Coating Equipment

Abstract

To provide a coating device which can suppress occurrence of abnormal noise that is apt to occur along with rotation of a rotary drum.SOLUTION: A coating device includes: a rotary drum which stores granules to be treated therein, with a rear end side thereof transmitted with a rotation force of a rotary driving mechanism, and which is rotationally driven around an axis thereof; and rotatably supporting roller mechanisms. The roller mechanism has a roller which rotates around a rotation axis center in parallel with a rotation axis center of the rotary drum, while, from below, supporting a support part being a cylindrical surface of the rotary drum. An outer diameter surface of the roller is formed in such a crowning shape that an outer diameter in an axial direction central part is larger than an outer diameter on an axial direction end.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a coating apparatus for coating, mixing, drying, etc., powdered or granular materials such as pharmaceuticals, foods, and agricultural chemicals, and in particular to a coating apparatus equipped with a rotary drum that is driven to rotate about its axis. [Background technology]

[0002] Coating equipment equipped with a ventilated rotating drum that rotates around its axis is used to apply film coating, sugar coating, etc. to pharmaceutical, food, pesticide, etc. tablets, soft capsules, pellets, granules, and other similar materials (hereinafter collectively referred to as powder and granular materials).

[0003] An example of a coating apparatus equipped with a rotating drum (coating pan) is disclosed in Patent Document 1. As shown in Figures 7 and 8, the coating apparatus described in Patent Document 1 includes a rotating drum 102 that contains powder or granular material to be treated and is driven to rotate about its axis by the rotational force of a rotation drive mechanism 101 transmitted to its rear end, and a roller mechanism 103 that rotatably supports the rotating drum 102 at its front end.

[0004] That is, it is rotated by a rotary drive mechanism 101 (for example, a motor, a reducer, a chain, a sprocket, etc.), but since the rotary drum 102 is heavy, a roller mechanism 103 is provided to support the front side of the rotary drum 102.

[0005] In this case, rollers 107 of roller mechanism 103 roll on a ring-shaped outer flange (mouth fitting) 106 provided along the opening edge of the front end opening 102a of the rotating drum 102, and two roller mechanisms 103 are provided on the front side of the device and support the mouth fittings 106 from below.

[0006] The roller (front support roller) 107 of the roller mechanism 103 is rotatably supported on a roller support shaft 110 that is supported by a bracket 109 provided on a housing 108. The roller 107 of the roller mechanism 103 is a resin roller whose outer diameter surface is cylindrical. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-976106 Summary of the Invention [Problem to be solved by the invention]

[0008] In the coating device described above, roller 107 rotates in synchronization with the rotation of rotating drum 102. However, in this case, roller 107 may become misaligned, and such misalignment may cause roller 107 to become less synchronized with the rotation of rotating drum 102, resulting in slippage and noise or damage to roller 107.

[0009] In view of the above circumstances, the present invention has as its technical object to provide a coating device that can suppress the generation of abnormal noise that is likely to occur as the rotating drum rotates. [Means for solving the problem]

[0010] The coating apparatus of the present invention, which was invented to solve the above problems, comprises a rotating drum that contains powder or granular material to be processed and is rotated about its axis by the rotational force of a rotation drive mechanism transmitted to its rear end, and a roller mechanism that rotatably supports the rotating drum at its front end, wherein the roller mechanism has rollers that rotate about a rotation axis parallel to the rotation axis of the rotating drum while being supported from below by a support portion consisting of the cylindrical surface of the rotating drum, and the outer diameter surface of the roller has a crowning shape such that the outer diameter at the axial center is larger than the outer diameter at the axial end. Note that the term "parallel" as used herein includes both parallel and approximately parallel, and approximately parallel refers to a range from the parallel state (perfectly parallel) that a person skilled in the art would recognize as a setting or manufacturing error.

