JP2011218252A - Fluid filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid filter having a constitution capable of ensuring a large filtering area.SOLUTION: An oil filter 1 has a constitution including: a filter case 10 formed with an elements arranged space S1, an inflow hole 21 and an outflow hole 24 of the case; and a filer element 40 mounted in the elements arranged space S1 dividing the space S1 into an inflow space S2 communicating to the inflow hole of the case and an outflow space S4 communicating to the outflow hole 24 of the case. The oil filter 1 also includes: a first filter medium 55 whose outer peripheral side of the filter case is in contact with th inflow space S2, and a second filter medium 65 disposed in the inner peripheral side; and a pair of end plates 70, 80 supporting both ends of the first and second filter media to form the outflow space S4 between the inner peripheral surface of the first filter medium and the outer peripheral surface of the second filter medium. On the upper end plate, a plate flow passage hole 75a is formed to connect the inflow space S2 and the inner peripheral space S5 of the second filter medium. On the lower end plate, a discharge hole 85 is formed to connect the outflow space S4 and the outflow hole of the case.

Description

  The present invention relates to a fluid filter for filtering a fluid such as oil, and further relates to a fluid filter provided with a detachable filter element.

  Since the lubricating oil used in various machines and the hydraulic oil in the hydraulic circuit of industrial hydraulic equipment are contaminated by use, it is necessary to appropriately filter. The oil filter used for filtering such hydraulic oil is provided in the middle of the hydraulic circuit piping, or connected to the end of the return side piping and provided in the oil tank. The oil filter includes a filter element that is detachably mounted in an element arrangement space in the filter case. For example, the filter element is formed by forming a plate-shaped filter paper into a pleated shape (chrysanthemum shape) with a predetermined width. And an end plate attached to each end on both ends of the filter medium (see, for example, Patent Document 1). In such an oil filter, when a fluid such as hydraulic oil passes through the filter medium, impurities mixed in the fluid are captured and removed by the filter medium.

Japanese Patent Laid-Open No. 10-328507

  In the oil filter configured as described above, it is desired to maintain the same filtration performance as before, while keeping the volume of the filter case small, in order to reduce the size and size. However, generally, when the inside of the filter case is made small, it is necessary to design the filter element accommodated in the filter case as much as that, and as a result, the effective filtration area of the filter medium is reduced and the filtration efficiency is lowered. was there.

  The present invention has been made in view of such problems, and provides a fluid filter having a configuration capable of ensuring a larger filtration area by effectively utilizing a limited space in a filter case. With the goal.

  In order to solve the above-mentioned problems, a fluid filter according to the present invention includes a filter case having an element arrangement space inside and an inflow hole and an outflow hole that communicate the element arrangement space and the outside, and an element arrangement. A filter element that is separated into an inflow space that communicates with the inflow hole and an outflow space that communicates with the outflow hole, and is detachably mounted in the element installation space. An inflow space is formed, and an outflow space is formed inside. The filter element includes a cylindrical first filter medium whose outer peripheral side is in contact with the inflow space in the filter case, a cylindrical second filter medium disposed on the inner peripheral side of the first filter medium, and an inner periphery of the first filter medium. A pair of end plates that cover and support both ends of the first and second filter media such that an outflow space is formed between the surface and the outer peripheral surface of the second filter media, and one of the pair of end plates. The end plate (for example, the upper end plate 70 in the embodiment) communicates with the inflow space and the inner peripheral space formed on the inner peripheral side of the second filter medium (for example, the plate flow hole 75a in the embodiment). The other end plate (for example, the lower end plate 80 in the embodiment) is formed with a discharge hole for communicating the outflow space with the outflow hole.

  The fluid filter configured as described above has a base portion formed with a relief hole that allows the inflow space and the outflow space to communicate with each other, and a valve body that opens and closes the relief hole. It is preferable to further include a relief valve that opens the relief hole by the valve body when the pressure becomes greater than a predetermined value by the pressure on the side.

  Further, it is preferable that the relief valve is detachably attached to one end plate, and the one end plate is configured to have a guide path that communicates the inflow space and the outflow space via the relief hole.

  Furthermore, the filter element has a cylindrical outer cylinder (for example, the first outer cylinder 51 in the embodiment) that covers the outer peripheral surface of the first filter medium and is attached to the end plate to form the outer peripheral portion of the filter element. The filter case has a retainer disposed on the bottom surface of the filter case in the element disposition space, and the outer cylinder has an upper inflow hole (for example, implementation) for allowing the fluid in the inflow space to pass through the filter medium. The first outer cylinder flow hole 52) and the lower inflow hole are formed, and the retainer is a plate contact portion that receives the lower end portion of the filter element when the filter element is mounted in the element disposition space. And a cylindrical portion projecting upward from the outer periphery of the plate contact portion and surrounding the lower outer periphery of the filter element (for example, the cylindrical portion 34 in the embodiment) A connecting portion (for example, a gasket holding portion 32 in the embodiment) that connects the discharge hole and the outflow hole in a liquid-tight state, and in a state where the filter element is mounted in the element arrangement space, the lower flow hole and the cylindrical portion It is preferable that the upper end of each is disposed so as to have substantially the same height.

