Filter case or filter case assembly set

Abstract

To provide a new filter case etc. which enables at least an entire length of the filter case to be reduced appropriately according to attributes of a machine tool and attributes of a user and enables easy management and operation during manufacturing, sales, or maintenance.SOLUTION: A filter case 1 is formed with a filter storage space, in which a liquid filter 100 is stored, and includes: a lowermost tier case part 2 disposed at a lowermost tier; an uppermost tier case part 3 disposed at an uppermost tier; and multiple intermediate case parts 4 stacked between the lowermost tier case part 2 and the uppermost tier case part 3. The respective intermediate case parts 4 are molded in the same form.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a filter case or a filter case assembly set in which a filter (filter element, filter medium) for filtering foreign matters such as sludge contained in a liquid such as oil is housed inside.

Background Art

[0002] For example, in machine tools for cutting metal materials such as electric discharge machines and machine tools for polishing metal materials, in order to enhance the cooling property, lubricity, rust prevention property, or chip adhesion prevention property during cutting, cutting oil (coolant liquid or processing liquid. Hereinafter, these are referred to as coolant liquid) is discharged to the cutting tool. And, after such coolant liquid is discharged to the cutting tool or the like, it is filtered by a predetermined liquid filter, foreign matters such as sludge generated as a result of metal processing are removed by the liquid filter, and it is often circulated and repeatedly used so as to be supplied to the cutting tool or the like again. In particular, when finely processing a metal material, if foreign matters such as sludge are mixed in the used coolant liquid, there is a risk not only of damaging the processing machine or the like but also of hindering high-precision processing. Against this background, in the technical field of metal processing, a filter with high filtration efficiency is required, and when the filterable time is short, there is a need to replace it early, so there is a strong market need for a filter having a function of extending the usable time as a filter.

[0003] Therefore, the applicant of the present application has proposed a novel liquid filter in which filter paper previously formed in a substantially rectangular shape is bent by mountain folding and valley folding at predetermined locations, and the above coolant liquid flows into the center (see Patent Documents 1 and 2). The liquid filter disclosed in this Patent Document 1 is configured such that by bending the above-mentioned filter paper, a plurality of inner tops and outer tops are formed, so that there is no bias in the filtered part and the whole is filtered evenly. Further, the liquid filter disclosed in Patent Document 2 is configured such that spacers are arranged at predetermined locations, and there is no bias in the filtered part by these spacers and the whole is filtered evenly.

[0004] These various liquid filters are housed in the liquid filter cases disclosed in the above-mentioned Patent Documents 1 and 2. The filter cases are formed in a substantially rectangular parallelepiped shape, and the four side plates constituting the liquid filter case have numerous perforations or drainage openings formed therein, through which the liquid (coolant) filtered by the liquid filter flows out to the outside. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-063743 [Patent Document 2] Japanese Patent Publication No. 2021-159819 [Overview of the project] [Problems that the invention aims to solve]

[0006] Incidentally, when the liquid filter housed in the filter case is used as an accessory for the aforementioned machine tool, for example, when it is placed or incorporated as an accessory in an electrical discharge machining (EDM) machine, the conditions related to the attributes of the EDM machine itself, such as its size, processing capacity, and available location or space, as well as the conditions related to the user's attributes, such as the frequency of use of the EDM machine, will vary. Therefore, it is conceivable to manufacture and provide a filter case tailored to the attributes of the EDM machine itself and the attributes of the user of the EDM machine.

[0007] However, if we were to manufacture filter cases corresponding to each of the above attributes and house liquid filters inside them, the number of product items would be enormous, and the manufacturing cost of each individual filter case would inevitably be enormous. Furthermore, a great deal of effort would be required for management and operation during manufacturing, sales, and maintenance.

[0008] Therefore, the present invention was proposed to solve the problems of the conventional filter cases and liquid filtration devices equipped with such filter cases described above, and aims to provide a novel filter case that allows the overall length of the filter case to be appropriately shortened according to the attributes of the machine tool and the attributes of the user, and thereby facilitates management and operation during manufacturing, sales, and maintenance. [Means for solving the problem]

[0009] The present invention was proposed to solve the above problems, and the first invention (the invention described in claim 1) relates to a filter case that is expandable in the height direction, or a plurality of small filters are stacked in it. It filters the liquid that flows into the interior and discharges it to the outside. A filter case having a filter housing space formed inside which a liquid filter is housed, comprising a bottom case part positioned at the bottom, an upper case part positioned at the top, and a plurality of intermediate case parts stacked between the bottom case part and the upper case part, An upper plate is placed on the topmost case part mentioned above and has a liquid inlet hole formed therein into which the liquid flows, Each of the above intermediate case parts is molded to the same shape. In addition, the above-mentioned multiple intermediate case parts are formed with drainage openings or drainage notches through which the liquid filtered by the above-mentioned liquid filter is discharged to the outside. It is characterized by the following:

[0010] In the filter case according to this first invention, since all of the intermediate case parts are molded to the same shape, even if, for example, one or two intermediate case parts are removed from a stack of six intermediate case parts to shorten the overall height (total length), the filter case will still function. Furthermore, in this invention, the liquid filter housed in the filter housing space is either expandable and contractible in the height direction, or consists of multiple small filters stacked on top of each other. Therefore, even if one or two intermediate case parts are removed, a liquid filter of a predetermined height can be housed in the filter case by reducing the size of the liquid filter or by removing some of the stacked small filters.

[0011] Furthermore, while it is preferable that the bottom, middle, and top case parts, which are components of this filter case, be made of resin, they may also be made of aluminum, iron, or other metal materials. In addition, the overall external shape of this filter case does not have to be a roughly rectangular parallelepiped or roughly cubic shape, but may also be molded into a cylindrical shape, as long as it has a filter housing space inside in which the above-mentioned liquid filter is housed. If the overall external shape of the filter case is formed in the shape of a rectangular parallelepiped, the planar shapes of the bottom filter case, the intermediate filter case, and the top case part will each have the appearance of a roughly rectangular frame. If the overall external shape of the filter case is formed in the shape of a roughly cube, the planar shapes of the bottom filter case, the intermediate filter case, and the top case part will each have the appearance of a roughly square frame. If the overall external shape of the filter case is formed in the shape of a cylinder, the planar shapes of the bottom filter case, the intermediate filter case, and the top case part will each have the appearance of a circular frame.

[0012] Furthermore, the second invention (the invention described in claim 2) is characterized in that, in the first invention, the uppermost case part and the lowermost case part are both molded to the same shape.

