JP7533538B2 - Shaftless Screw Conveyor - Google Patents

Description

The present invention relates to a shaftless screw conveyor that transports objects such as powders and granular materials.

One example of a shaftless screw conveyor is the conveying device described in Patent Document 1. This conveying device has a cylindrical case and shaftless screw blades that rotate within the case in a spiral shape. One end of the case is closed by a cover body with a through hole, while the other end is closed by a bearing plate. In other words, one end of the case is provided with only one bearing made up of a cover body with a through hole, while the other end of the case is provided with only one bearing made up of a bearing plate.

The helical shaftless screw blade does not have a central shaft extending along the axis that is the center of rotation. A support shaft is provided at each end of the shaftless screw blade so that it is coaxial with the axis of the shaftless screw blade. The support shaft on one end of the shaftless screw blade is rotatably supported by a cover with a through hole that serves as a bearing, and the support shaft on the other end is rotatably supported by a bearing plate that serves as a bearing.

JP 2019-210070 A

However, if there is only one bearing on each end of the case that rotatably supports the support shafts at both ends of the shaftless screw blade, which does not have a central shaft body, the following problem occurs. In other words, in this case, the support structure by the single bearing on each end of the shaftless screw blade becomes a pin joint structure rather than a rigid joint. Therefore, the center part between one end and the other end of the shaftless screw blade is prone to bending downward. As a result, there is a risk that the center part of the shaftless screw blade that bends downward may come into contact with the inner surface of the case.

Various aspects of the shaftless screw conveyor for solving the above problems will be described below.
[Aspect 1]
A spiral-shaped shaftless screw blade that does not have a central shaft extending along an axis that is the center of rotation;
a case having an inner surface extending in a direction along the axis while covering at least an outer periphery of the shaftless screw blade from below;
a support shaft provided at each end of the shaftless screw blade so as to be coaxial with the axis line;
a first bearing that rotatably supports each of the support shafts at a first position in a direction along the axis;
a second bearing that rotatably supports each of the support shafts at a second position that is spaced from the first position in a direction along the axis;
A shaftless screw conveyor comprising:

According to this configuration, the shaftless screw blade has support shafts at both ends supported by a first bearing and a second bearing that are spaced apart in the direction along the axis. Therefore, the support structure at both ends of the shaftless screw blade that is supported by the bearings can be a rigid joint structure rather than a pin joint. Therefore, the central portion between both ends of the shaftless screw blade is less likely to bend downward, reducing the risk of that central portion coming into contact with the inner surface of the case.

[Aspect 2]
When the direction of gravity is defined as a first direction, and a direction perpendicular to both the direction along the axis of the shaftless screw blade and the first direction is defined as a second direction,
The shaftless screw conveyor of [Aspect 1], wherein at least one of the first bearing and the second bearing is adjustable in position at least in the first direction in the first direction and the second direction.

If there is a manufacturing error in the case or the shaftless screw blade, there is a risk that the shaftless screw blade will come into contact with the inner surface of the case when the shaftless screw conveyor is assembled using them. In this regard, according to the above configuration, the positional relationship between the case and the shaftless screw blade can be adjusted by adjusting the position of at least one of the first bearing and the second bearing in at least the first direction of the first and second directions. Therefore, even if there is a manufacturing error in the case or the shaftless screw blade, the risk of the shaftless screw blade coming into contact with the inner surface of the case can be reduced by adjusting the position of at least one of the first bearing and the second bearing.

[Aspect 3]
The shaftless screw conveyor of [Aspect 2], wherein the first bearing and the second bearing are each independently adjustable in position at least in the first direction in the first direction and the second direction.

According to this configuration, the positions of the first bearing and the second bearing can be adjusted individually as necessary.
[Aspect 4]
A shaftless screw conveyor as described in [Aspect 2] or [Aspect 3], wherein the first bearing and the second bearing are supported by a bearing stand that is arranged so that their positions in at least the first direction and the second direction can be adjusted.

With this configuration, by adjusting the position of the bearing stand in at least the first direction, the positions of both the first bearing and the second bearing can be quickly and easily adjusted in at least the first direction.

[Aspect 5]
The shaftless screw conveyor according to [Aspect 4], wherein the bearing stand is attached to the end of the case so that its position relative to the end of the case can be adjusted.