  In addition, one end plate has a first plate that supports one end of the first filter medium, a second plate that supports one end of the second filter medium, and the central axes of the first and second filter media are coaxial. And a rib for connecting the first and second plates to each other.

  According to the fluid filter of the present invention, a double structure that effectively uses the limited space in the filter case and separately arranges the filter media on the outside and the inside to form a fluid flow path (filter path) for each filter medium. By doing so, even if the height and width dimensions of the filter are the same as the conventional one, it is possible to ensure a larger effective filtration area. Therefore, the filtration efficiency of the fluid is improved, the life of the filter element is extended, and the replacement frequency can be reduced.

  The filter medium is further provided with a relief valve that opens the relief hole when the pressure on the inflow space side exceeds the pressure on the outflow space side by a predetermined value or more, so that the filter medium is clogged and the inflow space is clogged. Since the fluid can be accurately relieved when the inside becomes an abnormal pressure, damage to the fluid filter can be prevented.

  In addition, the relief valve is detachably attached to one end plate, and this one end plate is configured to have a guide path that allows the inflow space and the outflow space to communicate with each other through a relief hole, thereby When the filter element is replaced due to the use of the filter, the filter medium and the end plate are replaced with new ones, and the relief valve can be reused.

  Further, the filter case is configured so that the lower flow hole of the outer cylinder and the upper end of the cylindrical portion of the retainer are arranged at substantially the same height when the filter element is mounted in the element disposition space. The fluid before filtration does not remain beyond the upper end of the retainer, and the fluid is prevented from being discharged to the outflow hole without being filtered.

  One end plate is configured to include ribs that connect the first and second plates so that the central axes of the first and second filter media are coaxial, thereby assembling the filter element with a simple configuration with high accuracy. be able to.

It is side surface sectional drawing which shows the oil filter which is an example of the fluid filter of this invention. The filter element which comprises a part of said oil filter is shown, (A) is a top view, (B) is side sectional drawing. The said filter element of the state which removed the relief valve is shown, (A) is a top view, (B) is side sectional drawing.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of an oil filter (return filter) 1 according to the present embodiment. First, using FIG. 1, an oil tank 2 is connected to an end of a return side pipe in a hydraulic circuit. An oil filter 1 that is mounted inside and filters hydraulic oil (return oil) will be described.

  The oil filter 1 is mainly composed of a filter case 10 having a cylindrical element arrangement space S1 therein and a filter element 40 that is detachably attached in the element arrangement space S1.

  The filter case 10 includes a tank flange 11 fixed to the upper surface portion of the oil tank 2, a case lid 13 detachably attached to the upper surface side of the tank flange 11, and a thin wall fixed to the bottom surface side of the tank flange 11. A cylindrical case body 20, a disk-shaped bottom plate 23 that closes the bottom surface of the case body 20, and a retainer 30 placed on the bottom plate 23 are mainly configured. The tank flange 11, the case lid 13, the case main body 20, and the bottom plate 23 are made of, for example, a non-ferrous metal such as an aluminum alloy or a metal material such as iron.

  The filter case 10 has an element arrangement space S1 in which the filter element 40 can be accommodated, and a hollow pipe-like return side pipe 22 is fitted into a case inflow hole 21 opened in a side surface of the case body 20. By joining, the return oil that passes through the return side pipe 22 from the oil tank 2 can flow into the element arrangement space S1. On the other hand, a case outflow hole 24 is formed at the center of the bottom plate 23 of the filter case 10, and a hollow pipe-shaped outlet pipe 25 is located upward (that is, in the element arrangement space S 1) from the case outflow hole 24. It is fitted and joined so as to extend.

  The tank flange 11 is formed in a hollow cylindrical shape, and an element insertion hole 12 through which the filter element 40 can be inserted in the vertical direction is formed at the center thereof. The case lid 13 is formed in a disc shape having a circular groove 14 on the lower surface side, and a disc-shaped spring support portion 15 protruding downward is formed at the center of the circular groove 14. One end of a set spring 16 is supported on the spring support portion 15, and the filter element 40 is pressed against the retainer 30 by the set spring 16. The case lid 13 is detachably attached to the tank flange 11 from above by a plurality of fixing screws (not shown) so as to close the element insertion hole 12 from the upper surface side. FIG. 1 shows a state in which the case lid 13 is detached from the tank flange 11.