[0013] In the filter case according to this second invention, since the uppermost case part and the lowermost case part are both molded to the same shape, they can be used as the uppermost and lowermost case parts, and the lowermost case part can also be used as the uppermost case part. In other words, with the filter case according to this second invention, it is not necessary to always place the uppermost case part at the top and the lowermost case part at the bottom; either can be placed at the bottom or the top. Furthermore, since the intermediate parts are also made to the same shape, if there are multiple intermediate case parts, any intermediate case part can be stacked in any position. Therefore, with this filter case, the effort required when stacking the parts as a filter case or when completing it as a liquid filtration device can be greatly reduced, and the assembly time can be greatly shortened.

[0014] Furthermore, the third invention (the invention described in claim 3) is the intermediate case part in either the first or second invention described above. Tsu The intermediate case part, the bottom case part, and the top case part are each characterized in that they are formed with drainage notches that form drainage openings for draining liquid filtered by the liquid filter to the outside, when the intermediate case part is stacked on top of the bottom case part, when the intermediate case parts are stacked on top of each other, and when the top case part is stacked on top of the intermediate case part.

[0015] The filter case according to this third invention specifies the position of a drainage opening for draining the liquid filtered by the liquid filter in the intermediate case parts, and includes the following two embodiments. In the former, the intermediate case part itself has a drainage opening formed therein for draining the liquid filtered by the liquid filter to the outside. In the latter, the intermediate case part, the bottom case part, and the top case part each have drainage notches formed therein for draining the liquid filtered by the liquid filter to the outside when the intermediate case part is stacked on the bottom case part, when the intermediate case parts are stacked on each other, and when the top case part is stacked on the intermediate case part. In the former embodiment, when the material is resin, the drainage opening is formed by cutting or drilling in a process after it has been molded. In contrast, in the latter case, where the material is resin and the molding is done using an injection molding machine, the above-mentioned post-processing steps become unnecessary, and the notches can be molded simultaneously with the other parts in a single molding process. Therefore, with a filter case in the latter configuration, the bottom case part, the intermediate case part, and the top case part can each be molded and manufactured in a considerably short time.

[0016] Furthermore, the number of drainage openings (including the drainage openings formed by the upper and lower notches) may be such that, if the overall shape of the filter case is roughly rectangular or cubic, there may be one or more openings on each side, and if the overall shape of the filter case is cylindrical, there may be multiple openings in the circumferential direction.

[0017] Furthermore, the fourth invention (the invention described in claim 4) is characterized in that, in either the first or second invention, the upper surface of the bottommost case part, the lower and upper surfaces of the intermediate case part, and the lower surface of the topmost case part are each relatively formed with one positioning portion that maintains the stacked state and the other positioning portion that engages with this one positioning portion.

[0018] In the filter case according to this fourth invention, the bottom case part, the intermediate case part, and the top case part are each relatively formed with a positioning part that maintains the stacked state and a positioning part that engages with the other positioning part, so that each can maintain the stacked state. In particular, even if liquid to be filtered flows into the liquid filter housed inside, and the internal pressure of the liquid filter increases significantly, causing the liquid filter to expand outward, and as a result this internal pressure acts on any of the bottom case part, intermediate case part, or top case part, each can maintain the stacked state.

[0019] Furthermore, the fifth invention (the invention described in claim 5) is characterized in that, in the fourth invention, one positioning portion and the other positioning portion are convex or concave ridges or grooves that are U-shaped or endless in plan view, and the one positioning portion which is the convex or concave ridge and the other positioning portion which is the concave ridge or convex ridge are engaged with each other.

[0020] In the filter case according to this fifth invention, the one positioning portion and the other positioning portion are convex or concave ridges or grooves that are U-shaped or endless in a plan view. For example, if the one positioning portion is a convex ridge that is U-shaped or endless in a plan view, the other positioning portion is a concave groove in a plan view, and the one positioning portion which is a convex ridge and the other positioning portion which is a concave groove are engaged with each other. Therefore, according to the fifth invention with this configuration, even if the internal pressure of the filter housed in the liquid filter case increases and this pressure acts on the bottom case part, intermediate case part, or upper case part that constitute the filter case, the stacked state can be maintained more effectively.

[0021] Furthermore, the sixth invention (the invention described in claim 6) is characterized in that, in the fourth invention, the upper surface of the lowest case part has both a positioning part on the lowest side as one of the positioning parts and a positioning part on the other side of the lowest part as the other positioning part, the lower surface of the uppermost case part has both a positioning part on the uppermost side as one of the positioning parts and a positioning part on the other side of the uppermost part as the other positioning part, the lower surface of the intermediate case part has a positioning part on the intermediate side that engages with the positioning part on the lowest side as the other positioning part, and a positioning part on the intermediate side that engages with the positioning part on the other side of the lowest part as one of the positioning parts, and the upper surface of the intermediate case part has a positioning part on the intermediate side that engages with the positioning part on the uppermost side as the other positioning part, and a positioning part on the intermediate side that engages with the positioning part on the other side of the uppermost part as one of the positioning parts.

[0022] In the filter case according to the sixth invention, on the upper surface of the lowermost case part, both a positioning part on one side of the lowermost side and a positioning part on the other side of the lowermost side are formed. The positioning part on one side of the lowermost side is formed as the one positioning part, and the positioning part on the other side of the lowermost side is formed as the other positioning part. Also, on the lower surface of the uppermost case part, a positioning part on one side of the uppermost side and a positioning part on the other side of the uppermost side are formed. The positioning part on one side of the uppermost side is formed as the one positioning part, and the positioning part on the other side of the uppermost side is formed as the other positioning part. Further, on the lower surface of each intermediate case part, an other positioning part on the intermediate side that engages with the positioning part on one side of the lowermost side and a positioning part on one side of the intermediate side that engages with the positioning part on the other side of the lowermost side are formed. The other positioning part on the intermediate side is the other positioning part, and the positioning part on one side of the intermediate side is the one positioning part. Also, on the upper surface of each intermediate case part, an other positioning part on the intermediate side that engages with the positioning part on one side of the uppermost side and a positioning part on one side of the intermediate side that engages with the positioning part on the other side of the uppermost side are formed. The other positioning part on the intermediate side is the other positioning part, and the positioning part on one side of the intermediate side is the one positioning part. That is, in the sixth invention, on each case part, both the one positioning part and the other positioning part are formed on each upper surface or lower surface or both upper and lower surfaces. Therefore, it is possible to further increase the strength of this filter case and enable it to sufficiently withstand the internal pressure.

[0023] Furthermore, the seventh invention (the invention described in claim 7) is characterized in that, in the fourth invention, the one positioning portion is formed in multiples on the upper surface of the bottommost case part and the upper surface of each intermediate case part, the other positioning portion is formed in multiples on the lower surface of each intermediate case part and the lower surface of the topmost case part, and even after the intermediate case part is rotated by a predetermined angle on a horizontal plane from a state in which the other positioning portion and one positioning portion formed on each intermediate case part engage with the one positioning portion formed on the bottommost case part and the other positioning portion formed on the topmost case part, the other positioning portion and one positioning portion formed on the intermediate case part are formed in a position that engages with the one positioning portion formed on the bottommost case part and the other positioning portion formed on the topmost case part, respectively.

