Powder sprinkling device and method of using the powder sprinkling device

Abstract

To provide a powder sprinkling device 1 capable of quickly and uniformly sprinkling powder to an object to be sprayed.SOLUTION: A powder sprinkling device 1 for sprinkling powder 2 to an object 3 to be sprayed comprises a sprinkling head 20 disposed above the object to be sprayed. The sprinkling head includes a storage cylinder 21 that stores the powder, a fixed mesh member 22 that is disposed in the bottom of the storage cylinder and that limits falling of the powder, a movable mesh member 23a disposed above the fixed mesh member, a rotary shaft 25 extending up from the movable mesh member, and a rotary driving unit 26 that rotates the rotary shaft.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a powder sprinkling device that sprinkles powder onto an object to be sprinkled. [Background technology]

[0002] Conventionally, with the aim of providing a powder supplying device capable of supplying powder containing fine particles at a constant supply rate, Japanese Patent Application Laid-Open No. 2015-160734 discloses a powder supplying device equipped with a rotating blade that rotates on a substantially vertical rotation axis above a cutout mesh provided at the discharge port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-160734 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the device disclosed in Patent Document 1 has the problem that the powder supply speed is slow, so it takes time to sprinkle the powder on the target object. There is also the problem that the amount of powder that falls varies depending on the distance from the rotation axis of the rotating blades.

[0005] SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and has as its object to provide a powder sprinkling device that can quickly and uniformly sprinkle powder onto an object to be sprinkled. [Means for solving the problem]

[0006] The powder sprinkling device of the present invention is A powder sprinkling device that sprinkles powder on an object to be sprinkled, The powder sprinkling device includes a sprinkling head that is placed above the object to be sprinkled, The sprinkling head is a storage cylinder portion for storing the powder; a fixed mesh member disposed on the bottom surface of the cylindrical storage portion and restricting the powder from falling; a movable mesh member disposed on the fixed mesh member; a rotation shaft extending upward from the movable mesh member; a rotation drive unit that rotates the rotation shaft, When the movable mesh member is stationary, the powder does not fall from the fixed mesh member, The powder falls from the fixed mesh member when the movable mesh member is rotating.

[0007] According to the powder sprinkling device of the present invention, when the movable mesh member is stationary, the powder particles on the fixed mesh member form an arch structure, blocking each other, creating a condition known as a bridge, preventing the powder from falling. On the other hand, when the movable mesh member is rotating, the arch structure is destroyed, allowing the powder to fall from the fixed mesh member. In the powder sprinkling device of the present invention, the movable mesh member and the fixed mesh member face each other. Therefore, even a slight rotation of the movable mesh member instantly destroys the arch structure on the entire surface of the fixed mesh member, allowing the powder to fall simultaneously from the entire surface of the fixed mesh member. This allows the powder to fall quickly and uniformly.

[0008] A preferred example of the powder sprinkling device of the present invention is: The movable mesh member has a protrusion on its upper surface.

[0009] In a preferred embodiment of the powder sprinkling device of the present invention, the upper surface of the movable mesh member is provided with protrusions, so that the powder can be loosened above the movable mesh member, and the powder can be expected to fall smoothly.

[0010] A preferred example of the powder sprinkling device of the present invention is: The upper surface of the movable mesh member is provided with protrusions extending radially from the rotation axis.

[0011] In a preferred example of the powder sprinkling device of the present invention, the protrusions extend radially from the rotation axis, so that the protrusions can loosen the powder above the movable mesh member and also reinforce the movable mesh member.

[0012] A preferred example of the powder sprinkling device of the present invention is: The movable mesh member has a reinforcing edge on its periphery.

[0013] According to a preferred example of the powder sprinkling device of the present invention, a reinforcing edge is provided on the periphery of the movable mesh member, thereby improving the strength of the movable mesh member.

[0014] A preferred example of the powder sprinkling device of the present invention is: The movable mesh member is provided with a masking member that limits the location where the powder falls.