  The retainer 30 is connected to the outer upper end of the gasket holding part 32 and the annular gasket holding part 32 having an L-shaped cross section in which a central hole for holding the gasket 31 is formed at the center in order from the inside. An annular plate contact portion 33 that receives the lower end portion, a thin cylindrical cylindrical portion 34 that extends upward from the outer end of the plate contact portion 33, and a U-shaped cross section that is connected to the outer end of the plate contact portion 33. A ring-shaped outer peripheral portion 35 is integrally formed, and is provided on the outlet pipe 25 through the gasket 31 supported by the gasket holding portion 32 so as to be freely detachable from above.

  Subsequently, the filter element 40 that is detachably disposed in the filter case 10 for filtering the return oil will be described with additional reference to FIGS. 2 and 3. Here, FIG. 2 is a plan view and a side sectional view of the filter element 40, and FIG. 3 is a plan view and a side sectional view showing the filter element 40 with a relief valve 90 and the like to be described later removed.

  The filter element 40 is mainly composed of a first element 50, a second element 60, an upper end plate 70, a lower end plate 80, a relief valve 90, and a handle 99. Each has a double structure provided with a filter medium for filtering the return oil.

  The first element 50 constituting the outer portion of the filter element 40 includes a first outer cylinder 51, a first inner cylinder 56 disposed inside the first outer cylinder 51, and an outer periphery of the first inner cylinder 56. The first filter medium 55 is arranged. Here, the 1st outer cylinder 51 and the 1st inner cylinder 56 are formed so that it can be incinerated with combustible resin materials, such as a plastic, paper, etc., for example.

  The first outer cylinder 51 is formed in a cylindrical shape with an outer diameter smaller than the inner diameter of the case body 10 so that a predetermined inflow space S2 is formed with respect to the inner peripheral surface of the case body 20. A plurality of first outer cylinder flow holes 52 penetrating from the outside toward the inside are formed in the upper portion as a pair of upper and lower sides at equal intervals in the circumferential direction. In addition, a plurality of lower flow holes 53 penetrating from the outside toward the inside are formed at equal intervals in the circumferential direction at the lower side portion of the first outer cylinder 51, and the height position of the lower flow holes 53 is In the state where the filter element 40 is mounted in the element arrangement space S1 of the filter case 10, the height is set to be substantially the same as the height of the upper end portion of the retainer 30.

  The first filter medium 55 is formed in a cylindrical shape with an outer diameter smaller than the inner diameter of the first outer cylinder 51 so that a predetermined outer peripheral space S3 is formed on the inner peripheral surface of the first outer cylinder 51, and The inner peripheral surface is mounted so as to come into contact with and contact with the outer peripheral surface of the first inner cylinder 56. The first filter medium 55 is formed by forming a plate-shaped filter paper into a pleated shape (chrysanthemum shape) with a predetermined width, or having a predetermined thickness by filter paper, glass fiber, nonwoven fabric, or the like.

  The first inner cylinder 56 is formed in a cylindrical shape along the inner peripheral surface of the first filter medium 55 using a punching metal or the like, and a large number of oils filtered by the first filter medium 55 can be circulated on the side surfaces thereof. A first inner cylinder flow hole 57 is formed. The first inner cylinder 56 and the first filter medium 55 are sandwiched between end plates 70 and 80 disposed at both ends of the first outer cylinder 51 in the cylindrical axis direction (vertical direction), respectively.

  On the other hand, the second element 60 constituting the inner portion of the filter element 40 includes a second outer cylinder 61, a second inner cylinder 66 disposed inside the second outer cylinder 61, and the second inner cylinder 66. It comprises a second filter medium (inner side filter medium) 65 disposed on the outer periphery. Here, the 2nd outer cylinder 61 and the 2nd inner cylinder 66 are formed so that it can be incinerated with combustible resin materials, such as a plastic, paper, etc., for example.

  The second outer cylinder 61 is formed with an outer diameter smaller than the inner diameter of the first inner cylinder 56 so that a predetermined outflow space S4 is formed with respect to the inner peripheral surface of the first inner cylinder 56, A large number of second outer cylinder flow holes (not shown) are formed on the side surface.

  The second filter medium 65 is formed in a cylindrical shape with an outer diameter slightly smaller than the inner diameter of the second outer cylinder 61, and is mounted so that its inner peripheral surface comes into contact with and contacts the outer peripheral surface of the second inner cylinder 66. ing. As with the first filter medium 55, the second filter medium 65 is formed by forming a plate-shaped filter paper into a pleated shape (chrysanthemum) with a predetermined width, or having a predetermined thickness by using filter paper, glass fiber, nonwoven fabric, or the like. It is formed.

