Filter device and filter device

Abstract

The present invention can prevent the outflow of bubbles contained in hydraulic oil. The present invention comprises: a first filter unit; a second filter unit provided below the first filter unit so as to overlap the first filter unit in plan view; and the third filtering unit is arranged on the first filtering unit or the second filtering unit. The first filter unit has: a housing; a first inflow part that causes a fluid to flow into the interior of the housing; a cylindrical first filter element provided inside the housing; and a first outflow part that causes the filtered fluid filtered by the first filter element to flow out from the first filter unit. The second filter unit has: a cylindrical second filter element provided inside the tank; a second inflow part which is provided between the first outflow part and the second filter element, and which has a second flow path that connects the first flow path and the hollow part of the second filter element; and a second outflow part provided below the second filter element and having a third flow path that connects the hollow part of the second filter element and the outside of the second filter element. The third filter unit has a filter part that covers at least one of the first flow path, the second flow path, and the third flow path.

Description

Technical Field

[0001] The present invention relates to a filter device and a filter apparatus. Background Art

[0002] Patent document 1 discloses a filter device comprising: a filter housing in the shape of a bottom cylinder, which is mounted on a tank for storing liquid and has an open upper end; a filter element, which is arranged inside the filter housing and has a first filter material in the shape of a cylinder; a cover body, which is arranged on the filter housing and the filter element in a manner covering the upper end of the filter housing, and the cover body has an air discharge hole that connects the space inside the filter element with the space outside the filter housing; an inflow portion that allows liquid to flow into the space inside the filter housing and outside the filter element; an outflow portion that connects the space inside the filter element with the space outside the filter housing; and a back pressure valve, which is arranged on the outflow portion.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2020 / 218357 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The invention described in Patent Document 1 closes the back-pressure valve during idling and opens it only after the engine is running. This prevents air (initial air) located inside the filter housing before the engine is running from flowing out of the outflow portion. However, in the invention described in Patent Document 1, if the hydraulic oil flowing into the filter device after the engine is running contains air bubbles, removing the bubbles is difficult.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a filter device and a filter device capable of preventing the outflow of bubbles contained in a fluid.

[0009] Solutions to Problems

[0010] 14. The filter device of claim 13, wherein the filter device comprises: a first filter unit; a second filter unit, which is arranged on the lower side of the first filter unit so as to overlap with the first filter unit in a plan view; and a third filter unit, which is arranged on the first filter unit or the second filter unit, wherein the first filter unit comprises: a housing; a first inlet portion, which is arranged in the housing and allows a fluid to flow into the interior of the housing; a first cylindrical filter element, which is arranged in the interior of the housing and allows the fluid to pass therethrough, thereby filtering the fluid; and a first outflow portion, which is arranged in the housing and has a function of allowing the fluid to pass through the first filter element. The filtered fluid flows out of the first flow path of the first filter unit, and the second filter unit has: a cylindrical second filter element, which is arranged inside the box; a second inlet portion, which is arranged between the first outflow portion and the second filter element and has a second flow path that connects the first flow path with the hollow portion of the second filter element; and a second outflow portion, which is arranged below the second filter element and has a third flow path that connects the hollow portion of the second filter element with the outside of the second filter element, and the third filter unit has a filter portion that covers at least one of the first flow path, the second flow path and the third flow path.

[0011] 14. The filter of claim 13, wherein the filter comprises a first filter element and a second filter element, wherein the first filter element is provided on a lower side of the first filter element so as to overlap with the first filter element in a plan view; and a third filter element is provided on the first filter element or the second filter element, wherein the first filter element comprises a housing; a first inlet portion provided in the housing and allowing a fluid to flow into the housing; a first cylindrical filter element provided in the housing and allowing the fluid to pass therethrough, thereby filtering the fluid; and a first outflow portion provided in the housing and allowing the fluid to flow therethrough. The filtered fluid after being filtered by the first filter element flows out of the first flow path of the first filter unit, and the second filter unit includes: a cylindrical second filter element, which is arranged inside the box; a second inlet portion, which is arranged between the first outflow portion and the second filter element and has a second flow path that connects the first flow path with the hollow portion of the second filter element; and a second outflow portion, which is arranged below the second filter element and has a third flow path that connects the hollow portion of the second filter element with the outside of the second filter unit, and the third filter unit has a filter portion that covers at least one of the first flow path, the second flow path and the third flow path.

[0012] According to the filter device of the present invention, the third filter unit having a filter portion is arranged so as to cover at least one of the first flow path, the second flow path, and the third flow path. Thus, bubbles are removed when the fluid passes through the third filter unit, thereby preventing bubbles contained in the fluid from flowing out of the filter device.

[0013] Alternatively, the second filter unit may include an upper end member disposed on the upper end side of the second filter element, the second flow path being formed in the upper end member, and the third filter unit may be formed of a plate-shaped mesh member and disposed on the upper end member so as to cover the second flow path. This simplifies the structure of the filter device.

[0014] Alternatively, the second outflow portion may include a lower end member disposed on the lower end side of the second filter element, the third flow path being formed in the lower end member, and the third filter unit being disposed in the hollow portion of the second filter unit so as to cover the third flow path. Since the hollow portion of the second filter unit is relatively wide, the third filter unit has a greater degree of freedom in its shape.

[0015] Alternatively, the filter portion may be a member in which the mesh member is provided in a cylindrical shape, the third filter unit may include a plate covering one end of the filter portion, and the end of the filter portion not provided with the plate may be provided on the lower end member. This may increase the filtration area of ​​the third filter unit.

[0016] Alternatively, the filter device may include a pressure relief valve provided in the first filter unit or the second filter unit, the housing may include a filter housing and a cover member provided on an upper side of the filter housing, the cover member may include the first inlet portion and a third outlet portion for allowing the hydraulic oil that has flowed into the interior of the cover member through the first inlet portion to flow out. Thus, the flow of the fluid can be changed according to the pressure within the filter device.

[0017] Effects of the Invention

[0018] According to the present invention, it is possible to prevent bubbles contained in a fluid from flowing out. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram schematically showing a box 100 in which a filter device 1 according to one embodiment of the present invention is installed.

[0020] Figure 2 It is a cross-sectional view schematically showing the filter device 1 .

