JP6971629B2 - Shaft sealing structure of powder device, powder device and shaft sealing member - Google Patents

Description

The present invention relates to a shaft sealing structure of a powder device, a powder device and a shaft sealing member, and more particularly to a shaft sealing structure, a powder device and a shaft sealing member of a powder device that handles powder using a rotating shaft.

Examples of the powder device that handles the powder in the container using the rotating shaft include a screw conveyor (screw feeder) and a rotary feeder. The rotating shaft has various shapes and structures depending on the application, such as those equipped with screw-shaped blades or disk-shaped blades. In such a device, the rotating shaft is rotated by a driving means such as a motor, and these driving means are generally provided outside the container.

Therefore, the axis of rotation needs to penetrate the outer wall of the container. In such a configuration, in order to suppress wear, damage, and power loss of parts, a hole larger than the diameter of the rotating shaft is often provided in the container, and the rotating shaft is often passed through the hole in a non-contact manner with the outer wall of the container. .. In this case, the problem is that the powder leaks from the gap between the rotating shaft and the inner wall of the hole.

As a shaft sealing structure for preventing powder leakage, for example, a contact-type sealing means such as a gland packing is used. However, if powder enters between the rotating shaft and the gland packing or shaft hole, the gland packing is likely to be worn and deteriorated. Therefore, it is necessary to frequently perform maintenance such as adjusting the pressing force of the gland packing or replacing the gland packing, which leads to an increase in cost when handling powder.

In order to improve the shaft sealing structure of the powder device, for example, in Patent Document 1, a gland packing is provided for a first annular groove in which a shaft sealing gas is sealed and a second annular groove in which grease is sealed. It is provided on the outside of the casing to prevent powder from being ejected to the outside (atmosphere) from the gap between the rotating shaft and the gland packing.

In Patent Document 2, a bearing body attached to a box body surrounding the rotating shaft outside the shaft hole through which the rotating shaft of the powder container penetrates, and a spiral protrusion formed on the outer periphery of the rotating shaft at a portion passing through the shaft hole. The powder leaking from the gap between the shaft hole and the rotating shaft to the box body side is pushed back into the powder container by the spiral protrusion caused by the rotation of the rotating shaft.

In Patent Document 3, in the rotary feeder, a partition plate having an insertion hole slightly larger than the rotating shaft is provided between the inside and the outside of the casing, and the gap between the insertion hole and the rotating shaft is provided toward the inside of the casing. Air is allowed to flow, and the powder or granular material that is about to come out of this gap is pushed back into the casing.

Jitsufuku 6-1096 Gazette Patent No. 5270965 Japanese Unexamined Patent Publication No. 8-119457

However, the shaft sealing device of Patent Document 1 does not have a configuration for suppressing powder from entering the gap between the rotating shaft and the gland packing, and it is difficult to suppress the cost for maintenance of the gland packing. ..

In the shaft sealing structure of Patent Document 2, protrusions are formed on the rotating shaft, but (i) the structure is such that the powder is pushed back by the rotational force of the rotating shaft when the powder is pushed back, so that the frictional force is large and the protrusions are worn. (Ii) The powder adheres to the inner peripheral surface of the shaft hole due to the rotational force of the rotating shaft and bites into the inner peripheral surface of the shaft hole, causing power loss and wear, scratches, and breakage of parts. (Iii) ) Since the rotating shaft is processed, it is troublesome to remove the rotating shaft and the processing is difficult (the shaft diameter changes when the shaft is shaved, and it is necessary to change the dimensions of other accessory equipment), (iv) Powder There is a problem that the cost is high because it is necessary to prepare a rotation shaft according to the type.

Further, in the configuration of Patent Document 3, since the unevenness of the air purge in the gap between the insertion hole and the rotating shaft is large, it is necessary to set the air amount based on the place where the flow rate is small, and it is necessary to supply a large amount of air. .. In addition, since it is necessary to push back the powder or granular material with the length of the gap between the insertion hole and the rotating shaft, that is, the stroke corresponding to the thickness of the partition plate, it falls in a device in which the rotating shaft is installed in the vertical direction. It is difficult to push back the incoming powder.

Therefore, the present invention has a shaft-sealed structure and powder of a powder device that can suppress powder leakage from a container that handles powder while reducing damage to the powder device, power loss in a rotating shaft, and maintenance cost. It is an object of the present invention to provide an apparatus and a shaft sealing member.

The present invention has been completed by finding that the above problems can be solved by the following aspects.

(Aspect 1)
A shaft-sealed structure of a powder device having a container for storing powder, a rotating shaft that penetrates the outer wall of the container in a non-contact manner, and a driving means provided outside the container to rotate the rotating shaft. The container is located between the bottom wall provided with a circular shaft hole through which the rotating shaft passes non-contact and leads from the inside to the outside of the container, and the inner peripheral surface of the shaft hole and the rotating shaft. A shaft sealing structure of a powder device, comprising an air supply means for sending gas from the outside to the inside, and having a spiral groove formed on the inner peripheral surface of the shaft hole.

(Aspect 2)
The shaft sealing structure of the powder device according to the first aspect, wherein the spiral groove has a shape in which the width of the groove widens toward the rotation axis.

(Aspect 3)
In the cross section including the axis of the rotation axis, assuming that the portion closest to the rotation axis between the adjacent valleys of the spiral groove is the peak of the mountain, the width of the top of the mountain in the cross section is the spiral. The shaft sealing structure of the powder device according to the second aspect, which is 1/5 or less of the groove pitch.

(Aspect 4)
The shaft sealing structure of the powder device according to the third aspect, wherein the top of the mountain is a point in the cross section.

(Aspect 5)
The shaft seal of the powder device according to aspect 3 or 4, wherein the spiral groove has two slopes sandwiching the top of the mountain, and the angle formed by the two slopes in the cross section is 30 to 75 degrees. structure.

(Aspect 6)
A side wall that is outside the shaft hole in the direction of the rotation center of the rotation axis and extends from the bottom wall toward the outside of the container, and a gas introduction portion that penetrates the side wall and leads to the air supply means. The shaft seal of the powder device according to any one of aspects 1 to 5, further comprising a gas sealing means arranged between the rotating shaft and the side wall at a position away from the container from the gas introducing portion. structure.

(Aspect 7)
The shaft sealing structure of the powder device according to the sixth aspect, wherein the shaft sealing member is provided with the shaft sealing member attached to the container, and the bottom wall, the side wall, and the gas introduction portion are provided on the shaft sealing member.

(Aspect 8)
The shaft sealing member is attached to the outside of the container, the container is provided with a through hole, and the rotating shaft passes through the through hole in a non-contact manner with the inner peripheral surface of the through hole, and the shaft hole is formed. The shaft sealing structure of the powder device according to the seventh aspect, wherein the through hole and the through hole communicate with each other.

(Aspect 9)
The shaft sealing structure of the powder device according to aspect 7 or 8, wherein the container and the shaft sealing member are in contact with each other on the entire circumference of the shaft hole.

(Aspect 10)
A container for storing powder, a rotating shaft that penetrates the outer wall of the container in a non-contact manner, a driving means provided outside the container for rotating the rotating shaft, and the rotating shaft passing through the rotating shaft in a non-contact manner. Air supply means for sending gas from the outside to the inside of the container between the bottom wall provided with a circular shaft hole leading from the inside of the container to the outside, the inner peripheral surface of the shaft hole, and the rotating shaft. A powder device comprising, and characterized in that a spiral groove is formed on the inner peripheral surface of the shaft hole.

(Aspect 11)
A shaft seal attached to a powder device having a container for storing powder, a rotating shaft that non-contactly penetrates the outer wall of the container, and a driving means provided outside the container to rotate the rotating shaft. A bottom wall which is a member and is provided with a circular shaft hole which is larger than the diameter of the rotating shaft and leads from the inside of the container to the outside, and the gas sent from the outside is sent to the inner peripheral surface of the shaft hole and the rotation. A shaft sealing member comprising a gas introduction portion leading to and from the shaft, and having a spiral groove formed on the inner peripheral surface of the shaft hole.

According to the present invention, the shaft sealing structure and powder of the powder device that can suppress the leakage of the powder from the container that handles the powder while reducing the damage of the powder device, the power loss in the rotating shaft, and the maintenance cost. Equipment and shaft sealing members can be provided.

