Rainwater storing material

Abstract

To provide a rainwater storing material capable of obtaining higher bearing force against load in a vertical direction.SOLUTION: A pillar part 7 is substantially circular in cross-sectional shape in a horizontal direction and includes protrusions 9 at predetermined intervals on an inner face side. The protrusions 9 are formed along the entire length of the pillar part 7. That is, the protrusion 9 is a rib formed in the vertical direction in the inner face of the pillar part 7. The protrusion 9 forms, in the inner face of the substantially circular pillar part 7, a protruded shape protruding toward a center side, and a part in a peripheral direction between the protrusion 9 and the protrusion 9 forms a recess shape relative to the protrusion 9. That is, in the horizontal cross-section of the pillar part 7 and in the inner face of the pillar part 7 the protrusion shape and the recess shape are repeatedly formed in a peripheral direction, and the protrusion shape and the recess shape continue in the vertical direction of the pillar part 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rainwater storage member used in a rainwater storage tank for storing rainwater underground. [Background technology]

[0002] In recent years, in order to prevent flood damage in the event of sudden heavy rain, rainwater storage tanks that temporarily store rainwater underground are used. With rainwater storage tanks, the stored rainwater can be gradually allowed to seep into the earth layer, a large amount of stored rainwater can be discharged into a river or the like over a sufficient period of time, or the stored rainwater can be pumped up and used as fire prevention water or the like. Such rainwater storage tanks are composed of multiple rainwater storage structures. The rainwater storage structures need to support the soil cover above and the weight of people and vehicles passing above. For this reason, the rainwater storage structures are formed by stacking multiple rainwater storage members that can support the weight from above.

[0003] Such rainwater storage members are generally composed of a flat base plate and multiple pillars standing on the base plate. In this case, taking into consideration manufacturing costs and ease of handling, the base plate and the pillars are integrally molded from resin or the like, and multiple rainwater storage members are stacked together with their pillars butted against each other to form a rainwater storage structure of a predetermined height (depth) (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-052349 A [Patent Document 2] JP 2010-209604 A Summary of the Invention [Problem to be solved by the invention]

[0005] Typically, the cross-sectional shape of the pillar is circular or rectangular, and has a tapered shape that becomes thinner toward the tip. This allows the pillars of multiple rainwater storage components to be stacked on top of each other during transportation and storage.

[0006] A typical column has, for example, an outer diameter D of about 100 mm and a wall thickness t of about 3 mm. However, the inventors discovered that if the diameter-thickness ratio (outer diameter D / thickness t) is large, local buckling (out-of-plane buckling), in which a portion of the member locally expands or contracts, occurs first in response to a compressive load, causing a decrease in strength before elastic buckling (Euler buckling) occurs.

[0007] One solution to this problem is to increase the wall thickness t of the pillars, but increasing the overall thickness of the pillars reduces the void ratio of the rainwater storage tank (i.e., the capacity to store rainwater, etc.). Also, if you try to make only part of the pillars thicker, there is a risk of sink marks or warping in the product due to the molding process, and when going from a thick to a thin part, the thickness must be gradually reduced. For this reason, it was difficult to increase the wall thickness of only part of the pillars.

[0008] In addition, in order to reduce the diameter-thickness ratio, one method is to reduce the outer diameter D. However, doing so will also reduce the second moment of area, making elastic buckling (Euler buckling) more likely to occur.

[0009] The present invention has been made in consideration of such problems, and aims to provide a rainwater storage member that can obtain higher resistance to vertical loads without reducing the void ratio of the rainwater storage tank. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present invention is a rainwater storage member for use in a rainwater storage structure, comprising a base plate and a column portion standing on the base plate, and characterized in that in a horizontal cross section of the column portion, an uneven shape is repeatedly formed in the circumferential direction on at least one of the outer surface or inner surface of the column portion, and the uneven shape is continuous in the vertical direction of the column portion.

[0011] It is desirable that the pillar portion has a tapered shape that becomes smaller in size toward the tip, and that the pillar portions of a plurality of rainwater storage members can be stacked on top of each other.

[0012] The horizontal cross-sectional shape of the pillar portion may be polygonal or circular, with recesses or protrusions protruding inward or outward at predetermined intervals in the circumferential direction.

[0013] The outer surface shape and the inner surface shape in a horizontal cross section of the column portions may not be similar, and when the column portions are completely overlapped, a gap may be formed in at least a portion of the circumferential direction between the inner surface of the outer column portion and the outer surface of the inner column portion in the horizontal cross section of the column portions.

