Fluid filter

Abstract

To provide a fluid filter less in fear of flowing out a cleanliness-reduced liquid to an external part when exchanging a filter element.SOLUTION: In a state of installing a filter case 20 supporting-storing a filter element 30 by an outside support member 41 and an inside support member 42 on a filter head 10, a flow of fluid between the outer periphery of the outside support member 41 and the inner periphery of the inside support member 42 is allowed by conforming an inside communication hole 424 to an outside communication hole 415, and in a state of removing a filter element 30 from a filter case 20 by removing the filter case 20 from the filter head 10, the flow of the fluid between the outer periphery of the outside support member 41 and the inner periphery of the inside support member 42 is limited or regulated when the inside communication hole 424 becomes a dislocated position to the outside communication hole 415.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a fluid filter for filtering fluids such as oil.

Background Art

[0002] Conventionally, fluid filters for filtering fluids such as water, fuel, oil, and air have been used in a wide range of industrial fields. In this type of fluid filter, a filter case that houses a cylindrical filter element inside is attached to the opening of a filter head, and fuel flowing in from the inflow path of the filter head is filtered by passing from the outside to the inside of the filter element, and the filtered fuel flows out from the inside of the filter element to the outflow path of the filter head (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Replacing the filter element in the fluid filter described above involves first removing the filter case and filter element from the filter head, then removing the old filter element from the filter case, setting the new filter element in the filter case (or attaching the new filter element to the outflow passage of the filter head), and finally reattaching the filter case to the filter head. Here, when removing the old filter element from the filter case, there is a risk that the unfiltered liquid that had accumulated on the outside of the filter element and the filtered liquid that had accumulated on the inside of the filter element may mix. If a new filter element is set in the filter case in this state, the liquid that has mixed the unfiltered and filtered liquids may flow into the newly set filter element, potentially causing a reduced level of cleanliness to be released to the outside.

[0005] This invention has been made in view of these problems, and aims to provide a fluid filter that reduces the risk of leaking liquid with reduced purity to the outside when replacing the filter element. [Means for solving the problem]

[0006] To solve the aforementioned problems, the fluid filter according to the present invention comprises a filter head having a fluid inlet and outlet, a bottomed cylindrical filter case formed with an open upper end and an internal space, the upper end of which is detachably attached to the filter head, a hollow cylindrical filter element detachably housed in the internal space of the filter case and filtering by passing fluid through it, and a component extending upward from the bottom surface within the internal space of the filter case, inserted into the hollow portion of the filter element housed in the internal space, and attaching the filter element The filter head is equipped with a detachable support member, and the filter case, which houses the filter element supported by the support member, is attached to the filter head, and the fluid flowing in from the inlet is filtered by passing it through the filter element and then discharged from the outlet, and the support member is equipped with a hollow cylindrical inner support member fixed to the bottom surface of the filter case and extending upward, and a hollow cylindrical outer support member that is fitted into the inner support member so as to be vertically relative to the inner support member and attached to the inner support member, and a plurality of internal communication lines in the hollow cylindrical wall of the inner support member A hole is formed, and a plurality of external communication holes are formed in the hollow cylindrical wall of the outer support member. When the filter case, which houses the filter element supported by the support member, is attached to the filter head, the internal communication holes are aligned with the external communication holes, allowing fluid flow between the outer circumference of the outer support member and the inner circumference of the internal support member. When the filter case is removed from the filter head and the filter element is removed from the filter case, the internal communication holes are offset from the external communication holes, restricting or regulating fluid flow between the outer circumference of the outer support member and the inner circumference of the internal support member.

[0007] Furthermore, in the fluid filter having the above configuration, it is preferable to have a biasing member that biases the outer support member upward relative to the inner support member, and when the filter case, which houses the filter element supported by the support member, is attached to the filter head, the outer support member moves downward against the biasing force of the biasing member, and the inner communication hole aligns with the outer communication hole, and when the filter case is removed from the filter head and the filter element is removed from the filter case, the outer support member moves upward due to the biasing force of the biasing member, and the inner communication hole is misaligned with the outer communication hole.

[0008] Furthermore, in the fluid filter having the above configuration, it is preferable to have a locking means for which the outer support member is fitted into the hollow portion of the filter element to house the filter element in the internal space of the filter case, and the filter element is moved downward against the biasing force of the biasing member to align the inner communication hole with the outer communication hole, thereby locking and holding the filter element within the filter case.

