Fluid filter
The fluid filter design addresses peeling issues by using defined strong and weak connections between the resin mesh and case, ensuring stable retention and prolonged filtration performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TAIYO GIKEN INDS
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-05
AI Technical Summary
Existing fluid filters face issues with the resin mesh portion peeling due to uneven stress distribution and bonding, leading to potential detachment over time, especially when made entirely of resin and integrally molded.
A fluid filter design with a resin mesh portion and case, featuring a ring-shaped opening holding portion with inward ribs and a closing retaining portion, ensuring strong connections at defined points while allowing weak connections elsewhere to manage stress concentration.
The design stabilizes the resin mesh portion's retention by concentrating stress at predefined strong connections, preventing peeling and maintaining filtration efficiency over time.
Smart Images
Figure 2026092475000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a fluid filter, and is useful, for example, as a filter for removing foreign substances from fuel supplied to an internal combustion engine.
Background Art
[0002] Patent Document 1 describes a fluid filter in which a metal mesh part is insert-molded into a resin case. Protrusions for holding the mesh part are formed in the mold so that the metal mesh part does not shift during insert molding. Therefore, most of the metal mesh part is embedded in the resin case, but at the position corresponding to the protrusion of the mold, the protrusion abuts against the mesh part. As a result, at the portion where the protrusion abuts, the resin case and the metal mesh part are not in contact with each other.
[0003] Further, Patent Document 2 describes a fluid filter in which both the mesh part and the case are made of nylon and the mesh part and the case are integrally formed.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0005] Compared with Patent Document 1, in the present disclosure, the mesh part is made of resin instead of metal. Further, compared with Patent Document 2, in the present disclosure, the mesh part and the case are not integrally molded. The present disclosure inserts a resin case into a pre-molded resin mesh part to join the mesh part and the case.
[0006] When adopting a configuration like that of this disclosure, it is conceivable that the opening-holding portion of the case and one end of the mesh portion, which is the opening, be bonded together so that the entire circumference of the opening-holding portion of the case is bonded to the entire circumference of the one end of the mesh portion. This is because it is thought that bonding around the entire circumference will ensure that the one end (opening) of the mesh portion is held securely. In the integrally molded filter of Patent Document 2, since it is integrally molded, the entire circumference of the one end (opening) of the mesh portion and the opening-holding portion of the case are integrated.
[0007] However, the inventors' investigations revealed that bonding the entire circumference of one end (opening) of the mesh portion to the entire circumference of the opening-holding portion of the case may actually result in insufficient retention of the mesh portion. This is because bonding the resin case and the resin mesh portion all around may cause partial peeling. When bonded all around, it is impossible to identify the location where peeling will occur. As a result, peeling will occur at the weakest point of adhesion. Once peeling occurs, stress that causes peeling tends to concentrate in the mesh portion at that point, and there is a risk that the peeling of the mesh portion will spread over time.
[0008] This disclosure was devised in view of this point, and aims to enable the resin mesh portion to be stably held for a long period of time by a resin case. [Means for solving the problem]
[0009] To solve this problem, the present disclosure adopts the following configuration. First, the fluid filter (100) of the present disclosure is assumed to have a mesh portion (150) for removing foreign matter from the fluid made of resin, and a case (140) that holds this mesh portion also made of resin. Furthermore, the present disclosure is assumed to have a cylindrical shape with one end (151) open and the side portion (153) closed. For this reason, the fluid filter of the present disclosure is also assumed to have a case that includes a ring-shaped opening holding portion (141) that holds the entire outer circumference of one end of the mesh portion, and a frame portion (143) that holds a part of the outer circumference of the side portion of the mesh portion.
[0010] In other words, in this disclosure, the opening-holding portion of the case and one end of the mesh portion are configured such that the entire circumference of the opening-holding portion faces the entire circumference of the one end. Furthermore, in this disclosure, multiple ribs (144) projecting in the inward direction are formed on the opening-holding portion of the case, spaced apart in the circumferential direction. This creates a strongly connected portion where only a portion of the circumferential direction of the one end is embedded within the ribs formed on a portion of the circumferential direction of the opening-holding portion, thus strongly connecting them to each other. As a result, the other parts of the opening-holding portion excluding the strongly connected portion in the circumferential direction and the other parts of the one end excluding the strongly connected portion in the circumferential direction constitute a weakly connected portion where the mesh portion is not embedded within the opening-holding portion.
[0011] According to this disclosure, stress between the mesh portion and the case will concentrate at a pre-defined strong connection point between one end of the mesh portion and the opening-holding portion of the case. However, since the area where stress will concentrate can be identified during the design phase, the connection point can be set in an area and position such that it will not peel off even if stress concentrates.