According to this configuration, the first and second bearings can be installed without requiring smooth ground or a dedicated foundation, by using the bearing pedestal attached to the end of the case as the installation location. Therefore, the installation work of the first and second bearings can be completed for the conveyor alone before the shaftless screw conveyor is installed at the usage location. In addition, if the case with the bearing pedestal attached is placed in a state where it is raised above the ground, the installation work of the first and second bearings becomes easier, and a rigid connection between the case and the bearings can be easily achieved while it is raised above the ground.

[Aspect 6]
The shaftless screw conveyor according to any one of [Aspect 1] to [Aspect 5], wherein the inner surface of the case is formed such that the gap between the inner surface at the central portion in the longitudinal direction which is the lowest point in the cross-sectional shape of the inner surface and the shaftless screw blade is larger than the gap between the inner surface at the lowermost point in the cross-sectional shape of the inner surface and the shaftless screw blade at both ends in the longitudinal direction.

A spiral-shaped shaftless screw blade that does not have a central shaft extending along the axis that is the center of rotation is more likely to bend downward in the center portion between both ends than a shafted screw blade that has a central shaft. Therefore, there is a risk that the bent center portion of the shaftless screw blade will come into contact with the inner surface of the case. In this regard, with the above configuration, the gap between the shaftless screw blade and the inner surface part that is the lowest part of the cross-sectional shape of the inner surface in the central portion in the longitudinal direction of the case is relatively larger than the gap in other parts. Therefore, even if the center portion between both ends of the shaftless screw blade bends downward, the risk that the bent center portion will come into contact with the inner surface of the case can be reduced.

The present invention reduces the risk of the central portion between both ends of the shaftless screw blade bending and coming into contact with the inner surface of the case.

FIG. 1 is a side view showing the overall configuration of a shaftless screw conveyor according to one embodiment. FIG. 2 is an exploded side view showing components of a shaftless screw conveyor. 3 is a cross-sectional view taken along line 3-3 in FIG. 1. 4 is a cross-sectional view taken along line 4-4 in FIG. 1. 5 is a plan view taken along line 5-5 in FIG. 2. 6 is a cross-sectional view taken along line 6-6 in FIG. 5. FIG. 2 is an exploded plan view showing components of the bearing unit. FIG. 2 is an exploded side view showing components of the bearing unit. 9 is a cross-sectional view taken along line 9-9 in FIG. 6. 7 is a cross-sectional view taken along line 10-10 in FIG. 6. 11 is an exploded front view of the components of the bearing unit shown in FIG. 10 . FIG.

Hereinafter, one embodiment of a shaftless screw conveyor will be described with reference to the drawings.
<Overall composition>
As shown in Fig. 1 and Fig. 2, the shaftless screw conveyor 11 includes a case 12, a shaftless screw blade 13, a pair of bearing units 14, and a drive motor 15. An inlet 16 for feeding transported materials such as powdered or granular materials into the case 12 is formed on the upper surface side of the case 12 near the left end in Fig. 1. On the other hand, an outlet 17 for discharging transported materials to the outside of the case 12 is formed on the lower surface side of the case 12 near the right end in Fig. 1. The bearing units 14 are provided at the right end and the left end of the case 12 in Fig. 1. In this embodiment, the drive motor 15 is provided in the left bearing unit 14 in Fig. 1 out of the left and right bearing units 14.

The shaftless screw blade 13 is supported at both ends by the bearing units 14 and is housed in the case 12 with its axis P, which is the center of rotation, coaxial with the axis of the case 12. In this state, the shaftless screw blade 13 rotates based on the drive of the drive motor 15. In other words, the shaftless screw conveyor 11 is configured to transport the transported material, which is input into the case 12 from the input port 16, through the case 12 as the shaftless screw blade 13 rotates based on the drive of the drive motor 15, and discharge it from the case 12 through the discharge port 17.

<Case>
1 and 2, the case 12 is configured to be cylindrical and capable of accommodating the shaftless screw blade 13 therein by joining the lower edge of the upper case 18 and the upper edge of the lower case 19. The upper case 18 has the aforementioned inlet 16 on the upper surface side near the left end in Fig. 2. Meanwhile, the lower case 19 has the aforementioned outlet 17 on the lower surface side near the right end in Fig. 2. An inspection door 20 that can be opened and closed when inspecting the inside of the case 12 is provided on the upper surface side of the portion of the upper case 18 near the right end in Fig. 2.

