Method for manufacturing a fluid filter device

Abstract

To manufacture a fluid filter device which enables even a filter which is finely netted and inelastic to be arranged as designed to secure high filtration performance and high welding strength between case half bodies and is excellent in airtightness, easily and inexpensively.SOLUTION: A filter sheet material F is stretched on a first welding flange 13 of a first case half body 10, and the filter sheet material F is temporarily fixed to a first inner welding surface 14a. A portion, which corresponds to an area between the first inner welding surface 14a and a first outer welding surface 15a, of the filter sheet material F is cut to obtain a filter sheet temporarily fixed to the first inner welding surface 14a and remove the rest of the filter sheet material F. The first welding flange 13 of the first case half body 10 and a second welding flange of a second case half body are overlapped to be welded.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a fluid filter device for filtering various fluids. [Background technology]

[0002] A known fluid filter device for filtering various fluids, as disclosed in Patent Document 1 for example, comprises a first case half made of resin and having an inlet through which the fluid flows in, a second case half made of resin and having an outlet through which the fluid flows out, and a sheet-like filter sandwiched between the two case halves.

[0003] When manufacturing this fluid filter device, first, a filter cut to a predetermined shape and both case halves are prepared. Then, the peripheral portion of the filter is sandwiched between the joint surfaces of the two case halves, and then a laser beam is irradiated from the outside of the case near both joint surfaces to melt the resin. When the molten resin solidifies, the two case halves are integrated with the filter sandwiched therebetween, and the fluid filter device is obtained. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-14733 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, for example, when the mesh of a filter is made finer to ensure the necessary filtering performance, the filter becomes soft and becomes a so-called stiff filter. A stiff filter easily deforms under its own weight without the application of an external force, and it is difficult to maintain a predetermined shape. When attempting to set such a stiff filter on the joining surface of the two case halves of Patent Document 1, the filter itself may deform, causing the peripheral portion of the filter to shift from the joining surface, or the filter may easily become wrinkled. If the peripheral portion of the filter shifts from the joining surface, some fluid may flow downstream without passing through the filter, resulting in a decrease in filtering performance. Similarly, the occurrence of wrinkles in the filter may also result in a decrease in filtering performance.

[0006] Furthermore, in Patent Document 1, if a filter were to be interposed between the joining surfaces of the two case halves, the filter would get in the way during welding, and the presence of the filter could reduce the welding strength of the two case halves or reduce the airtightness of the case.

[0007] The present disclosure has been made in consideration of these points, and its object is to enable a fluid filter device to be inexpensively and easily manufactured, which ensures high filtering performance even when the filter has fine mesh and little stiffness by arranging the filter as desired, while also ensuring high welding strength between the case halves, and which has excellent airtightness. [Means for solving the problem]

[0008] In order to achieve the above object, a first configuration of the present disclosure is premised on a method for manufacturing a fluid filter device in which a filter sheet is sandwiched between a first case half and a second case half constituting a cylindrical case of the fluid filter device and both case halves are welded together. The method for manufacturing a fluid filter device includes a preparation step of preparing the first case half provided with a first welding flange having a first inner welding surface located on the inside of the cylindrical case and a first outer welding surface located on the outside of the cylindrical case relative to the first inner welding surface, and the second case half provided with a second welding flange having a second inner welding surface located on the inside of the cylindrical case and a second outer welding surface located on the outside of the cylindrical case relative to the second inner welding surface; a filter sheet material is stretched over the first welding flange of the first case half, and the filter sheet is welded to the first inner welding surface. the first case half and the second case half having a welding flange, and a welding process for welding the first outer welding surface and the second outer welding surface together.

[0009] According to this configuration, a filter sheet material larger than the filter sheet provided in the fluid filter device is prepared in advance, and this filter sheet material can be temporarily fixed to the first inner welding surface of the first case half. As a result, when a filter sheet of a predetermined shape is obtained in a later process by cutting the portion of the filter sheet material corresponding to the portion between the first inner welding surface and the first outer welding surface, the deformation of the filter sheet is suppressed, and the displacement of the filter sheet from the first inner welding surface is suppressed. Then, by overlapping the first welding flange and the second welding flange and welding the first outer welding surface and the second outer welding surface, and the first inner welding surface and the second inner welding surface, respectively, the filter sheet is held in a predetermined position by the first inner welding surface and the second inner welding surface, so that high filtering performance is obtained. In addition, since the filter sheet is not interposed between the first outer welding surface and the second outer welding surface, the welding strength between the first outer welding surface and the second outer welding surface is increased, and high airtightness is obtained.