[0012] In addition to the foregoing disclosure, the mesh portion also has an opening at the other end (152), and the case further comprises a closing retaining portion (142) that holds the other end of the mesh portion. The closing retaining portion of the case has a disc-shaped bottom (1421) and a cylindrical rising portion (1422) that rises from the outer circumference of the bottom, and the rising portion of the closing retaining portion of the case and the other end of the mesh portion are configured such that the entire circumference of the rising portion faces the entire circumference of the other end, and the rising portion is connected to the other end. The cylindrical mesh portion is structured so that one end is held by the opening retaining portion and the other end is also held by the closing retaining portion. As a result, both ends of the mesh portion are held.
[0013] In yet another fluid filter of this disclosure, the rising portion of the closing retaining portion of the case has multiple closing ribs (147) that protrude in the inward circumferential direction and are spaced apart in the circumferential direction. A strong coupling portion is formed where only a portion of the other end of the mesh portion is embedded in the closing ribs formed in a part of the circumferential direction of the rising portion of the closing retaining portion, and the other portion of the rising portion of the closing retaining portion excluding the strong coupling portion in the circumferential direction and the other portion of the other end of the mesh portion excluding the strong coupling portion in the circumferential direction form a weak coupling portion where the mesh portion is not embedded in the rising portion of the closing retaining portion. Since the mesh portion also has a strong coupling portion at the other end, the retention of the mesh portion is strengthened.
[0014] In yet another case of this disclosure, the frame portion is continuous with the ribs formed in the opening-holding portion and the closing-end ribs formed in the rising portion of the closing-holding portion. By integrating the formation of the ribs and closing-end ribs with the frame portion, the strength of the frame portion and the ribs and closing-end ribs can be increased.
[0015] In other disclosures, multiple ribs are formed at equal intervals in the circumferential direction on the opening-holding portion of the case. Of the multiple ribs, the continuous ribs (145) that are continuous with the frame portion have a greater circumferential width than the discontinuous ribs (146) that are not continuous with the frame portion. Similarly, multiple closing portion ribs are formed at equal intervals in the circumferential direction on the rising portion of the closing-holding portion of the case. Of the multiple closing portion ribs, the continuous closing portion ribs (148) that are continuous with the frame portion have a greater circumferential width than the discontinuous closing portion ribs (149) that are not continuous with the frame portion. The mesh portion is securely held by the continuous ribs and the continuous closing portion ribs, and by using discontinuous ribs and discontinuous closing portion ribs, peeling of the mesh portion can be suppressed more effectively.
[0016] Further disclosures include the use of a fluid filter to remove foreign matter from fuel for an internal combustion engine. The resin constituting the mesh portion and the resin constituting the frame portion differ from each other in at least one of the following: the swelling rate due to the fuel and the rate of change between the dry state and the immersed state. The difference in rate of change can cause the mesh portion to peel off from the opening retaining portion of the case, but in this disclosure, the mesh portion is embedded in the rib to create a strong bond, so that the mesh portion does not peel off.
[0017] Further fluid filters of this disclosure include a passage member (110) that forms a passage chamber (111) for housing a case, an inlet passage (120) for allowing fluid to flow into the passage chamber, and an outlet passage (130) for allowing fluid to flow out of the passage chamber. The case and the inlet passage are integrally formed, and the passage member and the outlet passage are integrally formed. In this fluid filter, the fluid that flows into the passage chamber from the inlet passage passes through the mesh from the outer circumference of the side surface of the mesh and flows into the inner circumference of the mesh, and then flows from one end of the mesh to the outlet passage. By flowing the fluid through the inlet passage, passage chamber, mesh, and outlet passage, foreign matter can be removed from the fluid. [Brief explanation of the drawing]
[0018] [Figure 1] This figure shows the usage state of the fluid filter in this disclosure. [Figure 2] This is a cross-sectional view of an example of a fluid filter in this disclosure. [Figure 3] Figure 2 is a front view showing the case and mesh portion of the illustrated fluid filter. [Figure 4] This is a right side view of Figure 3. [Figure 5] Figure 3 is a perspective view showing the case and the opening retention part of the mesh section. [Figure 6] Figure 2 is a perspective view showing the mesh portion of the illustrated fluid filter. [Figure 7] Figure 2 is a perspective view showing the mold used for molding the fluid filter. [Figure 8]FIG. 7 is a perspective view showing a state in which a mesh portion covers the first core of the illustrated mold. [Figure 9] FIG. 7 is a perspective view showing an example of the illustrated mold being closed. [Figure 10] FIG. is a diagram for explaining the state of resin injection into the mold. [Figure 11] FIG. is a cross-sectional view showing the resin after molding and the opened mold. [Figure 12] FIG. is a diagram showing another usage state of the fluid filter of the present disclosure. [Figure 13] FIG. is a perspective view showing another example of the fluid filter of the present disclosure. [Figure 14] FIG. is a perspective view showing another example of the first core of the mold. [Figure 15] FIG. 14 is a cross-sectional view showing the case and the mesh portion of the fluid filter formed by the first core shown in the figure. [Figure 16] FIG. 15 is a perspective view of the fluid filter shown in the figure as viewed from the XVI-XVI line direction.