As shown in FIG. 1, the case 12 has support legs 21 at two locations spaced apart in the longitudinal direction. These support legs 21 support the case 12 in a floating state above the floor surface 22 on which the shaftless screw conveyor 11 is placed. Therefore, each bearing unit 14 provided at both ends of the case 12 is also floating above the floor surface 22.

<Shaftless screw blade>
The shaftless screw blade 13 is composed of a spiral strip having an axis P as its center of rotation, which is coaxial with the axis of the case 12 when it is housed in the case 12. As shown in Fig. 2, support shafts 23 each rotatably supported by a bearing unit 14 are provided on both ends of the shaftless screw blade 13 so as to be coaxial with the axis P of the shaftless screw blade 13. As shown in Figs. 1 and 2, the left support shaft 23, which is slightly longer than the right support shaft 23, has its tip drivingly connected to the drive motor 15.

As shown in FIG. 2, the shaftless screw blade 13 does not have a rigid central shaft, which is a given for a shafted screw blade (not shown). For this reason, the shaftless screw blade 13, which is made of, for example, stainless steel or wear-resistant steel, may bend slightly downward at its center portion between both ends. In that case, if the downwardly bent center portion of the shaftless screw blade 13 comes into contact with the inner surface 24 of the case 12, there is a risk that the inner surface 24 of the case 12 may be worn when the shaftless screw blade 13 rotates. Therefore, the shaftless screw conveyor 11 of this embodiment suppresses contact between the shaftless screw blade 13 and the inner surface 24 of the case 12 by forming the cross-sectional shape of the inner surface 24 of the case 12 as follows.

<Inside of the case>
As shown in Fig. 3 and Fig. 4, the case 12 has an inner surface 24 extending in a direction along the axis P of the shaftless screw blade 13 while covering the outer periphery of the shaftless screw blade 13 shown by the two-dot chain line in the figure from the outside in the radial direction. That is, the cross-sectional shape of the inner surface 24 of the case 12 is formed in an annular shape surrounding the outer periphery of the shaftless screw blade 13. The cross-sectional shape of the inner surface 24 of the upper case 18 extending in a direction along the axis P while covering the outer periphery of the shaftless screw blade 13 from above is formed in a broken line shape that is a regular octagon divided into two and convex upward. On the other hand, the cross-sectional shape of the inner surface 24 of the lower case 19 extending in a direction along the axis P while covering the outer periphery of the shaftless screw blade 13 from below is formed in a semicircular shape that is a circle slightly larger in diameter than the outer periphery of the shaftless screw blade 13 divided into two and convex downward.

The inner surface 24 of the case 12 is formed so that the inner surface portion 25, which is the lowest part of the cross-sectional shape of the inner surface 24 in the central portion in the longitudinal direction, is aligned, for example, horizontally, which is the direction in which the axis P of the shaftless screw blade 13 extends. The inner surface 24 of the case 12 is formed so that the inner surface portion 26, which is the lowest part of the cross-sectional shape of the inner surface 24 in the portions near both ends in the longitudinal direction, is inclined so that it gradually becomes vertically upward as it approaches the ends of the case 12. In this case, the shaftless screw blade 13 is housed in the case 12 so that its axis P is aligned horizontally, floating vertically upward from the inner surface 24 of the case 12.

Therefore, in the center of the length of the case 12, a gap C1 is formed between the inner surface portion 25, which is the lowest part in the cross-sectional shape of the inner surface 24 of the center portion, and the shaftless screw blade 13. In addition, in both ends of the length of the case 12, a gap C2 smaller than the gap C1 in the center of the case 12 is formed between the inner surface portion 26, which is the lowest part in the cross-sectional shape of the inner surface 24 of both ends, and the shaftless screw blade 13. In other words, the inner surface 24 of the case 12 is formed so that the gap C1 between the inner surface portion 25, which is the lowest part in the cross-sectional shape of the inner surface 24 of the center portion of the length, and the shaftless screw blade 13 is relatively larger than the gap C2 in other parts. Note that in Figures 3 and 4, the outward flange formed by protruding radially outward from the outer surface of the case 12 as shown in Figure 1 is omitted. In addition, in Figure 4, the discharge port 17, which opens to the lower side of the lower case 19 at the back side in the arrow direction from the position shown in Figure 1, is omitted.

<Bearing unit>
1 and 2 have the same configuration, except that the left bearing unit 14 supports the drive motor 15 via a support bracket 27. Therefore, in the following, the configuration of the bearing unit 14 attached to the right end of the case 12 in Figures 1 and 2 will be described as a representative example.