[0021] Figure 3 It is a cross-sectional view schematically showing the filter device 1 and is a diagram in which a main portion is enlarged.

[0022] Figure 4 It is a cross-sectional view schematically showing the filter device 1A.

[0023] Figure 5 It is a cross-sectional view schematically showing the filter device 1B.

[0024] Figure 6 It is a cross-sectional view schematically showing the filter device 2 .

[0025] Figure 7 It is a cross-sectional view schematically showing the filter device 2 and is a diagram in which a main portion is enlarged.

[0026] Figure 8 It is a cross-sectional view schematically showing the filter device 2A.

[0027] Figure 9 It is a cross-sectional view schematically showing the filter device 3 .

[0028] Figure 10 It is a cross-sectional view schematically showing the filter device 4 .

[0029] Figure 11 It is a cross-sectional view schematically showing the filter device 4A.

[0030] Figure 12 It is a cross-sectional view schematically showing the filter device 4B.

[0031] Figure 13 It is a cross-sectional view schematically showing the filter device 5 .

[0032] Figure 14 It is a cross-sectional view schematically showing the filter device 5A.

[0033] Figure 15 It is a cross-sectional view schematically showing the filter device 6 . DETAILED DESCRIPTION

[0034] The following describes embodiments of the present invention in detail with reference to the accompanying drawings. The filter device of the present invention is installed in the hydraulic circuit that supplies hydraulic fluid to the hydraulic system of a working machine (such as a hydraulic excavator or wheel loader) and filters the hydraulic fluid. However, the structure in which the filter device of the present invention is installed is not limited to the hydraulic circuit, and the fluid filtered by the filter device is not limited to hydraulic fluid. Furthermore, the present invention can be provided not only as a filter device but also as a filter device installed in a tank.

[0035] <First embodiment>

[0036] Figure 11 is a diagram showing the outline of a box 100 in which a filter device 1 according to one embodiment of the present invention is installed. Figure 1 In FIG. 1 , a main portion of the box 100 is shown through a perspective view, and some components are shown in cross-section (however, hatching indicating the cross-section is omitted).

[0037] The tank 100 is provided in a hydraulic circuit of hydraulic oil and stores the hydraulic oil L. In the hydraulic circuit, the hydraulic oil L is introduced into the tank 100 through a hydraulic device.

[0038] The tank 100 includes, for example, a box-shaped tank body 101 , the interior of which is a hollow space. The filter device 1 is mainly provided inside the tank body 101 .

[0039] The upper surface 101a of the box body 101 has a hole 101b formed therein for inserting the filter device 1. The filter device 1 is fixed to the box body 101 by providing a cover member 14 (described in detail later) and the like on the upper surface 101a.

[0040] The filter device 1 mainly includes a first filter unit 10 , a second filter unit 20 and a third filter unit 30 .

[0041] The second filter unit 20 is disposed below the first filter unit 10 so as to overlap the first filter unit 10 in a plan view (when viewed from the z-direction). The second filter unit 20 is disposed near the bottom surface 101c of the box body 101. The third filter unit 30 is disposed in either the first filter unit 10 or the second filter unit 20.

[0042] The central axes ax of the first filter unit 10 and the second filter unit 20 are oriented in substantially the same direction along the z direction. In this embodiment, the central axes ax of the first filter unit 10, the second filter unit 20, and the third filter unit 30 are aligned, but they may not be aligned.

[0043] A hole 101d is formed in the bottom surface 101c of the box body 101. The lower end portion of the second filter unit 20 is inserted into the hole 101d.

[0044] Figure 2 It is a cross-sectional view schematically showing the filter device 1 . Figure 3 1 is a cross-sectional view showing the outline of the filter device 1, and is a diagram showing an enlarged view of a main portion. Figure 2 , hatching showing cross sections is omitted.

[0045] The first filter unit 10 has a filter element 11 , a filter housing 12 , an inner component 13 , a cover member 14 and a valve 15 .

[0046] Filter element 11 (corresponding to the first filter element of the present invention) is a cylindrical (here, circular) member as a whole and is disposed within filter housing 12. Filter element 11 filters the hydraulic oil by allowing it to pass through. Filter element 11 primarily comprises an inner cylinder 111, filter medium 112, and plates 113 and 114.

[0047] The filter medium 112 is a member for filtering the hydraulic oil and has a generally cylindrical shape with a thickness in the radial direction. The filter medium 112 is formed by pleating filter paper made of synthetic resin, paper, etc., and connecting the two ends of the pleated filter paper to round it into a cylindrical shape.

[0048] The inner cylinder 111 is a substantially cylindrical metal member and is provided inside the filter medium 112. The height of the inner cylinder 111 is substantially the same as that of the filter medium 112. The inner cylinder 111 has a hole 111a formed substantially over its entire surface for passage of the hydraulic oil.

[0049] Plate 113 is provided at the lower end of inner cylinder 111 and filter medium 112, and plate 114 is provided at the upper end. Plates 113 and 114 are disk-shaped or bottomed cylindrical members, and are formed using resin or metal. Plate 113 has an opening 113a formed approximately in the center.

[0050] The plate 114 is provided with a valve 15. The valve 15 is a bypass valve, and is opened and closed according to the difference between the pressure inside the filter element 11 (space S3) and the pressure outside (space S2).

[0051] The filter housing 12 is a bottomed cylindrical member formed of metal. A cover member 14 is provided on the upper side of the filter housing 12. The filter element 11 is provided inside the filter housing 12 and the cover member 14 (equivalent to the housing of the present invention).

[0052] The filter housing 12 mainly includes a first housing 121, a second housing 122, and mounting members 123 and 124. The second housing 122 is integrally formed on the upper side of the first housing 121. It should be noted that the mounting members 123 and 124 are not essential.

[0053] The first housing 121 and the second housing 122 are cylindrical (here, cylindrical) members. The second housing 122 is located on the upper side (+z side) of the first housing 121. The second filter unit 20 is located on the lower side (-z side) of the first housing 121, and the cover member 14 is located on the upper side of the second housing 122.

[0054] An inner component 13 is provided inside the first housing 121 . The inner component 13 is a part of the filter housing 12 .

[0055] The internal component 13 mainly includes a first component 131 and a second component 132. In this embodiment, the internal component 13 is provided in the plate-shaped portion 121a provided in the hollow portion of the first housing 121, but the configuration of the internal component 13 in the first housing 121 is not limited thereto.