[0010] In the temporary fixing step according to the second aspect of the present disclosure, the filter sheet material can be temporarily fixed by laser welding to the first inner welding surface.

[0011] That is, since the laser beam used in laser welding can be changed in output, scanning speed, focal size, etc., the conditions for temporarily fixing the filter sheet material can be set in detail. Therefore, for example, optimal temporary fixing conditions can be selected according to the type of filter sheet material, and the filter sheet can be easily and reliably temporarily fixed.

[0012] In the preparation step relating to the third aspect of the present disclosure, the first case half having a step-down portion between the first inner welded surface and the first outer welded surface of the first welded flange is prepared, and in the removal step, the filter sheet material can be cut along the step-down portion.

[0013] According to this configuration, the filter sheet material can be easily cut by simply cutting it along the step-down portion. Also, since the filter sheet material is separated from the first welding flange at the step-down portion, the filter sheet material after cutting by, for example, laser light is less likely to melt and stick to the first welding flange, and the cut filter sheet material can be easily removed.

[0014] In a preparation process relating to the fourth aspect of the present disclosure, the first case half is prepared in which the step-down portion is formed by a groove between the first inner welding surface and the first outer welding surface of the first welding flange, and the first inner welding surface and the first outer welding surface are at the same height.

[0015] According to this configuration, in the welding step, the first outer weld surface and the second outer weld surface, and the first inner weld surface and the second inner weld surface can be efficiently welded under the same conditions. Effect of the Invention

[0016] As described above, the filter sheet material is temporarily attached to the first inner welding surface of the first case half, and then cut to remove unnecessary portions before welding both case halves together.This means that even a filter with a fine mesh and little stiffness can be arranged as desired in both case halves, ensuring high filtering performance, and a fluid filter device with excellent airtightness and high welding strength between the case halves can be manufactured cheaply and easily. [Brief description of the drawings]

[0017] [Figure 1] 1 is a perspective view of a fluid filter device manufactured by a manufacturing method according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a longitudinal sectional view of the fluid filter device. [Diagram 3] 3 is a cross-sectional view corresponding to the portion A in FIG. 2, illustrating a temporary fixing step. FIG. [Figure 4] FIG. 4 is a view equivalent to FIG. 3 and explaining how to cut the filter sheet material. [Diagram 5] FIG. 4 is a view corresponding to FIG. 3 and explaining the removal step. [Figure 6A] FIG. 4 is a view equivalent to FIG. 3 for explaining the state in which the welded flanges are joined together. [Figure 6B] FIG. 4 is a view equivalent to FIG. 3 and explaining the welding process. [Figure 7] FIG. 5 is a view corresponding to FIG. 3 and relating to a modified example of the temporary fixing step. [Figure 8] 11A and 11B are cross-sectional views showing a modified example of the welding step. [Figure 9A] FIG. 5 is a view corresponding to FIG. 4 and relating to a modified example of the welded flange. [Figure 9B] FIG. 6B is a view corresponding to FIG. 6A and relating to a modified example of the welded flange. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0019] Fig. 1 shows a fluid filter device 1 manufactured by a manufacturing method for a fluid filter device according to an embodiment of the present invention, and Fig. 2 is a vertical cross-sectional view of the fluid filter device 1. The fluid filter device 1 is used, for example, when filtering power steering oil circulating inside a power steering device of an automobile or oil inside a transmission, but it can also be used when filtering various other fluids such as oil, water, and gas, and its use is not particularly limited.