As shown in Figures 5 and 6, the bearing unit 14 includes a blocking plate 28, a bearing stand 29, a liner plate 30, a first bearing 31, and a second bearing 32. The blocking plate 28 is a flat plate whose contour shape is substantially the same as the cross-sectional shape of the case 12 shown in Figures 3 and 4. As shown in Figures 1 and 2, the blocking plate 28 is attached to the end of the cylindrical case 12 so as to block the opening at the end of the case 12. In addition, an insertion hole 33 is formed in the center of the blocking plate 28, through which each support shaft 23 provided at both ends of the shaftless screw blade 13 can be inserted.

<Bearing stand>
As shown in Figs. 7 and 8, the bearing base 29 includes a joint plate 34, a pair of side plates 35, and a support plate 36. The joint plate 34 is a rectangular flat plate smaller than the contour shape of the closure plate 28, and is joined to the closure plate 28 in a surface contact state when the shaftless screw conveyor 11 is assembled. The central part of the joint plate 34 is also formed with an insertion hole 37 through which each support shaft 23 provided at both ends of the shaftless screw blade 13 can be inserted. The pair of side plates 35 are formed of flat plates in the shape of a right triangle in a side view extending forward in parallel from both left and right side edges of the joint plate 34. The support plate 36 is formed of a strip-shaped plate horizontally installed between the lower end edges of the tip sides of the both side plates 35. The liner plate 30, which is a strip-shaped plate shorter in length than the support plate 36, is appropriately superimposed on the strip-shaped support plate 36.

<First bearing>
As shown in Fig. 9, the first bearing 31 includes a bearing portion 38 made of a bearing or the like that rotatably supports the tip portion of the support shaft 23 of the shaftless screw blade 13 by inserting the tip portion of the support shaft 23, and a base portion 39 that holds the bearing portion 38 so that the axis of the support shaft 23 is horizontal. The first bearing 31 is mounted on the support plate 36 of the bearing base 29. As shown in Figs. 5 and 6, the support plate 36 to which the first bearing 31 is mounted is located at a first position P1 that corresponds to the tip portion of the support shaft 23 in the direction along the axis P of the shaftless screw blade 13. Therefore, the first bearing 31 mounted on the support plate 36 located at the first position P1 can be said to be similarly located at the first position P1 in the direction along the axis P of the shaftless screw blade 13.

In this case, the first bearing 31 is mounted on the support plate 36 of the bearing base 29 with or without a liner plate 30 interposed therebetween. Therefore, the height position of the first bearing 31 can be adjusted at the first position P1 by adjusting the number of liner plates 30 interposed between the base portion 39 and the support plate 36 of the bearing base 29 so that the axis of the bearing portion 38 coincides with the axis P of the shaftless screw blade 13.

<Second bearing>
10 and 11, the second bearing 32 is attached to the front surface of the joining plate 34 of the bearing stand 29, which is the right side surface in Figs. 5 and 6, with a rectangular dustproof plate 40 interposed therebetween. The dustproof plate 40 also has an insertion hole 41 formed in the center thereof, through which each of the support shafts 23 provided on both ends of the shaftless screw blade 13 can be inserted. The second bearing 32 includes a bearing portion 42 made of a bearing or the like through which the support shaft 23 of the shaftless screw blade 13 is inserted and rotatably supported, and a holding member 43 that holds the bearing portion 42 so that its axis coincides with the axis line P of the shaftless screw blade 13.

As shown in Figures 5 and 6, the dustproof plate 40 to which the second bearing 32 is attached is located at a second position P2, which is closer to the base end of the support shaft 23 than the first position P1, where the first bearing 31 is located, in the direction along the axis P of the shaftless screw blade 13. Therefore, the second bearing 32 attached to the dustproof plate 40 can also be said to be located at a second position P2, which is away from the first position P1, in the direction along the axis P of the shaftless screw blade 13.

<Position adjustment mechanism>
Here, the direction of gravity, which is also a vertical direction perpendicular to the direction along the axis P of the shaftless screw blade 13, is defined as the first direction Z. Another horizontal direction perpendicular to both the direction along the axis P and the first direction Z is defined as the second direction X. In this case, as described above, the position of the first bearing 31 in the first direction Z, which is the height position, is adjustable by adjusting the number of liner plates 30 interposed between the base 39 and the support plate 36 of the bearing base 29. In the shaftless screw conveyor 11 of this embodiment, in addition to the position adjustment based on the adjustment of the number of liner plates 30, the positions of the first bearing 31 and the second bearing 32 in the first direction Z and the second direction X are adjustable by a position adjustment mechanism described below.