[0056] The second member 132 is provided to close the hollow portion of the first housing 121, dividing the interior of the first housing 121 into three spaces S1, S4, and S5. The space above the plate-shaped portion 121a and the second member 132 is space S1, and the space below the plate-shaped portion 121a and the second member 132 is space S5.

[0057] The first member 131 is disposed in space S1. An inlet pipe (not shown) is provided in first member 131, located in a hole 121c formed in the side of first housing 121. First member 131 serves as an inlet portion (corresponding to the first inlet portion of the present invention) for the flow of hydraulic oil into the interior of filter housing 12. Space S1 is the initial space into which hydraulic oil L flows from the inlet portion into filter device 1. From space S1, hydraulic oil flows into space S2, which is the space between first housing 121 and filter element 11.

[0058] The second member 132 includes a cylindrical portion 132a extending along the central axis ax. A hollow portion 132b of the cylindrical portion 132a passes through the cylindrical portion 132a, ie, the second member 132.

[0059] The lower end of the cylindrical portion 132a is inserted into the hole 121b formed in the plate-shaped portion 121a. Furthermore, by having the protrusion 132c provided near the upper end of the cylindrical portion 132a contact the plate 113 and inserting the cylindrical portion 132a into the opening 113a, the upper end of the cylindrical portion 132a is inserted into the filter element 11. Consequently, the hollow portion 132b (space S4) connects the hollow portion (space S3) of the filter element 11 with the space (space S5) below the second member 132 in the first housing 121.

[0060] The second member 132 and the first housing 121, which form spaces S4 and S5 (corresponding to the first flow path of the present invention), serve as an outflow portion (corresponding to the first outflow portion of the present invention) through which the fluid filtered by the filter element 11 (corresponding to the filtered fluid of the present invention) flows out. Furthermore, a plurality of holes 121d are formed in the portion of the first housing 121 forming space S5. However, the holes 121d are not essential.

[0061] The cover member 14 is a substantially plate-shaped member that covers the upper open end of the filter case 12. The cover member 14 is detachably provided with respect to the filter case 12 (here, the mounting member 124).

[0062] The cover member 14 includes a first cover 141 and a second cover 142. The first cover 141 is cylindrical and has a hollow portion 141a formed therein. The second cover 142 is plate-shaped and is provided to cover the hollow portion 141a. An elastic member 143 is provided between the lower surface 142a of the second cover 142 and the plate 114.

[0063] When the cover member 14 (here, the second cover 142) is removed from the filter housing 12, the filter element 11 can be pulled out from the upper open end of the filter housing 12. When the cover member 14 is installed in the filter housing 12, the elastic member 143 is clamped between the plate 114 and the second cover 142. The force of the elastic member 143 presses the plate 114, and thus the filter element 11, in the -z direction. This allows the filter element 11 to be positioned within the filter housing 12.

[0064] It should be noted that, in this embodiment, the cover member 14 includes the first cover 141 and the second cover 142 , but the form of the cover member 14 is not limited thereto. For example, the cover member 14 may be a single component.

[0065] The second filter unit 20 is, for example, a suction filter for preventing foreign matter from entering the hydraulic pump. The second filter unit 20 mainly includes a cylindrical portion 21 , a filter medium 22 , an upper end member 23 , and a lower end member 24 .

[0066] The cylindrical portion 21 is a metal, roughly cylindrical component, and is formed with a plurality of holes 21a on the side. The filter material 22 is formed by folding the metal mesh formed by spinning metal wire, and connecting the two ends of the folded metal mesh and rounding them into a cylindrical shape. The filter material 22 is arranged on the outside of the cylindrical portion 21. However, the cylindrical portion 21 is not essential. In addition, the mode of the filter material 22 is not limited to this.

[0067] The upper end member 23 is disposed on the upper end side of the cylindrical portion 21 and the filter material 22 (equivalent to the second filter element of the present invention). It should be noted that the upper end member 23 can be disposed directly on the upper ends of the cylindrical portion 21 and the filter material 22, or it can be disposed on the upper side of the cylindrical portion 21 and the filter material 22 via a member. The upper end member 23 has a recess 23a for inserting the cylindrical portion 21 and the filter material 22, and a cylindrical portion 23b disposed in the recess 23a. The cylindrical portion 23b protrudes upward (toward the first filter unit 10) from the recess 23a. When the cylindrical portion 23b is inserted into the first housing 121, the cylindrical portion 23b is fixed to the first housing 121. As a result, the first housing 121 is disposed on the upper end member 23. However, the method of providing the first housing 121 on the upper end member 23 is not limited to this.

[0068] The hollow portion 23 c of the recess 23 a (equivalent to the second flow path of the present invention) connects the space S4 (hollow portion 132 b ) and the hollow portion of the filter medium 22 (space S6 ), and the fluid filtered by the filter element 11 passes through the hollow portion 23 c .

[0069] The lower end member 24 is disposed at the lower end of the cylindrical portion 21 and the filter material 22. It should be noted that the lower end member 24 can be directly disposed at the lower ends of the cylindrical portion 21 and the filter material 22, or it can be disposed below the cylindrical portion 21 and the filter material 22 via a member. The lower end member 24 has a recessed portion 24a for inserting the cylindrical portion 21 and the filter material 22, and a cylindrical portion 24b for inserting into the hole 101d of the box 100. The hollow portion 24c of the lower end member 24 (equivalent to the third flow path of the present invention) connects the hollow portion of the filter material 22 with the exterior of the second filter unit 20.

[0070] The third filter unit 30 is a plate-shaped filter formed from a metal mesh formed by weaving metal wire. The third filter unit 30 is installed on the upper end member 23 so as to cover the hollow portion 23c. The mesh of the metal mesh constituting the filter portion of the third filter unit 30 is of the same mesh size as the mesh of the filter material 22, or has a mesh size finer than the mesh of the filter material 22.