[0020] The fluid filter device 1 includes a cylindrical case 2 and a filter sheet 3 (shown in FIG. 2). In this embodiment, the cylindrical case 2 is cylindrical, but is not limited thereto, and may be a square tube, or may be a tube having a complex cross-sectional shape. In this embodiment, the axis of the cylindrical case 2 extends in the vertical direction, but this is described only for convenience of explanation, and does not limit the posture during use or manufacturing. The axis of the cylindrical case 2 may be horizontal, for example, or may be inclined. In addition, the axis of the cylindrical case 2 does not need to be linear, and may be a curved cylindrical case, although not shown.

[0021] The cylindrical case 2 is composed of a first case half 10 and a second case half 20. When the axis of the cylindrical case 2 extends in the vertical direction, the first case half 10 is a member constituting the lower part of the cylindrical case 2, and the second case half 20 is a member constituting the upper part of the cylindrical case 2, but this is not limited thereto, and although not shown, the first case half may be a member constituting the upper part of the cylindrical case 2, and the second case half may be a member constituting the lower part of the cylindrical case 2. When the axis of the cylindrical case 2 extends in the horizontal direction, the first case half 10 is a member constituting a part on one side of the horizontal direction of the cylindrical case 2, and the second case half 20 is a member constituting a part on the other side of the horizontal direction of the cylindrical case 2. In other words, the divided structure of the cylindrical case 2 may be any structure.

[0022] The first case half 10 and the second case half 20 are formed by injection molding of nylon resin such as PA6, PA66, etc., but the resin material constituting the first case half 10 and the second case half 20 is not limited to nylon resin and may be any material that can be thermally welded. Furthermore, the molding method of the first case half 10 and the second case half 20 is not limited to injection molding and may be formed by another molding method.

[0023] The first case half 10 comprises a lower wall portion 11, a lower peripheral wall portion 12 extending upward from the peripheral edge of the lower wall portion 11, and a lower weld flange (first weld flange) 13 provided at the upper end of the lower peripheral wall portion 12. The lower wall portion 11, the lower peripheral wall portion 12, and the lower weld flange 13 are integrally molded. The lower wall portion 11 is provided with a lower pipe portion 11a that protrudes downward. The internal space of the lower pipe portion 11a communicates with the lower part of the internal space of the cylindrical case 2. The lower end of the lower pipe portion 11a opens downward, and this opening is an inlet 11b for allowing fluid to flow into the internal space of the cylindrical case 2.

[0024] The lower peripheral wall portion 12 is provided continuously in the circumferential direction of the cylindrical case 2. The lower welding flange 13 extends from the upper end of the lower peripheral wall portion 12 toward the radially outward direction of the cylindrical case 2 and also extends continuously in the circumferential direction. The extending direction of the lower welding flange 13 is horizontal, but may be inclined. On the upper surface of the lower welding flange 13, a first inner ridge portion 14 located on the inside of the cylindrical case 2 and a first outer ridge portion 15 located on the outside of the cylindrical case 2 are provided. The first inner ridge portion 14 and the first outer ridge portion 15 each extend continuously in the circumferential direction. In addition, the first inner ridge portion 14 and the first outer ridge portion 15 are provided with a radial gap therebetween, and a first groove 16 that opens upward is provided between the first inner ridge portion 14 and the first outer ridge portion 15. This first groove 16 forms a ring shape that is continuous in the circumferential direction and constitutes a step-down portion of the present invention.

[0025] As shown in Fig. 3, the upper surface of the first inner protrusion 14 is a first inner welding surface 14a located on the inner side of the cylindrical case 2. The upper surface of the first outer protrusion 15 is a first outer welding surface 15a located on the outer side of the cylindrical case 2 relative to the first inner welding surface 14a. The first inner welding surface 14a and the first outer welding surface 15a also form a ring shape that is continuous in the circumferential direction. The first inner welding surface 14a and the first outer welding surface 15a are provided at the same height, and when a virtual plane passing through the first inner welding surface 14a is assumed, for example, the first outer welding surface 15a is positioned on the virtual plane.

[0026] The first inner welding surface 14a is a surface to which the filter sheet 3 is temporarily fixed and a surface to which the filter sheet 3 is welded after being temporarily fixed, and is also a surface to be welded to a second inner welding surface 24a described later. On the other hand, the first outer welding surface 15a is a surface to which the filter sheet 3 is not welded and is a surface to be welded to a second outer welding surface 25a described later.