[0024] In the filter case according to this seventh invention, the other positioning portion and one positioning portion formed on each of the intermediate case parts are positioned to engage with the one positioning portion formed on the bottom case part and the other positioning portion formed on the top case part, respectively, even after the intermediate case part is rotated by a predetermined angle on the horizontal plane from that state, just as in the initial state before rotation. Therefore, the tasks of stacking the intermediate case parts on the bottom case part, stacking intermediate case parts on a specific intermediate case part, and stacking the top case part on the intermediate case part stacked on top of the top layer are all easy to perform.

[0025] Further, the eighth invention (the invention according to claim 8) is the fourth invention, wherein a plurality of the one positioning portions are respectively formed on the upper surfaces of the bottom case part and each of the intermediate case parts, and a plurality of the other positioning portions are respectively formed on the lower surfaces of each of the intermediate case parts and the lower surface of the uppermost case part. The other positioning portions and the one positioning portions formed on each of the intermediate case parts are formed at positions where the other positioning portions and the one positioning portions formed on the intermediate case parts respectively engage with the one positioning portions formed on the bottom case part and the other positioning portions formed on the uppermost case part even after the intermediate case part is rotated 180 degrees on a horizontal plane and after the intermediate case part is turned upside down with respect to the engaging state with the one positioning portions formed on the bottom case part and the other positioning portions formed on the uppermost case part.

[0026] The differences between this eighth invention and the seventh invention are mainly explained as follows: In the eighth invention, the outer shapes of the bottom case part, the intermediate case part, and the top case part are formed into a substantially rectangular shape in plan view. Therefore, in the seventh invention, the outer shapes of the bottom case part, the intermediate case part, and the top case part are not limited to those formed into a substantially rectangular shape in plan view (as in this eighth invention), but also include those formed into a circular shape, for example. However, in this eighth invention, it is limited to those formed into a substantially rectangular shape. Therefore, in this eighth invention, the outer shapes of the bottom case part, the intermediate case part, and the top case part are formed into a substantially rectangular shape and those formed into a square shape in plan view. Furthermore, in this eighth invention, even after the intermediate case part is rotated 180 degrees on a horizontal plane from a state in which the other positioning portion and the other positioning portion formed on each intermediate case part are engaged with the one positioning portion formed on the bottom case part and the other positioning portion formed on the top case part, the other positioning portion and the one positioning portion formed on the intermediate case part are not only formed in a position to engage with the one positioning portion formed on the bottom case part and the other positioning portion formed on the top case part, respectively, but also after the intermediate case part is inverted upside down, the other positioning portion and the one positioning portion formed on the intermediate case part are formed in a position to engage with the one positioning portion formed on the bottom case part and the other positioning portion formed on the top case part, respectively.

[0027] Therefore, according to the filter case of this eighth invention, the work of stacking the intermediate case parts on the bottommost case part, or stacking intermediate case parts on a specific intermediate case part, can be made easier by ensuring that one positioning part and the other positioning part are always engaged with each other, even if the intermediate case part is rotated 180 degrees on a horizontal plane or inverted upside down.

[0028] Also, the ninth invention (claim) 9 The invention described is a filter case assembly set used when assembling a filter case having a filter housing space formed inside in which a liquid filter is housed, comprising: a bottom case part to be placed at the bottom; an upper case part to be placed at the top; and a plurality of intermediate case parts, of any number selected, to be stacked between the bottom case part and the upper case part. An upper plate is placed on the topmost case part mentioned above and has a liquid inlet hole formed therein into which the liquid flows, including The intermediate case part is provided with a drainage opening through which the liquid filtered by the liquid filter is discharged to the outside, or the intermediate case part, the bottom case part, and the top case part are each provided with a drainage notch that forms a drainage opening through which the liquid filtered by the liquid filter is discharged to the outside when the intermediate case part is stacked on top of the bottom case part, when the intermediate case parts are stacked on top of each other, and when the top case part is stacked on top of the intermediate case part. It is characterized by becoming [this].

[0029] Even when using the filter case assembly set according to the ninth invention described above, it not only provides the same effects as the filter case according to the first invention described above, but also makes it possible to assemble a longer filter case by increasing the number of layers of the intermediate case parts. [Effects of the Invention]

[0030] According to the filter case of the present invention, the overall length of the filter case can be appropriately shortened according to the attributes of the machine tool and the user, and consequently, management and operation during manufacturing, sales, and maintenance can be made easier. Furthermore, according to the filter case assembly set of the present invention, the number of intermediate case parts to be stacked can be any number, so a filter case that is even more tailored to the attributes of the machine tool and the user can be assembled with a small number of parts. [Brief explanation of the drawing]

[0031] [Figure 1] This is a perspective view showing the appearance of the filter according to the embodiment. [Figure 2] Figure 1 shows an exploded perspective view of the filter case. [Figure 3] This is a perspective view showing the bottom case part from the bottom side. [Figure 4] This is a perspective view showing the bottom case part from the flat side. [Figure 5] This is a magnified perspective view of the lower box section of the bottom case part. [Figure 6] This is a magnified perspective view showing the lower corner box section of the bottom case part. [Figure 7] This is a magnified perspective view of the lower box section of the bottom case part. [Figure 8] This is a perspective view showing the intermediate case parts. [Figure 9] This is a bottom view showing the intermediate case parts. [Figure 10] This is a plan view showing the bottom plate. [Figure 11] This is a plan view showing the top plate. [Figure 12] This is a perspective view showing the filter case held in place by multiple retaining brackets. [Figure 13] This is an exploded perspective view showing the retaining clip. [Modes for carrying out the invention]

[0032] The filter case according to the best mode for carrying out the present invention will be described in detail below with reference to the drawings.

[0033] As shown in Figure 1 or Figure 2, the filter case 1 according to this embodiment comprises a bottom case part 2 positioned at the bottom, an upper case part 3 positioned at the top, a plurality (four) intermediate case parts 4 stacked between the bottom case part 2 and the upper case part 3, a bottom plate 5 positioned on the bottom surface of the bottom case part 2, an upper plate 6 positioned on the top surface of the upper case part 3, and eight long bolts 7 that integrate the lower case part 2, the upper case part 3, the plurality (four) intermediate case parts 4, the bottom plate 5, and the upper plate 6, and eight nuts 8 that are screwed onto the upper ends of these long bolts 7. In this embodiment, the filter case 1 consists of the bottom case part 2, the top case part 3, and the multiple (four) intermediate case parts 4, each integrally molded from resin (POM resin), while the bottom plate 5 and top plate 6 are made of stainless steel.

