沿う方向の速度成分）は極めて小さい。これにより、第１塗料拡散面３１Ａには他の第２塗料拡散面３１Ｂに比べて厚膜の液溜りが生じる。たとえば、３〜５０，０００ｒｐｍ程度の高速で回転する場合であっても、第１塗料拡散面３１Ａに生じる液膜は１０μｍ〜１００μｍに保つことができる。典型的な光輝性顔料の厚さが０．５μｍ〜１．５μｍの範囲であるから、塗料吐出開始時においては光輝性顔料が第１塗料拡散面３１Ａに衝突することは避けられないものの、これに続く光輝性顔料は第１塗料拡散面３１Ａに生じた液溜りの中に流入する。その結果、光輝性顔料の衝突エネルギーが液溜りで吸収されることになる。 In addition, since the first paint diffusion surface 31A is configured by a truncated cone side surface of less than 5 ° with respect to the rotation center axis CL, the centrifugal force acting on the paint reaching the first paint diffusion surface 31A. Among them, the speed component toward the tip of the bell cup 3 (that is, the speed component in the direction along the first paint diffusion surface 31A) is extremely small. As a result, a thick liquid pool is generated on the first paint diffusion surface 31A compared to the other second paint diffusion surface 31B. For example, even when rotating at a high speed of about 3 to 50,000 rpm, the liquid film generated on the first paint diffusion surface 31A can be kept at 10 μm to 100 μm. Since the thickness of the typical glitter pigment is in the range of 0.5 μm to 1.5 μm, it is inevitable that the glitter pigment collides with the first paint diffusion surface 31 </ b> A at the start of paint discharge. Subsequent glitter pigment flows into the liquid pool generated on the first paint diffusion surface 31A. As a result, the collision energy of the glitter pigment is absorbed by the liquid pool.

第１塗料拡散面３１Ａを通過した塗料は第２塗料拡散面３１Ｂに導かれる。本例の第２塗料拡散面３１Ｂは、上述したとおり回転中心軸ＣＬに向かう凸状の曲面であって、回転中心軸ＣＬとその接線とのなす角度が、ベルカップ本体３０の先端縁３３に向かうにしたがって徐々に大きくなる曲面とされている。これにより、個々の光輝性顔料の重心が第２塗料拡散面３１Ｂに接触したとしても、光輝性顔料の先端が第２塗料拡散面３１Ｂを摩耗させることがない。 The paint that has passed through the first paint diffusion surface 31A is guided to the second paint diffusion surface 31B. The second paint diffusing surface 31B of this example is a convex curved surface toward the rotation center axis CL as described above, and the angle formed between the rotation center axis CL and its tangent is at the tip edge 33 of the bell cup body 30. It is a curved surface that gradually increases as you go. Thereby, even if the center of gravity of the individual bright pigment comes into contact with the second paint diffusing surface 31B, the tip of the bright pigment does not wear the second paint diffusing surface 31B.

なお、ベルハブ４０を樹脂材料で構成すれば、フィードチューブ１５から吐出された塗料がベルハブ４０の内面に衝突した際のエネルギを樹脂材料の弾性により吸収することができる。第１塗料拡散面３１Ａに作用する遠心力による光輝性顔料の衝突速度に比べると、フィードチューブ１５からの供給液圧による塗料の速度は比較的に小さいため、樹脂製ベルブでも十分に耐えることができる。 If the bell hub 40 is made of a resin material, energy when the paint discharged from the feed tube 15 collides with the inner surface of the bell hub 40 can be absorbed by the elasticity of the resin material. Compared to the impact speed of the bright pigment due to the centrifugal force acting on the first paint diffusion surface 31A, the speed of the paint due to the hydraulic pressure supplied from the feed tube 15 is relatively small, so that even a resin bell can withstand sufficiently. it can.

《他の実施の形態》
図５は、本発明に係るベルカップ３の他の実施の形態を適用した回転霧化式静電塗装装置１の先端部を示す断面図、図６は図５のリング部材６０を示す斜視図である。なお、図１〜図４に示す第１の実施の形態に係る部材と共通する部材には同一の符号を付し、その説明をここに準用する。 << Other Embodiments >>
FIG. 5 is a sectional view showing the tip of the rotary atomizing electrostatic coating apparatus 1 to which another embodiment of the bell cup 3 according to the present invention is applied, and FIG. 6 is a perspective view showing the ring member 60 of FIG. It is. Note that members that are the same as the members according to the first embodiment shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is applied here.