First, as shown in Figs. 5 to 9, a first bolt 44, which is one of the position adjustment mechanisms, is provided at each tip of both side plates 35 of the bearing stand 29 so that it can be moved forward and backward by rotating with its tip abutting against the base portion 39 of the first bearing 31 on the support plate 36 from both sides. For example, when the first bolt 44 provided on the upper side plate 35 in Fig. 5 is screwed forward and the first bolt 44 provided on the lower side plate 35 in Fig. 5 is screwed back, the first bearing 31 on the support plate 36 is displaced downward in Fig. 5. In other words, the position of the first bearing 31 in the second direction X, which is the left-right position, can be adjusted by rotating both first bolts 44 provided to face both side plates 35.

As shown in Figures 10 and 11, a second vertical bolt 45 is provided on the lower edge of the dustproof plate 40 so that it can move up and down by rotating with its tip abutting from below against the lower edge of the retaining member 43 of the second bearing 32. A second horizontal bolt 46 is provided on the left side edge of the dustproof plate 40 in Figure 10 so that it can move horizontally by rotating with its tip abutting from the side against the left side edge of the retaining member 43 of the second bearing 32 in Figure 10.

For example, in FIG. 10, when the second vertical bolt 45 is screwed upward, the second bearing 32 attached to the front side of the dustproof plate 40 is displaced upward. That is, the position of the second bearing 32 in the first direction Z, which is the vertical position, can be adjusted by rotating the second vertical bolt 45, which is one of the position adjustment mechanisms provided on the dustproof plate 40. On the other hand, when the second horizontal bolt 46 is screwed to the right in FIG. 10, the second bearing 32 attached to the front side of the dustproof plate 40 is displaced to the right. That is, the position of the second bearing 32 in the second direction X, which is the horizontal left-right position, can be adjusted by rotating the second horizontal bolt 46, which is one of the position adjustment mechanisms provided on the dustproof plate 40.

As shown in FIG. 10, a third bolt 47, which is one of the position adjustment mechanisms, is provided on the front surface of the closure plate 28 below the area where the joining plate 34 of the bearing stand 29 is joined. The third bolt 47 is provided so that it moves up and down by rotating with its tip abutting against the lower edge of the joining plate 34 of the bearing stand 29 from below. Therefore, for example, when the third bolt 47 is screwed upward in FIG. 10, the bearing stand 29 attached to the front surface of the closure plate 28 is displaced upward. In other words, in this case, both the first bearing 31 and the second bearing 32 supported by the bearing stand 29 are displaced upward at the same time. That is, the first bearing 31 and the second bearing 32 supported by the bearing stand 29 can be simultaneously adjusted in the first direction Z, which is the vertical position, by rotating the third bolt 47, which is one of the position adjustment mechanisms provided on the closure plate 28.

<Action>
Next, the operation of the shaftless screw conveyor 11 of this embodiment will be described below, focusing on the centering adjustment process during the assembly process.

When assembling the shaftless screw conveyor 11, first, the shaftless screw blade 13 is housed in the lower case 19 of the case 12 from the disassembled state before assembly shown in FIG. 2. Next, the bearing unit 14 is temporarily assembled from the disassembled state before assembly shown in FIG. 7 and FIG. 8 and temporarily attached to the support shafts 23 at both ends of the shaftless screw blade 13. At this stage, the upper case 18 of the case 12 has not yet been joined to the lower case 19 from above. Then, in this state, a centering adjustment process is performed to align the axial centers of the first bearing 31 and the second bearing 32 in the bearing unit 14 with the axis P of the shaftless screw blade 13. After this centering adjustment process is performed, the upper case 18 is joined to the lower case 19 from above, completing the assembly of the shaftless screw conveyor 11.

As a premise, the components of the bearing unit 14 are fixed together in a joined state when assembled, and during the provisional assembly stage before the final fixing, the components can slide against each other to adjust their relative positional relationship. For example, the closing plate 28 and the joint plate 34 of the bearing base 29, which are a set of components, are finally fixed together by inserting a bolt into a through hole (not shown) formed in each of them, and then rotating a nut screwed onto the tip of the bolt in the tightening direction. In this case, the through holes formed in the closing plate 28 and the joint plate 34 are, for example, long holes along the direction of position adjustment or holes with a larger diameter than the outer diameter of the shaft of the bolt to be inserted. In the provisional assembly state, the nut screwed onto the tip of the bolt is tightened more loosely than when fixed. Therefore, when the closure plate 28 and bearing base 29 are still in a provisionally assembled state, the bolt shaft can be displaced within the through hole, which is a long hole or a large diameter hole, and the relative positional relationship between the components can be adjusted within the range in which this displacement is possible.