It is a figure which shows the cross section of the powder transport apparatus as 1st Embodiment of this invention. It is sectional drawing of the shaft sealing part of the powder transporting apparatus as 1st Embodiment of this invention, and the periphery thereof. 3A is a view of the shaft sealing member from the lower right to the upper left in FIG. 1, and FIG. 3B is a cross-sectional view taken along the line AA in FIG. 3A. It is a photograph which showed an example of the concrete shape of a spiral groove. This is a first modification of the shaft sealing portion in the first embodiment of the present invention. This is a second modification of the shaft sealing portion in the first embodiment of the present invention. It is an enlarged schematic cross-sectional view for demonstrating the detail of the shaft seal structure of the powder transport apparatus as 1st Embodiment of this invention. It is a figure which shows the 1st modification of the spiral groove in 1st Embodiment of this invention. It is a figure which shows the 2nd modification of the spiral groove in 1st Embodiment of this invention. It is a figure which shows the powder mixing apparatus as the 2nd Embodiment of this invention. It is a figure which shows the crushing apparatus as the 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the scope of the present invention is not limited thereto.

The powder device in the present invention is a device for processing powder such as a powder transport device (for example, the first embodiment), a powder stirring device (for example, the second embodiment), or a device for producing powder. The present invention is not limited to the above, and includes those in which powder is generated in a processing step such as a crushing device (for example, the third embodiment). That is, the powder device in the present invention refers to a device that handles powder using a rotating shaft inside the device or generates powder in processing of a material using the rotating shaft.

In the following embodiments, the "powder" refers to a powdery solid, and includes any of powder, powder, particles, fine powder, fine powder, fine particles, and the like. Further, the material, shape, dimensions, etc. of the powder are not particularly limited.

The devices in the following embodiments all include a rotating shaft. Further, the “axis line” used below means a line that is the center of rotation of the rotation shafts 141, 241 and 341 described later in each embodiment, unless otherwise specified. Further, the "shaft diameter" of the rotating shafts 141, 241, 341 and the "hole diameter" of each hole having a circle refer to the diameter unless otherwise specified.

In FIGS. 1 to 3 and 5 to 11 showing the respective embodiments, the z direction is the axial direction of the rotating shafts 141, 241, 341, the r direction is the radial direction of the circle centered on the axis, and the θ direction is the rotating shafts 141, 241. , 341 indicate the rotation direction. Further, the z, r, and θ directions indicate the same direction in each drawing in the same embodiment.

Further, in the following description, the direction of the arrow on the z-axis in the figure is the + z direction, the direction opposite to the arrow on the z-axis in the figure is the −z direction, and when the direction is not specified, the direction is the z direction without a sign. do. Regarding the r direction, the direction away from the axis is the + r direction, the direction approaching the axis is the −r direction, and if the direction is not specified, the direction is the r direction without a sign. Regarding the θ direction, when viewed in the direction of the arrow on the z-axis, the clockwise direction (the direction of the arrow in each figure) is the + θ direction, and the counterclockwise direction (the opposite direction of the arrow in each figure) is the −θ direction. If is not specified, the direction is set to θ without a sign.

<1. Powder transport device (first embodiment)>
FIG. 1 is a diagram showing a cross section of a powder transport device 1 as a first embodiment of the present invention. In FIG. 1, the top and bottom and left and right are the top and bottom and left and right of the paper surface, and here, the downward direction of the paper surface is the direction in which gravity is applied. The powder transport device 1 according to the present embodiment is an inclined screw conveyor that transports the powder P. The powder transport device 1 includes a powder container 11, a powder introduction section 12, a powder discharge section 13, a screw 14, a motor M, an air pump A, hoses 151 and 152, and a shaft sealing section 16. 17 and housings 181 and 182 are provided.

The powder container 11 stores the powder P transported in the powder transport device 1. In the present embodiment, the powder container 11 is a container having a cylindrical outer wall extending in the longitudinal direction (z direction) of the rotating shaft 141, which will be described later. The shape of the powder container 11 described here is an example thereof, and the shape can be appropriately changed depending on the usage conditions and the like. The outer wall of the powder container 11 constitutes a lower bottom portion 111 that constitutes the bottom of the lower right (-z side) end of the cylinder, a side wall 112 that forms the cylinder, and a bottom of the upper left (+ z side) end of the cylinder. It has an upper bottom portion 113 to be formed. The powder container 11 is connected to the introduction hole 114 for connecting to the powder introduction portion 12 on the lower right (-z) side of the side wall 112 and to the powder discharge portion 13 on the upper left (+ z) side of the side wall 112. The discharge hole 115 is provided. Further, the powder container 11 is provided with through holes 111a and 113a in the lower bottom portion 111 and the upper bottom portion 113, respectively. In the present embodiment, the through holes 111a and 113a are circular, and the center of the through holes 111a and 113a is on the axis of the rotating shaft 141, but other shapes such as an ellipse or a polygon may be used. Further, the lower bottom portion 111 is provided with a through hole 111b (FIG. 2) at a position corresponding to the through hole 161h (FIG. 3) of the shaft sealing member 161 described later, and the upper bottom portion 113 also has a similar through hole. It is provided.

The powder introduction unit 12 introduces the powder P into the powder container 11. As the introduction method, a method of connecting a hopper or the like above the powder introduction portion 12 to utilize gravity, or using a pump to flow air from the device or the like in the previous process toward the powder container 11 (+ z direction). Examples include, but are not limited to, a method using an air transport device for transporting.

The powder discharge unit 13 discharges the powder P transported to the upper left (+ z) side of the powder container 11 from the powder container 11 to the outside by the screw 14 described later. Examples of the discharge method include, but are not limited to, a method of dropping the powder P from the powder discharge unit 13, an air transport device, and the like.

The screw 14 has a rotating shaft 141 and a spiral blade 142. The shaft diameter of the rotating shaft 141 is smaller than the hole diameters of the through holes 111a and 113a. The rotary shaft 141 passes through the through hole 111a from the outside on the lower right side of the powder container 11 without contacting the inner peripheral surface of the through hole 111a, enters the powder container 11, and passes through the through hole 113a through the through hole 113a. It passes through the inner peripheral surface in a non-contact manner and exits to the outside on the upper left side of the powder container 11. That is, the rotating shaft 141 penetrates the outer wall of the powder container 11 in a non-contact manner. The rotary shaft 141 is further passed through a through hole 181a of the housing 181 on the lower right side, which will be described later, and one end 141a on the lower right (−z) side of the rotary shaft 141 is connected to the motor M. One end 141b on the upper left (+ z) side of the rotating shaft 141 is inserted into a bearing 182a provided in the housing 182 on the upper left side, which will be described later.

In the present embodiment, the spiral blade 142 is a blade having a spiral shape in the direction of a reverse screw (left-hand screw). The powder P introduced into the powder container 11 from the powder introduction unit 12 rides on the spiral blade 142. With this configuration, when the screw 14 rotates clockwise when viewed from the lower right side as shown in the figure, that is, in the + θ direction, the powder P placed on the spiral blade 142 moves from the lower right (-z) side to the upper left. It is transported to the (+ z) side. The shape of the spiral blade 142 described here is an example thereof in the present embodiment, and can be appropriately changed depending on the rotation direction of the screw 14, the properties of the powder P, the purpose of use, the design conditions, and the like.

Further, in the present embodiment, on the outer peripheral surface of the rotary shaft 141 of the screw 14, the portion facing the gland packing 163 (described later with reference to FIG. 2) is a rotary shaft sleeve 143 that covers the rotary shaft 141 all around. (Fig. 2) is provided. This is to suppress scratches and wear of the rotating shaft 141 due to friction between the rotating shaft 141 and sliding parts such as the gland packing 163. However, the present invention is not limited to this, and if the surface hardness of the rotary shaft 141 is high, if the rotary shaft 141 is scratched or worn by the time when the screw 14 is replaced, the rotary shaft sleeve 143 may not be attached. Sometimes it's good.

The motor M is a driving means for rotating the screw 14. In the present embodiment, the motor M is provided outside the lower right (-z) side of the powder container 11. The driving means of the screw 14 is not limited to the electric motor, and may be an internal combustion engine, an external combustion engine, wind power, hydraulic power, or the like. Further, in the present embodiment, the screw 14 is directly connected to the motor M, but power is transmitted from the motor M to the screw 14 via a speed reducing means such as a gear or a belt, a joint such as a universal joint, or other power transmission means. It may be configured to transmit.

The air pump A is installed outside the powder container 11 and is an air supply means for sending air to the shaft sealing portions 16 and 17 from the outside. In the present embodiment, the gas sent by the air pump A is air, but it may be another gas such as nitrogen gas in consideration of the properties of the powder P and the like. Further, the air supply means is not limited to the air pump, and a blower, a compressor, or the like may be used, or may be connected to an air supply line or the like installed in the plant.

The hose 151 connects the air pump A and the gas introduction portion 161e (described later with reference to FIG. 3) of the shaft sealing member 161 in the shaft sealing portion 16, and allows the air sent from the air pump A to be supplied into the shaft sealing member 161. Send to (space S described later).