[0011] In the coating device according to the present invention, the outer diameter of the roller is crowned so that the outer diameter at the axial center is larger than the outer diameter at the axial end, which serves to alleviate excessive pressure generated at the end of the contact area between the support part and the roller, making the surface pressure distribution uniform and concentrating stress on the roller near the roller core, thereby making it less likely for the roller to become misaligned.

[0012] It is preferable that the rollers of the roller mechanism are such that both axially outer ends of their outer diameter surfaces are not in contact with the support parts of the rotating drum, so that stress on the rollers can be more stably concentrated near the roller cores.

[0013] The crowning shape preferably has a continuous convex curvature over the entire length of the outer diameter surface of the roller, which makes the roller less susceptible to misalignment.

[0014] The rotating drum may comprise a drum body having a front opening that opens horizontally, and a ring-shaped outer flange provided along the edge of the front opening of the drum body, the ring-shaped outer flange having a tapered wall that increases in diameter from the inside of the drum to the outside of the drum, and the cylindrical surface of a secondary member attached to the ring-shaped outer flange forming a support portion on which the outer diameter surfaces of the rollers of the roller mechanism roll. With this configuration, the front side of the rotating drum can be stably supported by the roller mechanism, and since the inner diameter surface of the ring-shaped outer flange is a tapered surface that increases in diameter from the inside of the drum to the outside of the drum, the powder and granular material inside the rotating drum can be easily discharged.

[0015] The rotating drum may also include a drum body having a horizontally extending front-end opening and a ring-shaped outer flange provided along the edge of the front-end opening of the drum body, the ring-shaped outer flange forming a support portion on which the outer diameter surfaces of the rollers of the roller mechanism roll. This configuration allows the roller mechanism to stably support the front side of the rotating drum. Furthermore, since a secondary material having a cylindrical surface is not required, the number of parts can be reduced, improving the assembly of the coating device and reducing costs.

[0016] It is preferable that a pair of the roller mechanisms are disposed at a predetermined interval below the roller support portion, so that the rotating drum can be stably supported.

[0017] The rollers of the roller mechanism preferably have an inner diameter portion made of metal on the inner diameter side and an outer diameter portion made of resin or rubber on the outer diameter side. This configuration stabilizes the contact of the roller with the rotating drum, enabling stable synchronous rotation with the rotating drum. Moreover, the inner diameter side is a metal ring body, which effectively ensures the rigidity of the roller. [Effects of the Invention]

[0018] According to the present invention, the rollers are less likely to become misaligned, and the rollers of the roller mechanism rotate stably and synchronously with the rotation of the rotating drum, effectively preventing the generation of abnormal noise and preventing damage to the rollers, the support parts of the rotating drum, etc. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a longitudinal sectional view of a coating apparatus according to an embodiment of the present invention. [Figure 2] 1A and 1B show a rotary drum, in which FIG. 1A is a cross-sectional view and FIG. 1B is a longitudinal-sectional view. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] 3A and 3B show a roller mechanism, in which FIG. 3A is an enlarged cross-sectional view, and FIG. 3B is a simplified view showing the relationship between the roller support shaft and the receiving member. [Figure 7] 1 is a simplified side view of a conventional coating apparatus. [Figure 8] FIG. 1 is a simplified front view of a conventional coating apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] As shown in FIG. 1, the coating apparatus according to this embodiment includes a ventilated rotating drum 1 that is driven to rotate about an axis X that is parallel or substantially parallel to the horizontal. The rotating drum 1 is rotatably housed within a casing 2 and is driven to rotate by a rotation drive mechanism 3 disposed at its rear end. The rotating drum 1 is housed within an inner housing 4 within the casing 2, the space of which is airtightly sealed from the outside. A spray nozzle unit 5 having one or more spray nozzles 5a that spray a coating liquid or other spray liquid toward a powder or granular material layer is also disposed within the rotating drum 1. In this embodiment, the rotating drum 1 has a front opening 1e at its front end and a rear opening 1g at its rear end. Air intakes A1 and A2 are provided on the sides of the front opening 1e and the rear opening 1g, respectively.