  The second inner cylinder 66 is formed in a cylindrical shape along the inner peripheral surface of the second filter medium 65 using a punching metal or the like, and a large number of inner cylinder flow holes 67 are formed on the side surface. Further, a predetermined inner circumferential space S5 is formed surrounded by the inner circumferential surface of the second inner cylinder 66. The second inner cylinder 66 and the second filter medium 65, together with the first inner cylinder 56 and the first filter medium 55 described above, are end plates 70 and 80 respectively disposed at both ends of the outer cylinders 51 and 61 in the cylindrical axis direction. It is pinched by.

  The upper end plate 70 includes a first plate 71 fixed to the upper end surface of the first outer cylinder 51, a second plate 74 fixed to the upper end surface of the second outer cylinder 61, the first and second plates 71, 74 is provided with a plurality of ribs 77 provided at equal intervals in the circumferential direction to connect these plates 71, 74.

  On the upper surface side of the first plate 71, three clamps 72 having a substantially blade shape in plan view for fixing the relief valve 90 to the upper end plate 70 are pivotably mounted with the vertical axis as a central axis. An annular seal member 73 formed of an elastic member such as rubber is mounted on the upper surface side of the first plate 71 and on the inner side of each clamp 72.

  The second plate 74 includes a cylindrical connecting portion 75 having a hollow cylindrical shape extending in the vertical direction. The second connecting portion 74 is formed at the center of the cylindrical connecting portion 75 so as to have a smaller diameter than the inner diameter of the second inner cylinder 66. A plate circulation hole 75a is formed for communicating S2 and the inner circumferential space S5. An O-ring 76 for sealing the second plate 74 and the relief valve 90 is mounted in an O-ring groove formed on the side surface of the cylindrical connecting portion 75.

  The plurality of ribs 77 have a predetermined distance between the first plate 71 and the second plate 74 so that the predetermined outflow space S4 is formed between the first inner cylinder 56 and the second outer cylinder 61. The plates 71 and 74 are joined to each other at equal intervals in the circumferential direction in a separated state, and between the ribs 77, a guide path 77a (ribs) for relief oil flowing in from a relief hole 92 of a relief valve 90 described later. Are formed penetrating in the vertical direction.

  The lower end plate 80 includes a cylindrical dish-like base portion 81 having an opening 82 that opens downward, and the base portion 81 is attached to the outlet pipe 25 in a state where the filter element 40 is mounted in the filter case 10. It is designed to face the tip of the. On the lower surface side of the lower end plate 80, a seal member 83 formed of an elastic member such as rubber is mounted outside the base portion 81. The lower end plate 80 is formed with a communication portion 84 that extends upward and is inserted into the outflow space S4. The outflow space S4 is connected to the lower end plate 80 via an annular discharge hole 85 formed in the communication portion 84. And the opening 82 (and the outlet pipe 25) communicate with each other.

  In a state where the filter element 40 is mounted in the filter case 10, in the element arrangement space S 1 and above the filter element 40 (that is, in the vicinity of the element insertion hole 12 of the tank flange 11), in the inflow space S 2. An oil flow path 17 is formed to guide the oil that has flowed in (without passing through the first filter medium 55) to the second filter medium 65 of the second element 60, and a relief valve 90 serving as a safety valve is provided for the oil flow path 17. Is provided.

  The relief valve 90 includes a base 91 in which a relief hole 92 for circulating relief oil is formed, an annular pedestal 93 having an L-shaped cross section fixed below the base 91, and an outer surface of the base 91. An annular valve body 94 having an L-shaped cross-sectional view provided so as to be slidable in the vertical direction, a valve spring 95 interposed between the cradle 93 and the valve body 94, and a plurality of And an annular spring receiving portion 96 provided inside the base portion 91 via the rib 96a, and the clamp 72 is horizontally held at a predetermined angle in a state where the base portion 91 is fitted to the cylindrical connecting portion 75. By pivoting in the direction and engaging the base 91 and the clamp 72, the upper end plate 70 is detachably attached from above.

  The base portion 91 has a relief hole 92 and is formed in an annular shape having an L-shaped cross section, and outward from the outer end (upper end flange) of the sleeve portion 91a outward. A cylindrical base flow hole 91c for flowing return oil to the second filter medium is formed on the inner peripheral side of the sleeve portion 91a.

  The valve body 94 normally closes the relief hole 92 by the elastic biasing force of the valve spring 95, and the relief hole 92 does not communicate with the outflow space S 4 via the guide path 77 a formed between the ribs 77. It is configured. On the other hand, when the pressure in the oil flow passage 17 becomes an abnormal pressure exceeding a predetermined value, the valve element 94 is opened against the urging force of the valve spring 95 (the relief hole 92 is opened), and the relief is performed. The hole 92 and the outflow space S4 communicate with each other.