The other components of the bearing unit 14 are also provided with through holes, which are long holes or large diameter holes, that allow the relative positional relationship between the components of the bearing unit 14 to be adjusted. That is, the support plate 36 of the bearing stand 29, the liner plate 30, the base portion 39 of the first bearing 31, the dustproof plate 40, and the retaining member 43 of the second bearing 32 are also provided with long holes or through holes with a diameter larger than the outer diameter of the shaft portion of the bolt that is inserted for fixing. Then, the bearing unit 14 in which the components are temporarily assembled is temporarily attached to the support shaft 23 of the shaftless screw blade 13, and the next centering adjustment process is performed.

<Centering adjustment process>
The centering adjustment process is performed with, for example, at least one liner plate 30 attached to the support plate 36 of the bearing stand 29. The reason for this is that the number of liner plates 30 may be increased or decreased when adjusting the gap C1 between the shaftless screw blade 13 and the inner surface portion 25 of the central portion of the case 12 in the subsequent process.

First, the position of the second bearing 32 out of the first bearing 31 and the second bearing 32 in the first direction Z is adjusted. In this case, the second vertical bolt 45 provided on the lower edge of the dustproof plate 40 is rotated. This adjusts the horizontality of the support shaft 23, whose tip side is supported by the first bearing 31 at the first position P1 and whose base end side is supported by the second bearing 32 at the second position. Then, in this state, the size of the gap C1 between the shaftless screw blade 13, whose support shafts 23 at both ends are supported by the bearing units 14, and the inner surface portion 25 that is the lowest part of the cross-sectional shape in the center part of the lower case 19 of the case 12, is measured.

Then, the position of the bearing stand 29 in the first direction Z is adjusted so that the size of the gap C1 is the desired size suitable for transporting the transported object by the rotation of the shaftless screw blade 13. In this case, the third bolt 47 provided at the bottom of the closure plate 28 is rotated. This simultaneously adjusts the positions in the first direction Z of both the first bearing 31 and the second bearing 32, which are both supported by the bearing stand 29. In this case, if the size of the gap C1 is too large to be adjusted to the desired size by merely moving the bearing stand 29 downward in the first direction Z, the number of liner plates 30 interposed between the support plate 36 of the bearing stand 29 and the first bearing 31 is reduced.

On the other hand, if fine adjustment of the gap C1 is required after adjusting the position of the bearing stand 29 in the first direction Z, the position of the second bearing 32 in the first direction Z is adjusted again. In this case, the second vertical bolt 45 provided on the lower edge of the dustproof plate 40 is rotated. Next, the position of the shaftless screw blade 13 in the second direction X is adjusted. In this case, the first bolt 44 provided on both side plates 35 of the bearing stand 29 is rotated. In this case, if fine adjustment of the position of the shaftless screw blade 13 in the second direction X is required, the second horizontal bolt 46 provided on the side edge of the dustproof plate 40 on the left side in FIG. 10 is rotated.

＜Effects＞
(1) The shaftless screw blade 13 has support shafts 23 provided at both ends thereof supported by a first bearing 31 and a second bearing 32 spaced apart in a direction along the axis P. Therefore, the support structure at both ends of the shaftless screw blade 13 supported by the first bearing 31 and the second bearing 32 can be a rigid joint structure rather than a pin joint. Therefore, the central portion between both ends of the shaftless screw blade 13 is less likely to bend downward, reducing the risk that the central portion will come into contact with the inner surface 24 of the case 12.

(2) The positional relationship between the case 12 and the shaftless screw blade 13 can be adjusted by adjusting the positions of the first bearing 31 and the second bearing 32 in the first direction Z and the second direction X. Therefore, even if there is a manufacturing error in the case 12 or the shaftless screw blade 13, the risk of contact between the shaftless screw blade 13 and the inner surface 24 of the case 12 can be reduced by adjusting the position of at least one of the first bearing 31 and the second bearing 32 in a direction that eliminates the manufacturing error.