[0014] When the column portions are completely overlapped, it is desirable that, in a horizontal cross section of the column portions, the inner surface of the outer column portion and the outer surface of the inner column portion are in approximate point contact at multiple locations along at least a portion of the circumferential direction.

[0015] According to the present invention, in the horizontal cross section of the column portion, a concave-convex shape is repeatedly formed in the circumferential direction on at least one of the outer surface or the inner surface of the column portion, so that local buckling can be suppressed without increasing the thickness of the column portion.

[0016] In this case, since the pillar portion has a tapered shape in which the size decreases toward the tip, it is possible to stack the pillar portions of multiple rainwater storage members one on top of the other.

[0017] In this type of uneven shape, the horizontal cross-sectional shape of the column is polygonal or circular, and recesses or protrusions are formed that protrude inward or outward at predetermined intervals in the circumferential direction, allowing the column portions to overlap more deeply than, for example, when ribs or the like are formed.

[0018] In addition, by making the outer and inner shapes of the column parts not similar in horizontal cross section, gaps can be formed between the column parts when they are completely overlapped. This reduces friction when the column parts are overlapped, making it easier to disassemble the overlapped rainwater storage members into individual rainwater storage members.

[0019] In particular, when the column sections are completely overlapped, the inner surface of the outer column section and the outer surface of the inner column section are in approximate point contact at multiple locations over at least a portion of the circumferential direction at any horizontal cross-sectional position, thereby more efficiently minimizing the contact area between the two and suppressing friction. Effect of the Invention

[0020] According to the present invention, it is possible to provide a rainwater storage member capable of obtaining higher resistance to vertical loads. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2A is an exploded perspective view of the rainwater storage structure 1, and FIG. 2B is an assembled perspective view of the rainwater storage structure 1. [Diagram 2] (a) is a cross-sectional view of the rainwater storage structure 1, and (b) is a cross-sectional view along line AA in (a). [Diagram 3] 1A is a cross-sectional view of the rainwater storage members 3 stacked together, and FIG. 1B is a cross-sectional view taken along line BB in FIG. [Figure 4] 1A is a cross-sectional view of a column portion 7a, and FIG. 1B is a cross-sectional view of column portions 7a stacked one on top of the other. [Diagram 5] 1A is a cross-sectional view of a column portion 7b, and FIG. 1B is a cross-sectional view of column portions 7b stacked one on top of the other. [Figure 6]1A is a cross-sectional view of a column portion 7c, and FIG. 1B is a cross-sectional view of column portions 7c stacked one on top of the other. [Figure 7] 13A is a cross-sectional view of the column portion 7d when it is overlapped, and FIG. 13B is a cross-sectional view of the column portion 7e when it is overlapped. [Figure 8] 13A is a cross-sectional view of column portion 7f, FIG. 13B is a cross-sectional view of column portion 7g, and FIG. 13C is a cross-sectional view of column portion 7h. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a rainwater storage structure according to an embodiment of the present invention will be described. Fig. 1(a) is an exploded perspective view showing a rainwater storage structure 1, and Fig. 1(b) is an assembled perspective view showing the rainwater storage structure 1. Fig. 2(a) is a cross-sectional view of the rainwater storage structure 1, and Fig. 2(b) is a cross-sectional view (end view) taken along line AA in Fig. 2(a). The rainwater storage structure 1 is composed of a pair of rainwater storage members 3.

[0023] The rainwater storage structure 1 is constructed by stacking multiple rainwater storage members 3, and by arranging multiple rainwater storage structures 1 vertically and horizontally in a plan view, it is possible to form a specified space underground for storing rainwater.

[0024] The rainwater storage member 3 is integrally formed of a substrate 5 and a pillar portion 7 standing on the substrate 5. The substrate 5 is a plate-shaped member. Although an example is shown in which the substrate 5 is provided with four pillar portions 7, the number of pillar portions 7 standing on one substrate 5 is not particularly limited, and may be one or more.

[0025] The substrate 5 is a flat plate. In the illustrated example, the substrate 5 is a flat plate, but may have, for example, a plurality of holes through which rainwater can flow and ribs for improving strength. Even if the substrate 5 has such a complex shape, the rainwater storage member 3 can be easily manufactured by injection molding using, for example, a polyolefin resin.

[0026] The pillar portion 7 is formed so that, for example, the size becomes smaller (so that the inner diameter and the outer diameter become thinner) toward the tip. In addition, the bottom of the pillar portion 7 is open, and the inside of the pillar portion 7 is hollow. In this way, it is possible to stack a plurality of rainwater storage members 3 (pillar portions 7) facing in the same direction. The stacking of the rainwater storage members 3 will be described in detail later.