DETAILED DESCRIPTION OF THE INVENTION
[0019] An example of using the fluid filter 100 of the present disclosure in a marine internal combustion engine 10 is shown in FIG. 1. The atmospheric pressure fuel stored in the atmospheric pressure fuel tank 20 is pressurized to about 100 kPa by the low-pressure pump 30. At this time, the fluid filter 100 removes foreign substances from the fuel in the atmospheric pressure fuel tank. The fluid filter 100 includes a mesh portion 150 as described later. For the low-pressure pump 30, the size of the mesh portion 150 is about 100 mesh. Here, 100 mesh means a mesh having 100 meshes per inch (25.4 millimeters).
[0020] The fuel, pressurized by the low-pressure pump 30, is stored in the pressurized fuel tank 21. Then, it is pressurized to approximately 300-350 kilopascals by the high-pressure pump 31 and supplied to the injector 11 of the internal combustion engine 10. The fluid filter 100 is also used to remove foreign matter from the fuel supplied from the high-pressure pump 31 to the injector 11. The mesh portion 150 of the fluid filter 100 used for removing foreign matter from the fuel supplied to the injector 11 uses a finer mesh, approximately 420 count.
[0021] The injector 11 injects a metered predetermined amount of fuel into the intake passage 12 of the internal combustion engine 10. The fuel and intake air are drawn in, compressed, burned, and exhausted within the cylinder 13, and then exhausted through the exhaust passage 14. The intake passage 12 and exhaust passage 14 are opened and closed by the intake valve 15 and the exhaust valve 16. As the fuel burns, the piston 17 moves back and forth within the cylinder 13, and this reciprocating motion of the piston 17 is converted into rotational motion, which generates the rotation of the internal combustion engine 10.
[0022] Figure 2 shows a cross-section of the fluid filter 100. As described above, the fluid filter 100 is positioned upstream of the low-pressure pump 30 and downstream of the high-pressure pump 31. The basic configuration of both is the same except for the fineness of the mesh of the mesh section 150. Figure 2 shows the fluid filter 100 positioned downstream of the high-pressure pump 31.
[0023] The fluid filter 100 is equipped with a passage member 110 made of polyacetal. The passage member 110 forms a passage chamber 111 through which fuel flows. It is cylindrical in shape, with a diameter of approximately 30 millimeters and an axial length of approximately 60 millimeters. The fluid filter 100 also has an inlet passage section 120 through which fuel flows into the passage chamber 111. This inlet passage section 120 is also made of polyacetal. The inlet passage section 120 has a flange section 121 integrally formed to close the open end on one end of the passage member 110. A fuel pipe 40 is connected to the inlet passage section 120, and an inlet projection 122 is formed on the outer circumference as a mechanism to prevent the fuel pipe 40 from coming loose. Fuel from the fuel pipe 40 flows into the passage chamber 111 through an inflow passage 123 formed in the inlet passage section 120.
[0024] The other end of the passage member 110 is closed by a wall portion 112, and an outlet passage portion 130 is integrally formed in the wall portion 112. Therefore, the outlet passage portion 130 is also made of polyacetal. An outlet projection 131 is formed on the outer circumference of the outlet passage portion 130 as a mechanism to prevent the fuel pipe 40 from coming loose. Fuel that has flowed through the outflow passage 132 inside the outlet passage portion 130 is supplied to the injector 11 from the fuel pipe 40.
[0025] A case 140 that holds the mesh section 150 is located inside the passage chamber 111. As shown in Figure 3, the case 140 is formed integrally with the inlet passage section 120. Therefore, the case 140 is also made of polyacetal. The case 140 is connected to the flange section 121 of the inlet passage section 120 by connecting sections 124 formed in two places. The case 140 includes a ring-shaped opening retaining section 141, a disc-shaped closing retaining section 142, and a frame section 143 that connects the opening retaining section 141 and the closing retaining section 142. The opening retaining section 141 is ring-shaped, so fuel passes through its interior. On the other hand, the closing retaining section 142 blocks the flow of fuel. As shown in Figure 2, the closing retaining section 142 has a disc-shaped bottom section 1421 into which the fuel flow collides, and a cylindrical rising section 1422 that rises from the outer circumference of this bottom section 1421.