[0022] The front end of the casing 2 forms a chamber 2a, and the front of the chamber 2a is closed by a front panel 2b having an inspection window 2b1. In addition, a discharge port 2c for powder or granular material (processed powder or granular product: for example, tablets) is provided at the bottom of the chamber 2a.

[0023] The spray nozzle unit 5 is attached to the tip of an L-shaped support pipe 6 via a connecting pipe 7, and the base end of the support pipe 6 is connected to a vertical movement mechanism 8 attached to the inner surface of the front panel 2b. The vertical movement mechanism 8 allows the vertical position of the spray nozzle unit 5 to be adjusted manually or automatically (by an actuator mechanism such as an air cylinder or ball screw).

[0024] 2, in this embodiment, the rotating drum 1 has a peripheral wall 1a having a polygonal cross section (for example, a decagon or a dodecagon, which is a dodecagon in this embodiment), an end wall 1b continuing from the front end of the peripheral wall 1a, and an end wall 1c continuing from the rear end of the peripheral wall 1a. Each side surface of the peripheral wall 1a is provided with a ventilation portion formed by a porous portion. In this embodiment, ventilation sections are formed by attaching perforated plates to each side surface of the peripheral wall section 1a. The front end of the end wall section 1b is continuous with the rear end of the annular mouth ring section 1d, and a front-end opening 1e is provided at the front end of the mouth ring section 1d.

[0025] That is, the rotating drum 1 comprises a drum body 1A having a front end opening 1e and a rear end opening 1g that open horizontally, and the mouth ring portion 1d, which is a ring-shaped outer flange portion provided along the opening edge of the front end opening 1e of the drum body 1A.

[0026] The inner diameter surface 1d1 of the mouth ring portion (ring-shaped outer flange portion) 1d is formed in a shape that gradually widens in diameter toward the front, for example, a conical surface that gradually widens in diameter toward the front at a cone angle α (the angle formed with the axis of the rotating drum 1). The inclination angle α of the inner diameter surface 1d1 is preferably, for example, 5° or greater. A connecting portion 1f is provided at the rear end of the end wall portion 1c, and a rear-end opening 1g is provided in the connecting portion 1f. An extension portion 1h (see FIG. 1) that serves as a mount for drive system components that rotate the rotating drum 1 is connected to the connecting portion 1f. The inner diameter surface 1d1 of the mouth ring portion 1d need only be formed in a shape that gradually widens in diameter toward the front; it does not necessarily have to be formed in a conical surface. For example, the inner diameter surface 1d1 of the mouth ring portion 1d may be formed in a shape that gradually widens in diameter toward the front, like a curved surface.

[0027] In this embodiment, annular seal rings 13 are provided at both axial ends of the peripheral wall 1a of the rotating drum 1, and multiple partitions 14 are provided at predetermined intervals in the rotational direction on the outer periphery of the peripheral wall 1a. The partitions 14 are generally plate-shaped, have a longitudinal dimension that is approximately the same as the axial dimension of the peripheral wall 1a, and are arranged on the outer periphery of the peripheral wall 1a in a direction parallel to the axis of the rotating drum 1. Furthermore, the partitions 14 are respectively arranged on each of the apexes 1a2 and each of the side faces 1a1 of the polygonal peripheral wall 1a.

[0028] In this case, the rotational force of the rotary drive mechanism 3 is transmitted to the rear end of the rotary drum 1, causing it to rotate about its axis X. The rotary drum is rotatably supported at its front end by a pair of roller mechanisms 15, 15 provided on the chamber 2a side of the front end of the casing 2.