[0034] Furthermore, the bottom case part 2, the top case part 3, and the multiple (four) intermediate case parts 4 are frames with a storage space (the symbol is omitted) formed inside for housing the liquid filter 100, which will be described later, as shown in Figure 1 or Figure 2. The outer shapes of the bottom case part 2, the top case part 3, and the multiple (four) intermediate case parts 4 are formed in a roughly square shape, and the four surfaces formed on the outer circumference (front, back, left side, and right side) and the arc-shaped curved surfaces formed at each corner are all flush in the vertical direction, and the inner surfaces are also flush in the vertical direction, just like the outer surfaces. In addition, the bottom case part 2 and the top case part 3 are formed in the same shape as each other. The bottom case part 2 and the intermediate case parts 4 will now be described in detail.

[0035] As shown in Figure 3, the bottom case part 2 (top case part 3) of the bottom case part 2 includes a bottom plate portion 21 whose lower surface is the bottom surface of the entire bottom case part 2, an inner circumferential vertical plate portion 22 that rises from the inner circumferential end of the bottom plate portion 21 and surrounds the inside of the bottom case part 2, and an outer circumferential vertical plate portion 23 that rises from the outer circumferential end of the bottom plate portion 21 and faces the outer surface of the inner circumferential vertical plate portion 22. Furthermore, the outer circumference of each corner (reference numerals omitted) of the bottom case part 2 is part of the outer circumferential vertical plate portion 23 and is formed as an outer curved surface 23a that is curved in an arc shape, and the inner circumference of each corner (reference numerals omitted) of the bottom case part 2 is part of the inner circumferential vertical plate portion 22 and is formed as an inner curved surface 22a that is curved in an arc shape. Furthermore, as shown in Figure 3, eight through-holes 21a are formed on the lower surface of the bottommost case part 2, at the four corners and between each of the corners, through which the long bolts 7 are inserted.

[0036] Furthermore, the inner circumferential vertical plate portion 22 and the outer circumferential vertical plate portion 23 have eight lower-stage notches 22b and 23b, which are cut out from the upper end of the inner circumferential vertical plate portion 22 and the outer circumferential vertical plate portion 23 toward the middle downwards. These lower-stage notches 22b and 23b are formed in a roughly square shape in plan view, with two on each side. The positions of the two lower-stage notches 22b and 23b formed on a particular side are on both the left and right sides of the center of that particular side. Note that in the upper-stage case part 3, the lower-stage notches 22b and 23b are the upper-stage notches 32b and 33b. Furthermore, a rectangular parallelepiped-shaped lower box portion 25, with its top open, is formed between the lowest side notches 22b and 23b formed on each of the above sides. As shown in Figure 5, the outer side of these lower box portions 25 is made up of a part of the outer peripheral vertical plate portion 23, and the inner side is made up of a part of the inner peripheral vertical plate portion 22. In addition, this lower box portion 25 has one side that is continuous with the inside of the outer peripheral vertical plate portion 23 and the other side that is continuous with the outer peripheral vertical plate portion 22, and has opposing plate portions 25a and 25b that face each other. These opposing plate portions 25a and 25b, a part of the outer peripheral vertical plate portion 23 and a part of the inner peripheral vertical plate portion 22, and the bottom plate portion 21 form a box shape with a bottom. Furthermore, a cylindrical bolt insertion portion 26 is formed in the center of each of the lower box portions 25, communicating with each of the insertion holes 2d. Inside each of the lower box portions 25, first and second long ribs 26a, 26b and first and second short ribs 26c, 26d are formed to reinforce the cylindrical bolt insertion portion 26. One side of the first long rib 26a is continuous with the inner surface of one of the opposing plate portions 25a, and the other side is continuous with the outer surface of the cylindrical bolt insertion portion 26. The second long rib 26b is continuous with the inner surface of the other opposing plate portion 25b, and the other side is continuous with the outer surface of the cylindrical bolt insertion portion 26. Furthermore, one side of the first short rib 26c is continuous with the inner surface (inner side) of the inner vertical plate portion 22, and the other side is continuous with the outer surface of the cylindrical bolt insertion portion 26.Furthermore, one side of the second short rib 26d is continuous with the inner surface (inner side) of the outer peripheral upright portion 23, and the other side is continuous with the outer peripheral surface of the cylindrical bolt insertion portion 26.

[0037] Furthermore, between the bottommost side notches 22b and 23b, and at positions corresponding to the aforementioned corners, lower corner box sections 28 are formed. A total of four of these lower corner box sections 28 are formed, corresponding to the number of corners in the bottommost case part 2, and the overall shape is approximately L-shaped in plan view. As shown in Figure 6, the outer side of these lower corner box sections 28 is made up of a part of the outer peripheral vertical plate section 23, and the inner side is made up of a part of the inner peripheral vertical plate section 22. Furthermore, each of these lower corner box sections 28 has one side that is continuous with the inside of the outer peripheral vertical plate section 23 and the other side that is continuous with the outer peripheral of the inner peripheral vertical plate section 22, and has one and the other opposing plate sections 28a and 28b that are separated by a predetermined distance from the one opposing plate section 25a or the other opposing plate section 25b, and is formed into a box shape with a bottom and an open top by these one and the other opposing plate sections 28a and 28b, a part of the outer peripheral vertical plate section 23 and a part of the inner peripheral vertical plate section 22, and the bottom plate section 21. In addition, each of the corners that are the center of each of the lower corner box sections 28 has a corner-side cylindrical bolt insertion section 29 that is in communication with the respective insertion hole 2d. Within each of the lower corner box sections 28, there are first and second long ribs 29a and 29b, and first and second short ribs 29c and 29d, respectively, which reinforce the cylindrical bolt insertion section 29 on the corner side. The first long rib 29a has one side that is continuous with the inner surface of one of the opposing plate sections 28a, and the other side that is continuous with the outer circumferential surface of the cylindrical bolt insertion section 29. The second long rib 29b has one side that is continuous with the inner surface of the other opposing plate section 28b, and the other side that is continuous with the outer circumferential surface of the cylindrical bolt insertion section 29 on the corner side. The first short rib 29c has one side that is continuous with the inner circumferential surface (inner surface) of the outer vertical plate section 23, and the other side that is continuous with the outer circumferential surface of the cylindrical bolt insertion section 29 on the corner side. Furthermore, one side of the second short rib 29d is continuous with the inner surface (inner side) of the inner circumferential upright portion 22, and the other side is continuous with the outer surface of the cylindrical bolt insertion portion 29 on the corner side.