[0026] As shown in Figures 4 and 5, the opening holding portion 141 of the case 140 has multiple ribs 144 that protrude in the inward circumferential direction and are spaced apart in the circumferential direction. In this example, 16 ribs 144 are formed at equal intervals in the circumferential direction. Of these, 4 ribs 144 are continuous ribs 145 that are continuous with the frame portion 143. The remaining 12 ribs 144 are discontinuous ribs 146 that are not continuous with the frame portion 143. The frame portion 143 has a circumferential width of about 2 millimeters and a radial length of about 2.5 millimeters, so the continuous ribs 145 also have a circumferential width of about 2 millimeters. The radial thickness of the opening holding portion 141 is about 1.5 millimeters, so the radial height of the continuous ribs 145 is about 1 millimeter. Since the continuous ribs 145 are continuous with the frame portion 143, the strength of the frame portion 143 and the opening holding portion 141 can be increased.
[0027] The discontinuous ribs 146 are smaller than the continuous ribs 145, with a circumferential width of about 1 millimeter and a radial height of about 0.3 millimeters. However, the discontinuous ribs 146 have more ribs 144 formed on the opening holding portion 141. This makes the holding of the mesh portion 150 more secure. Details regarding the holding of the mesh portion 150 will be described later.
[0028] As shown in Figure 6, the mesh portion 150 is cylindrical with a diameter of approximately 20 millimeters, with one end 151 being open. The other end 152 is also open, and the side portion 153 is closed. Therefore, the mesh portion 150 is cylindrical with the ends of the side portion 153 being the one end 151 and the other end 152. The opening holding portion 141 of the case 140 holds the mesh portion 150 with its entire outer circumference facing the entire outer circumference of the one end 151 of the mesh portion 150. The closing holding portion 142 of the case 140 holds (connects) the mesh portion 150 with its entire outer circumference facing the entire outer circumference of the other end 152 of the mesh portion 150. On the other hand, since the frame portion 143 of the case 140 is formed in four sections spaced apart in the circumferential direction, it holds only a portion of the outer circumference of the mesh portion 150. Since the diameter of the mesh portion 150 is about 20 millimeters and the width of the frame portion 143 is about 2 millimeters, the frame portion 143 will only hold about 8 millimeters of the outer circumference length of about 65 millimeters.
[0029] The mesh section 150 is made of resin, but it is made of a different material than the case 140. In this example, the mesh section 150 is made of nylon. Polyacetal and nylon have different properties with respect to fuel. In the case of ethanol fuel, nylon swells by about 5.4 percent when immersed in ethanol fuel. In contrast, the swelling rate of polyacetal in ethanol fuel is about 0.7 percent.
[0030] After immersion in ethanol fuel, nylon shrinks by approximately 3 percent when removed from the fuel and dried. That is, the change in size from the swollen state to the dry state of nylon is 8.4 percentage points. On the other hand, polyacetal expands by approximately 0.2 percent from its initial state. Therefore, the change in size from the immersed state to the dry state of polyacetal is 0.5 percentage points. This difference in change rates significantly affects the bonding strength between the mesh section 150 and the case 140. This effect on bonding strength will be discussed later.
[0031] Next, a method for manufacturing the fluid filter 100 having the above structure will be described. In the fluid filter 100 of this disclosure, first, a nylon mesh portion 150 shown in Figure 6 is formed. Then, this mesh portion 150 is insert-molded into a polyacetal case 140.
[0032] Figure 7 shows a mold 200 used for insert molding. The mold 200 comprises a pair of outer molds 210 of the same shape, and a first core 220 and a second core 230 that are inserted into this pair of outer molds 210. The first core 220 has a cylindrical first sealing portion 221 formed thereon, which tightly contacts a cylindrical outer diameter first sealing portion 211 of the same shape formed on the outer mold 210. The second core 230 also has a cylindrical second sealing portion 231 formed thereon, which tightly contacts a cylindrical outer diameter second sealing portion 212 of the same diameter formed on the outer mold 210. This tight contact between the outer mold 210 and the first and second cores 220 and 230 creates a space inside the mold 200 that forms the case 140 and the entrance passage portion 120.