  The spring receiving portion 96 receives the other end portion of the set spring 16 for preventing the behavior of the filter element 40 in the filter case 10 in a state where the filter element 40 is mounted in the filter case 10. Yes. Further, the spring receiving portion 96 has an insertion hole 96b penetrating in the vertical direction at the center thereof, and the oil flowing into the base flow hole 91c of the base portion 91 passes between the ribs 96a together with the insertion hole 96b. It flows through the plate circulation hole 75a of the second plate 74 to the inner circumferential space S5 of the second inner cylinder 66.

  The handle 99 is pivotally connected to the extending portion 91b of the base 91 in the relief valve 90, and is configured to be swingable up and down between an upright position (pickup position) and a lying position. When the filter element 40 is inserted into and removed from the filter case 10, the handle 99 can be held in the upright position and held by the palm to carry the filter element 40. When the filter element 40 is mounted in the filter case 10, the handle 99 can be accommodated in a compact position by being placed in the lying position.

  As a procedure for assembling the filter element 40, first, the two elements 50, 60 are arranged so that the outflow space S4 is formed between the inner peripheral surface of the first element 50 and the outer peripheral surface of the second element 60. In a state of being attached to the lower end plate 80, the first plate 71 and the second plate 74 are attached from above. Then, a plurality of ribs 77 are joined between the two filter media 55 and 65 in a state in which the first filter media 55 and the second filter media 65 are centered so that the center axes of the vertical center axes coincide with each other. Thereby, the 1st filter medium 55 and the 2nd filter medium 65 can be arrange | positioned concentrically with sufficient precision. Here, a clearance portion 77b (see FIG. 3) with a predetermined gap is provided in a portion that receives the upper peripheral edge of the second plate 74 below the rib 77, and the filter media 55, 65 are provided by this clearance portion 77b. The filter element 40 can be appropriately assembled by absorbing dimensional errors in the height direction and the like and variations in the assembly.

  Thereafter, when the relief valve 90 is attached to the upper end plate 70, the sleeve portion 91a (base passage hole 91c) of the base 91 in the relief valve 90 and the cylindrical connecting portion 75 of the second plate 74 are fitted, With the extended portion 91b of the base portion 91 being in close contact with the seal member 73 of the upper end plate 74, the clamps 72 and the base portion 91 (extended portion) are rotated relative to each other by a predetermined angle. 91b) may be engaged.

  A case where return oil is filtered by the oil filter 1 configured as described above will be described. First, a procedure for attaching the filter element 40 to the filter case 10 will be described. Since the filter case 10 is mounted from the upper opening (element insertion hole 12) of the tank flange 11, the fixing screw is removed in advance to remove the case lid 13 from the tank flange 11. When the case lid 13 is removed, the upper opening (element insertion hole 12) of the tank flange 11 is opened.

  When the operator grasps the handle 99 and inserts the filter element 40 straight from above the filter case 10, the lower part of the filter element 40 enters the cylindrical portion 34 of the retainer 30, and the seal member 83 on the bottom surface of the lower end plate 80 moves the upper surface of the retainer 30. The filter element 40 is mounted in the filter case 10 in a state of being in contact with the filter case 10.

  After the filter element 40 is mounted, the case lid 13 is again attached to the tank flange 11 using a fixing screw, and the filter element 40 is moved to the filter case by the urging force of the set spring 16 supported by the case lid 13. 10 is held firmly. At this time, the filter element 40 is always urged downward by the set spring 16 and the weight of the filter element 40 causes the seal member 83 to be elastically deformed between the lower end plate 80 and the retainer 30 so as to be in close contact with both. Thus, the inflow space S2 of the filter case 10 and the outlet pipe 25 are kept liquid-tight. For this reason, return oil (oil that has not been filtered) does not leak from the inflow space S2 in the filter case 10 to the outlet pipe 25 through the space between the retainer 30 and the filter element 40.

  Next, the flow of return oil filtered by the oil filter 1 to which the filter element 40 is mounted as described above will be described with reference to FIG. 1 again. In FIG. 1, the oil flow is represented by an arrow F. The return oil flows from the outside of the oil tank 2 through the return side pipe 22 into the inflow space S2 in the filter case 10. At this time, the inside of the filter case 10 (element arrangement space S1) is almost filled with oil.