[0071] It should be noted that the filter portion constituting the third filter unit 30 can be a mesh-like component and is not limited to a metal mesh. For example, the filter portion of the third filter unit 30 can also be a woven resin wire, or a resin-adhesive wire arranged in a spider's nest, a mesh-like mesh, or a net formed by weaving ropes, etc. The mesh-like component of the present invention is a concept that includes such metal meshes, meshes, and nets. In addition, the third filter unit 30 can also be provided with other components (for example, a hollow circular plate-like component) around the periphery of the filter portion formed by the mesh-like component. Furthermore, the third filter unit 30 is not limited to a flat plate. The third filter unit 30 can be plate-like, and plates with curves (for example, wavy), plates with concave and convex surfaces, or plates with cage (bowl)-like curves are also included in the plate-like shape.

[0072] Next, use Figure 2 、 3 The function of the filter device 1 configured in this manner will be described. Figure 2 、 3 The arrows indicate the flow of the hydraulic oil.

[0073] During operation of the hydraulic system, hydraulic oil flows within the hydraulic circuit. The hydraulic oil flows into space S1 via first component 131. From space S1, the hydraulic oil flows into the space outside filter element 11 (space S2). As it flows from outside to inside filter element 11, it is filtered and flows into space S3. The filtered hydraulic oil flows downward from space S3 into spaces S4 and S5.

[0074] The hydraulic oil flowing into the space S5 partially flows out of the tank 100 through the hole 121 d depending on the flow rate, but most of it flows into the space S6 .

[0075] The third filter unit 30 is formed of a metal mesh, so the hydraulic oil can pass through the third filter unit 30, but air bubbles, particularly large air bubbles, are unlikely to pass through the third filter unit 30. Thus, air bubbles are removed from the hydraulic oil.

[0076] The hydraulic oil flowing into the space S6 through the third filter unit 30 partially flows out of the tank 100 or flows in from the tank 100 through the filter medium 22 depending on the flow rate, but most of it flows out of the filter device 1 through the hollow portion 24c. The hydraulic oil flowing out of the filter device 1 is guided to the pump of the hydraulic circuit.

[0077] When repeated filtration occurs, the pores of the filter material 112 become clogged, so the filter element 11 is replaced. The cover member 14 is removed from the filter housing 12, and the filter element 11 is then pulled upward. As a result, the filter element 11 is pulled out from the upper open end of the filter housing 12. Afterwards, when a new filter element 11 is inserted from the upper open end of the filter housing 12 and the cover member 14 is installed on the filter housing 12, the new filter element 11 is set inside the filter housing 12 and the cover member 14.

[0078] According to this embodiment, by providing the third filter unit 30 so as to cover the hollow portion 23c, it is possible to prevent the outflow of bubbles contained in the hydraulic oil. Furthermore, by providing the third filter unit 30 in a plate-like shape and installing it on the upper end member 23, the structure of the filter device 1 can be simplified. While a complex structure can easily cause problems during manufacturing and use, simplifying the structure of the filter device 1 can reduce these problems.

[0079] It should be noted that in this embodiment, the third filter unit 30 is composed of a plate-shaped metal mesh (filter portion), but the third filter unit 30 is not limited to this. For example, the third filter unit 30 may be a member having holes formed in a plate-shaped member and the holes covered with a plate-shaped metal mesh (filter portion).

[0080] In this embodiment, the third filter unit 30 is provided in the second filter unit 20 so as to cover the hollow portion 23c. However, the location of the third filter unit 30 is not limited thereto. For example, the third filter unit 30 may be provided in the first filter unit 10 so as to cover the hole 121b.

[0081] In addition, in this embodiment, the third filter unit 30 composed of a plate-shaped metal mesh is arranged in a manner covering the hollow portion 23c, but the manner in which the third filter unit 30 is arranged in a manner covering the hollow portion 23c is not limited to this. For example, a third unit having a filter portion formed of steel wool or the like may be inserted into the hollow portion 23c. In this case, the bubbles are captured by the filter portion, thereby preventing the discharge of the bubbles. However, when the flow rate increases, the bubbles captured by the filter portion may also be discharged together with the working oil. Therefore, it is desirable to use a mesh component that is almost impossible for bubbles to pass through for the third filter unit 30.

[0082] In this embodiment, the entire filter device 1 is disposed within the housing 100. However, the housing 100 is not limited thereto. For example, only the portion of the filter device 1 below the plate-shaped portion 121a may be disposed within the housing 100. Furthermore, if the hole 121d is not provided, only the second filter unit 20 may be disposed within the housing 100.

[0083] <Modification 1 of the First Embodiment>

[0084] Figure 4 1A is a cross-sectional view showing an outline of a filter device 1A according to a modified example. The filter device 1A is different from the filter device 1 in that a pressure relief valve 16 is provided. Figure 4 In FIG, hatching indicating a cross section is omitted. Note that description of the same parts as those of the filter device 1 will be omitted.

[0085] The filter device 1A mainly includes a first filter unit 10A, a second filter unit 20, and a third filter unit 30. The first filter unit 10A includes a filter element 11, a filter housing 12, an inner component 13, a cover member 14, a valve 15, and a pressure relief valve 16.

[0086] The pressure relief valve 16 is provided on the second member 132 so as to cover the hollow portion 132b. When the pressure in spaces S1 to S3 reaches a set pressure, the pressure relief valve 16 opens, allowing the hydraulic oil to flow from space S3 to space S4. Therefore, when the flow rate of the hydraulic oil is low, such as during idling, the pressure relief valve 16 does not open.

[0087] By providing the pressure relief valve 16 , when the flow rate increases during the operation of the hydraulic system, the oil filtered by the filter device 1A can be made to flow to the pump at a constant pressure.

[0088] <Modification 2 of the first embodiment>

[0089] Figure 5 2 is a cross-sectional view showing an outline of a filter device 1B according to a modified example. The filter device 1B is different from the filter device 1 in that a pressure relief valve 25 is provided. Figure 5 In FIG, hatching indicating a cross section is omitted. Note that description of the same parts as those of the filter device 1 will be omitted.

[0090] The filter device 1B mainly includes a first filter unit 10 , a second filter unit 20A, and a third filter unit 30 . The second filter unit 20A mainly includes a cylindrical portion 21 , a filter medium 22 , an upper end member 23A, a lower end member 24 , and a pressure relief valve 25 .

[0091] Upper end member 23A is located at the upper end of cylindrical portion 21 and filter medium 22. Upper end member 23 has a recessed portion 23a into which cylindrical portion 21 and filter medium 22 are inserted; a cylindrical portion 23b located within recessed portion 23a; and a mounting portion 24d. Mounting portion 24d is a member for mounting pressure relief valve 25 and is located within hollow portion 23c.