[0009] Furthermore, in the fluid filter having the above configuration, it is preferable that by releasing the locking mechanism from the state in which the filter element is locked and held within the filter case by the locking mechanism, the biasing member moves the outer support member upward relative to the inner support member, and moves the filter element supported by the outer support member upward so that its upper end protrudes above the upper opening of the filter case.

[0010] Furthermore, in the fluid filter having the above configuration, it is preferable that a first engaging portion extending in the vertical direction is formed on the inner circumferential surface of the outer support member, and a second engaging portion that engages with the first engaging portion is formed on the outer circumferential surface of the inner support member, thereby restricting relative rotation while allowing vertical relative movement of the outer support member with respect to the inner support member. [Effects of the Invention]

[0011] According to the fluid filter of the present invention, the support member inserted into the hollow portion of the filter element to detachably support the filter element is composed of a hollow cylindrical inner support member fixed to the bottom surface of the filter case and extending upward, and a hollow cylindrical outer support member fitted into the inner support member so as to be vertically movable relative to the inner support member and attached to the inner support member. When the filter case, which houses the filter element supported by the support member, is attached to the filter head, the inner communication hole formed in the hollow cylindrical wall of the inner support member aligns with the outer communication hole formed in the hollow cylindrical wall of the outer support member, allowing fluid flow between the outer circumference of the outer support member and the inner circumference of the inner support member. When the filter case is removed from the filter head and the filter element is removed from the filter case, the inner communication hole is positioned offset from the outer communication hole, restricting or regulating fluid flow between the outer circumference of the outer support member and the inner circumference of the inner support member. Therefore, when removing the filter element from the filter case, the risk of reduced-cleanliness fluid leaking to the outside is reduced.

[0012] Furthermore, in the fluid filter having the above configuration, preferably, a biasing member is provided that biases the outer support member upward relative to the inner support member, and when the filter case is removed from the filter head and the filter element is removed from the filter case, the outer support member moves upward due to the biasing force of the biasing member, and the inner communication hole is offset relative to the outer communication hole. With this configuration, the inner communication hole can be offset relative to the outer communication hole by removing the filter case from the filter head.

[0013] Furthermore, in the fluid filter having the above configuration, preferably, the outer support member is fitted into the hollow portion of the filter element to house the filter element in the internal space of the filter case, and the filter element is moved downward against the biasing force of the biasing member to align the inner communication hole with the outer communication hole, and the filter element is provided with a locking means to lock and hold the filter element inside the filter case. With this configuration, the inner communication hole can be aligned with the outer communication hole by locking and holding the filter element inside the filter case with the locking means.

[0014] Furthermore, in the fluid filter with the above configuration, preferably, by releasing the locking mechanism from the state in which the filter element is locked and held inside the filter case, the biasing member moves the outer support member upward relative to the inner support member, and the filter element supported by the outer support member moves upward so that its upper end protrudes above the upper opening of the filter case. With this configuration, when the locking mechanism releases the state in which the filter element is locked and held inside the filter case, the biasing member causes the filter element to protrude above the upper opening of the filter case, making it easier to remove the filter element from the filter case and facilitating the replacement of the filter element.

[0015] Furthermore, in the fluid filter with the above configuration, preferably, a first engaging portion extending in the vertical direction is formed on the inner circumferential surface of the outer support member, and a second engaging portion that engages with the first engaging portion is formed on the outer circumferential surface of the inner support member. The engagement of the first and second engaging portions allows for vertical relative movement of the outer support member with respect to the inner support member while restricting relative rotation. This configuration prevents circumferential displacement between the inner and outer communication holes. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view showing the appearance of the fluid filter according to the present invention. [Figure 2]It is a cross-sectional view showing the cross-section of the fluid filter in the vertical direction. [Figure 3] It is an exploded perspective view showing the main configuration of the fluid filter. [Figure 4] It is a perspective view showing the appearance of the members constituting the filter element of the fluid filter. FIG. 4(a) is a perspective view showing the appearance of the upper plate, and FIG. 4(b) is a perspective view showing the appearance of the lower plate. [Figure 5] It is a perspective view showing the configuration of the support member of the fluid filter. FIG. 5(a) is a perspective view showing the appearance of the outer support member, and FIG. 5(b) is a perspective view showing the appearance of the inner support member. [Figure 6] It is a cross-sectional view showing the state of each part when the support member of the fluid filter is attached into the filter case. [Figure 7] It is a perspective view showing the state when looking down from above the opening of the filter case removed from the filter head of the fluid filter. [Figure 8] It is a cross-sectional view showing the movement of each part when the filter element is attached into the filter case. [Figure 9] It is a perspective view showing the movement of the lower plate of the filter element with respect to the retainer in the filter case when the filter element is attached into the filter case. [Figure 10] It is a cross-sectional view showing the movement of each part when the filter case containing the filter element is attached to the filter head.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the appearance of the fluid filter 1 of the present embodiment. FIG. Ⅱ is a longitudinal cross-sectional view at the position of the A-A' line shown in FIG. 1. FIG. 3 is an exploded perspective view showing the main configuration of the fluid filter 1. When referring to the vertical direction of the fluid filter 1 of the present embodiment, it follows the direction of the arrow shown in FIG. 1.