The hose 152 connects the air pump A and the gas introduction portion of the shaft sealing member in the shaft sealing portion 17 (the shaft sealing portion 17 has the same configuration as the shaft sealing portion 16 (FIG. 2), so illustration is omitted). Then, the air sent from the air pump A is sent to the shaft sealing member in the shaft sealing portion 17.

The shaft sealing portion 16 suppresses the powder P from leaking to the outside of the powder container 11 from the gap between the lower bottom portion 111 and the rotating shaft 141 of the screw 14. The shaft sealing portion 17 suppresses the powder P from leaking to the outside of the powder container 11 from the gap between the upper bottom portion 113 and the rotating shaft 141 of the screw 14. The structure of the shaft sealing portion 16 will be described later with reference to FIG. Since the shaft sealing portion 17 has the same configuration as the shaft sealing portion 16 in the present embodiment, the description thereof will be omitted.

The housings 181 and 182 are attached to the lower bottom portion 111 and the upper bottom portion 113 of the powder container 11, respectively, and cover the shaft sealing portions 16 and 17, respectively. A circular through hole 181a larger than the shaft diameter of the rotating shaft 141 of the screw 14 is provided on the bottom surface of the housing 181 on the lower bottom portion 111 (−z) side. The rotating shaft 141 passes through the through hole 181a in a non-contact manner with the housing 181. In the present embodiment, the center of the through hole 181a is on the axis of the rotating shaft 141.

A bearing 182a is provided on the housing 182 on the upper bottom portion 113 (+ z) side. The bearing 182a rotatably supports one end 141b on the upper left side of the rotating shaft 141. For the bearing 182a, for example, a ball bearing or the like is used, but the bearing is not limited as long as it can rotatably support the rotating shaft 141 of the screw 14.

<2. Shaft sealing structure of powder transport equipment>
FIG. 2 is a diagram showing a cross section of the shaft sealing portion 16 of the powder transport device 1 as the first embodiment of the present invention and its periphery. The shaft sealing portion 16 includes a shaft sealing member 161, a bolt 162a, a nut 162b, a gland packing 163, a lantern ring 164, a packing retainer 165, a packing retainer bolt 166a, and a spring 166b. Further, between the bottom wall 161b of the shaft sealing member 161 (described later (FIG. 3 (a) and (b))) and the gland packing 163, the side wall 161a of the shaft sealing member 161 (described later (FIG. 3 (a))). A space S is provided between (b))) and the rotating shaft 141. As can be seen from FIG. 3A, the bolt hole 161d (similarly, the bolt 166a and the spring 166b in FIG. 2) and the gas introduction portion 161e, which will be described later, are not on the same cross section. In 2, it is shown on the same cross section.

In the present embodiment, the shaft sealing member 161 accommodates the gland packing 163, which will be described later, and is detachably attached to the outside of the powder container 11. In the present embodiment, the shaft sealing member 161 is a separate part from the powder container 11. Therefore, it is possible to replace only the shaft sealing member 161 according to the type of the powder P, the usage conditions of the device, or as a consumable item, and it is possible to reduce the maintenance cost of the equipment.

3A is a view of the shaft sealing member 161 viewed from the lower right to the upper left in FIG. 1 (in the direction of the z-axis arrow), and FIG. 3B is a view in FIG. 3A. It is a cross-sectional view of AA. The shaft sealing member 161 has a cylindrical side wall 161a extending in the axial direction (z direction) of the rotating shaft 141, and a bottom wall 161b and a side wall 161a having a bottom surface of the cylinder at one end of the side wall 161a on the powder container 11 (+ z) side. It has a flange 161c extending toward the outside (+ r direction) of the side wall 161a at one end on the powder container 11 (+ z) side. In the present embodiment, the bottom wall 161b and the flange 161c form a continuous flat surface on the powder container 11 (+ z) side.

The side wall 161a is outside the shaft hole 161f, which will be described later, in the projection in the axis (z) direction. A bolt hole 161d is provided at the end of the side wall 161a on the motor M (−z) side toward the powder container 11 side (+ z direction). The bolt holes 161d are provided at four locations along the circumference (θ direction) about the axis of the rotating shaft 141. The bolt hole 161d is screwed with the packing holding bolt 166a described later. Here, the nominal diameter of the bolt hole 161d is smaller than the thickness of the side wall 161a. The number of bolt holes 161d can be appropriately changed depending on the performance required for the shaft sealing member 161 and the design conditions such as peripheral parts. The thickness of the side wall 161a, the length in the axial direction (z direction), the nominal diameter of the bolt hole 161d, and the pitch are the strength required for the shaft sealing member 161, the pressing force of the packing retainer 165 described later, and the positional relationship with peripheral parts. It is appropriately determined according to the design conditions such as.

Further, the side wall 161a has a gas introduction portion 161e that penetrates the side wall 161a in the thickness direction (r direction) on the powder container 11 (+ z) side from the gland packing 163 described later and connects to the hose 151. With this configuration, the air sent from the air pump A passes through the hose 151, reaches the gas introduction portion 161e, and is guided to the space S. In the present embodiment, the gas introduction portions 161e are provided at two locations facing each other with the rotating shaft 141 interposed therebetween, and the two hoses 151 connected to the respective gas introduction portions 161e meet at positions (not shown). There is. The number and position of the gas introduction portions 161e are not limited to this, and can be appropriately changed depending on the design conditions and the like.

The bottom wall 161b is provided with a circular shaft hole 161f that penetrates the bottom wall 161b. In projection in the axis (z) direction, the shaft hole 161f is inside the side wall 161a. In the present embodiment, the center of the shaft hole 161f is on the axis of the rotating shaft 141. The shaft hole 161f communicates with the through hole 111a of the powder container 11. The hole diameter of the shaft hole 161f is larger than the shaft diameter of the rotating shaft 141 of the screw 14. Therefore, the rotating shaft 141 passes through the shaft hole 161f without contacting the inner peripheral surface of the shaft hole 161f (FIG. 2). With this configuration, the air guided to the space S is sent to the gap between the inner peripheral surface of the shaft hole 161f and the outer peripheral surface of the rotating shaft 141, and the inner peripheral surface of the shaft hole 161f and the outer peripheral surface of the rotating shaft 141 are sent. It flows from the outside of the powder container 11 toward the inside (+ z direction).

A spiral groove 161 g is formed on the inner peripheral surface of the shaft hole 161f. FIG. 4 is a photograph showing an example of a specific shape of the spiral groove 161 g.

In the present embodiment, the spiral groove 161 g is provided in the right-handed screw direction in accordance with the rotation direction (+ θ direction) of the screw 14. When the screw 14 rotates in the reverse direction (rotation in the −θ direction), it is preferable that the spiral groove 161 g is provided in the direction of the reverse screw (left-handed screw). That is, it is preferable that the direction of the spiral groove 161 g and the rotation direction of the screw 14 are aligned. According to this configuration, when a large-sized powder P in the spiral groove 161 g comes into contact with the rotary shaft 141 of the screw 14, the frictional force between the powder P and the rotary shaft 141 causes the powder P to be in contact with the rotary shaft 141. A force that pushes the powder P back into the powder container 11 works by using the spiral groove 161 g as a guide. Further, it can be expected that the rotation of the rotating shaft 141 further increases the flow velocity of the air flowing in the spiral groove 161 g and rectifies the air flow.

Details of the groove size of the spiral groove 161 g, the positional relationship with the rotating shaft 141, and the size relationship between the shaft hole 161f and the through hole 111a of the powder container 11 will be described later with reference to FIG. 7. The thickness of the bottom wall 161b is preferably determined not only in consideration of the required strength but also in consideration of the length of the shaft hole 161f required for pushing back the powder P by the air flow. The length of the shaft hole 161f is determined in consideration of the pitch of the spiral hole, the gap with the screw 14, the size of the powder P, and the like.

The flange 161c is provided with four through holes 161h at equal intervals on the circumference centered on the axis of the rotating shaft 141. In the present embodiment, the through hole 161h is circular, and the hole diameter is larger than the nominal diameter of the bolt 162a described later. The thickness and size of the flange 161c and the number, arrangement, and hole diameter of the through holes 161h can be appropriately changed depending on design conditions such as the size of the bolt 162a described later and the dimensional tolerance of parts. Further, the shape of the through hole is not limited to a circle, and may be an elongated hole extending along the θ direction.