[0033] More specifically, the opening-holding portion 222 of the first core 220 and the outer diameter opening-holding portion 213 of the outer mold 210 form a space corresponding to the opening-holding portion 141 of the case 140. The frame-forming portion 223 of the first core 220 and the outer diameter frame-forming portion 214 of the outer mold 210 form a space corresponding to the frame portion 143 of the case 140. The space corresponding to the closing-holding portion 142 of the case 140 and the space corresponding to the flange portion 121 of the inlet passage portion 120 are formed by the first tip portion 224 of the first core 220, the second tip portion 232 of the second core 230, and the flange-forming portion 215 of the outer mold 210. The inlet passage portion 120 is formed by the second core 230 and the outer diameter outlet passage forming portion 216 of the outer mold 210.
[0034] The second core 230 has a gate 233 formed therein for injecting molten polyacetal resin into a closed space. To insert mold the mesh portion 150, the mesh portion 150 is placed over the first core 220 as shown in Figure 8. Specifically, the other end 152 of the mesh portion 150 is aligned with the first tip 224 of the first core 220. Furthermore, the side portion 153 of the mesh portion 150 is brought into contact with the side of the first core 220, including the frame forming portion 223. Note that the frame forming portion 223 of the first core 220 is not shown in Figure 8. Finally, one end 151 of the mesh portion 150 is positioned so that the opening holding forming portion 222 of the first core is exposed by about 1 to 2 millimeters, thus completing the placement of the mesh portion 150.
[0035] With the mesh portion 150 placed over the first core 220, the mold 200 is closed as shown in Figure 9. Then, molten polyacetal resin is injected into the space of the mold 200 from the gate 233. Since the melting point of polyacetal is 180-190 degrees Celsius, the polyacetal resin is heated to about 200 degrees Celsius and then injected. On the other hand, the melting point of the nylon that makes up the mesh portion 150 is about 220 degrees Celsius. Therefore, as shown in Figure 10, the mesh portion 150 is not melted by the molten polyacetal resin. That is, the molten polyacetal resin passes through the mesh of the mesh portion 150. In the opening holding forming portion 222 of the first core 220, the ribs 144 are formed by the polyacetal resin that has passed through the mesh of the mesh portion 150.
[0036] Even in areas of the opening-holding forming section 222 where ribs 144 are not formed, polyacetal resin that will become the opening-holding section 141 of the case 140 is filled into the opening-holding forming section 222. This filling polyacetal resin is pressed against the inner surface of the opening-holding forming section 222 through the mesh section 150 by the injection pressure. Therefore, even in areas where ribs 144 are not formed, the molten polyacetal resin penetrates between the mesh of the mesh section 150. The same is true for the rising section 1422 of the closing-holding section 142. Due to the injection pressure, the polyacetal resin that forms the closing-holding section 142 penetrates between the mesh of the other end 152 of the mesh section 150.
[0037] As a result of injection molding of the polyacetal resin, only a portion of the circumferential direction of one end 151 of the mesh portion 150 is embedded within the rib 144 formed on a portion of the circumferential direction of the opening holding portion 141 of the case 140. At the location where the mesh portion 150 is embedded corresponding to this rib 144, the mesh portion 150 and the case 140 form a strongly bonded portion that is strongly connected to each other.
[0038] Furthermore, the parts of the case 140 other than the strongly bonded portion corresponding to the circumferential rib 144 of the opening holding portion 141, and the parts of the mesh portion 150 other than the strongly bonded portion of one end 151 of the mesh portion 150, are connected only by the opening holding portion 141 fitting between the mesh of the mesh portion 150. However, since the polyacetal resin forming the opening holding portion 141 fits into the mesh of the mesh portion 150, adhesion between the opening holding portion 141 and the mesh portion 150 occurs even in the parts other than the strongly bonded portion. However, in the parts other than the strongly bonded portion, the mesh portion 150 is not embedded in the opening holding portion 141, so the bonding force is still weak. Therefore, weak bonding portions are formed in the parts other than the strongly bonded portion.
[0039] As described above, the space corresponding to the frame portion 143 of the case 140 is formed by the frame forming portion 223 of the first core 220 and the outer diameter frame forming portion 214 of the outer mold 210. Therefore, although not shown in the figures, in the frame portion 143, the mesh portion 150 is sandwiched between the frame forming portion 223 of the first core 220 and the outer diameter frame forming portion 214 of the outer mold 210. As a result, the mesh portion 150 is embedded within the frame portion 143 by the injection of molten polyacetal resin.