[0092] When the pressure in spaces S1 to S5 reaches a set pressure, the pressure relief valve 25 opens, allowing the hydraulic oil to flow from space S5 to space S6. Therefore, when the flow rate of the hydraulic oil is low, such as during idling, the pressure relief valve 25 closes, and the mounting portion 24d and the pressure relief valve 25 cover the hollow portion 23c.

[0093] By providing the pressure relief valve 25 , when the flow rate increases during the operation of the hydraulic system, the oil filtered by the filter device 1B can be made to flow to the pump at a constant pressure.

[0094] <Second embodiment>

[0095] Figure 6 It is a cross-sectional view schematically showing a filter device 2 according to the second embodiment. Figure 7 2 is a cross-sectional view showing the outline of the filter device 2, and is a diagram showing an enlarged view of the main part. Figure 6 In FIG, hatching indicating a cross section is omitted. Note that description of the same parts as those of the filter device 1 will be omitted.

[0096] The filter device 2 mainly includes a first filter unit 10, a second filter unit 20B, and a third filter unit 30A. The third filter unit 30A is provided in the hollow portion (space S6) of the second filter unit 20B.

[0097] The second filter unit 20B mainly includes a cylindrical portion 21 , a filter medium 22 , an upper end member 23 , and a lower end member 24A.

[0098] The lower end member 24A is disposed at the lower end of the cylindrical portion 21 and the filter medium 22. The lower end member 24 includes a recessed portion 24a, a cylindrical portion 24b, and a mounting portion 24d. The mounting portion 24d is formed at the upper end of the cylindrical portion 24b and is provided with the third filter unit 30A. However, the method of mounting the third filter unit 30A to the lower end member 24A is not limited to this.

[0099] The third filter unit 30A is provided so as to cover the hollow portion 24 c . The third filter unit 30A mainly includes a cylindrical portion 31 , a filter medium 32 , an upper end member 33 , and a lower end member 34 .

[0100] The cylindrical portion 31 is a metal, roughly cylindrical member with multiple holes 31a formed on its side. The filter material 32 is a filter material (so-called pleated filter material) formed by folding a metal mesh formed by spinning metal wire, connecting the two ends of the folded metal mesh and rounding it into a cylindrical shape. The filter material 32 is arranged outside the cylindrical portion 21. The mesh of the filter material 32 is the same as the mesh of the filter material 22, or a mesh finer than the mesh of the filter material 22.

[0101] It should be noted that the cylindrical portion 31 is not essential. In addition, the filter medium 32 is not limited to a metal mesh, and may be a pleated filter medium formed by folding a mesh member such as a mesh.

[0102] The upper end member 33 is disposed above the cylindrical portion 31 and the filter element 32. The upper end member 33 includes a recessed portion 33a into which the cylindrical portion 31 and the filter element 32 are inserted, and a plate-shaped portion 33b covering the hollow portion of the recessed portion 33a. Therefore, the hydraulic oil cannot pass through the upper end member 33.

[0103] The lower end member 34 is provided at the lower end of the cylindrical portion 31 and the filter medium 32. The lower end member 34 has a recessed portion 34a into which the cylindrical portion 31 and the filter medium 32 are inserted. The inner side of the recessed portion 34a is a hollow portion 34b through which the hydraulic oil can pass.

[0104] Figure 6 、 7 The arrows indicate the flow of the hydraulic oil. The hydraulic oil flowing from space S1 into space S2 is filtered by flowing from the outside to the inside of the filter element 11 and flows into space S3. The filtered hydraulic oil flows downward into space S3 and then into spaces S4 and S5.

[0105] The hydraulic oil flowing into space S5 partially flows out of tank 100 through hole 121d depending on the flow rate (for example, when the flow rate into tank 100 is high), but the majority of the hydraulic oil flows into space S6. Space S6 is provided with third filter unit 30A, so the hydraulic oil flowing into space S6 passes through filter material 22 and flows into tank 100. Furthermore, if the flow rate of hydraulic oil flowing into tank 100 decreases during hydraulic circuit operation, the hydraulic oil stored in tank 110 passes through filter material 22 and flows into space S6.

[0106] The hydraulic oil flowing into space S6 passes through filter medium 32 to remove air bubbles and flows into the hollow portion (space S7) of third filter unit 30. The hydraulic oil flowing into space S7 flows out of filter device 1 through hollow portion 24c and is guided to the pump of the hydraulic circuit.

[0107] According to this embodiment, by providing the third filter unit 30A so as to cover the hollow portion 24c, it is possible to prevent the outflow of bubbles contained in the hydraulic oil. Furthermore, the hollow portion (space S6) of the second filter unit 20B is relatively wide, allowing for a greater degree of flexibility in the shape of the third filter unit 30A. For example, the third filter unit 30A can be formed as a pleated filter material as in this embodiment, or it can be formed in a plate shape.

[0108] Furthermore, according to the present embodiment, by using the pleated filter medium 32 , the filtration area can be increased and the pressure loss can be reduced.

[0109] It should be noted that, in this embodiment, the filter material 32 formed by folding the metal mesh pleats is arranged to cover the hollow portion 24c, but the method of the filter material 32 is not limited to this. For example, a cylindrical member connected to the two ends of a plate-shaped metal mesh can also be arranged as a filter material to cover the hollow portion 24c. However, by using a pleated filter material for the filter material 32, the filtration area can be further increased. Alternatively, a plate-shaped filter material can also be arranged to cover the hollow portion 24c.

[0110] In this embodiment, the filter device 2 includes the third filter unit 30A provided on the lower end member 24A, but the filter device 2 may include the third filter unit 30 and the third filter unit 30A. In other words, the filter device may include a plurality of third filter units.

[0111] <Modification 1 of the Second Embodiment>

[0112] Figure 8 : is a cross-sectional view showing the outline of a filter device 2A according to a modified example. Figure 8Filter device 2A differs from filter device 2 in that it is provided with a pressure relief valve 16. Note that description of the same parts as those of filter devices 1A and 2 will be omitted.

[0113] The filter device 2A mainly includes a first filter unit 10A, a second filter unit 20B, and a third filter unit 30A. The first filter unit 10A includes a pressure relief valve 16, so that when the flow rate increases during the operation of the hydraulic system, the oil filtered by the filter device 2A can flow to the pump at a constant pressure.