(3) The first bearing 31 and the second bearing 32 are each capable of adjusting their positions independently, so that their positions in the first direction Z and the second direction X can be adjusted individually as needed.

(4) By adjusting the position of the bearing stand 29 in the first direction Z, the positions of both the first bearing 31 and the second bearing 32 in the first direction Z can be quickly and easily adjusted.
(5) By using the bearing stand 29 attached to the end of the case 12 as the installation location, the first bearing 31 and the second bearing 32 can be installed without requiring a smooth ground or a dedicated foundation. Therefore, the installation work of the first bearing 31 and the second bearing 32 can be completed for the shaftless screw conveyor 11 alone before the conveyor is installed at the place of use.

(6) If the case 12 to which the bearing stand 29 is attached is positioned in a floating state above the floor surface 22, the installation work of the first bearing 31 and the second bearing 32 can be easily performed, and a rigid connection between the case 12 and the first bearing 31 and the second bearing 32 can be easily achieved while the case 12 is floating above the ground or floor surface 22.

(7) In the case 12, the gap C1 between the inner surface portion 25, which is the lowest part in the cross-sectional shape of the inner surface 24 in the central part in the longitudinal direction, and the shaftless screw blade 13 is relatively larger than the gap C2 in other parts of the case 12. Therefore, even if the central part between both ends of the shaftless screw blade 13 bends downward, the risk of the bent central part coming into contact with the inner surface 24 of the case 12 can be reduced.

<Example of change>
The above embodiment may be modified as shown in the following modified examples. In addition, the configurations included in the embodiment may be arbitrarily combined with the configurations included in the following modified examples, or the configurations included in the following modified examples may be arbitrarily combined with each other.

- The case 12 may be configured such that the gap C1 between the inner surface portion 25, which is the lowest part of the cross-sectional shape of the inner surface 24 at the center part in the longitudinal direction, and the shaftless screw blade 13 is the same as the gap C2 at other parts. In other words, the case 12 may be a cylindrical body in which the cross-sectional shape of the inner surface 24 is the same shape at all parts in the longitudinal direction of the case 12.

The case 12 may be placed directly on the floor surface 22 without having the support legs 21. In this case, the bearing stand 29 of the bearing unit 14 is also placed on the floor surface 22.
The case 12 may be composed of only the lower case 19. In other words, the case 12 may have an inner surface 24 that extends in the direction along the axis P while covering the outer periphery of the shaftless screw blade 13 from at least the lower side.

The cross-sectional shape of the inner surface 24 of the lower case 19 of the case 12 does not have to be a semicircular shape that is convex downward. In other words, it is sufficient that the cross-sectional shape of the lowermost inner surface portion 25 of the inner surface 24 is a shape that covers the outer periphery of the shaftless screw blade 13 from below and is an inner surface shape that can transport the transported object in the direction of the discharge port 17 of the case 12 as the shaftless screw blade 13 rotates.

- The case 12 may be configured so that the shaftless screw blade 13 is inserted into the cylindrical case 12 from the opening on one end side from the beginning, rather than being formed into a cylindrical body by joining the upper case 18 to the lower case 19 after the shaftless screw blade 13 is housed therein.

- The first bolt 44 does not have to be provided. In other words, the bearing stand 29 may be configured to be fixed so that its position cannot be adjusted relative to the end of the case 12. Even in this case, the positions of the first bearing 31 and the second bearing 32 can be adjusted at least in the first direction Z of the first direction Z and the second direction X by rotating the first bolt 44, the second vertical bolt 45, and the second horizontal bolt 46 and adjusting the number of liner plates 30.

- A bolt that moves back and forth in the left-right direction by rotating with its tip abutting the side edge of the joint plate 34 of the bearing stand 29 from the side may be provided on at least one of the left and right sides of the area where the joint plate 34 of the bearing stand 29 is joined on the front surface of the closure plate 28. In other words, a position adjustment mechanism that can adjust the position of the bearing stand 29 in the second direction X may be further provided. In this way, the positions of the first bearing 31 and the second bearing 32 in the second direction X can be adjusted simultaneously.

- The first bolt 44 does not have to be provided. In other words, the first bearing 31 may be configured such that its position in the first direction Z, which is the direction of gravity, is adjustable, but its position in the second direction X, which is the horizontal direction perpendicular to the axis P, cannot be adjusted.

- The liner plate 30 does not have to be provided. In this case, the position of the first bearing 31 in the first direction Z is adjusted by the third bolt 47, which adjusts the position of the bearing stand 29 in the first direction Z.