[0027] The top of the column portion 7 is provided with a fitting protrusion 11 and a fitting hole 13. A through hole is provided in the fitting protrusion 11. The fitting hole 13 is of a size that allows the fitting protrusion 11 to be inserted. The rainwater storage members 3 can be stacked and connected together by butting the column portions 7 of the rainwater storage members 3 against each other, and then fitting the fitting protrusions 11 and fitting holes 13 together.

[0028] As shown in FIG. 2(b), the column portion 7 has a substantially circular cross-sectional shape in the horizontal direction, and protrusions 9 are provided at a predetermined interval on the inner surface side. The protrusions 9 are formed over substantially the entire length of the column portion 7. That is, the protrusions 9 are ribs formed in the vertical direction on the inner surface of the column portion 7. The protrusions 9 are formed in a convex shape that protrudes toward the center on the substantially circular inner surface of the column portion 7, and the area between the protrusions 9 in the circumferential direction is concave with respect to the protrusions 9. That is, in the horizontal cross section of the column portion 7, an uneven shape is repeatedly formed in the circumferential direction on the inner surface of the column portion 7, and this uneven shape continues in the vertical direction of the column portion 7.

[0029] Fig. 3(a) is a cross-sectional view showing the state in which the rainwater storage members 3 are stacked on top of each other during transportation or storage, and Fig. 3(b) is a cross-sectional view (end view) of line BB in Fig. 3(a). As described above, the pillar portion 7 has a tapered shape in which the diameter becomes smaller toward the tip, so that the pillar portion 7 of the lower rainwater storage member 3 can be inserted into the lower opening of the pillar portion 7 of another rainwater storage member 3 above, thereby stacking them on top of each other.

[0030] Here, by forming the convex portion 9 on the inner surface of the column portion 7, the overlapping margin between the column portions 7 becomes shallower compared to when there is no convex portion, but the convex portion 9 on the inner surface of the outer column portion 7 comes into contact with the outer surface of the inner column portion 7, forming a gap 15 between the convex portions 9. This allows the contact area between the column portions 7 to be reduced when the column portions 7 are overlapped. If the column portions 7 without the convex portion 9 are completely fitted into each other, the contact area becomes large, causing large friction, and a large force is required to remove the column portions 7 from the overlapped state. In contrast, by providing the convex portion 9 to reduce the contact area, the force required to remove the column portions 7 from the overlapped state is reduced, improving workability.

[0031] The protrusions 9 may be formed on the outer surface of the column portion. FIG. 4(a) is a horizontal cross-sectional view of the column portion 7a. The column portion 7a is substantially similar to the column portion 7, but the protrusions 9 are formed on the outer surface of the column portion 7a at a predetermined interval in the circumferential direction. That is, the protrusions 9 are convex shapes that protrude outward on the outer surface of the substantially circular column portion 7a, and the space between the protrusions 9 in the circumferential direction is concave with respect to the protrusions 9. That is, in the horizontal cross-section of the column portion 7a, an uneven shape is repeatedly formed on the outer surface of the column portion 7a in the circumferential direction, and this uneven shape continues in the vertical direction of the column portion 7a.

[0032] In this way, it is sufficient that the uneven shape is repeatedly formed in the circumferential direction on at least one of the outer surface or inner surface of the column portion in the horizontal cross section of the column portion. When protrusions 9 are provided on both the inner and outer surfaces, the circumferential positions of the protrusions 9 on the inner and outer surfaces may be made different. In this way, the positions of the protrusions 9 are dispersed, the effect of local thick portions during manufacturing is suppressed, and interference between the protrusions 9 when overlapping can be avoided.

[0033] According to the first embodiment, in the rainwater storage structure 1 in which the tips of the column portions 7 of a pair of rainwater storage members 3 are stacked and arranged opposite each other, the column portions 7 are not simply circular or polygonal, but have rib-like protrusions 9 formed on the inner and outer surfaces, so that the occurrence of out-of-plane buckling due to vertical loads can be efficiently suppressed.

[0034] In addition, because the column portions 7 have a tapered shape, they can be overlapped with each other. At this time, the contact area of ​​the inner and outer surfaces of the column portions 7 when overlapped is reduced by the protrusions 9, and the force required for separation can be reduced. In the above-mentioned embodiment, the horizontal cross-sectional shape of the column portion 7 is approximately circular, but the protrusions 9 may be provided on at least one of the inner and outer surfaces of the polygon.