[0015] In a preferred embodiment of the powder sprinkling device of the present invention, the masking member is provided on the movable mesh member side, so that powder that has entered between the masking member and the fixed mesh member is quickly discharged. This makes it possible to suppress wear on the fixed mesh member and the movable mesh member at the locations where the masking member is located, particularly when the powder is of high hardness. [Effects of the Invention]

[0016] As described above, the powder sprinkling device of the present invention can sprinkle powder quickly and uniformly onto an object to be sprinkled. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating a powder sprinkling device according to an embodiment of the present invention. [Figure 2] 10A and 10B are diagrams illustrating the configuration of the movable mesh member and the fixed mesh member and their surroundings. [Figure 3] 10A and 10B are diagrams illustrating protrusions of a movable mesh member. [Figure 4] 10 is another view illustrating the protrusions of the movable mesh member. FIG. [Figure 5] FIG. 2 is a diagram illustrating a masking member. [Figure 6] FIG. 10 is another view illustrating the masking member. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the powder sprinkling device 1 according to the present invention will be described in detail with reference to the accompanying drawings. Note that the meshes of the fixed mesh member 22 and the movable mesh member 23a in each drawing are shown schematically and may differ from the actual meshes.

[0019] As shown in Figures 1 and 2, the powder sprinkling device 1 of this embodiment includes a storage tank 10, a screw conveyor 11, a sprinkling head 20, a collection tank 12, and a workpiece transport unit (not shown). Note that the storage tank 10, screw conveyor 11, collection tank 12, and workpiece transport unit are not essential components and may be omitted in some cases. For example, it is possible for a person to refill the storage tank 10 with powder 2 using a shovel or the like, and then manually transport the workpiece 3 below the sprinkling head 20. Also, shown in the lower right of Figure 1 is a plan view of the workpiece 3, which is an example of an object 3 to be sprinkled.

[0020] The storage tank 10 stores the powder 2 to be sprinkled on the target object 3. In this embodiment, silicon carbide (SiC) is used as the powder 2. By adhering this powder to a fastening surface such as a washer, when the target object is fastened with a bolt, the axial force of the bolt causes the silicon carbide particles to bite into the washer and its opposing surface, preventing misalignment of the fastening surface (see Japanese Patent No. 6764162 for details).

[0021] The screw conveyor 11 transports the powder 2 that has dropped from the storage tank 10 to the sprinkling head 20, and is driven by a motor (not shown).

[0022] The sprinkling head 20 sprinkles powder 2 onto the object 3 to be sprayed, and comprises a storage cylinder portion 21, a fixed mesh member 22, a movable mesh member 23a, a reinforcing edge portion 24, a rotating shaft 25, a rotation drive portion 26, and a powder sensor 27.

[0023] The storage cylinder portion 21 is a cylindrical member that stores the powder 2. The storage cylinder portion 21 is not limited to a cylindrical shape as in this embodiment, and may be, for example, an inverted truncated cone shape or a combination of a cylinder and an inverted truncated cone.

[0024] The fixed mesh member 22 is disposed near the bottom surface of the storage cylinder 21 and is a mesh member that restricts the fall of the powder 2. The mesh size is preferably such that, when there is no stimulus such as vibration, the particles of the powder 2 on the fixed mesh member 22 form an arch structure, creating a blocked state, and when a stimulus such as vibration is applied, the arch structure breaks, allowing the powder 2 to fall from the fixed mesh member 22. Therefore, the mesh size of the fixed mesh member 22 varies depending on the material and size of the powder 2. In this embodiment, a plain-woven wire mesh is used for the fixed mesh member 22, and when the particle size (grain size) of the powder 2 is #120 mesh (the grain size of abrasives for grinding wheels specified by the Japanese Industrial Standards, F120 specified by JIS R 6001), the mesh size is 0.28 millimeters.

[0025] The movable mesh member 23a is disposed on the fixed mesh member 22 and is rotated by a rotary shaft 25 extending upward from the center of the movable mesh member 23a and a rotary drive unit 26 connected to the rotary shaft 25. The movable mesh member 23a also uses a plain-woven wire mesh. Regarding the gap s0 between the fixed mesh member 22 (see FIG. 3(A)), when plain-woven wire meshes are used for the fixed mesh member 22 and the movable mesh member 23a, as in this embodiment, it is preferable to make the gap s0 as narrow as possible so that the powder 2 falls faster. In this embodiment, the gap s0 is made as narrow as possible so that it is almost non-existent. However, the size of the gap s0 is not particularly limited as long as it is a distance that can destroy the arch structure.