  The return oil that has flowed into the inflow space S2 from the return side pipe 22 is changed in the direction of flow by hitting the outer wall of the cylindrical portion 34 of the retainer 30 (the flow is rectified), and moves upward in the inflow space S2. It flows toward the outer peripheral space S3 of the first filter medium 55 through the first outer cylinder flow hole 52 formed above the outer wall of the first outer cylinder 51 from the outer side to the inner side. At this time, the pressure of the return oil flowing in from the return side pipe 22 (inflow pressure) acts on the first outer cylinder 51 in the direction of pushing from the outside to the inside, so that the first outer cylinder 51 The outer peripheral space S3 having a predetermined clearance is formed between the first outer cylinder 51 and the first filter medium 55 even if the inner peripheral surface of the first outer cylinder 51 is pushed. However, the outer peripheral space S3 that also serves as an oil flow path by contacting the first filter medium 55 is not blocked.

  The oil that has flowed into the outer circumferential space S3 flows from the outside to the inside of the first filter medium 55. At this time, impurities such as dust mixed in the oil are filtered by the first filter medium 55. The oil filtered by the first filter medium 55 flows into the outflow space S4 through the first inner cylinder flow hole 57 of the first inner cylinder 56. In addition, since the inner periphery is contact | abutting with the outer periphery of the 1st inner cylinder 56, the 1st filter medium 55 does not deform | transform even if oil flows in from an outer peripheral direction (outer periphery space S3). The oil that has flowed into the outflow space S4 flows downward in the outflow space S4 and is discharged out of the oil filter 1 through the discharge hole 85 at the lower end.

  On the other hand, the total amount of return oil flowing into the inflow space S2 from the return side pipe 22 does not flow through the filtration path through which the first filter medium 55 is filtered through the first outer cylinder flow hole 52 described above. There is also a flow of oil further upward in S <b> 2 (above the first outer cylinder circulation hole 52), and this oil flows through the oil flow passage 17 above the relief valve 90, after which the spring receiving portion 96 is inserted. The hole 96b and the rib 96a pass through the plate flow hole 75a of the second plate 74 and the like, and proceed to the path flowing into the inner peripheral space S5 of the second inner cylinder 66.

  At this time, since the relief valve 90 is normally closed, even if the return oil from the inflow space S2 passes through the oil flow passage 17 above the relief valve 90, the oil is released from the relief hole 92. Thus, the oil does not flow into the outflow space S4. Therefore, there is no possibility that the oil that has not been filtered is discharged to the oil tank 2. Further, in a state where the distal end portion of the extending portion 91 b in the relief valve 90 is engaged with the plurality of clamps 72 of the upper end plate 70, the distal end portion of the extending portion 91 b is in close contact with the lower seal member 73 and sealed. Therefore, the oil flowing through the oil circulation hole 17 is prevented from flowing directly between the base 91 and the first plate 71 (without passing through the second filter medium 65) to the outflow space S4. Furthermore, since the O-ring 76 attached to the cylindrical connecting portion 75 seals the fitting portion between the outer peripheral surface of the cylindrical connecting portion 75 and the inner peripheral surface of the base 91 of the relief valve 90, The oil flowing through the base flow hole 91c of the base 91 is prevented from flowing directly from the fitting portion to the outflow space S4 (without passing through the second filter medium 65).

  The oil that has flowed into the inner circumferential space S5 from the oil flow passage 17 flows from the inside to the outside of the second filter medium 65 through the second inner cylinder flow hole 67 in the second inner cylinder 66. Impurities mixed inside are filtered by the second filter medium 65. The oil filtered by the second filter medium 65 flows into the outflow space S4 through the second outer cylinder inflow hole 62 of the second outer cylinder 61.

  The oil that has flowed into the outflow space S4 through the second filter medium 65 merges with the oil that has flowed in through the first filter medium 55 (the first element 50) in the outflow space S4, and the inside of the outflow space S4 is downward. It flows toward the outside, is discharged from the discharge hole 85 at the lower end to the outside of the oil filter 1, and finally flows into the oil tank 2 through the outlet pipe 25.

  In this way, the oil that has flowed into the inflow space S2 from the return side pipe 22 has two paths: a path that flows from the outside of the first element 50 toward the inside and a path that flows from the inside of the second element 60 toward the outside. Since the flow is divided into the paths and filtered by the respective filter media 55 and 65, the effective filtration area can be increased in the limited space in the filter case 10, and the oil filtration efficiency can be improved.