[0018] As shown in Fig. 1, the fluid filter 1 filters the hydraulic oil flowing in from the inlet 101 formed in the filter head 10 by the filter element 30 (see Figs. 2 and 3) housed in the filter case 20, and discharges it from the outlet 102 formed in the filter head 10. As shown in Fig. 2, a relief valve 11 is provided inside the inlet 101 of the filter head 10. When the pressure of the hydraulic oil flowing in from the inlet 101 becomes larger than a predetermined value with respect to the pressure of the hydraulic oil flowing out from the outlet 102, the relief valve 11 opens and allows the hydraulic oil flowing in from the inlet 101 to flow directly out to the outlet 102.

[0019] As shown in Fig. 2, an opening is formed below the filter head 10 so that the upper end of the filter case 20 can be attached. On the inner peripheral surface of this opening, a female thread 103 on the head side (more specifically, see Fig. 10(a)) that engages with the male thread 201 formed on the outer periphery of the upper part of the filter case 20 (also see Fig. 3) is formed. Also, at the center position of the opening of the filter head 10, a fitting port 104 is provided into which a fluid communication port 337 (also see Fig. 3) formed at the center of the upper plate 33 of the filter element 30 is fitted. This fitting port 104 communicates with the outlet 102 of the filter head 10.

[0020] The filter case 20 has a bottomed cylindrical shape with an open upper end and an internal space (see Figure 3). A mounting hole 203 is formed in the center of the inner bottom of the filter case 20, to which the tip of the inner support member 42 is attached. A case-side female thread 204 is formed on the inner circumferential surface of this mounting hole 203 (see Figure 7(a) for more details), and the case-side female thread 204 is screwed into a support member-side male thread 421 (see Figure 3) formed on the tip of the inner support member 42. Furthermore, the retainer 21 and the compression coil spring 22 are fixed between the inner support member 42 and the inner bottom of the filter case 20 by screwing the support member-side male thread 421 and the case-side female thread 204 together. As shown in Figure 3, two engaging protrusions 211 are formed on the inner circumferential surface of the retainer 21 at opposing positions, each having a linear convex shape that extends in the axial direction of the filter case 20. These engaging protrusions 211 engage with engaging grooves 344 formed in the lower plate 34, which will be described later (details will be described later).

[0021] As shown in Figure 2, the filter element 30 consists of a filter medium 31, a protector 32 that houses the filter medium 31, an upper plate 33 fixed to the upper ends of the filter medium 31 and the protector 32, and a lower plate 34 fixed to the lower ends of the filter medium 31 and the protector 32. The filter medium 31 is formed into a roughly hollow cylindrical shape with a chrysanthemum-shaped cross-section by joining the ends of a filter medium folded in a bellows-like manner. The protector 32 has a cylindrical shape and houses the filter medium 31 inside. In addition, as shown in Figure 3, the surface of the protector 32 is provided with numerous small holes 321, and the hydraulic fluid that passes through these small holes 321 is filtered by the filter medium 31. The upper end surfaces of the filter medium 31 and the protector 32 are fixed to the upper plate 33, and the lower end surfaces of the filter medium 31 and the protector 32 are fixed to the lower plate 34. The filter media 31 and protector 32 can be fixed to the upper plate 33 and lower plate 34 by bonding with adhesive, or by conventional methods.