[0038] Furthermore, in this bottom-tier case part 2, a protrusion and a groove, described later, are formed side by side on the upper end of each of the four lower box sections 25, and a protrusion, described later, is formed on the upper end of two of the four lower corner box sections 28, while a groove, described later, is formed on the upper end of the other two lower corner box sections 30.Therefore, below, among the four lower box sections 25, the lower box section 25 located on the front side of the bottom-tier case part 2 shown in Figure 4 will be referred to as lower box section 25(A), the lower box section 25 located on the rear side as lower box section 25(B), the lower box section 25 located on the left side as lower box section 25(C), and the lower box section 25 located on the right side as lower box section 25(D), and the left of the lower box section 25(A) The lower corner box portion 28 located on the side will be referred to as lower corner box portion 28(A), the lower corner box portion 28 located to the right of the lower corner box portion 25(A) will be referred to as lower corner box portion 28(B), the lower corner box portion 28 located to the left of the lower corner box portion 25(B) will be referred to as lower corner box portion 28(C), and the lower corner box portion 28 located to the right of the lower corner box portion 25(B) will be referred to as lower corner box portion 28(D). The formation positions of the convex and concave shapes will be explained accordingly.

[0039] First, as shown in Figure 5, a U-shaped protrusion 11 is formed on the left side of the upper surface of the lower box portion 25(A), and a U-shaped groove 12 is formed on the right side of the upper surface of the lower box portion 25A. That is, the protrusion 11 and the groove 12 are formed adjacent to each other on the upper surface of the lower box portion 25A. The protrusion 11 is one of the positioning parts or one of the lowermost positioning parts that constitute the present invention, and the groove 12 is the other positioning part or the other lowermost positioning part that constitutes the present invention. Furthermore, the protrusion 11 is formed by rising from the upper surface of the outer peripheral vertical plate portion 23, the upper surface of the inner peripheral vertical plate portion 22, and the upper surface of one of the opposing plate portions 25a, and the groove 12 is formed by recessing downward from the upper surface of the outer peripheral vertical plate portion 23, the upper surface of the inner peripheral vertical plate portion 22, and the upper surface of the other opposing plate portion 25b. The height of the protrusion 11 and the depth of the groove 12 are the same. Furthermore, as shown in Figure 5, a protrusion 13 is formed in a U-shape in plan view on the front side of the upper surface of the lower box portion 25(C), and a groove 14 is formed in a U-shape in plan view on the back side of the upper surface of the lower box portion 25(C). In other words, the protrusion 13 and the groove 14 are formed adjacent to each other on the upper surface of the lower box portion 25(C). The protrusion 13 is one of the positioning parts or one of the lowermost positioning parts that constitute the present invention, and the groove 14 is the other positioning part or the other lowermost positioning part that constitutes the present invention. Furthermore, the protrusion 13 is formed by rising from the upper surface of the outer vertical plate portion 23, the upper surface of the inner vertical plate portion 22, and the upper surface of the other opposing plate portion 25b, and the groove 14 is formed by recessing downward from the upper surface of the outer vertical plate portion 23, the upper surface of the inner vertical plate portion 22, and the upper surface of the one opposing plate portion 25a. The heights of the protrusion 11 and the protrusion 13 are the same, and the depths of the groove 12 and the groove 14 are the same.

[0040] As can be seen from comparing Figures 5 and 7, the lower box section 25(B) is positioned where the lower box section 25(A) is located when the bottom case part 2 is rotated 180 degrees on a horizontal plane. Similarly, the lower box section 25(D) is positioned where the lower box section 25(C) is located when the bottom case part 2 is rotated 180 degrees on a horizontal plane. In other words, the lower box sections 25(A) and 25(B), and the lower box sections 25(C) and 25(D) are formed at point-symmetrical positions to each other. Therefore, a detailed explanation of the protrusions (reference numerals omitted) and grooves (reference numerals omitted) formed on the lower box sections 25(B) and 25(D) is omitted.

[0041] Next, as shown in Figure 6, an endless groove 16 is formed on the upper surface of the lower corner box portion 28(A), having a shape substantially the same as the shape of the lower corner box portion 28(A) in a plan view. Furthermore, an endless ridge 17 is formed on the upper surface of the lower corner box portion 28(C), having a shape substantially the same as the shape of the lower corner box portion 28(C). The endless groove 16 is the other positioning portion or the other positioning portion on the lowest stage that constitutes the present invention, and the endless ridge 17 is the one positioning portion or the one positioning portion on the lowest stage that constitutes the present invention. The depth of the endless groove 16 and the depth of the endless ridge 17 are the same.

[0042] Furthermore, the lower corner box portion 28(C) is positioned where the lower corner box portion 28(B) ends when the bottommost case part 2 is rotated 180 degrees on a horizontal plane. Similarly, the lower corner box portion 28(D) is positioned where the lower corner box portion 28(A) ends when the bottommost case part 2 is rotated 180 degrees on a horizontal plane. In other words, the lower corner box portions 28(A) and 28(D), as well as the lower corner box portions 28(B) and 28(C), are formed at point-symmetrical positions to each other. Therefore, a detailed explanation of the protrusions (reference numerals omitted) and grooves (reference numerals omitted) formed on the lower corner box portions 28(C) and 28(D) is omitted.

[0043] As mentioned earlier, the top-tier case part 3 is formed by stacking the bottom-tier case part 2 (described in detail above) upside down. Since the bottom-tier case part 3 has the same configuration as the top-tier case part 3, a detailed explanation is omitted.

[0044] Next, the intermediate case part 4 will be described in detail with reference to Figure 1 or Figure 2. As shown in Figure 1, in the filter case 1 according to this embodiment, four intermediate case parts 4 are stacked vertically. Also, as explained earlier, the external shape of the intermediate case part 4 is formed to be approximately square in a plan view, similar to the lower case part 2 and the uppermost case part 3. Therefore, for example, the external shape of the intermediate case part 4 when rotated 180 degrees around the center from the state shown in Figure 8 is the same. Furthermore, even when the intermediate case part 4 is inverted vertically from the state shown in Figure 8, its shape remains the same as before the inversion. However, for the sake of explanation, the configuration of the intermediate case part 4 will be described below using the terms front, left side, back, and right side as shown in Figure 8.

[0045] First, as shown in Figure 8, the intermediate case part 4 comprises an inner circumferential vertical plate portion 42 surrounding the inside of the intermediate case part 4, and an outer circumferential vertical plate portion 43 facing the outer surface of the inner circumferential vertical plate portion 42. Furthermore, the outer circumference of each corner (reference numerals omitted) of the intermediate case part 4 is part of the outer circumferential vertical plate portion 43 and is formed as an outer curved surface 43a that curves in an arc shape, and the inner circumference of each corner (reference numerals omitted) of the intermediate case part 4 is part of the inner circumferential vertical plate portion 42 and is formed as an inner curved surface 42a that curves in an arc shape.