[0026] Furthermore, the mesh size of the movable mesh member 23a is preferably equal to or larger than the mesh size of the fixed mesh member 22, preferably 4 to 6 times larger. In this embodiment, the movable mesh member 23a employs mesh sizes of 1.3 to 1.38 mm. Given this size, it is more preferable that the mesh size be 4.6 to 4.9 times larger than that of the fixed mesh member 22. This is because if the mesh size of the movable mesh member 23a is too small, the powder 2 will not pass through the mesh and will not fall properly. Furthermore, if the mesh size of the movable mesh member 23a is too large, the arch structure formed on the fixed mesh member 22 will only be partially destroyed, making it difficult to sprinkle the powder 2 quickly and uniformly. For both the fixed mesh member 22 and the movable mesh member 23a, known materials such as punched metal can be used in addition to the plain-woven wire mesh described above.

[0027] The reinforcing edge portion 24 is an annular member provided on the periphery of the movable mesh member 23a, and constitutes the edge of the movable mesh member 23a. The reinforcing edge portion 24 can improve the strength of the movable mesh member 23a.

[0028] The rotating shaft 25 is a known shaft member. In this embodiment, the lower end of the rotating shaft 25 extends to the fixed mesh member 22, but the lower end may be configured to be floating above the upper surface of the fixed mesh member 22.

[0029] A known electric motor or the like can be used for the rotation drive unit 26, and it is preferable to use a stepping motor, servo motor, or the like that can precisely control the rotation. Note that rotation is intended to include not only continuous movement of the movable mesh member 23a in one direction, but also small movements and reversal of the direction.

[0030] In this embodiment, the powder sensor 27 is provided on the side of the storage cylinder 21 and detects when the powder 2 has accumulated in the storage cylinder 21. Based on the detection result, a control unit (not shown) or the like controls the operation of the screw conveyor 11. The recovery tank 12 receives and recovers the powder 2 that has spilled from the object 3 to be sprayed.

[0031] The workpiece transport unit (not shown) transports the object 3 to be sprayed from the outside to below the sprinkling head 20. This workpiece transport unit holds the object 3 to be sprayed, for example, by grasping the end 4 of the workpiece 3, which is the object 3 to be sprayed.

[0032] Next, referring to Figures 3(A) and (B), a movable mesh member 23b according to another embodiment will be described. Figure 3(A) is a longitudinal cross-sectional view of a portion of the sprinkling head 20, and Figure 3(B) is a plan view of the movable mesh member 23b (the same applies to Figures 4(A) and (B) and Figures 5(A) and (B)). The same components as those in the above-described embodiment are designated by the same reference numerals, and their description will be omitted. The movable mesh member 23b of this embodiment has protrusions 30a on its upper surface that rotate together with the movable mesh member 23b to loosen the powder 2. The shape, height, number, etc. of these protrusions 30a are not particularly limited. In this embodiment, four protrusions 30a are arranged radially, each having a length L of 1 / 4 to 1 / 3 of the radius of the movable mesh member 23b and a width w and height h of 1 to 5 mm. Of course, if the powder 2 stored in the storage tube portion 21 is prone to forming an arch structure, the number of protrusions 30a can be increased and their shape can be enlarged.

[0033] Next, a movable mesh member 23c according to another embodiment will be described with reference to FIGS. 4A and 4B. The movable mesh member 23c of this embodiment has four protrusions 30b on its upper surface, extending radially from the rotation axis 25 to the periphery of the movable mesh member 23c, offset by 90 degrees in a plan view. These protrusions 30b rotate together with the movable mesh member 23a, not only enabling the powder 2 to be loosened over a wide range, but also serving as a frame for the movable mesh member 23c, thereby improving the strength of the movable mesh member 23c. The width and height of these protrusions 30b are the same as those of the protrusions 30a. Furthermore, the number of protrusions 30b is not limited to four as shown in this figure, and other numbers may be used, such as two, three, or eight, offset by 45 degrees in a plan view.