[0029] As shown in Figures 3 to 5, each roller mechanism 15 is provided in the casing 2, placed on a support frame 16, and comprises a pair of support plates 18, 18 erected on a base plate 17 fixed to the support frame 16, a support shaft 19 supported by these support plates 18, 18, and a rotating body 21 rotatably fitted around this support shaft 19 via a bearing 20 (see Figure 6).

[0030] 6(a), the rotating body 21 includes a roller 24 having an inner diameter portion 22 made of metal on the inner diameter side and an outer diameter portion 23 made of resin or rubber on the outer diameter side, and a pair of clamping plates 26 that clamp and hold the roller 24. In this case, the inner diameter portion 22 is formed of a short cylinder and has an inner flange 22a provided in the center of the inner diameter surface in the axial direction, and in a state where it is clamped by the pair of clamping plates 26, 26, the outer ring of the bearing 20 fitted onto the support shaft 19 is clamped between the inner diameter side ring-shaped bulge 26a of the clamping plates 26 and the inner flange 22a of the inner diameter portion 22.

[0031] The support shaft 19 is composed of a support shaft main body 19a and outer fitting bodies 19b, 19b fitted onto the axial end sides of the support shaft main body 19a. A spacer 27 is fitted onto the axial center of the support shaft main body 19a, and the inner ring of the bearing 20 is sandwiched between the spacer 27 and the outer fitting bodies 19b, 19b.

[0032] In this case, the pair of clamping plates 26 and the rotating body 21 are integrated by bolt connections 30. That is, one of the clamping plates 26 is formed with a hole portion 31 consisting of an outer large-diameter hole 31a and an inner small-diameter hole 31b, a bolt insertion hole 32 is formed in the outer diameter portion 23 of the rotating body 21, and a screw hole 33 is provided in the other clamping plate 26. Then, a bolt member 34 is inserted from the side of one of the clamping plates 26, and the threaded portion of the bolt member 34 is screwed into the screw hole 33 of the other clamping plate 26. As a result, the rotating body 21 and the pair of clamping plates 26 are integrated and become rotatable around the support shaft 19. In this case, the head portion 34a of the bolt member 34 is fitted into the outer large-diameter hole 31a of the hole portion 31 of one of the clamping plates 26.

[0033] 6(a) and 6(b), notched recesses 18a are formed at the upper ends of the support plates 18, 18 serving as receiving members, and the end of the support shaft 19 is fitted into the notched recesses 18a, 18a. In this case, flat surface portions 41, 41 facing each other are formed at the end of the support shaft 19, and the flat surface portions 41, 41 engage with the side surfaces of the notched recesses 18a. This prevents the support shaft 19 from rotating.

[0034] As described above, the outer diameter portion 23 is made of resin or rubber. Examples of suitable resin materials include MC nylon (a registered trademark of Quadrant Polypenco Japan Co., Ltd.), nylon 6, POM (polyacetal), and PTFE (polytetrafluoroethylene). Examples of suitable rubber materials include NR (natural rubber), CR (chloroprene), NBR (nitrile rubber), IIR (butyl rubber), EPDM (ethylene-propylene rubber), Q (silicone rubber), FKM (fluororubber), and U (urethane). The inner diameter portion 22 may be made of various metals, such as carbon steel, stainless steel, aluminum, titanium, and high-nickel alloys.

[0035] Compared to nylon resin, MC nylon is a material with superior mechanical strength and durability, self-lubricating properties, and excellent sliding properties, and it also has excellent wear resistance, especially under heavy loads. It also has heat resistance, able to withstand temperatures of 120°C during continuous use. It also has chemical resistance, making it resistant to organic solvents, oils, and alkaline chemicals. This makes MC nylon ideal for rollers used in this type of coating equipment.

[0036] The outer diameter surface 24a of the roller 24 has a crowned shape in which the outer diameter at the axial center is larger than the outer diameter at the axial end. The crowning shape may be a single crowning formed by a single arc, a compound crowning formed by multiple arcs, or a logarithmic crowning. Furthermore, the outer diameter surface 24a of the roller 24 may have a continuous convex curvature over the entire length (full crowning), in which the axial center of the outer diameter surface 24a of the roller 24 is straight and the axial end portions are arc-shaped.