[0027] The width of the first outer welded surface 15a and the width of the first inner welded surface 14a are set to be the same. Note that the width of the first outer welded surface 15a may be set to be wider than the width of the first inner welded surface 14a, or the width of the first inner welded surface 14a may be set to be wider than the width of the first outer welded surface 15a.

[0028] As shown in FIG. 2 etc., the second case half 20 includes an upper wall portion 21, an upper peripheral wall portion 22 extending downward from the peripheral edge of the upper wall portion 21, and an upper welding flange (second welding flange) 23 provided at the lower end of the upper peripheral wall portion 22. The upper wall portion 21, the upper peripheral wall portion 22, and the upper welding flange 23 are integrally molded. The upper wall portion 21 is provided with an upper pipe portion 21a that protrudes upward. The internal space of the upper pipe portion 21a communicates with the upper part of the internal space of the cylindrical case 2. The upper end portion of the upper pipe portion 21a opens upward, and this opening is an outlet port 21b for allowing the fluid in the internal space of the cylindrical case 2 to flow out to the outside.

[0029] The upper peripheral wall portion 22 is provided continuously in the circumferential direction of the cylindrical case 2. The diameter of the lower end of the upper peripheral wall portion 22 and the diameter of the upper end of the lower peripheral wall portion 12 are set to be the same. The upper welding flange 23 is a portion that is overlapped from above with the lower welding flange 13, and the upper welding flange 23 and the lower welding flange 13 have the same diameter. The upper welding flange 23 extends from the lower end of the upper peripheral wall portion 22 toward the radially outward direction of the cylindrical case 2 and extends continuously in the circumferential direction. The extension direction of the upper welding flange 23 may be the same as that of the lower welding flange 13, and does not have to extend horizontally. The lower surface of the upper welding flange 23 is provided with a second inner ridge portion 24 located on the inside of the cylindrical case 2 and a second outer ridge portion 25 located on the outside of the cylindrical case 2. The second inner ridge portion 24 and the second outer ridge portion 25 each extend continuously in the circumferential direction. The second inner ridge portion 24 and the second outer ridge portion 25 are provided with a radial gap between them, and a second groove 26 that opens downward is provided between the second inner ridge portion 24 and the second outer ridge portion 25. The second groove 26 has a ring shape that continues in the circumferential direction. The second groove 26, together with the first groove 16, serves as a burr storage portion that stores burrs generated during welding, which will be described later.

[0030] As shown in FIG. 6A, the lower surface of the second inner protrusion 24 is a second inner welding surface 24a located on the inner side of the cylindrical case 2. The lower surface of the second outer protrusion 25 is a second outer welding surface 25a located on the outer side of the cylindrical case 2 with respect to the second inner welding surface 24a. The second inner welding surface 24a and the second outer welding surface 25a also form a continuous ring shape in the circumferential direction. The second inner welding surface 24a and the second outer welding surface 25a are provided at the same height as the first inner welding surface 14a and the first outer welding surface 15a. The second outer welding surface 25a is provided with a welding rib 25b protruding downward in a continuous ring shape in the circumferential direction.

[0031] The second inner welding surface 24a is a surface to which the temporarily fixed filter sheet 3 is welded, and is also a surface to be welded to the first inner welding surface 14a. On the other hand, the second outer welding surface 25a is a surface to which the filter sheet 3 is not welded, and is a surface to be welded to the first outer welding surface 15a. The widths of the second outer welding surface 25a and the second inner welding surface 24a are set similarly to the first outer welding surface 15a and the first inner welding surface 14a.

[0032] In addition, since Figure 2 shows the state after the lower weld flange 13 and the upper weld flange 23 have been welded together, the portions that constituted the first inner weld surface 14a, the first outer weld surface 15a, the second inner weld surface 24a, and the second outer weld surface 25a have melted.