[0034] Next, referring to Figures 5(A) and (B), an embodiment in which masking members 31 and 32 are provided on the movable mesh member 23d will be described. These masking members 31 and 32 are plate-like members that are circular or circumferential in plan view and are used to limit the location where the falling powder 2 falls. For example, when sprinkling powder 2 on the roughly doughnut-shaped washer portion 5 of the workpiece 3 as shown in Figure 1, it is not necessary to allow the powder 2 to fall near the center and periphery of the fixed mesh member 22. In this case, using the masking members 31 and 32 can prevent the powder 2 from falling on unnecessary areas, thereby saving powder material.

[0035] In this embodiment, the masking members 31 and 32 are disposed on the side of the movable mesh member 23d. Therefore, powder 2 that has entered the gap s1 between the fixed mesh member 22 and the movable mesh member 23d below the masking members 31 and 32 is quickly discharged by its own weight. The masking members 31 and 32 may be positioned above the lower end of the movable mesh member 23a, and may be substituted by, for example, crushing the mesh of the movable mesh member 23d at the location that is to be masked.

[0036] 6, when the masking members 131, 132 are arranged on the side of the fixed mesh member 122, the powder 2 that has entered the gap s2 between the fixed mesh member 122 and the movable mesh member 123 above the masking members 131, 132 cannot be discharged. As a result, this causes wear on the fixed mesh member 122 and the movable mesh member 123, which is undesirable.

[0037] Next, a method of using the powder sprinkling device 1 will be described based on the components of the powder sprinkling device 1 described above.

[0038] First, the screw conveyor 11 is driven by the powder sensor 27 and a control unit and motor (not shown), and a predetermined amount of powder 2 is accumulated in the storage tube 21. Next, the workpiece 3, which is the object to be sprayed, is transported below the sprinkling head 20 by the workpiece transport unit (not shown). The movable mesh member 23a is then rotated by the rotation drive unit 26 and the rotation shaft 25, and the powder 2 is sprinkled onto the object to be sprayed. At this time, the washer portion 5 of the workpiece 3 to which the powder 2 is to be attached is coated with wet adhesive or paint, and the fallen powder 2 adheres to the workpiece 3 by this adhesive or paint. Next, the workpiece 3 is turned over, etc., and excess powder 2 on the surface of the workpiece 3 falls into the recovery tank 12. After the workpiece 3 is turned over, powder 2 can also be sprinkled on the backside of the workpiece 3. After the workpiece 3 has been attached with the powder 2, the workpiece 3 is transported out by the workpiece transport unit.

[0039] As described above, according to the powder sprinkling device 1 of this embodiment, the movable mesh member 23a instantly destroys the arch structure of the powder 2 across the entire surface of the fixed mesh member 22. This causes the powder 2 to fall simultaneously from the entire surface of the fixed mesh member 22, allowing the powder 2 to fall quickly and uniformly onto the object 3 to be sprinkled.

[0040] For example, when attempting to drop powder 2 onto a workpiece 3 using a storage tube 21 approximately 50 mm in diameter, a method using only blades, such as that described in Patent Document 1 (JP 2015-160734 A), required 0.5 to 1.0 seconds of drive time for the rotary drive unit 26 to drop powder 2 per drop using a four-blade device. Furthermore, with the device described in Patent Document 1, the amount of powder 2 dropped varies depending on the distance from the rotation axis 25. When attempting to drop powder 2 onto the entire workpiece 3, a heap of powder 2 may occur only on a portion of the top surface of the workpiece 3. When this occurs, powder 2 first accumulates on a portion of the workpiece 3, and the undried paint applied to the workpiece 3 is absorbed by the powder 2 there due to capillary action. As a result, less paint is applied to areas where powder 2 has not yet been sprinkled, preventing sufficient adhesion of the powder 2 to those areas. Furthermore, even if capillary action does not occur, the powder 2 may push paint or the like to areas where there is no powder 2, causing the film thickness of the paint or the like to change, preventing the powder 2 from adhering uniformly.

[0041] On the other hand, in the powder sprinkling device 1 of this embodiment, the drive time of the rotation drive unit 26 that drops the powder 2 per cycle is, for example, 0.2 seconds in the embodiment with four protrusions 30b shown in Figures 4(A) and (B), and 0.04 seconds in the embodiment with eight protrusions 30b. Furthermore, because the powder 2 drops from the entire surface of the fixed mesh member 22, the powder 2 is deposited evenly and flatly on the upper surface of the workpiece 3. As a result, not only can the powder 2 be uniformly attached to the workpiece 3, but the cycle time can be shortened and the amount of powder 2 used can be reduced.