[0037] Furthermore, since the inner diameter surface 1d1 of the mouth ring portion 1d is formed in a shape that gradually widens toward the front, the outer diameter surface 1d2 of the mouth ring portion 1d also has a shape that gradually widens toward the front. In other words, the mouth ring portion (ring-shaped outer flange portion) 1d has a tapered wall. For this reason, the rollers 24 of the roller mechanism 15 cannot roll on the outer diameter surface 1d2 of the mouth ring portion 1d.

[0038] Therefore, in this coating apparatus, a secondary member 45 is attached to the mouth ring portion 1d as shown in FIG. 5. The secondary member 45 has a first portion 45a in the shape of a vertical flat ring that is connected to the mouth ring portion 1d by welding or other fastening means, and a second portion 45b in the shape of a short cylinder attached to the end wall portion 1b that is also connected by welding or other fastening means. The outer diameter end of the first portion 45a and the axial outer end of the second portion 45b are integrally connected by welding or other fastening means. Therefore, the cylindrical surface of the second portion 45b of the secondary member serves as the support portion 42 on which the outer diameter surfaces 24a of the rollers 24 of the roller mechanism 15 roll. In this case, the support portion 42 is formed by a recessed surface 45b1 provided on the outer diameter surface of the second portion 45b.

[0039] 4, a pair of roller mechanisms 15 are disposed at a predetermined distance below the support portion 42. With respect to a vertical axis Oa perpendicular to the rotation axis O of the rotating drum 1, one roller mechanism 15A is tilted clockwise, for example, by 35 degrees, as viewed from the front, and the other roller mechanism 15B is tilted counterclockwise, for example, by 35 degrees, as viewed from the front. In this case, when the tilt angle of one roller mechanism 15A is θ1 and the tilt angle of the other roller mechanism 15B is θ2, θ1 = θ2. Note that θ1 + θ2 can be varied in various ways as long as it is not too small, causing the rollers 24 of each roller mechanism 15A and 15B to come into contact with each other, or too large, causing the rollers 24 of each roller mechanism 15A and 15B to be unable to support the support portion 42 of the rotating drum from below.

[0040] The axial length of support portion 42 is set to be longer than the axial length of roller 24. When the axial length of roller 24 is L1 (see FIG. 5) and the axial length of support portion 42 is L2 (see FIG. 5), for example, L2=1.5×L1 to 2.5×L1. Furthermore, when the diameter of roller 24 (diameter of the axial center portion) is D1 (see FIG. 4) and the diameter of support portion 42 is D2 (see FIG. 4), for example, D2=4.5×D1 to 6.5×D1. Note that these dimensional relationships are not limited to those in the present invention, but setting them in this manner has the advantage of more stably supporting support portion 42 of rotating drum 1 by roller mechanisms 15, 15.

[0041] The radial thickness of the outer diameter portion 23 and the radial thickness of the inner diameter portion 22 can be set arbitrarily, and the radial thickness of the outer diameter portion 23 and the radial thickness of the inner diameter portion 22 can be the same or different. For example, if the outer diameter dimension of the roller 24 is D1 (see FIG. 4) and the radial thickness of the outer diameter portion 23 is B (see FIG. 6), then B can be approximately 0.2×D1 to 0.3×D1, and if the radial thickness of the inner diameter portion 22 is C (see FIG. 6), then C can be approximately 0.06×D1 to 0.08×D1. These dimensional relationships are not limited to these approximate dimensions in the present invention, but can be set variously depending on the materials of the outer diameter portion 23 and the inner diameter portion 22. That is, the size and material of each member can be selected so that the roller mechanism exhibits optimal strength and rigidity to support the support portion 42 of the rotating drum 1.