[0022] Figure 4 shows the external shapes of the upper plate 33 and the lower plate 34. In Figure 4, (a) is a perspective view showing the external shape of the upper plate 33 when viewed from diagonally below (in other words, a perspective view of the back side of the upper plate 33), and (b) is a perspective view showing the external shape of the lower plate 34 when viewed from diagonally below. As shown in Figure 4(a), the back side of the upper plate 33 has a peripheral edge portion 331 that extends downward along its outer edge. Flexible fixing members 332 extend diagonally upward from two opposing locations on this peripheral edge portion 331, and engaging projections 333 are formed at their tips. These engaging projections 333 engage with engaging recesses 202 (see Figure 3) formed on the upper inner side of the filter case 20. Furthermore, a lever member 334 is formed on the engaging projection 333 to bend the fixing member 332. As shown in Figure 2, when the engaging projection 333 is engaged with the engaging recess 202, for example, as indicated by the arrow in Figure 8(c), the tip of the lever member 334 can be bent inward, causing the fixing member 332 to bend and releasing the engagement between the engaging projection 333 and the engaging recess 202.

[0023] Returning to Figure 4(a), an inner cylinder portion 335 is formed to protrude downward from the center of the back surface of the upper plate 33. Two engagement grooves 336 are formed on the inner circumferential surface of this inner cylinder portion 335 at opposing positions, which engage with the engagement projection 412 formed on the upper end of the outer support member 41, which will be described later. Also, as shown in Figures 2, 3 and 6, a fluid communication port 337 is formed to protrude upward from the center of the upper surface of the upper plate 33, for allowing the hydraulic oil filtered by the filter material 31 to flow to the filter head 10. Furthermore, as shown in Figure 4(a), on the back side of the upper plate 33, the plane from the outside of the inner cylinder portion 335 to the inside of the aforementioned peripheral edge portion 331 becomes a fixing surface 338 to which the filter material 31 and protector 32 are fixed.

[0024] As shown in Figure 4(b), a support member insertion opening 341 is provided in the center of the lower plate 34 through which the outer support member 41 is inserted. A flange contact surface 342 is formed on the lower peripheral edge of this support member insertion opening 341, which contacts the upper surface of the flange portion 411 (see Figure 5(b)) formed on the lower part of the outer support member 41. Six engagement recesses 343, each consisting of an engagement groove 344 and a guide portion 345, are provided on the lower outer peripheral surface of the lower plate 34 at equal intervals in the circumferential direction of the lower plate 34. The engagement groove 344 is formed sandwiched between a long vertical surface 346 extending downward from the upper surface of the lower plate 34 and a short vertical surface 347 that is shorter than the long vertical surface 346 extending downward from the upper surface of the lower plate 34. Furthermore, the inclined surface extending from the lower end of the long vertical surface 346 to the lower end of the short vertical surface 347, which forms the engagement groove 344 to the right in Figure 4(b), serves as the guide portion 345. Alternatively, it can be said that the inclined surface extending from the lower end of the short vertical surface 347 to the lower end of the long vertical surface 346, which forms the engagement groove 344 to the left in Figure 4(b), also serves as the guide portion 345.

[0025] As shown in Figure 2, the support member 40 is inserted into the hollow portion of the filter material 31 of the filter element 30 described above, and supports the filter material 31 from the inside against the pressure of the hydraulic fluid applied to the outside of the filter material 31. The support member 40 is composed of an outer support member 41 and an inner support member 42, as shown in Figure 5. Figure 5 is a perspective view showing the external shape of the outer support member 41 and the inner support member 42, where (a) is a perspective view of the outer support member 41 and (b) is a perspective view of the inner support member 42.

[0026] As shown in Figure 5(a), the outer support member 41 has a cylindrical shape, and two upward-extending engaging protrusions 412 are formed on its upper end surface at opposing positions. A flange 411 is formed on the lower outer peripheral surface of the outer support member 41, which abuts against the flange contact surface 342 shown in Figure 4(b), and the lower end of the filter element 30 is supported by this flange 411. On the lower part of the inner peripheral surface of the outer support member 41, there is an inner support member contact surface 413 (as shown in Figure 5(a)). Areas indicated by hatching are formed. The inner support member 42 contacts the outer support member contact surface 422 (see Figure 5(b)). On this inner support member contact surface 413, upward-extending linear engagement protrusions 414 are formed at opposing positions. In addition, the surface (hollow cylindrical wall) of the outer support member 41 is provided with multiple oval-shaped outer communication holes 415 that extend in the circumferential direction.