[0033] The filter sheet 3 is not particularly limited, but is composed of a metal net, a resin net, a nonwoven fabric, etc., with a mesh size of 200 mesh or more. Such a mesh with a fine mesh is flexible and easily deformed by its own weight. The outer shape of the filter sheet 3 is set so that its outer peripheral edge is located slightly outside the outer peripheral edge of the first inner welding surface 14a and inside the inner peripheral edge of the first outer welding surface 15a. In other words, the outer peripheral edge of the filter sheet 3 is located within the first groove 16. As a result, the outer peripheral edge of the filter sheet 3 does not reach the first outer welding surface 15a, and is not welded to the first outer welding surface 15a.

[0034] The filter sheet 3 is sandwiched in the vertical direction (thickness direction) between the lower welded flange 13 and the upper welded flange 23. Moreover, the filter sheet 3 is not cut in advance, but is set in the first case half 10 and temporarily fixed, as described below, and then cut into the above-mentioned predetermined shape.

[0035] (Method of manufacturing a fluid filter device) Next, a manufacturing method of the fluid filter device 1 configured as described above will be described. First, as shown in Fig. 3, the first case half 10 and the second case half 20 (shown in Fig. 6A) are prepared, and a filter sheet material F is also prepared. The filter sheet material F is the material of the filter sheet 3 shown in Fig. 2, and is a roll of material that is sufficiently larger than the filter sheet 3. In addition, a setting jig 100 for holding the first case half 10, a clamp 200 for holding the filter sheet material F, a pressing jig 300 for pressing the filter sheet material F, and a laser welding device 400 are prepared. This completes the preparation process.

[0036] The setting jig 100 has a recess 100a formed therein that opens upward and into which the lower weld flange 13 of the first case half 10 fits. The first case half 10 can be positioned at a predetermined position by fitting the lower weld flange 13 of the first case half 10 into this recess 100a from above.

[0037] The clamp 200 comprises a lower clamping material 201 and an upper clamping material 202, which can be brought into contact with and separated from each other in the vertical direction. The lower clamping material 201 and the upper clamping material 202 are separated from each other in the vertical direction, and then the filter sheet material F is inserted between the lower clamping material 201 and the upper clamping material 202. Thereafter, the lower clamping material 201 and the upper clamping material 202 are brought into close proximity with each other, whereby the filter sheet material F can be clamped and held by the clamp 200.

[0038] The pressing jig 300 is configured to be movable in the vertical direction by a drive mechanism (not shown), and can be switched between a position where it presses the first outer protrusion 15 of the first case half 10 from above, and a position above and away from the first outer protrusion 15. The shape of the lower end of the pressing jig 300 is set so as not to cover the first inner protrusion 14.

[0039] The laser welding apparatus 400 has a laser transmitter 401, a control unit 402 that controls the laser transmitter 401, and a laser nozzle 403 for irradiating a target position with the laser light L output from the laser transmitter 401. The control unit 402 is capable of controlling the output of the laser light L, the size of the focus, and the like. For example, when a user inputs the output of the laser light L and the size of the focus individually, the control unit 402 receives the input values. The control unit 402 controls the laser transmitter 401 so that the output and size of the focus of the laser light L are the ones input by the user, thereby allowing the desired laser light L to be output from the laser nozzle 403.

[0040] In addition, the laser nozzle 403 can be moved so as to trace a predetermined trajectory by a driving device (not shown) such as a robot. The trajectory and the moving speed (scanning speed of the laser light L) at this time can be arbitrarily set by the user.

[0041] During the preparation process, the pressing jig 300 is moved upward. After that, the first case half 10 is held by the setting jig 100. Also, the filter sheet material F held by the clamp 200 is placed on the first case half 10. Thereafter, the pressing jig 300 is moved downward to a position where the first outer protrusion 15 of the first case half 10 is pressed from above. Since the filter sheet material F is placed on the first outer protrusion 15, the filter sheet material F is pressed against the first outer welding surface 15a of the first outer protrusion 15. This allows the filter sheet material F to be stretched over the lower welding flange 13 of the first case half 10. Also, the first case half 10 can be positioned and stabilized at a predetermined position.