図５及び図６に示す実施形態のベルカップ３は、第１塗料拡散面３１Ａにリング部材６０が着脱可能に埋設されている点が図１に示す第１の実施の形態と相違する。本例のリング部材６０は、ダイヤモンドライクカーボンＤＬＣをコーティングした金属材料、樹脂材料又はゴム材料により構成することができる。本例のリング部材６０は、第１塗料拡散面３１Ａのうちの、少なくともベルハブ４０の通孔４１の先端部が相対する位置を含んだ位置に埋設され、リング部材６０の表面と第１塗料拡散面３１Ａの表面とが面一になるように埋設されている。本例のリング部材６０は、図６に示すように一箇所に切り込み部６１が形成され、これによりリング部材６０を強く摘まむと縮径し、放すと自己弾性により原形に戻る。リング部材６０をベルカップ本体３０に装着する場合には、リング部材６０を強く摘まんで縮径させた状態でベルカップ本体３０に形成した環状凹部３７に嵌合させる。またリング部材６０を取り外す場合には、同様にして縮径させて取り外せばよい。 The bell cup 3 of the embodiment shown in FIGS. 5 and 6 is different from the first embodiment shown in FIG. 1 in that a ring member 60 is detachably embedded in the first paint diffusion surface 31A. The ring member 60 of this example can be made of a metal material, a resin material, or a rubber material coated with diamond-like carbon DLC. The ring member 60 of the present example is embedded in a position including at least a position where the tip end portion of the through hole 41 of the bell hub 40 faces in the first paint diffusion surface 31A, and the surface of the ring member 60 and the first paint diffusion surface. The surface 31A is embedded so as to be flush with the surface. As shown in FIG. 6, the ring member 60 of this example has a cut portion 61 formed at one location, so that when the ring member 60 is firmly picked, the diameter is reduced, and when released, the ring member 60 returns to its original shape by self-elasticity. When the ring member 60 is attached to the bell cup body 30, the ring member 60 is fitted into an annular recess 37 formed in the bell cup body 30 in a state where the ring member 60 is strongly picked and reduced in diameter. Further, when removing the ring member 60, the diameter may be reduced and removed in the same manner.

このようにしたベルカップ３にあっては、塗料に含まれる光輝性顔料が最も強く衝突する位置に着脱可能なリング部材６０を埋設しているので、摩耗の程度が大きい場合にはリング部材６０のみを交換すればよく、ベルカップ本体３０を交換する必要がなくなる。 In the bell cup 3 configured as described above, the detachable ring member 60 is embedded at the position where the glitter pigment contained in the paint collides most strongly. It is not necessary to replace the bell cup body 30.

また、リング部材６０をゴム材料や弾性樹脂材料などの弾性材料から構成すれば、図７に示すように、ベルカップ本体３０の高速回転による遠心力が作用した場合に当該リング部材６０が圧縮される。これにより、ベルカップ本体３０の環状凹部３７と圧縮されたリング部材６０の部分に凹状の液溜り溝６２が生じるので、ここに一定量の塗料が溜り、光輝性顔料の衝突エネルギの吸収効果がさらに大きくなる。なお、ベルカップ本体３０の回転速度を低下すればリング部材６０は元の形状に復元するので、洗浄用シンナを用いた洗浄性には何ら悪影響を及ぼさない。 If the ring member 60 is made of an elastic material such as a rubber material or an elastic resin material, the ring member 60 is compressed when a centrifugal force due to the high-speed rotation of the bell cup body 30 is applied, as shown in FIG. The As a result, a concave liquid reservoir groove 62 is formed in the annular concave portion 37 of the bell cup body 30 and the compressed ring member 60, so that a certain amount of paint is accumulated therein, and the effect of absorbing the collision energy of the glitter pigment is obtained. It gets bigger. Note that if the rotational speed of the bell cup body 30 is decreased, the ring member 60 is restored to its original shape, so that the cleaning performance using the cleaning thinner is not adversely affected.

また、図５に示す実施の形態では、第１塗料拡散面３１Ａと第２塗料拡散面３１Ｂとの境界部分を非連続な曲面としている。すなわち、第１塗料拡散面３１Ａの終端から第２塗料拡散面３１Ｂの始端に移行する面は、その角度が急激に変化する曲面とされている。このように構成することで第１塗料拡散面３１Ａの長さを充分に設定することができるので、この第１塗料拡散面３１Ａに生じる液溜り量が増加し、光輝性顔料の衝突エネルギの吸収効果がさらに大きくなる。なお、図５に示すベルカップ本体３０にリング部材６０を埋設する構成と、リング部材６０を弾性材料とする構成と、第１塗料拡散面３１Ａと第２塗料拡散面３１Ｂとの境界部分を非連続な曲面とする構成とは、それぞれ独立して採用することができる。 In the embodiment shown in FIG. 5, the boundary portion between the first paint diffusion surface 31A and the second paint diffusion surface 31B is a discontinuous curved surface. That is, the surface that transitions from the terminal end of the first paint diffusion surface 31A to the start end of the second paint diffusion surface 31B is a curved surface whose angle changes abruptly. With this configuration, the length of the first paint diffusing surface 31A can be set sufficiently, so that the amount of liquid pool generated on the first paint diffusing surface 31A increases and the collision energy of the glitter pigment is absorbed. The effect is further increased. In addition, the structure which embeds the ring member 60 in the bell cup main body 30 shown in FIG. 5, the structure which uses the ring member 60 as an elastic material, and the boundary part of 31 A of 1st coating material diffusion surfaces and the 2nd coating material diffusion surface 31B is non-exposed. Each of the continuous curved surfaces can be employed independently.