[0046] Furthermore, the intermediate case part 4 has eight lower intermediate side notches 42b, 42b formed on each side of the intermediate case part 4, which is roughly square in shape when viewed from the rear. These lower intermediate side notches 42b, 42b are cut out from below towards the middle of the inner vertical plate portion 42 and the outer vertical plate portion 43. These lower intermediate side notches 42b, 42b are symmetrical to the bottom side notches 22b, 23b formed on the bottom case part 2. The lower intermediate side notches 42b, 42b and the bottom side notches 22b, 23b form a drainage opening 1a in the filter case 1, as shown in Figure 1, through which the liquid filtered by the liquid filter housed inside the filter case 1 is drained to the outside. In other words, these drainage openings 1a appear as two drainage openings 1a each on the front, left side, back, and right side of the filter case 1 when the intermediate case parts 4 are stacked on top of the bottom case part 2.

[0047] Furthermore, the intermediate case part 4 has eight upper intermediate side notches 42c and 43c formed on each side of the intermediate case part 4, which is roughly square in shape when viewed from above, with the notches cut out from the upper part towards the middle of the inner vertical plate portion 42 and the outer vertical plate portion 43. These upper intermediate side notches 42c and 43c are formed symmetrically with respect to the lower intermediate side notches 42b and 43b. On the lower side of the intermediate case part 4, between the lower intermediate side notches 42b and 43b formed on each side and the lower intermediate side notches 42c and 43c, an intermediate lower box portion 45 is formed, with the lower end open. Except for the convex ridges 54 and concave grooves 53 described later, these intermediate lower box portions 45 are formed symmetrically with respect to the lower box portions 25 formed on the bottommost case part 2. Furthermore, the cylindrical bolt insertion portion 47, the first and second long ribs 47a, 47b, and the first and second short ribs 47c, 47d formed within these intermediate lower box portions 45 are also molded symmetrically with respect to the portion formed on the lowest stage case part 2. In addition, on the lower side of this intermediate case part 4, an intermediate lower corner box portion 48, a corner-side cylindrical bolt insertion portion 49 formed within the intermediate lower corner box portion 48, the first and second long ribs 49a, 49b, and the first and second short ribs 49c, 49d are formed at positions corresponding to the corner portions. These intermediate lower corner box sections 48, etc., are formed symmetrically with respect to the lower corner box section 28, the corner cylindrical bolt insertion section 29, the first and second long ribs 29a, 29b, and the first and second short ribs 29c, 29d formed on the bottommost case part 2, except for the endless convex ribs 54 and endless recessed grooves 53 described later.

[0048] Furthermore, on the lower surface of the intermediate lower box section 45 that constitutes this intermediate case part 4, there is a U-shaped groove 53 into which the protrusion 13 formed on the upper surface of the lower box section 25 of the bottom case part 2 is inserted or fitted, and a U-shaped protrusion 54 is formed into which the protrusion 13 is inserted or fitted into a groove 14 aligned with the protrusion 13. In addition, on the lower surfaces of the two intermediate lower corner box sections 48 that are diagonally opposite each other among the four intermediate lower corner box sections 48, there is an endless groove 57 into which the endless protrusion 17 formed on the upper surface of the lower corner box section 28 of the bottom case part 2 is inserted or fitted, and on the lower surfaces of the other two intermediate lower corner box sections 48, there is an endless protrusion 56 into which the endless groove 16 is inserted or fitted. The U-shaped groove 53 and the endless groove 56 are the other positioning part that constitutes the present invention, while the U-shaped protrusion 54 and the endless protrusion 56 are the other positioning part that constitutes the present invention.

[0049] Furthermore, an intermediate plate portion 41 is formed at a position half the height between the inner circumferential vertical plate portion 42 and the outer circumferential vertical plate portion 43 that constitute this intermediate case part 4. This intermediate plate portion 41 has one side that is continuous with the inner surface of the inner circumferential vertical plate portion 42 and the other side that is continuous with the inner surface of the outer circumferential vertical plate portion 43. As shown in Figure 9, the intermediate plate portion 41 has a plurality of circular through-holes 41a formed therein that allow the liquid filtered from the groove-like space formed between the inner circumferential vertical plate portion 42 and the outer circumferential vertical plate portion 43 to be discharged downwards.

[0050] Furthermore, the portion of the intermediate case part 4 above the intermediate plate portion 41 is molded to the same shape as the upper part of the bottom case part 2, so a detailed explanation of this portion is omitted. Four intermediate case parts 4, each with the above configuration, are stacked, and the topmost case part 3 is stacked on top of the uppermost intermediate case part 4, as explained earlier. The shape of the lower surface of this topmost case part 3 is the same as the bottommost case part 2, but inverted, and is also the same as the shape of the portion of the intermediate case part 4 below the intermediate plate portion 41, so a detailed explanation of the topmost case part 3 is omitted as previously stated.

[0051] Furthermore, as shown in Figure 10, the lower plate 5 described at the beginning is molded to the same shape as the lower surface of the bottom case part 2, and has eight through holes 5a formed at positions corresponding to the positions of the through holes 21a formed in the bottom case part 2, through which the long bolts 7 are inserted. On the other hand, as shown in Figure 11, the upper plate 6 is molded to the same external shape as the lower plate 5, and has eight through holes 6a formed in each of the upper plates 6 through which the long bolts 7 are inserted. In the center of the upper plate 6, there is a liquid inlet hole 6b through which liquid filtered by the liquid filter flows in, or which communicates with the inside of a pipe (not shown) through which this liquid flows in. Each of the long bolts 7 consists of a shaft portion 7b with a head 7a formed at its lower end, and a threaded portion 7c screwed onto the upper end side surface of the shaft portion 7b. These long bolts 7 are inserted through the following holes: the shaft portion 7b of each bolt 7 is inserted into the through hole 5a formed in the lower plate 5, the through hole 21a and cylindrical bolt insertion portion 26 or corner-side cylindrical bolt insertion portion 29 formed in the lowermost case part 2, the cylindrical bolt insertion portion 47 or corner-side cylindrical bolt insertion portion 49 formed in each of the intermediate case parts 4, the through hole (reference numeral omitted) formed on the upper surface of the uppermost case part 3, and the through hole 6a formed in the upper plate 6. The nuts 8 are then screwed onto the threaded portion 7c of each long bolt 7 protruding from the upper plate 6, and as each nut 8 is screwed in, the entire filter case 1 is firmly integrated. The length of the threaded portion 7c formed on the eight long bolts 7 is such that fastening with the long bolts 7 and nuts 8 is possible even when one or more of the intermediate case parts 4 are removed during assembly. Then, as described above, once the entire filter case 1 is firmly integrated, as shown in Figure 1, the lowermost notches 22b, 23b and the lower intermediate notches 42b, 43b, the upper intermediate notches 42c, 43c and the lower intermediate notches 42b, 43b, and the upper intermediate notches 42c, 43c and the uppermost notches 32b, 33b formed in the uppermost case part 3 each form a drainage opening 1a.