[0042] After the filter sheet material F is stretched, the laser welding device 400 is operated to output a laser beam L from the laser nozzle 403 toward the first inner welding surface 14a of the first inner protrusion 14. Since the filter sheet material F is disposed on the first inner welding surface 14a, the filter sheet material F absorbs the laser beam L and generates heat. The first inner welding surface 14a also generates heat in the same manner. The amount of heat generated per unit time at this time can be adjusted by the output of the laser beam L, the size of the focal point, and the scanning speed, and is set to a heat amount that can melt the first inner welding surface 14a and weld the filter sheet material F to the first inner welding surface 14a to temporarily fix it. When the resin solidifies, the filter sheet material F is temporarily fixed to the first inner protrusion 14. This is the temporary fixing process by laser welding.

[0043] The output, focal size, and scanning speed of the laser light L in the temporary fixing process are conditions for temporary fixing. As an example of the conditions for temporary fixing, a 50W type MD-F5200 manufactured by Keyence Corporation is used as the laser device, and for example, the output of the laser light L is 40W, the focal size is set to 0mm with spot variable, the scanning speed is 0.2m / sec, the number of times the laser light is scanned is 1 time / rotation, etc. When the filter sheet material F is a resin or nonwoven fabric, the above conditions for temporary fixing are set so that the filter sheet material F does not burn out.

[0044] In the temporary fixing process, the laser light L may be scanned in a circular manner along the first inner welding surface 14a to weld the filter sheet material F in a circular manner, or the laser light L may be moved along the first inner welding surface 14a and intermittently irradiated to weld the filter sheet material F in a spot-like manner.

[0045] After the filter sheet material F has been temporarily fixed, the pressing of the pressing jig 300 on the filter sheet material F is released, as shown in Fig. 4. Note that the pressing jig 300 is not shown in Fig. 4.

[0046] Next, the filter sheet material F is cut at a portion corresponding to the area between the first inner welding surface 14a and the first outer welding surface 15a. That is, first, the output, focal size, and scanning speed of the laser light L are set to values ​​that allow cutting of the filter sheet material F. The output, focal size, and scanning speed of the laser light L at this time are conditions for cutting, and an example of the conditions for cutting is, for example, the output of the laser light L is 40 W, the focal size is set to 0 mm with spot variable, the scanning speed is 0.12 to 0.17 m / sec, and the number of times the laser light is scanned is 1 time / circle. The conditions for cutting are set so that the energy density of the laser light L is higher than that in the temporary fixing process. The laser welding device 400 itself can be the same as that in the temporary fixing process.

[0047] Then, when the laser light L is moved along the first groove 16 so as to be irradiated into the first groove 16, the filter sheet material F is cut along the first groove 16. In this manner, the filter sheet material F only needs to be cut along the first groove 16, and therefore cutting can be easily performed. By cutting the filter sheet material F, the filter sheet 3 temporarily fixed to the first inner welding surface 14a can be obtained.

[0048] Also, the remaining filter sheet material F is removed. Specifically, as shown in FIG. 5, the remaining filter sheet material F can be removed by moving the clamp 200 upward relative to the setting jig 100 while holding the remaining filter sheet material F with the clamp 200, or by moving the setting jig 100 downward relative to the clamp 200. At this time, since the distance between the position on the filter sheet material F where the laser light L is irradiated and the inner peripheral edge of the first outer welding surface 15a is α, the heat generated in the filter sheet material F is not easily transmitted to the first outer welding surface 15a, and the filter sheet material F is not welded to the first outer welding surface 15a. In addition, since the filter sheet material F is separated from the lower welding flange 13 in the first groove 16, for example, the filter sheet material F after cutting by the laser light L is not easily melted to the lower welding flange 13, and the filter sheet material F after cutting can be easily removed. This is the removal process.