[0040] After the injected polyacetal resin has solidified, the outer mold 210 and the first core 220 and second core 230 are separated, as shown in Figure 11. This mold opening produces a fluid filter 100 in which the case 140 with the mesh portion 150 insert-molded and the inlet passage portion 120 are integrally molded. To obtain the fluid filter 100 shown in Figure 2, the passage member 110 and the outlet passage portion 130 are further integrally molded in another mold. Then, the opening of the passage member 110 and the flange portion 121 of the inlet passage portion 120 are welded together to complete the fluid filter 100.
[0041] Fuel flows into the completed fluid filter 100 from the fuel piping 40 on the left side of Figure 2 into the inlet passage 123 of the inlet passage section 120. The fuel flowing in from the inlet passage 123 collides with the bottom 1421 of the closing retaining section 142 of the case 140, spreads radially, and flows into the passage chamber 111. The diameter of the inlet passage 123 is about 10 millimeters, while the diameter of the passage chamber 111 is about 30 millimeters, so the fuel flow velocity decreases in the passage chamber 111. This decrease in flow velocity makes it easier to separate foreign matter from the fuel.
[0042] Furthermore, the other end 152 of the mesh portion 150 is covered by the rising portion 1422 of the closing retaining portion 142 of the case 140, so it is not directly subjected to the pressure associated with the fuel flow. That is, the fuel flow is stagnant at the other end 152 of the mesh portion 150, so the connection with the rising portion 1422 of the closing retaining portion 142 is maintained. The fuel that flows into the passage chamber 111 flows from the outer circumference to the inner circumference along the side portion 153 of the mesh portion 150. Since the side portion 153 of the mesh portion 150 is embedded in the frame portion 143 of the case 140, the mesh portion 150 does not detach from the frame portion 143 even when subjected to the fuel flow.
[0043] Similar to the frame portion 143, one end 151 of the mesh portion 150 is embedded in the opening-holding portion 141 of the case 140 in a portion corresponding to the rib 144, so it does not peel off from the opening-holding portion 141. Here, even if a portion corresponding to the rib 144 is not formed, the polyacetal resin forming the opening-holding portion 141 will penetrate into the mesh of the mesh portion 150, so as described above, a certain degree of weak bonding (adhesion) is possible. However, if the polyacetal resin is only weakly bonded (adhered) by penetrating into the mesh of the mesh portion 150, there is a risk that the mesh portion 150 will peel off from the opening-holding portion 141.
[0044] This is because, as mentioned above, the properties of the nylon that constitutes the mesh portion 150 and the polyacetal that constitutes the case 140 are different. The rate of change when the resin is immersed in fuel and swells, and the rate of change when the resin that has swollen in fuel is dried and shrinks, are different for nylon and polyacetal. Based on this difference in the rate of change, there is a risk that the mesh portion 150 will peel off from the opening holding portion 141 at some point over a long period of time. If one end 151 of the mesh portion 150 is held by a weak bond around the entire circumference of the opening holding portion 141, the location where this peeling occurs will be completely random. Once peeling occurs, stress concentrates at that point, accelerating the peeling. As a result, the fuel will flow through the part that has peeled off from the opening holding portion 141, causing further peeling. Consequently, the filtration performance of the fluid filter 100 will deteriorate.
[0045] In contrast, in this example, the mesh portion 150 is embedded and molded into the rib 144 of the opening holding portion 141, resulting in a strong bond between the mesh portion 150 and the opening holding portion 141. Stress that attempts to separate the mesh portion 150 from the opening holding portion 141 occurs in this strongly bonded portion, but since the strongly bonded portion is formed with the stress attempting to separate it calculated in advance, the mesh portion 150 will not peel off. If only the stress calculation for bond strength is required, it is possible to use only continuous ribs 145 that are continuous with the frame portion 143 as the rib 144. This is because the continuous rib 145 has a larger circumferential width than the discontinuous rib 146, so the holding strength of the mesh portion 150 can be obtained even with only the continuous rib 145.
[0046] However, since the frame portion 143 covers only a part of the side portion 153 of the mesh portion 150, if only continuous ribs 145 are used, the gaps between the continuous ribs 145 will be wide. If the gaps between the continuous ribs 145 are only weakly bonded by the polyacetal resin penetrating the mesh of the mesh portion 150, the possibility of the mesh portion 150 peeling off from the opening holding portion 141 at this point cannot be ruled out. Therefore, although it is possible to use only continuous ribs 145, combining continuous ribs 145 with discontinuous ribs 146 is more desirable in preventing the mesh portion 150 from peeling off.
[0047] Conversely, it is also possible to eliminate the continuous ribs 145 and make all of them discontinuous ribs 146. Even with only discontinuous ribs 146, if a large number of ribs 144 are arranged at appropriate intervals in the circumferential direction, it is possible to prevent the mesh portion 150 from peeling off from the opening holding portion 141.