[0027] Next, the inner support member 42 has a cylindrical shape as shown in Figure 5(b), and its outer diameter is smaller than the inner diameter of the outer support member 41. This makes it possible to insert the inner support member 42 into the outer support member 41. A male thread 421 is formed on the lower tip of the inner support member 42. The male thread 421 is designed to screw into a female thread 204 (see Figure 6(a)) formed on the inner circumferential surface of a mounting hole 203 provided at the bottom of the filter case 20. An outer support member contact surface 422 is formed on the lower part of the surface (hollow cylindrical wall) of the inner support member 42, which contacts the inner support member contact surface 413 shown in Figure 5(a). This outer support member contact surface 422 is provided with an engaging recess 423 that engages with the engaging projection 414 shown in Figure 5(a). Furthermore, multiple oval-shaped inner communication holes 424 extending in the circumferential direction are provided on the surface of the inner support member 42 at positions corresponding to the outer communication holes 415 shown in Figure 5(a).

[0028] When attaching the outer support member 41 and inner support member 42 described above to the filter case 20, first insert the lower tip of the inner support member 42 through the upper opening of the outer support member 41. Then, align the position of the engaging recess 423 of the inner support member 42 with the position of the engaging projection 414 of the outer support member 41, and bring the outer support member contact surface 422 into contact with the inner support member contact surface 413. As a result, the engaging projection 414 and the engaging recess 423 engage, and while engaged, the outer support member 41 can move downward relative to the inner support member 42, and the inner support member 42 can move upward relative to the outer support member 41, but rotation in the circumferential direction of the outer support member 41 and the inner support member 42 is restricted. Therefore, it is possible to prevent the circumferential positional misalignment of the outer communication hole 415 and the inner communication hole 424.

[0029] When assembling the support member 40 into the filter case 20, with the retainer 21 and compression coil spring 22 placed on the bottom surface of the filter case 20, the support member side male thread 201 formed on the tip of the inner support member 42 is screwed into the case side female thread 204 formed in the mounting hole 203 provided on the bottom of the filter case 20. As this screwing progresses, the compression coil spring 22 is compressed by the flange portion 411 formed on the lower part of the outer support member 42, and the retainer 21 and compression coil spring 22 are fixed to the bottom surface of the filter case 20. At this time, the inner support member contact surface 413 of the outer support member 41 (see Figure 5(a)) and the outer support member contact surface 422 of the inner support member 42 (see Figure 5(b)) are in contact, and in this state, the position of the outer communication hole 415 and the position of the inner communication hole 424 are completely offset. Therefore, the outside of the outer support member 41 and the inside of the inner support member 42 are separated.

[0030] Then, as shown in Figure 6(b), when the male screw 421 on the support member side is fully screwed in, the retainer 21 is fixed to the bottom surface of the filter case 20 by the inner support member 42. At this time, the contact surface 413 of the inner support member and the contact surface 422 of the outer support member are still in contact, so the outside of the outer support member 41 and the inside of the inner support member 42 are separated. Also, since the compression coil spring 22 has room to compress further, the outer support member 41 is in a state where it can move further downward.

[0031] Next, the flow of the hydraulic fluid filtered by the fluid filter 1 with the above-described configuration will be explained with reference to Figures 2 and 7. Here, Figure 7 is a perspective view of the opening of the filter case 20 as seen from above, with the filter case 20 removed from the filter head 10. As shown by the arrow in Figure 2, the hydraulic fluid flowing in from the inlet 101 of the filter head 10 reaches the upper surface of the upper plate 33. Here, as shown in Figure 7, a gap G is provided between the opening of the filter case 20 and the upper plate 33, and the hydraulic fluid that reaches the upper surface of the upper plate 33 flows into this gap G. The hydraulic fluid that flows into the gap G passes through the small holes 321 of the protector 32 (see Figure 3), is filtered by the filter material 31 as shown in Figure 2, and then flows into the inside of the inner support member 42 through the outer communication hole 415 of the outer support member 41 and the inner communication hole 424 of the inner support member 42. The hydraulic fluid then flows from the inside of the inner support member 42 through the fluid communication hole 338 of the upper plate 33 into the filter head 10 and flows out to the outside from the outlet 102.

[0032] Next, with reference to Figures 8 to 10, the movement of each part when replacing the filter element 30 inside the filter case 20 will be explained. Figure 8 is a cross-sectional view showing the process from removing the filter element 30 from the filter case 20 to installing the new filter element 30 into the filter case 20. Figure 9 is a perspective view showing the process from when the filter element 30 is installed in the filter case 20 until the engagement groove 344 of the lower plate 32 engages with the engagement projection 211 of the retainer 21. Figure 10 is a cross-sectional view showing the process from when the filter case 20 with the filter element 30 installed is installed into the filter head 10.