  Here, when clogging occurs in the filter media 55 and 65, the pressure of oil in the inflow space S2 and the inner peripheral space S5 increases, and the pressure difference between the spaces S2 and S5 and the outflow space S4 exceeds a predetermined pressure. Become. Therefore, the oil flowing through the oil inflow passage 17 acts on the valve body 94 with a force greater than the urging force of the valve spring 95, and the valve body 94 is pushed downward against the urging force of the valve spring 95. Thus, the oil flow passage 17 and the outflow space S4 are communicated with each other. Accordingly, the oil flowing through the oil flow passage 17 directly flows into the outflow space S4 from the relief hole 92 without passing through the filter media 55 and 65 (the oil flow at this time is indicated by an arrow F ′ in FIG. 1), and the lower end portion The oil filter 1 is discharged from the discharge hole 85 to the outside of the filter element 40 to prevent the oil filter 1 from being damaged.

  Since the oil filter 1 configured as described above is clogged with the filter media 55 and 65 due to long-term use (the performance of the filter media 55 and 65 is reduced), the filter is periodically (every predetermined replacement time). Although it is necessary to replace the element 40, the removal of the filter element 40 is performed in the reverse order of the attachment.

  When the case lid 13 is removed for the replacement of the filter element 40, the oil in the filter case 10 falls to a level L0 substantially the same as the oil level in the oil tank 2. At this time, when the oil level drops, the oil remaining in the filter case 10 flows into the filter element 40 from the lower circulation hole 53 provided below the side wall surface of the first outer cylinder 51 (the oil at this time). 1 is indicated by an arrow F ″ in FIG. 1, and is filtered when passing through the first filter medium 55 and is discharged out of the filter element 40 from the discharge hole 85 at the lower end portion. There is no risk of being discharged from the pipe 25 to the oil tank 2. Further, the lower outflow hole 53 is formed with the height of the upper end portion of the retainer 30 (cylindrical portion 34) in a state where the filter element 40 is mounted on the filter case 10. Since the oil is provided at substantially the same height, the oil flows from the lower flow hole 53 to the filter element until the oil level drops to the vicinity of the upper end of the retainer 30 as described above. To be flowed into the preparative 40 the filtration, the oil does not remain over the height of the upper end of the retainer 30 in the filter case 20.

  Thereafter, when the operator holds and lifts the handle 99 attached to the filter element 40, the filter element 40 is lifted upward, and the filter element 40 can be discharged from the filter case 10.

  Although the unfiltered oil remains in the filter case 10 from which the filter element 40 has been discharged, the oil level of the oil is adjusted below the height of the retainer 30 by the lower flow hole 53. There is no possibility that the remaining oil before filtration flows into the oil tank 2 from the outlet pipe 25 beyond the upper end of the retainer 30.

  Further, impurities such as dust trapped in the first and second filter media 55 and 65 may fall off the filter media 55 and 65 when the filter element 40 is discharged or when the engine is stopped. An outer peripheral space S3 is formed between the first filter medium 55 and the first outer cylinder 51, and an inner peripheral space S5 is formed inside the second filter medium 65 (second inner cylinder 66). , 65 are all contained in the spaces S3, S5. Therefore, it is possible to prevent impurities released from the filter media 55 and 65 from falling and accumulating in the filter case 10 and to reduce the maintenance burden in the filter case 10. A lower flow hole 53 is formed in the first outer cylinder 51. The lower flow hole 53 is formed in a direction (radial direction) substantially perpendicular to the direction in which the impurities fall from the filter medium 55. There is almost no risk of falling into the lower flow hole 53 and being discharged into the inflow space S2.

  Furthermore, since impurities (metal dust or the like) in the oil that is about to settle to the bottom surface of the filter case 20 in the inflow space S2 accumulate in the outer peripheral portion 35 of the retainer 30, the retainer 30 is taken out from the filter case 10. Thus, impurities can be easily removed. Therefore, it becomes possible to further reduce the maintenance burden in the filter case 10.

  After the filter element 40 is discharged from the filter case 10, the relief valve 90 is easily removed from the filter element 40 by releasing the engagement between the plurality of clamps 72 and the extended portions 91 b of the relief valve 90. be able to. The relief valve 90 and the handle 99 part removed from the filter element 40 can be used repeatedly by washing and the like and then reattaching to a new filter element 40 (excluding the relief valve 90 and the handle 99). Therefore, when the filter element 40 reaches the replacement time, only the assembly part composed of the elements 50 and 60 and the end plates 70 and 80 can be discarded, and the remaining relief valve 90 and the handle 99 can be reused. This reduces the amount of waste and saves resources.

  According to the oil filter 1 configured as described above, the filter medium 55 and 65 are separately arranged on the outer side and the inner side by effectively utilizing the limited space in the filter case 10, and the oil distribution path (filtering) for each filter medium. With the double structure that forms the (path), it is possible to secure a larger effective filtration area even if the height and the radial dimension of the filter are the same as the conventional one. Therefore, the oil filtration efficiency is improved, the life of the filter element is extended, and the replacement frequency can be reduced.