[0048] Here, we will provide a supplementary explanation as the injection molding methods for the continuous rib 145 and the discontinuous rib 146 differ somewhat. The molding method shown in Figure 10 above illustrates the molding of the discontinuous rib 146. Specifically, the discontinuous rib 146 is formed when the molten resin that flows through the outer mold 210 to form the opening holding portion 141 passes through one end 151 of the mesh portion 150 and flows towards the first core 220. On the other hand, the continuous rib 145 is formed by injection molding in the same manner as the frame portion 143. Specifically, the molten resin that flows through the frame forming portion 223 on the first core 220 side and the molten resin that flows through the outer diameter frame forming portion 214 on the outer mold 210 side are connected via one end 151 of the mesh portion 150 to form the continuous rib 145.
[0049] The above description represents a preferred embodiment of the present disclosure, but the present disclosure is not limited to the above embodiment and can be modified in various ways. For example, as shown in Figure 12, only one fuel pump 32 may be provided, and fuel may be supplied to the injector 11 from a single fuel pump 32. Furthermore, the fluid filter 100 of the present disclosure is not specialized for removing foreign matter from fuel, but can also be used to remove foreign matter from other fluids. For example, in a system that uses seawater for cooling, the fluid filter 100 of the present disclosure may be used to remove foreign matter from seawater.
[0050] The passage members 110, the inlet passage section 120, and the outlet passage section 130 are useful components when used together with the fuel piping 40. However, the fluid filter 100 of this disclosure does not necessarily have to be used together with the fuel piping 40. For example, it can be placed inside an atmospheric pressure fuel tank 20 or a pressure fuel tank 21. In that case, the passage members 110, etc., are not necessary. The essential components of the fluid filter 100 of this disclosure are the mesh section 150 and the case 140. The size of the case 140 is also just an example as described above. The size can be appropriately selected depending on the application. Similarly, the fineness of the mesh of the mesh section 150 can be appropriately selected depending on the application.
[0051] In the example shown in Figure 5, the rib 144 was formed up to the tip of the opening holding portion 141, but the rib 144 only needs to be formed in the area corresponding to the mesh portion 150. As mentioned above, the mesh portion 150 is about 1 to 2 millimeters away from the tip. Therefore, as shown in Figure 13, the rib 144 may be formed to a position slightly recessed from the tip. Even in this case, the first core 220 will not interfere with the outer mold 210.
[0052] In the example described above, the connection between the other end 152 of the mesh section 150 and the rising portion 1422 of the closing-holding section 142 was made a weak connection in which the molten resin penetrates the mesh of the mesh section 150. This is because the fuel flow is stagnant around the other end 152, so problems are unlikely to occur even with only a weak connection. However, it is preferable to form a partially strong connection even at the rising portion 1422 of the closing-holding section 142.
[0053] Figure 14 shows the first core 220 that forms the strong joint. In this example, the first core has a closing rib recess 225 that forms the closing rib 147 (shown in Figures 15 and 16) circumferentially spaced, continuous with the first tip portion 224. As shown in Figure 16, the closing rib 147 is paired with the rib 144 of the opening holding portion 141. Specifically, four continuous closing ribs 148 that are continuous with the frame portion 143 are formed at equal intervals in the circumferential direction. Three discontinuous closing ribs 149 are formed at equal intervals between adjacent continuous closing ribs 148. The continuous closing ribs 148 are continuous with the continuous rib 145 via the frame portion 143. The discontinuous closing ribs 149 are formed at positions corresponding to the discontinuous rib 146.
[0054] The first core 220 has a frame forming portion 223 that extends to the opening holding forming portion 222, forming a continuous rib forming recess 2231. Furthermore, near the first tip portion 224, the frame forming portion 223 forms a closed portion continuous rib forming recess 2232. Also, in the opening holding forming portion 222 of the first core 220 shown in Figure 14, a rib recess 226 is formed at a position corresponding to the closed portion rib recess 225.
[0055] In the example described above, the mesh portion 150 is made of nylon and the case 140 is made of polyacetal. This is a suitable example for constructing a fluid filter 100 for ethanol fuel. However, the resin material is not limited to this example. When the resin material differs between the mesh portion 150 and the case 140, both the swelling rate due to the fuel and the rate of change between the dry state and the immersed state are usually different. However, even if only one of the swelling rate due to the fuel or the rate of change between the dry state and the immersed state differs, the fluid filter 100 of this disclosure is still beneficial for improving durability.