[0052] Furthermore, a liquid filter 100 is housed inside the filter case 1 with this configuration to filter out liquids such as coolant that flow into it. As shown in Figure 2, the liquid filter 100 has an overall rectangular parallelepiped shape, with an inlet space 100a formed in the center through which liquid flows. Therefore, the liquid flows into the inlet space formed in the liquid filter 100 and is filtered, and the filtered liquid is discharged to the outside from the liquid filter 100 and then drained to the outside through the drainage opening 1a formed in the filter case 1.

[0053] Therefore, according to the filter case 1 of the above-described embodiment, since all four intermediate case parts 4 have the same shape, one or two of these four intermediate case parts 4 can be appropriately removed depending on the attributes of the user, such as the attributes of various machine tools such as electrical discharge machines and the frequency of use, to create a filter case 1 that is shorter in height than the filter case 1 shown in Figure 1 or Figure 2. Furthermore, in the filter case 1, the outer shape of the bottom case part 2, the top case part 3, and the intermediate case parts 4 in plan view is formed to be approximately square, the bottom case part 2 and the top case part 3 have the same shape as each other, and the intermediate case parts 4 can be stacked not only after being rotated 180 degrees on a plane but also after being inverted upside down, so the assembly work of this filter case 1 can be carried out very quickly. Furthermore, this also makes it extremely easy for the user or maintenance worker to replace the liquid filter 100, which has been used for a certain period of time and is housed inside, with a new one, even when disassembling and then reassembling it. In particular, with this filter case 1, for example, when stacking the next intermediate case part 4 on top of a specific intermediate case part 4 stacked on the lower level, if the U-shaped groove 53 formed on the lower intermediate case part 4 and the U-shaped protrusion 54 formed on the upper side do not correspond to each other, this incorrect situation can be easily recognized by the worker, and this incorrect situation can be easily resolved by rotating the intermediate case part 4 stacked on top by 90 degrees on a horizontal plane. Therefore, with this filter case 1, it is sufficiently guaranteed that the stacking work of the intermediate case parts 4, etc., can be performed without error and in a short time, even by an inexperienced worker. It is preferable that the liquid filter 100 housed inside this filter case 1 is one that can be contracted in the height direction, or that intermediate case parts 100 of the same height as the intermediate case part 4 are connected vertically.By using a liquid filter 100 with this structure, it can be housed in the filter case 1 in a predetermined number of intermediate case parts 4 that are appropriately selected.

[0054] In the above embodiment, the filter case 1 is formed in an overall shape that is roughly rectangular, and in a plan view it is formed in a roughly square shape. Therefore, in a plan view the shapes of the bottom case part 2, the top case part 3, and each intermediate case part 4 are formed in a roughly square shape. However, in the present invention, the overall shape of the filter case is formed in a cylindrical shape, and needless to say, the shapes of the bottom case part, the top case part, and each intermediate case part in a plan view are also formed in a cylindrical shape. Accordingly, the bottom plate and top plate are also formed in a circular shape, and one or more cylindrical liquid filters may be housed inside. Furthermore, in the filter case 1 according to the above embodiment, the lowest case part 2, the uppermost case part 3, and the intermediate case part 4 have notches 22b, 23b on the lowest side, 42b, 43b on the lower intermediate side, or 42c, 32c on the upper intermediate side, and these notches (reference numerals omitted) jointly close off to form the drainage opening 1a. However, the drainage opening constituting the present invention may also be formed by having drainage openings (not shown) that are closed off in the lowest case part 2, the uppermost case part 3, and the intermediate case part 4 themselves.

[0055] Furthermore, although the filter case 1 according to the above embodiment uses the four intermediate case parts 4 as its components, it may also use three intermediate case parts 4 or six intermediate case parts 4. Moreover, if the lowermost case part 2 and uppermost case part 3, which are components of the filter case 1, are each used, for example, seven or eight of the intermediate case parts 4, and eight of the long bolts 7 and nuts 8 are used as one set, then the filter case assembly set may consist of seven or eight liquid filters 100, each of which is stacked vertically, with multiple sets of eight long bolts 7 of different lengths depending on the number of intermediate case parts 4 selected. Such a filter case assembly set may be stored in packaging material not shown, or it may be kept at the assembly site.

[0056] With this filter case assembly set, as with the filter case 1 according to the embodiment described above, it is possible to remove intermediate case parts 4 that make up the assembled filter case 1 to change its length, or to add intermediate case parts 4 again to a filter case 1 that has been changed to a shorter length. Furthermore, within the range of the number of intermediate case parts 4 included in the filter case assembly set, it is possible to select any number of intermediate case parts 4 and stack them, so that the filter case 1 can be completed to better suit the attributes of the machine tool and the attributes of the user.

[0057] Furthermore, in the filter case 1 according to the above embodiment, eight long bolts 7 and eight nuts 8 were used as a means to maintain the stacked state. However, as this means to maintain the stacked state, the entire filter case 1, in which the bottom case part 2, multiple (four) intermediate case parts 4, and the top case part 3 are stacked, may also be secured by multiple endlessly stretchable belts (not shown), which are then used to maintain the stacked state. By using multiple such stretchable belts as the means to maintain the stacked state instead of the eight long bolts 7 and eight nuts 8, even if one or two of the intermediate case parts 4 are removed, the stretching action of the stretchable belts can absorb any change in the height of the filter case 1. The filter case assembly set may also include multiple such stretchable belts. Moreover, the means to maintain the stacked state may also consist of, for example, one and the other retaining fittings 71, 72, a bolt 73, and a nut 74, as shown in Figure 12. As shown in Figure 13, the bolt 73 comprises a shaft portion 73a with threads (indicated by the symbol omitted) on its outer circumference and a head portion 73b formed at the lower end of the shaft portion 73a. The retaining brackets 71 and 72 are both molded to the same shape. The retaining bracket 71 consists of a pressure contact plate portion 71a whose lower surface is pressed against the upper surface of the upper plate 6, a hanging plate portion 71b that hangs down from the base end of the pressure contact plate portion 71a, and a horizontal plate portion 71c that protrudes from the lower end of the hanging plate portion 71b in a direction away from the filter case 1, and the overall side shape is molded to be crank-shaped. An insertion hole 71d is drilled in the center of the horizontal plate portion 71c through which the shaft portion 73a of the bolt 73 is inserted. Furthermore, the other retaining bracket 72 consists of a pressure contact plate portion 72a whose upper surface is pressed against the lower surface of the lower plate 5, an upright plate portion 72b that rises from the base end of the pressure contact plate portion 72a, and a horizontal plate portion 72c that protrudes from the upper end of the upright plate portion 72b in a direction away from the filter case 1, and the overall side shape is formed in a crank shape. An insertion hole 72d is drilled in the center of the horizontal plate portion 72c through which the shaft portion 73a of the bolt 73 is inserted.Therefore, by placing the pressure contact plate portion 71a of one of the retaining brackets 71 on the upper plate 6, and positioning the pressure contact plate portion 72a of the other retaining bracket 72 below the lower surface of the lower plate 5, inserting the shaft portion 73a of the bolt 73 through the insertion hole 72d into the insertion hole 71d, and screwing the nut 74 onto the shaft portion 73a from above the horizontal plate portion 71c with a washer 75 in between, the horizontal plate portions 71c and 72c are brought close to each other, the lower surface of the pressure contact plate portion 71a is pressed against the upper plate 6, and the upper surface of the pressure contact plate portion 72a is pressed against the lower surface of the lower plate 5, and as a result, the one retaining bracket 71 and the other retaining bracket 72 can work together to firmly hold the stacked state of the entire filter case 1. Furthermore, by using these retaining brackets 71, 72, etc., on both sides, as shown in Figure 12, for example, a total of four of the above-mentioned stacking means, the stacked state of the entire filter case 1 can be firmly and securely maintained, not only when one or more of the intermediate case parts 4 described earlier are removed, but also when one or more intermediate case parts 4 are added and stacked. Note that the retaining brackets 71, 72, bolts 73 and nuts 74 may be included in the filter case assembly set. [Explanation of Symbols]