[0049] Then, the process proceeds to the welding process. In the welding process, the first case half 10 is transferred to an ultrasonic welding set jig 101. The ultrasonic welding set jig 101 is formed with a recess 101a into which the lower welding flange 13 of the first case half 10 fits, and the recess 101a is opened upward. As shown in FIG. 6A, the second case half 20 is brought from above the first case half 10, and the lower welding flange 13 of the first case half 10 and the upper welding flange 23 of the second case half 20 are overlapped. The first outer welding surface 15a and the welding rib 25b of the second outer welding surface 25a are pressed against each other to weld them together. In addition, the first inner welding surface 14a and the second inner welding surface 24a are welded together. For example, ultrasonic welding can be used as the welding method. In the ultrasonic welding method, an ultrasonic welding horn 500 is prepared. The ultrasonic welding horn 500 is pressed against the upper surface of the upper welding flange 23 of the second case half 20. By vibrating the ultrasonic welding horn 500 in this state, frictional heat is generated between the first outer welding surface 15a and the second outer welding surface 25a and between the first inner welding surface 14a and the second inner welding surface 24a, and the first outer welding surface 15a and the second outer welding surface 25a melt, and the first inner welding surface 14a and the second inner welding surface 24a melt. As the resin solidifies, the first outer welding surface 15a and the second outer welding surface 25a are hermetically welded over the entire circumference, and the first inner welding surface 14a and the second inner welding surface 24a are welded over the entire circumference. The molten resin of the first inner welding surface 14a and the second inner welding surface 24a penetrates into the filter sheet 3, so that after solidification, the filter sheet 3 is firmly held in the cylindrical case 2. Burrs W generated toward the inside of the cylindrical case 2 during welding are accommodated in the first groove 16 and the second groove 26.

[0050] (Modification of temporary fixing process) In the above-mentioned temporary fixing step, the filter sheet material F is temporarily fixed using the laser light L, but the present invention is not limited to this. For example, as shown in FIG. 7, the filter sheet material F may be temporarily fixed using a heat press. In this modification, a press mold 550 that can be heated to a temperature equal to or higher than the melting temperature of the resin is prepared. Then, in the temporary fixing step, the press mold 550 is pressed against the filter sheet material F to heat the first inner welding surface 14a. This allows the first inner welding surface 14a to melt and weld the filter sheet material F.

[0051] (Modification of the welding process) In the above welding process, the lower welding flange 13 and the upper welding flange 23 are welded using ultrasonic welding, but the method is not limited to this, and for example, as shown in FIG. 8, a hot plate welding method may be used. In this modification, a hot plate 560 capable of heating to a temperature equal to or higher than the melting temperature of the resin, and a first set jig 561 and a second set jig 562 for hot plate welding are prepared. The first set jig 561 is formed with a recess 561a that opens upward and into which the lower welding flange 13 of the first case half 10 fits. The second set jig 562 is formed with a recess 562a that opens downward and into which the upper welding flange 23 of the second case half 20 fits.

[0052] With the first case half 10 held by a first setting jig 561 and the second case half 20 held by a second setting jig 562, the lower welding flange 13 and the upper welding flange 23 are arranged at a predetermined interval in the vertical direction. In this state, a hot plate 560 is inserted between the lower welding flange 13 and the upper welding flange 23 to heat each part, and then the hot plate 560 is removed. Thereafter, the lower welding flange 13 and the upper welding flange 23 are overlapped, thereby welding the first outer welding surface 15a and the second outer welding surface 25a, and welding the first inner welding surface 14a and the second inner welding surface 24a.

[0053] (Effects of the embodiment) As described above, according to this embodiment, the filter sheet material F can be temporarily fixed to the first inner welded surface 14a using the laser light L while being stretched over the lower welded flange 13 of the first case half 10. As a result, when the filter sheet material F is cut at a portion corresponding to between the first inner welded surface 14a and the first outer welded surface 15a in the later removal process to obtain the filter sheet 3 of a predetermined shape, deformation of the filter sheet 3 is suppressed, and displacement of the filter sheet 3 from the first inner welded surface 14a is suppressed.

[0054] Then, by overlapping the lower welding flange 13 and the upper welding flange 23 and welding the first outer welding surface 15a and the second outer welding surface 25a, and the first inner welding surface 14a and the second inner welding surface 24a, respectively, the filter sheet 3 is held in a predetermined position by the first inner welding surface 14a and the second inner welding surface 24a, so that high filtering performance is obtained. Also, since the filter sheet 3 is not interposed between the first outer welding surface 15a and the second outer welding surface 25a, the welding strength between the first outer welding surface 15a and the second outer welding surface 25a is increased, and high airtightness is obtained between the first outer welding surface 15a and the second outer welding surface 25a.