  Although the preferred embodiment of the present invention has been described so far, the present invention is not limited to this embodiment. For example, in the above-described embodiment, an example in which an oil filter (return filter) for filtering hydraulic oil in a hydraulic circuit is applied as a fluid filter is not limited to this. The same effect can be obtained when applied to a filter that filters other fluids such as fuel and fuel.

  In the above-described embodiment, the filter element 40 is assembled by engaging and connecting the relief valve 90 with the clamp 72 in the assembled state in which the elements 50 and 60 and the end plates 70 and 80 are assembled. Instead, the relief valve 90 may be detachably connected by screw fastening in the assembly state. Alternatively, the upper end plate 70 and the relief valve 90 may be configured as a single unit so that the number of parts can be collected and maintenance workability can be improved.

  Furthermore, in the above-described embodiment, the retainer 30 is configured to be detachable in the fill case 10, but the present invention is not limited to this. For example, the retainer is fixed to the outlet pipe 25, the bottom plate 23, and the like. Thus, it is possible to completely prevent the behavior of the retainer in the filter case 10. As exemplified in the present embodiment, even when the retainer 30 is configured to be detachable, for example, a fitting groove for fitting a part of the gasket 31 into the side surface of the outlet pipe 25 is formed, By providing an engaging means for detachably holding the bottom plate 23, the behavior of the retainer 30 can be further prevented.

1 Oil filter (fluid filter)
10 Filter case 21 Case inflow hole (Inflow hole)
24 Case outflow hole (outflow hole)
30 Retainer 32 Gasket holder (connection part)
33 Plate contact part 34 Cylindrical part (cylindrical part)
40 Filter element 51 First outer cylinder (outer cylinder)
52 1st outer cylinder flow hole (upper flow hole)
53 Lower flow hole 55 First filter medium 65 Second filter medium 70 Upper end plate 75a Plate flow hole (communication hole)
77 Rib 77a Guide path 80 Lower end plate 90 Relief valve 91 Base 92 Relief hole 94 Valve body S1 Element arrangement space S2 Inflow space S4 Outflow space S5 Inner peripheral space

Claims (5)

A filter case having an element arrangement space inside and having an inflow hole and an outflow hole communicating with the element arrangement space and the outside; an inflow space communicating with the inflow hole through the element arrangement space; and the outflow A filter element that is separated into an outflow space that communicates with the hole and is detachably mounted in the element disposition space, and the inflow space is formed outside the filter element in the filter case. A fluid filter formed by forming the outflow space,
The filter element is
A cylindrical first filter medium whose outer peripheral side is in contact with the inflow space in the filter case;
A cylindrical second filter medium disposed on the inner peripheral side of the first filter medium;
A pair of end plates that cover and support both ends of the first and second filter media such that the outflow space is formed between an inner peripheral surface of the first filter media and an outer peripheral surface of the second filter media; Prepared,
Of the pair of end plates, one end plate is formed with a communication hole that communicates the inflow space and an inner peripheral space formed on the inner peripheral side of the second filter medium, and the other end plate has the communication hole. A fluid filter, characterized in that a discharge hole for communicating the outflow space and the outflow hole is formed.   A base portion formed with a relief hole for communicating the inflow space and the outflow space; and a valve body for opening and closing the relief hole, wherein the pressure on the inflow space side is a predetermined value than the pressure on the outflow space side. The fluid filter according to claim 1, further comprising a relief valve that opens the relief hole by the valve body when it becomes larger. The relief valve is detachably attached to the one end plate,
3. The fluid filter according to claim 2, wherein the one end plate includes a guide path that allows the inflow space and the outflow space to communicate with each other through the relief hole. The filter element has a cylindrical outer cylinder that covers the outer peripheral surface of the first filter medium and is attached to the end plate to form the outer peripheral portion of the filter element;
The filter case has a retainer disposed on a bottom surface of the filter case in the element disposition space;
The outer cylinder is formed with an upper inflow hole and a lower inflow hole for allowing the fluid in the inflow space to pass through the filter medium,
The retainer includes a plate contact portion that receives a lower end portion of the filter element in a state in which the filter element is mounted in the element disposition space, and projects upward from an outer periphery of the plate contact portion. A cylindrical portion surrounding the lower outer periphery of the element, and a connecting portion that connects the discharge hole and the outflow hole in a liquid-tight state,
4. The filter element according to claim 1, wherein the lower flow hole and the upper end of the tubular portion are arranged at substantially the same height when the filter element is mounted in the element disposition space. The fluid filter according to any one of the above. The one end plate includes a first plate that supports one end of the first filter medium, a second plate that supports one end of the second filter medium, and the central axes of the first and second filter media are coaxial. The fluid filter according to claim 1, further comprising a rib connecting the first and second plates.

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