Return to FIG. 2 again. The bolt 162a and the nut 162b fix the shaft sealing member 161 to the lower bottom portion 111 of the powder container 11. The bolt 162a passes through the through hole 111a provided in the lower bottom portion 111 and the through hole 161h provided in the flange 161c of the shaft sealing member 161. The nut 162b is screwed with the bolt 162a on the outside (motor M side) of the flange 161c of the shaft sealing member 161. In the present embodiment, bolts and nuts are used as an example of means for fixing the shaft sealing member 161. However, the present invention is not limited to these, and when a material such as plastic is used, claw fitting or the like may be used. If it is not necessary to replace the shaft sealing member 161 or if it may be replaced together with the powder container 11, the method of fixing the shaft sealing member 161 to the powder container 11 is as follows, by welding or the like. The shaft sealing member 161 and the powder container 11 may be integrated.

When the shaft sealing member 161 is attached to the powder container 11, the shaft sealing member 161 and the lower bottom portion 111 of the powder container 11 are in contact with each other on the entire circumference of the through hole 111a and the shaft hole 161f. Further, the lower bottom portion 111 of the powder container 11 and the shaft sealing member 161 may be brought into contact with each other via a sealing material such as a gasket. With this configuration, it is possible to prevent the powder from entering the gap between the shaft sealing member 161 and the powder container 11 and to prevent the powder from leaking to the outside from the gap between the shaft sealing member 161 and the powder container 11. can. Further, it is possible to prevent the air in the space S from leaking to the outside through the gap between the shaft sealing member 161 and the powder container 11, and it is possible to efficiently send the air between the through hole 111a and the shaft hole 161f. can. The sealing material may be provided over the entire circumference of the through hole 111a and the shaft hole 161f, or may be partially provided at necessary positions according to the shapes of the bottom wall 161b and the lower bottom portion 111 of the powder container 11. The sealing material is not particularly limited to metal, resin, rubber, etc., but is easily elastically deformed so as to seal the gap between the powder container 11 and the shaft sealing member 161 and not to damage these parts. Those having strength that can withstand use are preferable. In addition, this configuration is a preferable example of this embodiment, and in consideration of usage conditions, manufacturing requirements, etc., a gap is partially provided between the shaft sealing member 161 and the lower bottom portion 111 of the powder container 11. May be good.

The gland packing 163 is a ring-shaped member or a spiral or ring-shaped member, and is arranged at a position (-z side) away from the powder container 11 from the spiral groove 161 g and the gas introduction portion 161e. .. The gland packing 163 is elastically deformable, and for example, a material such as fiber-reinforced hard rubber is used.

The gland packing 163 is housed between the side wall 161a of the shaft sealing member 161 and the rotating shaft sleeve 143 of the screw 14. The gland packing 163 abuts on the inner peripheral surface of the side wall 161a of the shaft sealing member 161 and the rotating shaft sleeve 143 of the screw 14 over the entire circumference of the rotating shaft 141, and presses them. With this configuration, the gap between the side wall 161a of the shaft sealing member 161 and the rotating shaft 141 is closed by the gland packing 163 and the rotating shaft sleeve 143, and the air guided to the space S is on the opposite side of the powder container 11 (motor M). It is possible to prevent leakage to the side (−z direction) and efficiently send air between the through hole 111a and the shaft hole 161f. That is, in the present embodiment, the gland packing 163 and the rotary shaft sleeve 143 are contact-type sealing means and function as gas sealing means for preventing air from leaking.

In the present embodiment, a plurality of gland packings 163 are housed side by side in the axial direction (z direction) of the rotating shaft 141. The structure of the gland packing sealing in the present embodiment is an example thereof, as long as it suppresses the air (gas) introduced into the space S from leaking to the opposite side (−z side) of the powder container 11. It is not limited to the configuration described here. For example, in addition to the gland packing, an oil seal, a lip seal, etc. may be mentioned, and a plurality of configurations may be used in combination.

The lantern ring 164 is a ring-shaped member having an I-shaped cross section, and is between the side wall 161a of the shaft sealing member 161 and the rotating shaft 141, and between the bottom wall 161b of the shaft sealing member 161 and the gland packing 163. That is, it is arranged in the space S. The end of the lantern ring 164 on the powder container 11 (+ z) side is in contact with the bottom wall 161b of the shaft sealing member 161 and the other end is on the motor M (-z) side of the gas introduction portion 161e. , Contact the gland packing 163.

There is a gap between the lantern ring 164 and the rotating shaft 141. Further, the lantern ring 164 is provided with a through hole 164a penetrating from the side wall 161a side to the rotation shaft 141 side. According to this configuration, a path (gas path) for guiding the air guided to the space S between the through hole 111a and the shaft hole 161f and the rotating shaft 141 is formed. The member is not limited to the lantern ring as long as it is a member capable of forming a gas path (gas path forming member). That is, it is a member having a structure in which gas is passed between the gas introduction portion 161e side and the rotary shaft 141 side while abutting on the bottom wall 161b of the gland packing 163 and the shaft sealing member 161 and forming a space between them. All you need is.

The packing retainer 165 includes a cylindrical body portion 165a and a flange 165b extending toward the outside (+ r) side of the body portion 165a at one end of the body portion 165a on the motor M side. The outer diameter of the body portion 165a is smaller than the inner diameter of the side wall 161a of the shaft sealing member 161. The inner diameter of the body portion 165a is larger than the outer diameter of the rotary shaft sleeve 143. The portion of the body portion 165a on the powder container 11 side is inserted between the side wall 161a of the shaft sealing member 161 and the rotary shaft sleeve 143, and one end of the body portion 165a on the powder container 11 side is the motor M of the gland packing 163. Contact one end of the side.

The flange 165b is provided with four through holes 165c at positions corresponding to the bolt holes 161d of the shaft sealing member 161. The packing holding bolt 166a, which will be described later, passes through the through hole 165c.

The packing retainer bolt 166a passes through the through hole 165c of the packing retainer 165 and is screwed into the bolt hole 161d of the shaft sealing member 161.

The spring 166b is an elastic member, one end (−z side) of which abuts on the flange of the packing presser bolt 166a, and the other end (+ z side) of which abuts on the flange 165b of the packing presser 165. Therefore, the spring 166b presses the packing presser 165 in the powder container 11 direction (+ z direction), and the packing presser 165 presses the gland packing 163 in the powder container 11 direction (+ z direction). Since the gland packing 163 is compressed in the rotation shaft 141 direction (z direction) by the packing retainer 165 and the lantern ring 164, a force that tends to extend in the radius (r) direction of the rotation shaft 141 acts.

Therefore, by tightening the packing holding bolt 166a, the force of the gland packing 163 pressing the rotary shaft sleeve 143 in the −r direction increases, and the force of sealing the air in the space S increases. The force for sealing the air in the space S can be adjusted by controlling the tightening torque of the packing holding bolt 166a or the like.

Further, the spring 166b pushes the packing holding bolt 166a toward the motor M side. Therefore, a frictional force is generated between the threaded portion (male screw) of the packing holding bolt 166a and the bolt hole 161d (female screw) of the shaft sealing member 161 to prevent the packing holding bolt 166a from loosening.

<3. Deformation example of shaft seal part>
FIG. 5 is a first modification of the shaft sealing portion 16 in the first embodiment of the present invention. Here, the shaft sealing member 161 is not used. The powder container 11 includes a side wall 161a, a bolt hole 161d, a gas introduction portion 161e, and a spiral groove 161g, and these configurations are the same as those of FIGS. 2 and 3 having the same reference numerals. In this configuration, the bottom wall 161b corresponds to the lower bottom portion 111 of the powder container 11, and the shaft hole 161f corresponds to the through hole 111a of the powder container 11, and the inner peripheral surface of the through hole 111a. A spiral groove 161 g is formed in the.

In this configuration, since the spiral groove 161 g can be provided until it reaches the inside of the powder container 11, the spiral groove 161 g can be lengthened without increasing the size of the apparatus. Alternatively, the portion where the side wall 161a or the like protrudes from the powder container 11 can be made smaller, and the device can be made smaller. Further, in this configuration, the number of parts in the entire device can be reduced, and it is not necessary to consider the accuracy when assembling the shaft sealing member 161 to the powder container 11.

FIG. 6 is a second modification of the shaft sealing portion 16 in the first embodiment of the present invention. Here, a protruding portion 161i is provided in which a part of the bottom wall 161b including the shaft hole 161f of the shaft sealing member 161 projects into the inside of the powder container 11. The inner peripheral surface of the through hole 111a of the powder container 11 faces or abuts on the side surface of the protrusion 161i. In FIG. 6, a gap is provided between the inner peripheral surface of the through hole 111a and the side surface of the protruding portion 161i in consideration of the processing accuracy of the component, but the flange 161c is powdered over the entire circumference. It is in contact with the lower bottom portion 111 of the body container 11. Therefore, a structure is established in which the lower bottom portion 111 of the powder container 11 and the shaft sealing member 161 are in contact with each other over the entire circumference of the shaft hole 161f, and powder is formed between the powder container 11 and the shaft sealing member 161. You can prevent your body from leaking.