[0055] The above-described embodiment is merely illustrative in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention.

[0056] 9A and 9B show modified examples of the welded flange. A first inner protrusion 140 located on the inside of the cylindrical case 2 is provided on the upper surface of the lower welded flange 130 of the first case half 10, and the upper surface of the first inner protrusion 140 is a first inner welded surface 140a located on the inside of the cylindrical case 2.

[0057] Furthermore, a stepped portion 160 is formed in a stepped shape on the upper surface of the lower welding flange 130 of the first case half 10, outside the first inner protrusion portion 140. Furthermore, a first outer welding surface 150a is formed on the upper surface of the lower welding flange 130 of the first case half 10, outside the stepped portion 160. Because the stepped portion 160 is formed, when the filter sheet material F is cut with laser light L, the cut filter sheet material F is less likely to melt and stick to the lower welding flange 130, and the cut filter sheet material F can be easily removed.

[0058] On the other hand, the lower surface of the upper welding flange 230 of the second case half 20 is provided with a second inner welding surface 240a located on the inside of the cylindrical case 2. This second inner welding surface 240a is welded to the first inner welding surface 140a. In addition, the lower surface of the upper welding flange 230 of the second case half 20 is provided with a second outer protrusion 250 on the outside of the second inner welding surface 240a. The lower surface of the second outer protrusion 250 is the second outer welding surface 250a located on the outside of the cylindrical case 2. The second outer welding surface 250a is provided with a welding rib 250b that is welded to the first outer welding surface 150a. In the case of this modified example, the above-mentioned temporary fixing process, removal process, and welding process can also be performed. [Industrial Applicability]

[0059] As described above, the manufacturing method of the fluid filter device according to the present invention can be used when manufacturing fluid filter devices that filter various fluids. [Explanation of symbols]

[0060] 1 Fluid filter device 2 Cylindrical case 3 Filter Sheet 10 First case half 13 Lower welding flange (first welding flange) 14a First inner welding surface 15a First outer welding surface 16 1st groove (stepped part) 20 Second case half 23 Upper welding flange (second welding flange) 24a 2nd inner welding surface 25a 2nd outer welding surface F Filter sheet material

Claims

1. A method for manufacturing a fluid filter device, comprising: sandwiching a filter sheet between a first case half and a second case half that constitute a cylindrical case of the fluid filter device; and welding the first and second case halves together, a preparation process for preparing the first case half including a first welding flange having a first inner welding surface located inside the cylindrical case and a first outer welding surface located outside the cylindrical case with respect to the first inner welding surface, and the second case half including a second welding flange having a second inner welding surface located inside the cylindrical case and a second outer welding surface located outside the cylindrical case with respect to the second inner welding surface; a temporary fixing step of stretching a filter sheet material over the first welding flange of the first case half and temporarily fixing the filter sheet material to the first inner welding surface; a removing step of cutting the filter sheet material at a portion corresponding to a portion between the first inner welding surface and the first outer welding surface to obtain the filter sheet temporarily attached to the first inner welding surface and removing the remaining filter sheet material; A manufacturing method for a fluid filter device, comprising a welding process of overlapping the first welding flange of the first case half and the second welding flange of the second case half, welding the first outer welding surface to the second outer welding surface, and welding the first inner welding surface to the second inner welding surface.

2. 2. The method for manufacturing a fluid filter device according to claim 1, In the temporary fixing step, the filter sheet material is temporarily fixed to the first inner welding surface by laser welding.

3. The method for producing the fluid filter device according to claim 1 or 2, In the preparation step, the first case half is prepared, the first case half having a stepped portion between the first inner welding surface and the first outer welding surface of the first welding flange, In the removing step, the filter sheet material is cut along the stepped portion.

4. 4. The method for producing a fluid filter device according to claim 3, In the preparation process, a groove between the first inner welding surface and the first outer welding surface of the first welding flange is formed as the step-down portion, and the first case half is prepared in which the first inner welding surface and the first outer welding surface are at the same height.

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