[0033] First, as shown in Figure 8(a), when removing the filter element 30 from the filter case 20, or inserting the filter element 30 into the filter case 20, the inner support member contact surface 413 and the outer support member contact surface 422 are in contact, similar to the state shown in Figure 6(b). As a result, the space between the outside of the outer support member 41 and the inside of the inner support member 42 is blocked. Therefore, even if hydraulic fluid remains in the filter case 20, for example, the hydraulic fluid before filtration and the hydraulic fluid after filtration will not mix. Consequently, there is little risk of reduced-clean hydraulic fluid leaking out of the fluid filter 1 after replacing the filter element 30.

[0034] In this embodiment, as shown in Figure 8(b), when the engaging projection 333 of the upper plate 33 is not engaged with the engaging recess 202 of the filter case 20, the positions of the outer communication hole 415 and the inner communication hole 424 are completely misaligned, and the space between the outside of the outer support member 41 and the inside of the inner support member 42 is blocked. However, when the filter element 30 is removed from the filter case 20, if the positions of the outer communication hole 415 and the inner communication hole 424 are misaligned (the area of ​​the hole communicating from the outside of the outer support member 41 to the inside of the inner support member 42 is reduced), it can be expected that the amount of hydraulic fluid with reduced cleanliness flowing into the inside of the inner support member 42 will be reduced.

[0035] Next, the new filter element 30 is inserted into the filter case 20, and the filter element 30 is rotated circumferentially so that the engaging projection 412 formed on the upper end of the outer support member 41 enters the engaging groove 336 of the upper plate 33 shown in Figure 4(a). Once the engaging projection 412 enters the engaging groove 336 and the filter element 30 is further inserted into the filter case 20, the guide portion 345 of the lower plate 34 (see Figure 4(b)) will eventually come into contact with the engaging projection 211 of the retainer 21, as shown in Figure 8(b). If the engaging groove 344 of the lower plate 34 shown in Figure 4(b) does not engage with the engaging projection 211 of the retainer 21, the upper plate 33 shown in Figure 7 is rotated clockwise. Then, the engaging projection 412 of the outer support member 41 comes into contact with the stepped surface st of the engaging groove 336 shown in Figure 4(b), and as a result, the filter material 31, protector 32, and lower plate 34 also rotate as the upper plate 33 rotates.

[0036] As a result, when the upper plate 33 is rotated clockwise, it becomes as shown in Figure 9(a). As the lower plate 34 rotates clockwise, the guide portion 345 moves clockwise while contacting the engaging projection 211 of the retainer 21. As shown in Figure 9(b), the filter element 30 gradually moves downward in accordance with the inclination of the guide portion 345, and the engaging groove portion 344 approaches the engaging projection 211. Finally, as shown in Figure 9(c), the long side vertical surface 346 of the lower plate 34 abuts against the engaging projection 211 of the retainer 21, restricting further rotation of the lower plate 34 and guiding the engaging groove portion 344 to the position of the engaging projection 211. This allows the lower plate 34 (and thus the filter element 30) to move downward along the engaging projection 211.

[0037] In this way, by forming a guide portion 345 at the lower part of the lower plate 34, the engagement groove portion 344 formed at the lower part of the lower plate 34 can be easily engaged with the engagement projection portion 211 of the retainer 21 simply by rotating the filter element 30 clockwise. Furthermore, since the six engagement recesses 343, each composed of an engagement groove portion 344 and a guide portion 345, are provided at equal intervals in the circumferential direction at the lower part of the lower plate 34, the angle by which the filter element 30 must be rotated clockwise before the engagement groove portion 344 of the lower plate 34 engages with the engagement projection portion 211 of the retainer 21 can be reduced.

[0038] Then, when the filter element 30 is lowered further in the state shown in Figure 9(c), the fixing member 332 of the upper plate 33 bends in the direction of the arrow in the figure, as shown in Figure 8(b). Subsequently, as shown in Figure 8(c), when the engaging projection 333 shown in Figure 4(a) enters the engaging recess 202 of the filter case 20, the bending of the fixing member 332 returns to its original position, and the engaging projection 333 and the engaging recess 202 engage, locking the upper plate 33 to the filter case 20. Furthermore, by lowering the filter element 30 further, the flange contact surface 342 of the lower plate 34 (see Figure 4(b)) pushes down the flange portion 411 of the outer support member 41 (see Figure 5(a)). As a result, the inner support member contact surface 413 and the outer support member contact surface 422 are separated, and the outer support member 41 moves downward relative to the inner support member 42, so that a part of the outer communication hole 415 overlaps with the inner communication hole 424, and the outside of the outer support member 41 and the inside of the inner support member 41 are in communication.