[0058] 1 filter case 1a Drain opening 2. Case parts for the bottom section 3. Case parts for the top section 4. Intermediate case parts 11. Protruding ridge (one of the positioning parts) 12. Recessed groove (positioning part for the other side) 13. Protruding ridge (one of the positioning parts) 14. Recessed groove (positioning part for the other side) 16. End-shaped protrusions (one positioning part) 17 Endless groove (positioning part for the other side) 22b, 23b Bottom notch 32b, 33b Bottom notch 42b Lower middle notch 42c Upper middle side notch

Claims

1. A filter case having a filter housing space formed inside in which a liquid filter is housed, which is expandable in the height direction or which consists of multiple small filters stacked in a row, filtering liquid that flows into the interior and discharging it to the outside, The system comprises a bottom-level case part positioned at the bottom, an uppermost case part positioned at the top, a plurality of intermediate case parts stacked between the bottom-level and uppermost case parts, and a top plate positioned on the uppermost case part with a liquid inlet hole formed therein into which the liquid flows. The filter case is characterized in that each of the above intermediate case parts is molded to the same shape, and the above multiple intermediate case parts are formed with drainage openings or drainage notches through which the liquid filtered by the liquid filter is discharged to the outside.

2. The filter case according to claim 1, characterized in that the uppermost case part and the lowermost case part are both molded to the same shape.

3. The intermediate case part is provided with a drainage opening through which the liquid filtered by the liquid filter is discharged to the outside, or, The filter case according to either claim 1 or 2, characterized in that each of the intermediate case part, the bottom case part, and the top case part is provided with a drainage notch that forms a drainage opening for draining the liquid filtered by the liquid filter to the outside when the intermediate case part is stacked on top of the bottom case part, when the intermediate case parts are stacked on top of each other, and when the top case part is stacked on top of the intermediate case part.

4. The filter case according to either claim 1 or 2, characterized in that the upper surface of the bottommost case part, the lower and upper surfaces of the intermediate case part, and the lower surface of the topmost case part are each relatively formed with one positioning part that holds the stacked state and the other positioning part that engages with the first positioning part.

5. The filter case according to claim 4, characterized in that the one positioning portion and the other positioning portion are convex or concave ridges or grooves that are U-shaped or endless in plan view, and the one positioning portion which is the convex or concave ridge and the other positioning portion which is the concave ridge or convex ridge are engaged with each other.

6. On the upper surface of the bottommost case part, both the one positioning part on the bottommost side, which serves as one of the positioning parts, and the other positioning part on the bottommost side, which serves as the other positioning part, are formed. On the lower surface of the uppermost case part, both the uppermost positioning portion, which serves as one of the positioning portions, and the other uppermost positioning portion, which serves as the other positioning portion, are formed. On the lower surface of the intermediate case part, the other positioning part on the intermediate side that engages with the other positioning part on the lowest stage side is formed as the other positioning part, and the other positioning part on the intermediate side that engages with the other positioning part on the lowest stage side is formed as the one positioning part. The filter case according to claim 4, characterized in that the upper surface of the intermediate case part has a positioning portion on the intermediate side that engages with one of the positioning portions on the uppermost side, and a positioning portion on the intermediate side that engages with the other positioning portion on the uppermost side, and a positioning portion on the intermediate side that engages with the other positioning portion on the uppermost side, is formed as one of the positioning portions.

7. Multiple of the aforementioned positioning portions are formed on the upper surface of the lowest case part and on the upper surface of each of the intermediate case parts, The other positioning portion is formed in multiple locations on the lower surface of each of the intermediate case parts and on the lower surface of the uppermost case part. The filter case according to claim 4, characterized in that, even after the intermediate case part is rotated by a predetermined angle on a horizontal plane from a state in which the other positioning portion and the other positioning portion formed on each of the intermediate case parts are engaged with the one positioning portion formed on the bottom case part and the other positioning portion formed on the top case part, the other positioning portion and the one positioning portion formed on the intermediate case part are formed in a position that engages with the one positioning portion formed on the bottom case part and the other positioning portion formed on the top case part, respectively.

8. Multiple of the aforementioned positioning portions are formed on the upper surface of the lowest case part and on the upper surface of each of the intermediate case parts, The other positioning portion is formed in multiple locations on the lower surface of each of the intermediate case parts and on the lower surface of the uppermost case part. The filter case according to claim 4, characterized in that the other positioning portion and the one positioning portion formed on each of the above intermediate case parts are formed in a position that engages with the one positioning portion formed on the bottom case part and the other positioning portion formed on the top case part, respectively, even after the intermediate case part is rotated 180 degrees on a horizontal plane from a state in which it engages with the one positioning portion formed on the bottom case part and the other positioning portion formed on the top case part, respectively, and after the intermediate case part is inverted upside down.

9. A filter case assembly kit used when assembling a filter case having a filter housing space formed inside in which a liquid filter is housed, The bottommost case part is placed at the bottom, The top-level case part is positioned at the very top, Multiple intermediate case parts, of any number, which are stacked between the bottom case part and the top case part, An upper plate is placed on the topmost case part mentioned above and has a liquid inlet hole formed therein into which the liquid flows, It includes, The above intermediate case part is provided with a drainage opening through which the liquid filtered by the liquid filter is discharged to the outside, or, A filter case assembly set characterized in that each of the intermediate case part, the bottom case part, and the top case part is formed with a drainage notch that forms a drainage opening for draining the liquid filtered by the liquid filter to the outside when the intermediate case part is stacked on top of the bottom case part, when the intermediate case parts are stacked on top of each other, and when the top case part is stacked on top of the intermediate case part.

Images