In this configuration, since the spiral groove 161 g can be put inside the powder container 11, the spiral groove 161 g can be lengthened without increasing the size of the apparatus. Alternatively, the portion of the shaft sealing member 161 protruding from the powder container 11 can be made smaller, and the device can be made smaller as a whole.
<4. Details of the shaft sealing structure of the powder transport device>

FIG. 7 is an enlarged schematic cross-sectional view for explaining the details of the shaft sealing structure of the powder transport device 1 as the first embodiment of the present invention. In the present embodiment and the modification described with reference to FIGS. 8 and 9, the peak 161j is a rotation axis between adjacent valleys of the spiral groove 161g in a cross section including the axis of the rotation axis 141. It refers to the part (point or line) closest to 141 (the same applies to the modification described later). That is, the peak 161j of the mountain is a series of these portions three-dimensionally, and if it is a point on the cross section, it is a line three-dimensionally, and if it is a line on the cross section, it is a surface three-dimensionally. Further, the valley bottom 161k means a portion (point or line) farthest from the rotating shaft 141 between adjacent mountains of the spiral groove 161 g in the cross section including the axis of the rotating shaft 141. That is, the valley bottom 161k is three-dimensionally a series of these portions, and if it is a point on the cross section, it is three-dimensionally a line, and if it is a line on the cross section, it is three-dimensionally a surface.

In the present embodiment, the spiral groove 161g has a shape in which adjacent slopes intersect, that is, a triangle in a cross section including an axis. Not limited to this, the cross section including the axis of the spiral groove 161 g may have other shapes such as a trapezoid, a square, a semicircle, and a sinusoidal curve. However, the shape in which the width of the groove widens toward the rotating shaft 141 (axis line) is easy to manufacture, the pressure loss of the air flowing through the spiral groove 161 g can be suppressed, and the powder P is the spiral groove 161 g. It is also possible to prevent clogging. It is considered that when the amount of powder P clogged in the spiral groove 161 g increases, it becomes difficult for air to flow in the spiral groove 161 g, and the powder P cannot be efficiently pushed back into the powder container 11. Further, when the powder P is clogged in the spiral groove 161 g, the powder P is also sandwiched between the spiral groove 161 g and the rotary shaft 141, resulting in power loss when driving the screw 14, the rotary shaft 141, and the shaft sealing member. It can cause wear, scratches, and breakage of 161.

In the present embodiment, in the cross section including the axis, the peak 161j of the mountain is the apex of the mountain, is three-dimensionally ridge-shaped, and is formed as a spiral line. Therefore, when the powder P reaches between the top of the mountain 161j and the rotary shaft 141, the powder P moves in either the powder container 11 side (+ z direction) or the motor M side (-z direction). Also spreads between the surface of the spiral groove 161 g and the outer peripheral surface of the rotating shaft 141. Therefore, it is possible to prevent the powder P from being sandwiched and deposited between the top of the mountain 161j and the rotating shaft 141. Then, it is possible to suppress power loss, wear, scratches, and breakage of the rotating shaft 141 and the shaft sealing member 161 when driving the screw 14 due to the biting of the powder P.

Further, in the present embodiment, the inner peripheral surface of the through hole 111a of the powder container 11 coincides with the virtual cylinder C in contact with the valley bottom 161k of the spiral groove 161g. That is, the distance between the valley bottom 161k and the axis is equal to the distance between the inner circumference of the through hole 111a and the axis. The diameter of the through hole 111a may be larger than that of the cylinder C in consideration of the accuracy of the mounting position, the dimensional tolerance of the parts, and the like.

In FIG. 7, the width of the spiral groove 161 g is w, the angle of the mountain (= angle of the valley) is α, and the distance between the top of the mountain 161j and the rotation axis 141 is d. Here, the width w of the spiral groove 161 g is the distance between the peaks 161j of the adjacent mountains. Further, the angle α of the mountain means the angle formed by the slopes adjacent to each other with the mountain top 161j or the valley bottom 161k in the cross section including the axis.

In the present embodiment, since the peak 161j of the mountain is a point in the cross section including the axis, the width w of the spiral groove 161g is the same as the pitch. Therefore, it is preferable that the width w of the spiral groove 161 g is determined in consideration of the particle size of the powder P and an appropriate pitch for efficiently pushing the powder P back.

The wider the width w of the spiral groove 161 g, the more the pressure loss generated when air enters the spiral groove 161 g can be reduced. Therefore, the powder P in the spiral groove 161 g is efficiently pushed back without increasing the pressure of the air supplied by the air pump A. However, if the width w is wide, the number of particles that can enter the spiral groove 161 g becomes large and large, so that the pressure of air required to push them back also increases. Further, if the width w is wider than necessary, the flow velocity of the air flowing in the spiral groove 161 g may decrease, and the force for pushing back the powder P may be weakened.

Further, the wider the width w of the spiral groove 161 g, the longer the pitch (= width w) of the spiral groove 161 g. As the pitch of the spiral groove 161 g becomes longer, the angle formed by the spiral groove 161 g and the axis (z) direction becomes smaller. Therefore, the air sent from the gas introduction portion 161e via the space S can be efficiently flowed into the spiral groove 161 g, and the powder P in the spiral groove 161 g can be pushed back with a large force. .. Further, since the path length of the spiral groove 161 g is shortened, the pressure loss of the air flowing through the spiral groove 161 g can be reduced, but in order to secure a sufficient distance for pushing back the powder P, the bottom wall 161b (FIG. It may be necessary to increase the thickness of 3 (a)).

The narrower the width w of the spiral groove 161 g, the narrower the air flow path of the spiral groove 161 g, so that the pressure loss generated when the air enters the spiral groove 161 g becomes larger. Therefore, in order to push back the powder P in the spiral groove 161 g, it is necessary to increase the output of the air pump A. Further, if the spiral groove 161 g is too thin, the powder P tends to be clogged in the path.

Further, the narrower the width w of the spiral groove 161 g, the shorter the pitch (= width w) of the spiral groove 161 g. When the pitch of the spiral groove 161 g becomes short, the angle formed by the spiral groove 161 g and the axis (z) direction becomes large. Therefore, when air enters the spiral groove 161 g, it becomes a resistance and a pressure loss occurs. Therefore, in order to push back the powder P, it is necessary to increase the pressure of the air supplied by the air pump A. On the other hand, if the pitch of the spiral groove 161 g is shortened, the path length of the spiral groove 161 g becomes long, so that the powder P can be sufficiently pushed back even if the bottom wall 161b (FIG. 3A) is thin. ..

In consideration of the above, the width w of the spiral groove 161 g is preferably 0.75 times or more, more preferably 1.0 times or more the particle size D50 of the powder P, and 1 It is more preferably 2 times or more, and most preferably 1.5 times or more. Here, D50 is the particle size of the particles having a size cumulatively 50% from the smallest in the mass-based particle size distribution of the powder P. Not limited to D50, the numerical value after D, that is, when DX is used, indicates the particle size of the particles having a cumulative X% from the smaller particle size in the mass-based particle size distribution.

Further, the width w of the spiral groove 161 g is preferably 5 times or less, more preferably 4 times or less, and further preferably 3 times or less the particle size D50 of the powder P. The width w is more preferably 2 times or less, and most preferably 1.5 times or less the particle size D50 of the powder P. The preferable range of the width w value of the spiral groove 161 g described here is for general powder, and the optimum width w value may not be in this range depending on the shape, properties, etc. of the powder P. be.

The angle α of the mountain will be described. If the angle α of the mountain is sufficiently large, it is possible to prevent the powder P from being caught in the spiral groove 161 g, and by extension, to prevent the powder P from being clogged in the path. However, if the angle α of the mountain is too large, the air flowing through the spiral groove 161 g tends to leak from the gap between the mountain top 161j and the rotating shaft 141, and the force to push back the powder P along the spiral groove 161 g is weak. Become. Considering these facts, the angle α of the mountain is preferably 30 to 75 degrees, more preferably 45 to 75 degrees, and most preferably 60 degrees.