上記中空シャフト１３が本発明に係る回転軸に相当する。 The hollow shaft 13 corresponds to the rotating shaft according to the present invention.

１…回転霧化式塗装装置
１１…ハウジング
１２…エアーモータ
１３…中空シャフト
１４…塗料供給装置
１５…フィードチューブ
１６…高圧電源
１７…エアー吐出口
１８…エアー供給装置
１９，２０…エアー通路
２１…ねじ部
３…ベルカップ
３０…ベルカップ本体
３１…塗料拡散面
３１Ａ…第１範囲（第１塗料拡散面）
３１Ｂ…第２範囲（第２塗料拡散面）
３２…外面
３３…先端縁（塗料拡散面の終点）
３４，３５…ねじ部
３６…環状凸部
３７…環状凹部
４０…ベルハブ
４１…通孔
４２…スカート部
４３…凹状曲面
４４…凸状曲面
４５…洗浄孔
４６…ねじ部
５０…スペーサ
５１…環状凸部
６０…リング部材
６１…切り込み部
６２…液溜り溝
ＣＬ…回転中心軸 DESCRIPTION OF SYMBOLS 1 ... Rotary atomization type coating device 11 ... Housing 12 ... Air motor 13 ... Hollow shaft 14 ... Paint supply device 15 ... Feed tube 16 ... High-voltage power supply 17 ... Air discharge port 18 ... Air supply device 19, 20 ... Air passage 21 ... Screw part 3 ... Bell cup 30 ... Bell cup body 31 ... Paint diffusing surface 31A ... First range (first paint diffusing surface)
31B ... 2nd range (2nd paint diffusion surface)
32 ... outer surface 33 ... tip edge (end point of paint diffusion surface)
34, 35 ... threaded portion 36 ... annular convex portion 37 ... annular recessed portion 40 ... bell hub 41 ... through hole 42 ... skirt portion 43 ... concave curved surface 44 ... convex curved surface 45 ... cleaning hole 46 ... threaded portion 50 ... spacer 51 ... annular convex Part 60 ... ring member 61 ... notch part 62 ... liquid pool groove CL ... rotation center axis

Claims

A bell cup body that is attached to the tip of the rotary shaft of a rotary atomizing coating device with a feed tube inserted in the center, and paint is discharged from the feed tube to the paint diffusion surface on the inner surface thereof;
The bell cup body is attached to the center of the base end, the paint is discharged from the feed tube to the inner surface of the bell cup body, and the paint is spread through the plurality of through holes provided in the outer peripheral portion of the bell cup body. In a bell cup provided with a bell hub that leads to the base end of
The first range on the base end side of the bell cup body of the paint diffusing surface is composed of a first paint diffusing surface whose angle with the rotation axis is more than 0 ° and less than 5 °,
The bell cup of the rotary atomizing coating apparatus, wherein the second range extending from the first paint diffusing surface to the tip edge of the bell cup main body is formed by a convex curved surface facing the rotation axis.

The bell cup of the rotary atomizing coating apparatus according to claim 1, wherein a skirt portion that smoothly approaches the first paint diffusing surface from the through hole is formed at a tip portion of the through hole of the bell hub.

The inner surface of the bell hub is
A concave curved surface formed in the center of the inner surface of the bell hub that faces the tip of the feed tube, and toward the proximal direction of the bell cup body;
The rotary atomizing coating apparatus according to claim 1, further comprising: a convex curved surface that is continuous with the concave curved surface and is formed on an outer peripheral portion of the inner surface of the bell hub toward the proximal end of the bell cup body. Bell cup.

The bell cup of the rotary atomizing coating apparatus according to any one of claims 1 to 3, wherein the bell cup body is formed of a metal material, and a ring member is embedded in the first paint diffusion surface.

The bell cup of the rotary atomizing coating apparatus according to claim 4, wherein the ring member is detachably embedded.

The bell cup of the rotary atomizing coating apparatus according to claim 4 or 5, wherein the ring member is made of an elastic material.

The bell cup of the rotary atomizing coating apparatus according to any one of claims 1 to 6, wherein the bell hub is formed of a resin material.