[0042] Furthermore, the protrusions 30a, 30b provided on the upper surface of the movable mesh member 23a can accommodate powder 2 that is prone to forming arch structures and causing large bridges. Furthermore, in a configuration in which the protrusions 30b are radially arranged, the strength of the movable mesh member 23c is increased, making it possible to accommodate powder 2 with a high specific gravity and to increase the size of the sprinkling head 20.

[0043] Furthermore, the reinforcing edge portion 24 not only improves the strength of the movable mesh member 23a, but also suppresses wear around the movable mesh member 23a.

[0044] The powder sprinkling device 1 described above is an example of the present invention, and its configuration can be modified as appropriate within the scope of the invention. [Explanation of symbols]

[0045] 1 Powder sprinkling device, 2 Powder, 3 Sprinkle object (workpiece), 4 End, 5 Washer part, 10. Storage tank, 11. Screw conveyor, 12. Recovery tank, 20··Sprinkling head, 21,121··Storage tube portion, 22,122··Fixed mesh member, 23a,23b,23c,23d,123··Movable mesh member, 24··Reinforcing edge portion, 25,125··Rotating shaft, 26··Rotating drive unit, 27··Powder sensor, 30a, 30b··Protrusions, 31, 32, 131, 132··Masking members, s0, s1, s2: Gap, L: Length, h: Height, w: Width

Claims

1. A powder sprinkling device that sprinkles powder on an object to be sprinkled, The powder sprinkling device includes a sprinkling head that is placed above the object to be sprinkled, The sprinkling head is a storage cylinder portion for storing the powder; a fixed mesh member disposed on the bottom surface of the cylindrical storage portion and restricting the powder from falling; A movable mesh member is disposed on the fixed mesh member and has a mesh size that is 4 to 6 times that of the fixed mesh member; a rotation shaft extending upward from the movable mesh member; a rotation drive unit that rotates the rotation shaft, When the movable mesh member is stopped, the powder does not fall from the fixed mesh member, A powder sprinkling device characterized in that the powder falls from the fixed mesh member when the movable mesh member rotates.

2. A powder sprinkling device that sprinkles powder on an object to be sprinkled, The powder sprinkling device includes a sprinkling head that is placed above the object to be sprinkled, The sprinkling head is a storage cylinder portion for storing the powder; a fixed mesh member configured by a wire mesh and disposed on the bottom surface of the cylindrical storage portion to restrict the powder from falling; a movable mesh member arranged on the fixed mesh member and made of a wire mesh; a rotation shaft extending upward from the movable mesh member; a rotation drive unit that rotates the rotation shaft, When the movable mesh member is stopped, the powder does not fall from the fixed mesh member, A powder sprinkling device characterized in that the powder falls from the fixed mesh member when the movable mesh member rotates.

3. A powder sprinkling device as described in Claim 2, wherein the mesh size of the movable mesh member is 4 to 6 times the mesh size of the fixed mesh member.

4. 4. The powder sprinkling device according to claim 1, wherein the upper surface of the movable mesh member is provided with protrusions extending radially from the rotation shaft.

5. A method of using a powder sprinkling device according to any one of claims 1 to 4, comprising: Apply wet adhesive or paint to the workpiece, The workpiece is transported under the sprinkling head by a workpiece transport unit, The movable mesh member is rotated by the rotation drive unit and the rotation shaft to sprinkle the powder onto the workpiece; A method for using a powder sprinkling device, characterized in that the workpiece is inverted to allow excess powder on the workpiece surface to fall off.

6. A method of using the powder sprinkling device according to claim 4, comprising: Apply wet adhesive or paint to the workpiece, The workpiece is transported under the sprinkling head by a workpiece transport unit, The movable mesh member is rotated by the rotary drive unit and the rotary shaft for 0.04 to 0.2 seconds to sprinkle the powder onto the workpiece; A method for using a powder sprinkling device, characterized in that the workpiece is inverted to allow excess powder on the workpiece surface to fall off.

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