Regarding the distance d between the peak 161j and the rotating shaft 141, the longer the distance d, the smaller the particle size of the powder P that can pass through the gap between the peak 161j of the spiral groove 161g and the rotating shaft 141. growing. The velocity component in the axis (z) direction of the particles passing through this gap is larger than the velocity component in the axis (z) direction of the particles passing through the spiral groove 161 g. That is, the particles passing between the top of the mountain 161j and the rotating shaft 141 have a high velocity toward the outside of the powder container 11 along the direction of the rotating shaft 141. Further, the path for exiting the powder container 11 through between the mountain peak 161j and the rotating shaft 141 is much shorter than the path through the spiral groove 161g. Therefore, in order to reliably push back the particles passing through the gap between the peak 161j of the spiral groove 161g and the rotating shaft 141, it is necessary to allow a large amount of air to flow through this gap. From this, the distance d should be short.

For example, the diameter of the portion of the rotating shaft 141 facing the spiral groove 161g is d1, the diameter of the virtual cylinder in contact with the peak 161j of the spiral groove 161g is d2, and the diameter between the rotating shaft 141 and the peak 161j. Assuming that the particle size of the powder P that may be passed through is D ₁ , _{it is conceivable that D 1} ≧ d = (d2-d1) / 2. Here, _{the value of D 1} is preferably determined between D50 and D90, more preferably between D60 and D80, and even more preferably D70.

However, the rotating shaft 141 may have a deflection (the distance between the outer peripheral surface of the rotating shaft 141 and the axis changes due to elastic deformation or the like due to rotation) during rotation. Therefore, it is preferable to determine the design value of the distance d in consideration of this. As an example, assuming that the width of the frame of the rotation shaft 141 is Δd, D ₁ ≧ d = {(d2-d1 + Δd / 2)} / 2.

In addition, since tolerances (dimensional tolerances and geometrical tolerances) due to the processing accuracy of the parts and deviations between the parts occur due to assembly accuracy and the like, the distance between the axis of the rotary shaft 141 and the outer peripheral surface of the rotary shaft 141, and rotation. The distance between the axis of the shaft 141 and the peak 161j of the spiral groove 161g is not always constant.

As an example, the tolerance of the distance between the axis of the rotating shaft 141 and the outer peripheral surface of the rotating shaft 141 is ± Δd _A , and the tolerance of the distance between the axis of the rotating shaft 141 and the peak 161j of the spiral groove 161 g is ± Δd. When these factors are taken into consideration in the above equation as _{B, it is preferable that D 1} ≧ d (nominal value) = {(d2-d1 + Δd / 2)} / ² _{+ (Δd A} 2 + Δd _B ² ) ^1/2. ..

Further, when the rotation shaft 141 and the spiral groove 161 g are designed so as not to come into contact with or interfere with each other in consideration of the above-mentioned deflection and tolerance, for example, d (nominal value)> (Δd _A ² + Δd _B ² ) ^1/2 + Δd. It is preferably / 2.

The performance of the shaft sealing structure of the powder P, which is affected by the respective values of the width w of the spiral groove 161 g, the angle α of the mountain, and the distance d between the peak 161j of the mountain and the rotating shaft 141, will be described separately. rice field. However, in the case of a shape like the present embodiment, the width w of the spiral groove 161 g, the angle α of the peak, and the distance d correlate with each other, so that the usage conditions and the like are taken into consideration when actually designing the shaft sealing structure. Then, it may be based on a function containing these values.

For example, as shown in FIG. 7, when the maximum diameter of the virtual sphere P _i capable of entering a spiral groove 161g and D _2, a geometrical calculation, the width w, mountain angle alpha, The relational expression of the distance d and the diameter D _{2 can be derived.} In this relation, for example, when the constraint condition a diameter D _2, the greater mountain angle α is, the width w becomes large, i.e., the pitch of the helical groove 161g is lengthened. It should _{be noted that the larger the value of D 2,} the more the powder P can be prevented from being clogged in the spiral groove 161 g, and the air flow path of the spiral groove 161 g becomes thicker, so that the air pressure loss can be reduced. can. However, _{if the value of D 2} is too large, a large amount of large particles enter the spiral groove 161 g, so that there is a possibility that many particles will come out of the powder container 11. _{Therefore, it is preferable that the value of D 2} used for the above relational expression is appropriately determined based on the particle size distribution of the powder P such as D50 and D70.

Designed to maximize the effect of this embodiment by grasping the correlation of each value in this way and considering the influence of each value on the performance of the shaft seal structure (as described above). Can contribute to.

<5. Deformation example of spiral groove>
FIG. 8 is a diagram showing a first modification of the spiral groove 161 g in the first embodiment of the present invention. In this modification, the peaks and valleys of the spiral groove 161 g have roundness with respect to the shape of FIG. 7. According to this configuration, since the peak of the spiral groove 161 g is not sharp, it becomes easy to secure the processing accuracy. In addition, it is possible to prevent the mountain of the spiral groove 161 g from being easily deformed. Further, it is possible to prevent the ridge of the spiral groove 161 g from damaging other parts during assembly or the like.

The definition of the mountain peak 161j is as described above, and in this modification, the mountain peak 161j is a point in the cross section including the axis (FIG. 8). That is, the peak 161j of the mountain is a series of these points, and is a three-dimensional spiral line. Similarly, according to the above definition, the valley bottom 161k is a point on the cross section and is a three-dimensional spiral line.

FIG. 9 is a diagram showing a second modification of the spiral groove 161 g in the first embodiment of the present invention. In this modification, the peak of the spiral groove 161 g is chamfered with respect to the shape of FIG. 7, and the valley bottom 161 k has a roundness. According to this configuration, it is easy to make the height of the peak 161j of the spiral groove 161g, that is, the distance d between the peak 161j and the rotation shaft 141 constant at the time of processing. In addition, it is possible to prevent the mountain of the spiral groove 161 g from being easily deformed.

In this case, in the cross section including the axis (FIG. 9), the peak 161j of the mountain becomes a line. That is, the peak 161j of the mountain three-dimensionally forms a spiral band having a surface that maintains a constant distance from the outer peripheral surface of the rotating shaft 141. Let w1 be the width of the mountain peak 161j in the cross section including the axis (FIG. 9). When the width w1 is large, the powder is sandwiched between the top of the mountain 161j and the rotating shaft 141, and it becomes easy to deposit. Therefore, it is preferable that the width w1 of the mountain top 161j is narrow.

In consideration of the above, the width w1 of the mountain top 161j is preferably 1/5 or less, more preferably 1/10 or less, and 1/10 or less of the pitch (= w + w1) of the spiral groove 161g. It is more preferably 20 or less.

<6. Effect of 1st Embodiment of this invention>
According to the first embodiment of the present invention described above, the shaft hole 161f and the rotating shaft 141 are non-contact, that is, the rotating shaft 141 penetrates the powder container 11 in a non-contact manner. Therefore, the damage of the powder transport device 1 and the maintenance cost due to the damage can be reduced. Further, it is possible to suppress the power loss in the rotating shaft 141.

Further, the powder P that enters between the shaft hole 161f and the outer peripheral surface of the rotating shaft 141 is pushed back to the inside of the powder container 11 by the air flowing between the shaft hole 161f and the outer peripheral surface of the rotating shaft 141. Therefore, it is possible to prevent the powder P from leaking from between the shaft hole 161f and the outer peripheral surface of the rotating shaft 141. Therefore, the cost for cleaning the powder P leaked to the outside of the apparatus can be reduced, and the wear and deterioration of the sliding member due to the powder P reaching the sliding member such as the gland packing 163 can be prevented. It is possible to reduce the maintenance cost of parts.

Further, a spiral groove 161g is formed on the inner peripheral surface of the shaft hole 161f of the shaft sealing member 161. The path from the inside of the powder container 11 to the outside through the spiral groove 161 g is longer than the path that does not pass through the spiral groove 161 g. Therefore, a sufficient path length is secured to push back the powder P, and the powder P is more reliably prevented from leaking from the powder container 11.

Then, it is considered that the air sent from the gas introduction portion 161e to the outer peripheral surface of the shaft hole 161f flows through the spiral groove 161 g in the direction from the outside to the inside of the powder container 11 at a higher speed. As a result, it is considered that the powder in the spiral groove 161 g is pushed back more strongly toward the inside of the powder container 11. Further, it is considered that the air flow becomes uniform in the spiral groove 161 g, and it can be expected that the amount of air that must be sent is reduced.

Further, in the first embodiment of the present invention, in the gap between the rotating shaft 141 of the screw 14 and the shaft hole 161f of the shaft sealing member 161, the spiral groove 161g that serves as a guide for the air and the powder P is outside ( It is arranged in the shaft hole 161f). Then, since the air and powder P flowing in the spiral groove 161 g move so as to rotate around the rotating shaft 141, when a force (centrifugal force) in the direction away from the axis of the rotating shaft 141 (+ r direction) acts. Conceivable. Therefore, it can be expected that the powder P and the air flowing through the gap between the rotating shaft 141 and the shaft hole 161f are pressed against the spiral groove 161g and effectively guided along the spiral groove 161g.