[0114] <Third embodiment>

[0115] Figure 9 : is a cross-sectional view showing the outline of the filter device 3 according to the third embodiment. Figure 9 In FIG, hatching indicating a cross section is omitted. Note that description of the same parts as those of the filter device 1 will be omitted.

[0116] The filter device 3 mainly includes a first filter unit 10, a second filter unit 20C, and a third filter unit 30B. The third filter unit 30B is provided in the second filter unit 20C.

[0117] The second filter unit 20C mainly includes a cylindrical portion 21 , a filter medium 22 , an upper end member 23B, and a lower end member 24 .

[0118] The upper end member 23B is located at the upper end of the cylindrical portion 21 and the filter medium 22. The upper end member 23B comprises a recess 23a into which the cylindrical portion 21 and the filter medium 22 are inserted; a cylindrical portion 23b disposed within the recess 23a; and a mounting portion 23e. The mounting portion 23e is a member for mounting the third filter unit 30B and is located within the hollow portion 23c. A hole 23f (equivalent to the second flow path of the present invention) is formed in the mounting portion 23e.

[0119] The third filter unit 30B is provided so as to cover the hole 23f. The space outside the third filter unit 30B is a space S5, and the space inside the third filter unit 30B is a space S8.

[0120] The 3rd filter unit 30B mainly comprises filter material 35 and upper end member 36.Filter material 35 is formed into cylindrical shape by connecting the two ends of mesh components such as metal mesh, mesh piece.The mesh of filter material 35 is the same coarseness as the mesh of filter material 22 or the mesh finer than the mesh of filter material 22.It should be noted that, in the present invention, cylindrical shape is not limited to the cylinder whose cross-sectional shape in the face perpendicular to the axis is circular.For example, the cross-sectional shape in the face perpendicular to the axis of filter material 35 can also be polygonal shape, elliptical shape etc.

[0121] An upper end member 36 is provided at the upper end of the filter medium 35. The upper end member 36 covers the hollow portion of the filter medium 35. Therefore, the hydraulic oil cannot pass through the upper end member 36.

[0122] The lower end of the filter material 35 is disposed on the mounting portion 23e. In a plan view, the hole 23f is located at a position overlapping with the filter material 35 or inside the filter material 35. For example, the lower end of the filter material 35 is disposed along the periphery of the hole 23f.

[0123] Figure 9 The arrows indicate the flow of the hydraulic oil. The hydraulic oil flowing into space S1 is filtered by flowing from the outside to the inside of the filter element 11 and flows into space S3. The filtered hydraulic oil flows downward and flows into space S5 through space S3 and space S4.

[0124] The hydraulic oil flowing into the space S5 passes through the filter medium 35 to remove air bubbles, and flows into the space S6 via the space S8. Thereafter, the hydraulic oil flows out of the filter device 1 via the hollow portion 24c and is guided to the pump of the hydraulic circuit.

[0125] According to this embodiment, the third filter unit 30B is provided to cover the hole 23f, thereby preventing the outflow of bubbles contained in the hydraulic oil. In addition, the cylindrical filter medium 35 can increase the filtration area compared to the plate-shaped third filter unit 30.

[0126] It should be noted that the filter device 3 of this embodiment does not include a pressure relief valve, but a pressure relief valve may be provided. For example, a second filter unit 20A including a pressure relief valve 25 may be used instead of the second filter unit 20 .

[0127] <Fourth embodiment>

[0128] Figure 10 : is a cross-sectional view showing the outline of the filter device 4 according to the fourth embodiment. Figure 10 , hatching indicating cross sections is omitted. The filter device 4 is characterized in that the inlet portion is provided on the cover member compared to the filter device 1 of the first embodiment. Hereinafter, description of the same parts as the filter device 1 will be omitted.

[0129] The filter device 4 mainly includes a first filter unit 10C, a second filter unit 20, and a third filter unit 30. The first filter unit 10C includes a filter element 11, a filter housing 12B, an inner component 13A, a cover member 14A, and a valve 15.

[0130] The filter housing 12B is a tubular (here, cylindrical) member as a whole and is formed from metal. The filter housing 12 primarily comprises a first housing 121B, a second housing 122A, and mounting members 123 and 124. The heights of the first housing 121B and the first housing 121 in the z-direction, and the heights of the second housing 122A and the second housing 122 in the z-direction, are different.

[0131] An internal member 13A is installed within the first housing 121B. The internal member 13A is attached to the plate portion 121a to block the hollow portion of the first housing 121B, dividing the interior of the first housing 121B into three spaces: S2, S4, and S5. The space above the plate portion 121a and the internal member 13A is space S2, and the space below the plate portion 121a and the internal member 13A is space S5.

[0132] The inner member 13A mainly includes a plate-shaped portion 13a and a cylindrical portion 13b. The plate-shaped portion 13a is provided along the plate-shaped portion 121a and is in contact with the plate 113.

[0133] The cylindrical portion 13b extends along the central axis ax. The hollow portion 13c of the cylindrical portion 13b defines a space S4. The hollow portion 13c extends through the cylindrical portion 13b, that is, the inner member 13A. The inner member 13A and the first housing 121, which form spaces S4 and S5, serve as an outflow portion (equivalent to the first outflow portion of the present invention) through which the fluid filtered by the filter element 11 flows out.

[0134] The lower end of the cylindrical portion 13b is inserted into the hole 121b. Furthermore, by inserting the cylindrical portion 13b into the opening 113a, the upper end of the cylindrical portion 13b is inserted into the filter element 11. Thus, the hollow portion 13c (space S4) connects the spaces S3 and S5.

[0135] Cover member 14A is a generally plate-shaped member that covers the upper open end of filter housing 12B. Cover member 14A is detachably mounted on filter housing 12B (here, mounting member 124). Filter element 11 is housed within filter housing 12B and cover member 14A (equivalent to the housing of the present invention).

[0136] The cover member 14A includes a first cover 141A and a second cover 142. The first cover 141A is cylindrical and has a hollow portion 141a. Furthermore, a cylindrical portion 141b is provided on the side of the first cover 141A. The hydraulic oil flows into the space S1 through the hollow portion 141c of the cylindrical portion 141b. The cylindrical portion 141b serves as an inlet for the fluid to flow into the filter case 12 (equivalent to the first inlet portion of the present invention).