[0042] In the coating device configured as described above, when the rotary drive mechanism 3 is driven to rotate the rotary drum 1, the roller rotates (rolls) around the rotation axis O1 that is parallel to the rotation axis O of the rotary drum 1 while being supported from below by the support part 42 of the rotary drum 1. Note that the term "parallel" as used above includes both a parallel state and an approximately parallel state, and the term "approximately parallel" refers to a range from the parallel state (perfectly parallel) that a person skilled in the art would recognize as a setting or manufacturing error.

[0043] In this case, the outer diameter surface 24a of the roller 24 has a crowning shape in which the outer diameter at the axial center is larger than the outer diameter at the axial end, which serves to alleviate excessive pressure generated at the end of the contact area between the support part 42 and the roller 24 and make the surface pressure distribution uniform, allowing stress on the roller 24 to be concentrated near the roller core. As a result, the roller 24 is less likely to become misaligned, and the roller 24 of the roller mechanism 15 rotates stably and synchronously with the rotation of the rotating drum 1, effectively preventing the generation of abnormal noise and preventing damage to the roller 24, the support part 42 of the rotating drum 1, etc.

[0044] The crowning shape preferably has a continuous convex curvature along the entire length of the outer diameter surface 24a of the roller 24. This configuration makes the roller 24 less likely to become misaligned. In this case, it is preferable that both axially outer ends of the outer diameter surface 24a of the roller 24 of the roller mechanism 15 do not come into contact with the support portion 42 of the rotating drum 1. This configuration allows the stress on the roller 24 to be more stably concentrated near the roller core. The curvature of the outer diameter surface 24a of the roller 24 can be changed depending on the load from the rotating drum 1, the material of the roller 24, etc., and may be any curvature that allows the stress on the roller 24 to be concentrated near the roller core.

[0045] In this embodiment, the rotating drum 1 includes a drum main body 1A having a front-end opening that opens horizontally, and a ring-shaped outer flange 1d provided along the edge of the front-end opening 1e of the drum main body 1A, the ring-shaped outer flange 1d being a tapered wall that increases in diameter from the inside of the drum toward the outside, and the cylindrical surface of a secondary member 45 attached to the ring-shaped outer flange forming a support portion 42 on which the outer diameter surfaces 24a of the rollers 24 of the roller mechanism 15 roll. With this configuration, the front side of the rotating drum 1 can be stably supported by the roller mechanism 15, and since the ring-shaped outer flange 1d is a tapered wall that increases in diameter from the inside of the drum toward the outside, and the inner diameter surface 1d1 of the ring-shaped outer flange 1d is a tapered surface that increases in diameter from the inside of the drum toward the outside, the rotating drum 1 has excellent dischargeability for powder and granular material.

[0046] However, if the ring-shaped outer flange 1d is not tapered and the outer diameter surface 1d2 of the ring-shaped outer flange 1d is cylindrical, the outer diameter surface of the ring-shaped outer flange 1d can form the support portion 42 on which the outer diameter surface 24a of the roller 24 of the roller mechanism 15 rolls, without the need for the secondary member 45. This configuration reduces the number of parts, improves the assembly of the coating device, and reduces costs. Even when the secondary member 45 is not provided, the axial length of the support portion 42 formed by the cylindrical surface of the outer diameter surface 1d2 of the ring-shaped outer flange 1d is set longer than the axial length of the roller 24. For example, when the axial length of the roller 24 is L1 and the axial length of the support portion 42 is L2, L2 can be approximately 1.5 × L1 to 2.5 × L1. Furthermore, When the diameter of the roller 24 (diameter of the central portion in the axial direction) is D1 and the diameter of the support portion 42 is D2, for example, D2 can be approximately 4.5×D1 to 6.5×D1. Of course, the present invention is not limited to these.