Further, since the centrifugal force exerts a force on the powder P in the direction away from the rotating shaft 141, it is considered that the powder P in the spiral groove 161 g can be suppressed from adhering to the rotating shaft 141. .. Therefore, it is possible to prevent power loss caused by the powder P being sandwiched between the spiral groove 161 g and the rotary shaft 141, and scratches, wear, and breakage of the rotary shaft 141 and the shaft sealing member 161.

Further, the following effects can be predicted for the motion and the applied force of the air and the powder P between the peak 161j of the spiral groove 161g and the rotation shaft 141. The air flow between the peak 161j of the spiral groove 161g and the rotating shaft 141 is different from the air flow in the spiral groove 161g. Therefore, it is considered that turbulence occurs at the boundary between these air. Then, it is considered that the powder P between the peak 161j of the mountain and the rotating shaft 141 moves to the spiral groove 161g due to the turbulent flow.

In addition to the above actions, the following actions can also be predicted. The air flow in the spiral groove 161g is considered to be faster than the air flow between the peak 161j and the rotating shaft 141. In that case, the air pressure in the spiral groove 161 g is lower than the air pressure between the peak 161j and the rotating shaft 141 (Bernoulli's theorem). It is considered that the powder P between the peak 161j and the rotating shaft 141 is drawn into the spiral groove 161g due to this pressure difference.

Due to these predicted effects, it is considered that the force applied to the powder P of the spiral groove 161 g in the direction away from the rotating shaft 141 becomes stronger, and the powder P can be further suppressed from adhering to the rotating shaft 141.

As described above, according to the configuration of the present embodiment, it is possible to suppress the leakage of powder from the container that handles the powder while reducing the damage of the powder transport device 1, the power loss in the rotary shaft 141, and the maintenance cost. It is possible to provide a shaft sealing structure of the powder transporting device 1, a shaft sealing member 161 of the powder transporting device 1 and the powder transporting device 1.

<7. Powder mixing device (second embodiment)>
FIG. 10 is a diagram showing a powder mixing device 2 as a second embodiment of the present invention. In FIG. 10, the top and bottom and left and right are the top and bottom and left and right of the paper surface, and here, the downward direction of the paper surface is the direction in which gravity is applied. The powder mixing device 2 according to the present embodiment is a device for stirring and mixing the first powder P1 and the second powder P2. The powder mixing device 2 includes a powder container 21, a screw 24, a motor M, an air pump A, a hose 251, a shaft sealing portion 26, and a housing 281. The particle size of the first powder P1 and the second powder P2 is not particularly limited, and in the present embodiment, there are two types of powder, but even if three or more types are stirred and mixed. good. The powder mixing device 2 described here is an example, and is not limited to this as long as it is a device that mixes two or more types of powder using a rotating shaft.

The powder container 21 is a container for accommodating the first powder P1 and the second powder P2 to be mixed in the powder mixing device 2. In the present embodiment, the powder container 21 is a container having a bottom portion 211 and a cylindrical side portion 212 extending upward (+ z direction) from the bottom portion 211, and the upper portion is open. The shape of the powder container 21 described here is an example thereof, and the shape can be appropriately changed depending on the usage conditions and the like. Further, the structure of the powder container 21 is not limited to this, and a lid or a ceiling may be provided above. In that case, for example, the introduction port of the powder P1 and P2 and the discharge port of the mixed powder (P1 + P2) can be provided on the lid or the ceiling.

The bottom portion 211 of the powder container 21 is provided with a circular through hole 211a. Further, for example, the powder discharge port may be provided on the bottom portion 211 of the powder container 21.

The screw 24 has a rotating shaft 241 and a propeller-shaped blade 242 for mixing and stirring powder by rotation. The shaft diameter of the rotary shaft 241 is smaller than that of the through hole 211a, and the rotary shaft 241 passes through the through hole 211a from the lower outside of the powder container 21 to the bottom 211 in a non-contact manner and enters the powder container 21. That is, the rotary shaft 241 penetrates the outer wall of the powder container 21 in a non-contact manner. The propeller-shaped blade 242 for mixing and stirring the screw 24 may be a blade having a paddle-shaped or ribbon-shaped shape other than the propeller-shaped blade, and the first powder P1 and the second powder P2 are stirred and mixed. Any shape can be used. The rotary shaft 241 is further passed through the through hole 281a of the housing 281, and one end 241a on the lower (−z) side is connected to the motor M.

The motor M is a driving means for rotating the screw 24, and is the same as in the first embodiment. As the motor M rotates the screw 24, the first powder P1 and the second powder P2 contained in the powder container 21 are stirred and mixed by the propeller-shaped blade 242. The driving means of the screw 24 is not limited to the electric motor, and may be an internal combustion engine, an external combustion engine, wind power, hydraulic power, or the like. Further, as described in the first embodiment, a power transmission means may be interposed between the motor M and the screw 24.

The air pump A is installed outside the powder container 21 and is a means for sending air from the outside to the shaft sealing portion 26 via the hose 251. Since it is the same as the first embodiment, the description thereof will be omitted.

The hose 251, the shaft sealing portion 26, and the housing 281 have the same structures as the hose 151, the shaft sealing portion 16 (FIGS. 2 to 9), and the housing 181 in the first embodiment, respectively, and description thereof will be omitted here.

Although the powder mixing device of the second embodiment is a vertical type, a horizontal powder mixing device is also known, and it is clear that the shaft-sealed structure of the present invention can be similarly applied to the horizontal powder mixing device. Is.

<8. Crushing device (third embodiment)>
FIG. 11 is a diagram showing a crushing device 3 as a third embodiment of the present invention. In FIG. 11, the left and right sides are the left and right sides of the paper surface, and here, the front side direction of the paper surface is the upward direction, the back direction of the paper surface is the downward direction, that is, the back direction of the paper surface is the direction in which gravity is applied. The crushing device 3 according to the present embodiment is a device for crushing the raw material RM into a crushed product CM. In this apparatus, debris, dust, etc. contained in the raw material RM or generated in the process of crushing are referred to as powder P.

The crushing device 3 includes a container 31, a raw material introduction section 32, a powder discharge section 33, a rotor 34, a motor M, an air pump A, hoses 351, 352, a shaft sealing section 36, 37, and a housing 381. 382 and. Here, the raw material RM may be not only a lumpy material but also a particulate or powder. Therefore, the crushing includes not only crushing the agglomerated raw material but also the operation of breaking only the agglutination of the agglomerated powder (secondary particles) to obtain the primary particles or the secondary particles having less agglutination. That is, crushing here is an operation for obtaining a piece of material or particles smaller than the raw material.

The container 31 stores the raw material RM introduced into the crushing device 3, the crushed crushed product CM, and the powder P. In the present embodiment, the container 31 is a container having a cylindrical outer wall extending in the direction (z direction) of the rotation shaft 341 described later. The shape of the container 31 described here is an example thereof, and the shape can be appropriately changed depending on the usage conditions and the like. The outer wall of the container 31 has a left bottom portion 311 that constitutes the bottom of the left (-z side) end of the cylinder, a side portion 312 that forms the cylinder, and a right that constitutes the bottom of the right (+ z side) end of the cylinder. It is composed of a bottom 313. The container 31 has a raw material introduction hole 314 connected to the raw material introduction section 32 on the upper side (front of the paper surface) of the side portion 312 and a discharge hole 315 connected to the powder discharge section 33 on the lower side (back of the paper surface) side of the side portion 312. And a fixed blade 316 is provided on the inner wall of the side portion 312.

The left bottom portion 311 and the right bottom portion 313 are provided with circular through holes 311a and 313a for passing the rotation shaft 341 of the rotor 34, which will be described later, respectively. The configuration of the through holes 311a and 313a is the same as that of the through holes 111a and 113a in the first embodiment.

In the present embodiment, the fixed blade 316 is a plate-shaped member having a blade portion 316a facing in the direction (−r direction) of the rotor 34 and having the rotation direction (θ direction) as the thickness direction. Further, in the present embodiment, the fixed blades 316 are composed of a pair of the fixed blades 316 facing each other with the rotor 34 sandwiched between the outside of the rotor 34, but the present invention is not limited to this, and the fixed blades 316 may be located at one place along the rotation direction (θ direction). It may be provided at three or more places. In the present embodiment, as an example, as shown in FIG. 11, the blade portion 316a has a saw-like shape.

The raw material introduction unit 32 is a portion for charging the raw material RM into the container 31 from the upper side (front of the paper surface) of the container 31. Specific examples of the structure of the raw material introduction unit 32 include, but are not limited to, a hopper provided on the raw material introduction hole 314 of the container 31.