[0056] Furthermore, in the fluid filter 100 of this disclosure, it is also possible to use the same resin material for the resin material constituting the mesh portion 150 and the resin material constituting the case 140. Of course, the fact that the resin material constituting the mesh portion 150 and the resin material constituting the case 140 are different is a significant and important matter when considering the durability of the fluid filter 100 of this disclosure. However, for manufacturing reasons, etc., even if the same resin material is used, it may be possible to use it in the fluid filter 100 of this disclosure when insert molding the mesh portion 150 into the case 140. [Explanation of Symbols]
[0057] 100 Fluid Filters 140 cases 141 Opening holding part 142 Closing holding part 143 Frame section 144 Ribs 147 Closing rib 150 mesh section 151 One end 152 Other end 153 Side part
Claims
1. A fluid filter (100) comprising a resin mesh section (150) for removing foreign matter from a fluid and a resin case (140) for holding this mesh section, The mesh portion is cylindrical with one end (151) open and the side portion (153) closed. The case comprises a ring-shaped opening holding portion (141) that holds the entire outer circumference of one end of the mesh portion, and a frame portion (143) that holds a part of the outer circumference of the side portion of the mesh portion. Multiple ribs (144) protruding in the circumferential direction are formed on the opening holding portion of the case, spaced apart in the circumferential direction. The opening-holding portion of the case and the one end of the mesh portion are strongly connected to each other, with the entire circumference of the opening-holding portion facing the entire circumference of the one end, and only a portion of the one end is embedded in the rib formed on a part of the opening-holding portion in the circumferential direction. The other parts of the opening-holding portion excluding the strongly connected portion in the circumferential direction and the other parts of the one end excluding the strongly connected portion in the circumferential direction constitute a weakly connected portion in which the mesh portion is not embedded within the opening-holding portion. Fluid filter.
2. The mesh portion also has an opening at the other end (152), The case further comprises a closing retaining portion (142) that holds the other end of the mesh portion, The closing retaining portion of the case has a disc-shaped bottom portion (1421) and a cylindrical rising portion (1422) that rises from the outer circumference of the bottom portion. The rising portion of the closing retaining portion of the case and the other end of the mesh portion are such that the entire circumference of the rising portion faces the entire circumference of the other end, and the rising portion is connected to the other end. The fluid filter according to claim 1.
3. Multiple closing ribs (147) that protrude in the circumferential direction are formed on the rising portion of the closing retaining portion of the case, spaced apart in the circumferential direction. A strong coupling portion is formed in the closing portion rib formed in the circumferential direction of a part of the rising portion of the closing holding portion, with only a part of the other end of the mesh portion embedded in the circumferential direction, thereby strongly coupling them together. The other part of the rising portion of the closing holding portion excluding the strong coupling portion in the circumferential direction and the other part of the other end of the mesh portion excluding the strong coupling portion in the circumferential direction constitutes a weak coupling portion in which the mesh portion is not embedded in the rising portion of the closing holding portion. The fluid filter according to claim 2.
4. The frame portion of the case is continuous with the rib formed in the opening holding portion, and is continuous with the closing portion rib formed in the rising portion of the closing holding portion. The fluid filter according to claim 3.
5. The multiple ribs are formed at equal intervals in the circumferential direction on the opening-holding portion of the case, Of the multiple ribs, the continuous rib (145) that is continuous with the frame portion has a larger circumferential width than the discontinuous rib (146) that is not continuous with the frame portion. The multiple closing ribs are formed at equal intervals in the circumferential direction on the rising portion of the closing holding portion of the case, Of the multiple closing ribs, the continuous closing rib (148) that is continuous with the frame has a larger circumferential width than the discontinuous closing rib (149) that is not continuous with the frame. The fluid filter according to claim 4.
6. The fluid filter removes foreign matter from the fuel for the internal combustion engine (10). The resin constituting the mesh portion and the resin constituting the frame portion differ from each other in at least one of the following: their swelling rate due to fuel and their rate of change between the dry state and the immersed state. The fluid filter according to claim 1.
7. The fluid filter further comprises a passage member (110) that forms a passage chamber (111) for housing the case, an inlet passage section (120) for allowing fluid to flow into the passage chamber, and an outlet passage section (130) for allowing fluid to flow out of the passage chamber. The case and the entrance passage are formed integrally, The passage member and the exit passage portion are formed integrally, The fluid that flows into the passage chamber from the inlet passage flows through the mesh portion from the outer circumference of the side portion of the mesh portion into the inner circumference of the mesh portion, and then flows into the outlet passage from one end of the mesh portion. The fluid filter according to claim 1.