[0137] Figure 10The arrows indicate the flow of hydraulic oil. The hydraulic oil flows into space S1 (here, hollow portion 141a) via cylindrical portion 141b (hollow portion 141c). From space S1, the hydraulic oil flows into the space outside filter element 11 (space S2). The hydraulic oil is filtered as it flows from outside to inside filter element 11, and then flows into space S3. The filtered hydraulic oil flows downward from space S3 into spaces S4 and S5.

[0138] The hydraulic oil flowing into the space S5 partially flows out of the tank 100 through the hole 121d according to the flow rate, but most of it flows into the space S6. At this time, the hydraulic oil passes through the third filter unit 30. At this time, bubbles in the hydraulic oil are removed.

[0139] The hydraulic oil flowing into the space S6 through the third filter unit 30 partially flows out of the tank 100 or flows in from the tank 100 through the filter medium 22 depending on the flow rate, but most of it flows out of the filter device 1 through the hollow portion 24c. The hydraulic oil flowing out of the filter device 1 is guided to the pump of the hydraulic circuit.

[0140] According to the present embodiment, similarly to the filter device 1 , the third filter unit 30 is provided so as to cover the hollow portion 23 c , thereby preventing the outflow of bubbles contained in the hydraulic oil.

[0141] <Modification 1 of the Fourth Embodiment>

[0142] Figure 11 1 is a cross-sectional view showing an outline of a filter device 4A according to a modified example. The filter device 4A is different from the filter device 4 in that a pressure relief valve 16 is provided. Figure 11 In FIG, hatching indicating a cross section is omitted. Note that description of the same parts as those of the filter devices 1, 1A, and 4 will be omitted.

[0143] The filter device 4A mainly includes a first filter unit 10D, a second filter unit 20, and a third filter unit 30. The first filter unit 10D includes a filter element 11, a filter housing 12B, an inner component 13A, a cover member 14A, a valve 15, and a pressure relief valve 16.

[0144] The pressure relief valve 16 is provided on the cylindrical portion 13b so as to cover the hollow portion 13c. This allows the oil filtered by the filter device 4A to flow to the pump at a constant pressure when the flow rate increases during the operation of the hydraulic system.

[0145] It should be noted that in the filter device 4A having the pressure relief valve 16, the cover member 14A may be provided with a cylindrical portion (not shown) separate from the cylindrical portion 141b. This cylindrical portion serves as an outflow portion (equivalent to the second outflow portion of the present invention) through which the hydraulic oil flowing into the space S1 via the cylindrical portion 141b flows out. While the hydraulic oil flowing out of the hollow portion 24c is directed to the main pump, the hydraulic oil flowing out of this outflow portion is directed to a pump separate from the main pump, such as a priming pump.

[0146] <Modification 2 of the Fourth Embodiment>

[0147] Figure 12 2 is a cross-sectional view showing an outline of a filter device 4B according to a modified example. The filter device 4B is different from the filter device 4 in that a pressure relief valve 25 is provided. Figure 5 In FIG, hatching indicating a cross section is omitted. Note that description of the same parts as those of the filter devices 1, 1B, and 4 will be omitted.

[0148] The filter device 4B mainly includes a first filter unit 10C, a second filter unit 20A, and a third filter unit 30. By providing a pressure relief valve 25 in the second filter unit 20A, the oil filtered by the filter device 1B can be allowed to flow to the pump at a constant pressure when the flow rate increases during the operation of the hydraulic system.

[0149] Note that, in the filter device 4B having the pressure relief valve 25 , similarly to the filter device 4A, the cover member 14A may be provided with a cylindrical portion (equivalent to the third outflow portion of the present invention) different from the cylindrical portion 141 b .

[0150] <Fifth embodiment>

[0151] Figure 13 : is a cross-sectional view showing the outline of the filter device 5 according to the fifth embodiment. Figure 13 , hatching indicating cross sections is omitted. Filter device 5 is characterized by being provided with an inlet portion on a cover member relative to filter device 2 of the second embodiment. Hereinafter, description of the same parts as filter devices 1 to 4 will be omitted.

[0152] The filter device 5 mainly includes a first filter unit 10C, a second filter unit 20B, and a third filter unit 30A.

[0153] According to the present embodiment, similarly to the filter device 2 , the third filter unit 30A is provided so as to cover the hollow portion 24 c , thereby preventing the outflow of bubbles contained in the hydraulic oil.

[0154] <Modification 1 of the Fifth Embodiment>

[0155] Figure 14 : is a cross-sectional view showing the outline of a filter device 5A according to a modified example. Figure 14 In the figure, hatching indicating cross sections is omitted. Filter device 5A differs from filter device 5 in that it is equipped with a pressure relief valve 16. Filter device 5A primarily comprises a first filter unit 10D, a second filter unit 20B, and a third filter unit 30A. Pressure relief valve 16 allows the oil filtered by filter device 5A to flow to the pump at a constant pressure when the flow rate increases during operation of the hydraulic system.

[0156] <Sixth embodiment>

[0157] Figure 15 : is a cross-sectional view showing the outline of the filter device 6 according to the sixth embodiment. Figure 15 , hatching indicating cross sections is omitted. Filter device 6 is characterized by being provided with an inlet portion on a cover member relative to filter device 3 of the third embodiment. Hereinafter, description of the same parts as filter devices 1 to 4 will be omitted.

[0158] The filter device 6 mainly includes a first filter unit 10C, a second filter unit 20C, and a third filter unit 30B. The third filter unit 30B is provided in the second filter unit 20C.

[0159] According to the present embodiment, similarly to the filter device 3 , the third filter unit 30B is provided so as to cover the hole 23 f , thereby preventing the outflow of bubbles contained in the hydraulic oil.

[0160] While the embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the specific structures are not limited to these embodiments and include design changes within the scope of the present invention. For example, the above-mentioned embodiments have been described in detail to facilitate understanding of the present invention and are not necessarily limited to the embodiments having all the structures described. In addition, a portion of the structure of an embodiment may be replaced with the structure of another embodiment, and other structures may be added, deleted, or replaced with the structure of an embodiment.