[0035] By forming such an uneven shape over almost the entire length of the column, the strength of the entire column 7 can be efficiently improved and local buckling can be suppressed. However, the uneven shape may be formed intermittently in the longitudinal direction of the column 7, or may be formed only in the overlapping parts when the column parts 7 are overlapped with each other.

[0036] Moreover, if there is no need to overlap the column parts 7, the column part 7 does not have to be tapered. Moreover, the column part 7 may not be tapered, and only the convex part may be tapered (the height of the convex part is reduced toward the tip), or both the column part 7 and the convex part may be tapered. In this way, the taper angle of the column part 7 and the taper angle of the convex part (i.e., the taper angle of the inner and outer surfaces of the column part 7) can be changed. Therefore, when the column parts 7 are overlapped, the contact area between them can be minimized. In addition, the convex part may be tapered so that the width becomes thinner toward the tip. In this way, the contact area between the convex part and the column part can be further reduced.

[0037] Next, a second embodiment will be described. In the following description, the same components as those in the first embodiment are given the same reference numerals as those in Figs. 1 to 4, and duplicated descriptions will be omitted. Fig. 5(a) is a horizontal cross-sectional view of a column portion 7b according to the second embodiment. The column portion 7b has a configuration substantially similar to that of the column portion 7, but its shape is different.

[0038] The horizontal cross-sectional shape of the column portion 7b is a polygon, with recesses or protrusions that protrude inward or outward at a predetermined interval in the circumferential direction. For example, in the illustrated example, the vertices of a regular dodecagon form the protrusions 9a, and each side of the vertex of the regular dodecagon is folded inward to form the recesses 9b. In this way, the column portion 7b is roughly a star-shaped regular polygon.

[0039] In this way, by forming the convex portions 9a and the concave portions 9b repeatedly in the circumferential direction, it is possible to obtain a higher resistance to vertical loads compared to a case in which the column portions 7b are simple regular polygons.

[0040] In this way, according to the second embodiment, like the first embodiment, out-of-plane buckling can be efficiently suppressed.

[0041] In addition, since the column portion 7b has a tapered shape like the column portion 7, they can be overlapped. FIG. 5(b) is a cross-sectional view showing the column portions 7b overlapped with each other. The column portions 7b have substantially the same thickness over the entirety, so the outer and inner shapes are substantially similar. In this case, when the column portions 7b are overlapped, the inner surface of the outer column portion 7b and the outer surface of the inner column portion 7b come into surface contact (line contact in a horizontal cross section) over substantially the entire circumference. In this way, when the contact area of ​​the inner and outer surfaces of the overlapped column portions 7b becomes large, a larger force is required to remove the inner column portion 7b from the outer column portion 7b due to the frictional force.

[0042] Alternatively, a column portion 7c as shown in Fig. 6(a) may be used. The column portion 7c has a shape similar to that of the column portion 7b, but the outer and inner shapes are slightly different. Normally, in a resin molded product, the corners are not made perfectly angular, but are chamfered at the ends. In this case, the size of the chamfer is generally made approximately the same for each part, but in the illustrated example, for example, the curved shape (radius of curvature R1) on the outer side of the protrusion 9a is different from the curved shape (radius of curvature R2) on the inner side, with R2>R1.

[0043] 6(b) is a horizontal cross-sectional view of such column sections 7c overlapping each other. Since the outer and inner shapes of the protrusions 9a of column section 7c are different, the tip of protrusion 9a of inner column section 7c makes approximate point contact with the inner side of outer column section 7c, and the linear portions that come into contact with each side do not make line contact, forming gaps 15.

[0044] In this way, by making the outer and inner shapes of the column portion 7c in the horizontal cross section not similar at any position in the height direction but changing a part of the shape, when the column portions 7c are completely overlapped, the inner surface of the outer column portion 7c and the outer surface of the inner column portion 7c are in approximate point contact at multiple points in at least a part of the circumferential direction in the horizontal cross section of the column portions, and a gap 15 is formed between them in at least a part of the circumferential direction. This reduces the contact area and reduces the force required to remove the inner column portion 7b from the outer column portion 7b.

[0045] In the column portion 7c, instead of changing the shape (such as chamfered shape) of the inner and outer surfaces of the protrusion 9a, the shape of the inner and outer surfaces of the recess 9b may be changed in a similar manner. The chamfered shape of the inner and outer surfaces may be C-chamfered. In the case of C-chamfering, the chamfered portion is linear, so the contact portion between the chamfered portions is not strictly a point contact. However, in the present invention, the term "approximate point contact" refers to a state in which only the vicinity of the inner and outer tips of the protrusion 9a and the recess 9b are in contact, and the straight line (or curved line) between the protrusion 9a and the recess 9b is not in line contact.