The powder discharge unit 33 is a part for discharging the generated crushed product CM from the container 31 to the outside. In the present embodiment, the crushed product CM is dropped from the container 31 by gravity, but the present invention is not limited to this, and a method such as sucking the crushed product CM out of the container 31 by negative pressure may be used.

The rotor 34 has a rotating shaft 341 and a body portion 342. Since the configuration of the rotary shaft 341 is the same as that of the rotary shaft 141 of the first embodiment, the description thereof will be omitted. On the outer peripheral surface of the body portion 342, a plurality of grooves 342a having the circumferential direction (θ direction) about the axis of the rotating shaft 341 as the longitudinal direction are provided in the axial direction (z) of the rotating shaft 341. A rotary blade 342b is attached to the groove 342a. The rotary blade 342b may be detachably attached using bolts or the like, or may be integrated with the body portion 342 by adhesion, welding, or the like. The end portion on the outer (+ r) side of the rotary blade 342b projects from the outer peripheral surface of the body portion 342 to the outer (+ r) side, and has a shape corresponding to the blade portion 316a of the fixed blade 316. As an example of the shape of the outer (+ r) end of the rotary blade 342b, when the rotor 34 rotates and the rotary blade 342b comes closest to the fixed blade 316, the outer (+ r) end of the rotary blade 342b becomes , The shape facing the blade portion 316a of the fixed blade 316 with a constant gap can be mentioned. With this configuration, when the rotor 34 rotates, the material that has entered between the outer peripheral surface of the rotary blade 342b and the blade portion 316a of the fixed blade 316 is crushed by a shearing force to generate a crushed product CM.

The motor M is a driving means for rotating the rotor 34. Since the motor M is the same as that of the first embodiment, the description thereof will be omitted. Further, as described in the first embodiment, a power transmission means may be interposed between the motor M and the rotor 34.

The air pump A is installed outside the container 31 and is a means for sending air from the outside to the shaft sealing portions 36 and 37 via the hoses 351 and 352, and is the same as the first embodiment. Therefore, the description thereof will be omitted.

The hoses 351 and 352, the shaft sealing portions 36 and 37, and the housings 381 and 382 are the same as the hoses 151 and 152, the shaft sealing portions 16 (FIGS. 2-9), 17 and the housings 181 and 182 in the first embodiment, respectively. Since it has the structure of, the description thereof is omitted here. The shaft sealing portions 36 and 37 are configured to push the powder P generated mainly in the process of crushing back into the container 31, and the size of the spiral groove of the shaft sealing member, the spiral groove and the rotation. It is preferable to design the gap with the shaft 341 according to the assumed size of the powder P. That is, in the present embodiment, the shaft sealing portions 36 and 37 prevent dust and the like (powder P) contained in the raw material RM or generated in the process of crushing from leaking to the outside of the container 31. It is provided in.

As a modification of the crushing device, for example, there is also a device in which a plurality of rotors each equipped with a rotary blade are provided and the rotary blades are engaged with each other to apply a shearing force to the material in the meshed portion to crush the material. Conceivable. In such a device, a shaft sealing portion may be provided on each rotating shaft.

<9. Other embodiments>
The three embodiments of the present invention have been described above, but these are only examples of a number of embodiments, and other containers such as granulation, classification, drying, storage, filling, etc., using a rotating shaft. It is applicable to the device that processes the powder inside.

1: Powder transport device 11: Powder container 111a, 113a: Through hole 14: Screw 141: Rotating shaft 143: Rotating shaft sleeve 151, 152: Hose 16, 17: Shaft sealing portion 161: Shaft sealing member 161a: Side wall 161b : Bottom wall 161e: Gas introduction portion 161f: Shaft hole 161g: Spiral groove 161i: Protrusion portion 161j: Mountain top 163: Gland packing 164: Lantern ring w: Spiral groove width w 1: Mountain top width 2: Powder mixing device 21: Powder container 211a: Through hole 24: Screw 241: Rotating shaft 251: Hose 26: Shaft sealing part 3: Crushing device 31: Container 311a, 313a: Through hole 34: Rotor 341: Rotating shaft 36 , 37: Shaft seal M: Motor A: Air pump S: Space

Claims (9)

A container for storing powder and
A rotating shaft that penetrates the outer wall of the container in a non-contact manner,
A shaft sealing structure of a powder device provided outside the container and having a driving means for rotating the rotating shaft.
A bottom wall provided with a circular shaft hole through which the rotating shaft passes non-contactly and leads from the inside to the outside of the container.
A side wall that is outside the shaft hole and extends from the bottom wall toward the outside of the container in a projection in the direction of the center of rotation of the rotation axis.
A gas introduction portion that penetrates the side wall and leads to the air supply means,
A gas sealing means provided between the rotating shaft and the side wall at a position away from the container from the gas introducing portion is provided.
It is possible to send gas from the outside to the inside of the container between the inner peripheral surface of the shaft hole and the rotating shaft.
A spiral groove is formed on the inner peripheral surface of the shaft hole, and the spiral groove has a shape in which the width of the groove widens toward the rotation axis, and the cross section including the axis of the rotation axis. Assuming that the portion closest to the axis of rotation between adjacent valleys of the spiral groove is the summit of the mountain, it has two slopes sandwiching the summit of the mountain, and the angle formed by the two slopes in the cross section is A shaft-sealed structure of a powder device characterized by having a temperature of 30 to 75 degrees. Width of the top of the mountain in the cross section, sealing structure of a powder according to claim 1 is 1/5 of the pitch of the helical grooves. The shaft sealing structure of the powder device according to claim 2 , wherein the top of the mountain is a point in the cross section. Includes a shaft sealing member attached to the container, the shaft sealing member, wherein a bottom wall, a side wall, according to any one of claims 1 to 3 and the gas introduction section is provided Shaft sealing structure of powder equipment. The shaft sealing member is attached to the outside of the container, the container is provided with a through hole, and the rotating shaft passes through the through hole in a non-contact manner with the inner peripheral surface of the through hole, and the shaft hole is formed. The shaft sealing structure of the powder device according to claim 4 , wherein the through hole and the through hole communicate with each other. The shaft sealing structure of the powder device according to claim 4 or 5 , wherein the container and the shaft sealing member are in contact with each other on the entire circumference of the shaft hole. Claims 1 to 1, wherein the bottom wall is formed as a part of the outer wall of the container, includes a shaft sealing member attached to the container, and the shaft sealing member is provided with the side wall and the gas introduction portion. The shaft sealing structure of the powder device according to any one of 3. A container for storing powder and
A rotating shaft that penetrates the outer wall of the container in a non-contact manner,
The driving means for rotating the rotating shaft and
A bottom wall provided with a circular shaft hole through which the rotating shaft passes non-contactly and leads from the inside to the outside of the container.
A side wall that is outside the shaft hole and extends from the bottom wall toward the outside of the container in a projection in the direction of the center of rotation of the rotation axis.
A gas introduction portion that penetrates the side wall and leads to the air supply means,
A gas sealing means provided between the rotating shaft and the side wall at a position away from the container from the gas introducing portion is provided.
It is possible to send gas from the outside to the inside of the container between the inner peripheral surface of the shaft hole and the rotating shaft.
A spiral groove is formed on the inner peripheral surface of the shaft hole, and the spiral groove has a shape in which the width of the groove widens toward the rotation axis, and the cross section including the axis of the rotation axis. Assuming that the portion closest to the axis of rotation between adjacent valleys of the spiral groove is the summit of the mountain, it has two slopes sandwiching the summit of the mountain, and the angle formed by the two slopes in the cross section is A powder device characterized by having a temperature of 30 to 75 degrees. A container for storing powder and
A rotating shaft that penetrates the outer wall of the container in a non-contact manner,
A shaft sealing member provided outside the container and attached to a powder device having a driving means for rotating the rotating shaft.
A bottom wall that is larger than the diameter of the rotating shaft and has a circular shaft hole that leads from the inside to the outside of the container.
A side wall that is outside the shaft hole and extends from the bottom wall toward the outside of the container in a projection in the direction of the center of rotation of the rotation axis.
A gas introduction portion that penetrates the side wall and leads to the air supply means is provided.
A spiral groove is formed on the inner peripheral surface of the shaft hole, and the spiral groove has a shape in which the width of the groove widens toward the rotation axis, and the cross section including the axis of the rotation axis. Assuming that the portion closest to the axis of rotation between adjacent valleys of the spiral groove is the summit of the mountain, it has two slopes sandwiching the summit of the mountain, and the angle formed by the two slopes in the cross section is A shaft sealing member characterized by having a temperature of 30 to 75 degrees.

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