[0039] When removing the filter element 30 from the filter case 20 in the state shown in Figure 8(c), bending the lever member 334 of the upper plate 33 inward (bending it in the direction of the arrow in Figure 8(c)) causes the fixing member 332 to bend inward into the filter case 20, thereby releasing the engagement of the engaging projection 333 with the engaging recess 202. At this time, the biasing force of the compression coil spring 22 pushes up the outer support member 41, causing the filter element 30 to move upward, and as shown in Figure 8(b), the upper plate 33 protrudes to a position higher than the opening of the filter case 20. This makes the filter element 30 easier to grasp and easier to remove from the filter case 20.

[0040] Next, referring to Figure 10, the movement of each part when attaching the filter case 20 (see Figure 8(c)) containing the filter element 30 to the filter head 10 will be explained. In Figure 10(b), an enlarged view of the area m1 enclosed by the dashed line is also shown. In Figure 10(c), an enlarged view of the area m2 enclosed by the dashed line is also shown.

[0041] First, as shown in Figure 10(a), the male thread 201 on the case side of the filter case 20, which houses the filter element 30, is screwed into the female thread 103 on the head side of the filter head 10. As this screwing progresses, the filter case 20 gradually moves upward, and eventually the fluid communication port 337 of the upper plate 33 fits into the fitting port 104 of the filter head 10. As the screwing progresses further, as shown in Figure 10(b), the open end face of the fitting port 104 comes into contact with the upper plate 33. In this state, as shown in the enlarged view of region m1, the filter head There is still a gap between the case contact surface 105 of the do 10 and the open end surface 205 of the filter case 20, and there is room for the engaging projection 333 formed on the upper plate 33 to move downward inside the engaging recess 202 of the filter case 20 (see Figure 8(c)). As the screwing of the filter case 20 progresses, the filter case 20 rises along with the screwing, but the upper plate 33 (and thus the filter element 30) is prevented from rising by the open end surface of the fitting opening 104.

[0042] Therefore, inside the filter case 20, the outer support member 41 remains stationary while only the inner support member 42 rises as the filter case 20 is screwed in, causing the position of the inner communication hole 424 to approach the position of the outer communication hole 415. Then, as shown in Figure 10(c) and the enlarged view of region m2, when the open end face 205 of the filter case 20 contacts the case contact surface 105 of the filter head 10, the upward movement of the filter case 20 due to screwing stops, and at this point the positions of the outer communication hole 415 and the inner communication hole 424 coincide. This completes the attachment of the filter case 20 to the filter head 10. To remove the filter case 20 from the filter head 10, the movements are in the reverse order of those described above.

[0043] Here, when removing the filter case 20 from the filter head 10 (see Figure 10(a)) from the state in which the filter case 20 is attached to the filter head 10 (see Figure 10(c)), the engaging projection 333 of the upper plate 33 engages with the engaging recess 202 of the filter case 20. Therefore, when removing the filter case 20 from the filter head 10, the fluid communication hole 337 of the upper plate 33 is pulled out from the fitting opening 104 of the filter head 10. Consequently, when replacing the filter element 30, the procedure is to replace the filter element 30 housed inside the removed filter case 20 with a new one, and then attach the filter case 20 containing the new filter element 30 to the filter head 10.

[0044] If the engaging projection 333 of the upper plate 33 and the engaging recess 202 of the filter case 20 were not formed, the procedure for replacing the filter element 30 may differ depending on the orientation in which the fluid filter 1 is positioned. For example, suppose the fluid filter 1 is positioned in the opposite orientation to that shown in Figure 10(c), where the filter head 10 is positioned above the filter case 20, where the filter head 10 is positioned below the filter case 20 (in other words, the filter case 20 is positioned above the filter head 10). In this case, when the filter case 20 is removed from the filter head 10, there is a possibility that only the filter case 20 will be removed while the fluid communication hole 337 of the upper plate 33 remains engaged with the fitting opening 104 of the filter head 10.