[0047] It is preferable that a pair of roller mechanisms 15 are disposed at a predetermined interval below the support portion 42. With this configuration, the rotating drum 1 can be supported stably.

[0048] The roller 24 of the roller mechanism 15 preferably has an inner diameter portion 22 made of metal on the inner diameter side and an outer diameter portion 23 made of resin or rubber on the outer diameter side. This configuration stabilizes the contact of the roller 24 with the rotating drum 1, enabling stable synchronous rotation with the rotating drum 1. Moreover, the inner diameter side is a metal ring body, which effectively ensures the rigidity of the roller 24.

[0049] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. Various modifications are possible, and for example, the present invention is not limited to coating devices equipped with a rotating drum having a polygonal cross-sectional shape on the peripheral wall, but can be similarly applied to coating devices equipped with a rotating drum having a circular, conical, or polygonal conical cross-sectional shape on the peripheral wall. Furthermore, the present invention is not limited to coating devices with a so-called jacketless structure, but can be similarly applied to coating devices with a structure in which a jacket is attached to the peripheral wall of the rotating drum. Furthermore, the present invention is not limited to coating devices in which the rotating drum is driven to rotate around an axis parallel or approximately parallel to the horizontal line, but can be similarly applied to coating devices in which the rotating drum is driven to rotate around an axis inclined with respect to the horizontal line. [Explanation of symbols]

[0050] 1 rotating drum 1A Drum body 1d Ring-shaped outer flange (mouth ring) 15, 15A, 15B roller mechanism 22 Inner diameter 23 Outer diameter part 24 Laura 24a Outer diameter surface 42 Support part 45 Sub-material

Claims

1. A coating device comprising: a rotary drum in which powder or granular material to be processed is accommodated, the rotary drum being rotated about its axis by a rotational force transmitted from a rotary drive mechanism to a rear end thereof; and a roller mechanism rotatably supporting the rotary drum at a front end thereof, The roller mechanism has a roller that rotates around a rotation axis parallel to the rotation axis of the rotating drum while being supported from below on a support portion that is the cylindrical surface of the rotating drum, and the outer diameter surface of the roller has a crowning shape in which the outer diameter at the axial center is larger than the outer diameter at the axial end, and the crowning shape has a continuous convex curvature along the entire length of the outer diameter surface of the roller.

2. The coating apparatus described in Claim 1, characterized in that the rotating drum comprises a drum body having a front end opening that opens horizontally, and a ring-shaped outer flange portion that is provided along the opening edge of the front end opening of the drum body, and the ring-shaped outer flange portion forms a support portion on which the outer diameter surfaces of the rollers of the roller mechanism roll.

3. A coating device comprising a rotary drum in which powder or granular material to be processed is accommodated and which is driven to rotate about its axis by the rotational force of a rotary drive mechanism transmitted to its rear end, and a roller mechanism which rotatably supports the rotary drum at its front end, the roller mechanism has a roller that rotates around a rotational axis parallel to the rotational axis of the rotating drum while being supported from below on a support portion that is the cylindrical surface of the rotating drum, the outer diameter surface of the roller has a crowning shape such that the outer diameter at the axial center is larger than the outer diameter at the axial end, the rotating drum has a drum main body with a front end opening that opens horizontally, and a ring-shaped outer flange portion provided along the opening edge of the front end opening of the drum main body, the ring-shaped outer flange portion being a tapered wall portion that expands in diameter from the inside of the rotating drum, and the cylindrical surface of a secondary material attached to the ring-shaped outer flange portion forms a support portion on which the outer diameter surface of the roller of the roller mechanism rolls.

4. 4. The coating apparatus according to claim 1, wherein the roller mechanism is provided as a pair at a predetermined interval below the support portion.

5. The coating device according to any one of claims 1 to 4, characterized in that the rollers of the roller mechanism have an inner diameter portion made of metal on the inner diameter side and an outer diameter portion made of resin or rubber on the outer diameter side.

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