[0046] Also, the method of changing the shape of the inner and outer surfaces of the column is not limited to changing the chamfer shape. Fig. 7(a) is a horizontal cross-sectional view showing the state in which column 7d is superimposed. In column 7d, protrusions 9 are formed on the outer surface of protrusion 9a and the inner surface of recess 9b. As described above, protrusions 9 are formed continuously in the up-down direction in the form of ribs. In this way, for a substantially star-shaped polygon like column 7, protrusions 9 may be formed on at least one of the inner and outer surfaces in a part of the circumferential direction, as in column 7.

[0047] FIG. 7(b) is a horizontal cross-sectional view showing the state where the pillar portions 7e are overlapped. In the pillar portions 7e, the straight line portions between the inner and outer surfaces are not parallel. That is, the thickness of the pillar portions 7e varies slightly depending on the circumferential portion. For example, in the illustrated example, the thickness of the top of the convex portion 9a is thin, and the thickness of the bottom of the concave portion 9b is thick, and the thickness gradually changes. In this way, by making the inner and outer surfaces of the horizontal cross section not parallel in a portion of the circumferential direction, a gap 15 can be formed.

[0048] The shape in which the protrusions 9a and the recesses 9b are alternately formed in the circumferential direction may be a pillar portion 7f as shown in Fig. 8(a). The pillar portion 7f has a shape in which each side of a basic shape of a substantially rectangular shape is recessed inward. That is, the corners of the substantially rectangular shape become the protrusions 9a, and the inward recessed portions formed on each side become the recesses 9b.

[0049] Similarly, a pillar portion 7g as shown in Fig. 8(b) may be used. A pillar portion 7f has a shape in which a part of each side of a basic shape of a substantially triangle is recessed inward. That is, the corners of the substantially triangle become the protrusions 9a, and the inward recessed parts formed on each side become the recesses 9b.

[0050] Alternatively, a column portion 7h as shown in Fig. 8(c) may be used. The column portion 7f is formed by recessing inward at a predetermined interval in the circumferential direction from a basic shape of a substantial circle. That is, the inward recessed portion becomes a recess 9b, and the arc portion between the recesses 9b becomes a protrusion 9a. In this way, if the horizontal cross-sectional shape of the column portion is polygonal or circular and has recesses or protrusions protruding inward or outward at a predetermined interval in the circumferential direction, the occurrence of out-of-plane buckling due to a load in the vertical direction can be efficiently suppressed.

[0051] The recesses 9b shown in Figures 8(a) to 8(c) may be convex so as to protrude outward. Also, for each embodiment, the inner and outer surfaces may not be completely similar in shape, and the shapes may be partially changed so that gaps 15 are formed when the plates are stacked, as shown in Figures 6 to 7.

[0052] Although the embodiment of the present invention has been described above with reference to the attached drawings, the technical scope of the present invention is not limited to the above-described embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0053] 1. Rainwater storage structure 3. Rainwater storage material 5... Circuit board 7, 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h...Column section 9, 9a………Convex part 9b...Concave 11.... Fitting protrusion 13.... Fitting hole 15...Gap

Claims

1. A rainwater storage member used in a rainwater storage structure, A substrate and a column portion standing on the substrate, A rainwater storage member characterized in that, in a horizontal cross-section of the column portion, an uneven shape is formed repeatedly in the circumferential direction on at least one of the outer surface or inner surface of the column portion, and the uneven shape is continuous in the vertical direction of the column portion.

2. The rainwater storage member according to claim 1, characterized in that the column portion has a tapered shape that becomes smaller in size toward the tip, and the column portions of multiple rainwater storage members can be stacked on top of each other.

3. A rainwater storage member as described in claim 1 or claim 2, characterized in that the horizontal cross-sectional shape of the column portion is polygonal or circular, and has concave or convex portions that protrude inward or outward at predetermined intervals in the circumferential direction.

4. A rainwater storage member as described in claim 2, characterized in that the outer and inner shapes of the column portions in a horizontal cross section are not similar, and when the column portions are completely overlapped, a gap is formed in at least a portion of the circumferential direction between the inner surface of the outer column portion and the outer surface of the inner column portion in the horizontal cross section of the column portions.

5. A rainwater storage member as described in claim 2, characterized in that when the column portions are completely overlapped with each other, in a horizontal cross-section of the column portions, the inner surface of the outer column portion and the outer surface of the inner column portion are in approximate point contact at multiple points along at least a portion of the circumferential direction.

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