[0045] In such cases, the procedure for replacing the filter element involves first removing the filter case 20 from the filter head 10, then pulling out the fluid communication hole 337 of the filter element 30 from the fitting port 104 of the filter head 10, fitting the fluid communication hole 337 of the new filter element 30 into the fitting port 104, and finally attaching the filter case 20 to the filter head 10. Therefore, the procedure for replacing the filter element 30 may differ depending on the orientation in which the fluid filter 1 is positioned, which could complicate the replacement process.

[0046] In contrast, in the fluid filter 1 of this embodiment, the engaging projection 333 of the upper plate 33 engages with the engaging recess 202 of the filter case 20. Therefore, regardless of the orientation of the fluid filter 1, the filter case 20 is always removed from the filter head 10 with the filter element 30 housed inside. This has the advantage that the procedure for replacing the filter element 30 is consistent regardless of the orientation in which the fluid filter 1 is positioned.

[0047] Furthermore, the fluid filter according to the present invention can be used, for example, as a return filter to filter the hydraulic fluid that returns from a hydraulic device after it has been supplied from a tank to a hydraulic device by a hydraulic pump, or as a suction filter to filter the hydraulic fluid supplied from the tank to the hydraulic pump. In addition, the filtration target is not limited to hydraulic fluid; similar effects can be obtained by applying it to filters of other fluids such as fuel. [Explanation of Symbols]

[0048] 1. Fluid filter 10 filter heads 20 filter cases 30 filter elements 31 Filter media 32 Protector 33 Upper Plate 24 Lower Plate 40 Support member 41 Outer support member 42 Inner support member

Claims

1. A filter head having a fluid inlet and outlet, A filter case formed in a bottomed cylindrical shape with an open upper end and an internal space, the upper end of which is connected to the filter head and detachably attached, A hollow cylindrical filter element is detachably housed within the internal space of the filter case and performs filtration by allowing fluid to pass through it. The filter case comprises a support member that extends upward from the bottom surface within the internal space of the filter case, is inserted into the hollow portion of the filter element housed within the internal space, and detachably supports the filter element. The filter case, which houses the filter element supported by the support member, is attached to the filter head, and the fluid flowing in from the inlet is filtered by passing it through the filter element before being discharged from the outlet. The support member comprises a hollow cylindrical inner support member fixed to the bottom surface of the filter case and extending upward, and a hollow cylindrical outer support member fitted into the inner support member so as to be vertically movable relative to the inner support member and attached to the inner support member. Multiple internal communication holes are formed in the hollow cylindrical wall of the inner support member, and multiple external communication holes are formed in the hollow cylindrical wall of the outer support member. With the filter case, in which the filter element is supported and housed by the support member, attached to the filter head, the inner communication hole aligns with the outer communication hole, allowing fluid flow between the outer circumference of the outer support member and the inner circumference of the inner support member. A fluid filter characterized in that, when the filter case is removed from the filter head and the filter element is removed from the filter case, the inner communication hole is positioned offset from the outer communication hole, and the fluid flow between the outer circumference of the outer support member and the inner circumference of the inner support member is restricted or regulated.

2. The system includes a biasing member that biases the outer support member upward relative to the inner support member, With the filter case, in which the filter element is supported and housed by the support member, attached to the filter head, the outer support member moves downward against the biasing force of the biasing member, and the inner communication hole aligns with the outer communication hole. The fluid filter according to claim 1, characterized in that when the filter case is removed from the filter head and the filter element is removed from the filter case, the outer support member moves upward due to the biasing force of the biasing member, and the inner communication hole is offset relative to the outer communication hole.

3. The fluid filter according to claim 2, characterized in that the outer support member is fitted into the hollow portion of the filter element to house the filter element in the internal space of the filter case, and the filter element is moved downward against the biasing force of the biasing member so that the inner communication hole is aligned with the outer communication hole, and the locking means is provided to lock and hold the filter element within the filter case.

4. The fluid filter according to claim 3, characterized in that by releasing the locking means from the state in which the filter element is locked and held within the filter case by the locking means, the biasing member moves the outer support member upward relative to the inner support member, and moves the filter element supported by the outer support member upward so that its upper end protrudes above the upper opening of the filter case.

5. A first engaging portion extending in the vertical direction is formed on the inner circumferential surface of the outer support member. A second engaging portion is formed on the outer circumferential surface of the inner support member, which engages with the first engaging portion. The engagement of the first engaging portion and the second engaging portion with respect to the inner support member The fluid filter according to any one of claims 1 to 4, characterized in that it restricts relative rotation while allowing relative vertical movement of the outer support member.

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