[0161] In the present invention, the term "substantially" encompasses not only strictly identical conditions but also errors and variations that do not compromise the identity. For example, "substantially orthogonal" is not limited to strictly orthogonal conditions but encompasses errors of several degrees. Furthermore, for example, the term "orthogonal," "parallel," or "coinciding" encompasses not only strictly orthogonal, parallel, or "coinciding" conditions but also approximately parallel, approximately orthogonal, or approximately "coinciding" conditions.

[0162] In the present invention, "near" refers to an area within a certain range (which can be arbitrarily set) near a reference position. For example, "near an end" refers to an area within a certain range near the end, and the concept may or may not include the end.

[0163] Description of Reference Numerals

[0164] 1, 1A, 1B, 2, 2A, 3, 4, 4A, 4B, 5, 5A, 6: Filter device

[0165] 10, 10A, 10C, 10D: First filter unit

[0166] 11: Filter element

[0167] 12, 12B: filter housing

[0168] 13, 13A: Internal components

[0169] 13a: plate-shaped part

[0170] 13b: Cylindrical part

[0171] 13c: Hollow part

[0172] 14, 14A: Cover member

[0173] 15: Valve

[0174] 16: Pressure relief valve

[0175] 20, 20A, 20B, 20C: Second filter unit

[0176] 21: Cylindrical part

[0177] 21a: Hole

[0178] 22: Filter material

[0179] 23, 23A, 23B: Upper end components

[0180] 23a: concave part

[0181] 23b: Cylindrical part

[0182] 23c: Hollow part

[0183] 23d: Installation department

[0184] 23e: Installation

[0185] 23f: hole

[0186] 24, 24A: Lower end member

[0187] 24a: concave part

[0188] 24b: Cylindrical part

[0189] 24c: Hollow part

[0190] 25: Pressure relief valve

[0191] 30, 30A, 30B: The third filter unit

[0192] 31: Cylindrical part

[0193] 31a: Hole

[0194] 32, 35: Filter material

[0195] 33, 36: Upper end member

[0196] 33a: concave part

[0197] 33b: plate-shaped part

[0198] 34: Lower end member

[0199] 34a: concave part

[0200] 34b: Hollow part

[0201] 100: box

[0202] 101: Box body

[0203] 101a: Upper surface

[0204] 101b: Hole

[0205] 101c: bottom surface

[0206] 101d: Hole

[0207] 110: Box

[0208] 111: Inner tube

[0209] 111a: Hole

[0210] 112: Filter material

[0211] 113, 114: board

[0212] 113a: Opening

[0213] 121, 121B: First shell

[0214] 121a: plate-shaped part

[0215] 121b, 121c, 121d: holes

[0216] 122, 122A: Second shell

[0217] 123, 124: Installation components

[0218] 131: First component

[0219] 132: Second part

[0220] 132a: Cylindrical part

[0221] 132b: Hollow part

[0222] 132c: convex part

[0223] 141, 141A: First cover

[0224] 141a: Hollow part

[0225] 141b: Cylindrical part

[0226] 141c: Hollow part

[0227] 142: Second cover

[0228] 142a: Lower surface

[0229] 143: Elastic member.

Claims

1. A filter device, characterized in that: The filter device comprises: a first filter unit; a second filter unit disposed below the first filter unit so as to overlap the first filter unit in a plan view; and A third filter unit is provided in the first filter unit or the second filter unit. The first filter unit has: case; a first inflow portion, which is provided in the housing and allows the fluid to flow into the interior of the housing; a cylindrical first filter element disposed inside the housing and allowing the fluid to pass therethrough to filter the fluid; as well as a first outflow portion provided in the housing and having a first flow path for allowing the filtered fluid filtered by the first filter element to flow out of the first filter unit; The second filter unit has: a second filter element in a cylindrical shape, disposed inside the tank; a second inflow portion provided between the first outflow portion and the second filter element and having a second flow path communicating the first flow path with the hollow portion of the second filter element; as well as a second outflow portion disposed below the second filter element and having a third flow path communicating the hollow portion of the second filter element with the outside of the second filter element; The third filter unit includes a filter portion that covers at least one of the first flow path, the second flow path, and the third flow path.

2. The filter device according to claim 1, characterized in that The second filter unit has an upper end member provided on the upper end side of the second filter element. The second flow path is formed in the upper end member, The third filter unit is formed of a plate-shaped mesh member and is provided on the upper end member so as to cover the second flow path.

3. The filter device according to claim 1, characterized in that The second outflow portion has a lower end member provided on the lower end side of the second filter element. The third flow path is formed in the lower end member, The third filter unit is installed in the hollow portion of the second filter unit so as to cover the third flow path.

4. The filter device according to claim 3, characterized in that The filter portion is a member in which a mesh member is provided in a cylindrical shape. The third filter unit includes a plate covering one end of the filter portion. An end of the filter portion on a side where the plate is not provided is provided at the lower end member.

5. The filter device according to any one of claims 1 to 4, characterized in that The filter device includes a pressure relief valve provided on the first filter unit or the second filter unit. The housing includes a filter housing and a cover member provided on an upper side of the filter housing. The cover member includes the first inflow portion and a third outflow portion for causing the hydraulic oil that has flowed into the interior of the cover member through the first inflow portion to flow out.

6. A filtering device, characterized in that: The filtering device comprises: box; a first filter unit provided so as to protrude from an upper surface of the box toward an interior of the box; a second filter unit disposed on a lower side of the first filter unit so as to overlap with the first filter unit in a plan view; as well as A third filter unit is provided in the first filter unit or the second filter unit. The first filter unit has: case; a first inflow portion, which is provided in the housing and allows the fluid to flow into the interior of the housing; a cylindrical first filter element disposed inside the housing and allowing the fluid to pass therethrough to filter the fluid; as well as a first outflow portion provided in the housing and having a first flow path for allowing the filtered fluid filtered by the first filter element to flow out of the first filter unit; The second filter unit has: a second cylindrical filter element disposed inside the tank; a second inflow portion provided between the first outflow portion and the second filter element and having a second flow path communicating the first flow path with the hollow portion of the second filter element; as well as a second outflow portion disposed below the second filter element and having a third flow path communicating the hollow portion of the second filter element with the outside of the second filter unit; The third filter unit includes a filter portion that covers at least one of the first flow path, the second flow path, and the third flow path.

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