- As a mechanism for adjusting the position of the first bearing 31 in the first direction Z, a bolt may be provided on the support plate 36 of the bearing stand 29, which moves up and down by rotating with its tip abutting from below against the underside of the base portion 39 of the first bearing 31.

- The second horizontal bolt 46 does not have to be provided. In other words, the second bearing 32 may be configured such that its position in the first direction Z, which is the direction of gravity, is adjustable, but its position in the second direction X, which is the horizontal direction perpendicular to the axis P, cannot be adjusted.

- The first bearing 31 and the second bearing 32 that support the support shaft 23 at both ends of the shaftless screw blade 13 at the first position P1 and the second position P2 may be configured to be attached to the bearing base 29 with one of them being adjustable in position and the other being non-adjustable in position.

- The second vertical bolt 45 does not have to be provided. In this case, the position of the second bearing 32 in the first direction Z is adjusted by the third bolt 47, which adjusts the position of the bearing stand 29 in the first direction Z.

The position adjustment mechanism that allows the position of the bearing base 29, the first bearing 31, and the second bearing 32 to be adjusted may be a structure using bolts such as the first bolt 44, or may be another mechanical structure such as a cylinder mechanism equipped with an extendable rod.

REFERENCE SIGNS LIST 11... Shaftless screw conveyor 12... Case 13... Shaftless screw blade 23... Support shaft 24... Inner surface 25... Inner surface location 26... Inner surface location 29... Bearing stand 31... First bearing 32... Second bearing C1... Gap C2... Gap P... Axis P1... First position P2... Second position X... Second direction Z... First direction

Claims (3)

A spiral-shaped shaftless screw blade that does not have a central shaft extending along an axis that is the center of rotation;
a case having an inner surface extending in a direction along the axis while covering an outer periphery of the shaftless screw blade from at least a lower side;
a support shaft provided at each end of the shaftless screw blade so as to be coaxial with the axis line;
a first bearing that rotatably supports each of the support shafts at a first position in a direction along the axis;
a second bearing that rotatably supports each of the support shafts at a second position that is spaced from the first position in a direction along the axis;
Equipped with
When the direction of gravity is defined as a first direction, and a direction perpendicular to both the direction along the axis of the shaftless screw blade and the first direction is defined as a second direction,
At least one of the first bearing and the second bearing is adjustable in position in at least the first direction,
A shaftless screw conveyor , characterized in that the first bearing and the second bearing are each independently adjustable in position in at least the first direction in the first direction and the second direction . A spiral-shaped shaftless screw blade that does not have a central shaft extending along an axis that is the center of rotation;
a case having an inner surface extending in a direction along the axis while covering at least an outer periphery of the shaftless screw blade from below;
a support shaft provided at each end of the shaftless screw blade so as to be coaxial with the axis line;
a first bearing that rotatably supports each of the support shafts at a first position in a direction along the axis;
a second bearing that rotatably supports each of the support shafts at a second position that is spaced from the first position in a direction along the axis;
Equipped with
When the direction of gravity is defined as a first direction, and a direction perpendicular to both the direction along the axis of the shaftless screw blade and the first direction is defined as a second direction,
At least one of the first bearing and the second bearing is adjustable in position in at least the first direction,
the first bearing and the second bearing are supported by a bearing stand that is provided so as to be adjustable in position at least in the first direction among the first direction and the second direction,
13. A shaftless screw conveyor, comprising: a bearing stand attached to an end of the case so that its position relative to the end of the case can be adjusted. A spiral-shaped shaftless screw blade that does not have a central shaft extending along an axis that is the center of rotation;
a case having an inner surface extending in a direction along the axis while covering at least an outer periphery of the shaftless screw blade from below;
a support shaft provided at each end of the shaftless screw blade so as to be coaxial with the axis line;
a first bearing that rotatably supports each of the support shafts at a first position in a direction along the axis;
a second bearing that rotatably supports each of the support shafts at a second position that is spaced from the first position in a direction along the axis;
Equipped with
The shaftless screw conveyor is characterized in that the inner surface of the case is formed so that the gap between the inner surface at the central part in the longitudinal direction, which is the lowest point in the cross-sectional shape of the inner surface, and the shaftless screw blade is larger than the gap between the inner surface at the lowest point in the cross-sectional shape of the inner surface at both ends in the longitudinal direction and the shaftless screw blade .

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