JP6866216B2 - Filter device - Google Patents

Description

The present invention relates to a filter device.

In Patent Document 1, a suction passage is provided in the lower part of a substantially cylindrical container, a return passage is provided on the side surface of the container, an inner cylinder is vertically hung from the top of the container, and the height direction of the container is provided on the outer peripheral surface of the inner cylinder. A power steering oil tank in which a rectifying plate extending to the above is projected is disclosed. In this power steering oil tank, the flow of oil that swirls in the circumferential direction in the container is obstructed by the rectifying plate, so that the velocity component in the circumferential direction of the oil is reduced and the occurrence of swirl in the container is prevented. To.

Japanese Unexamined Patent Publication No. 2000-095125

In the filter device, the spiral flow of the liquid (swirl flow) swirling in the container in the circumferential direction is effective for removing the air contained in the liquid. Since the air that has passed through the filter causes a malfunction, it is desirable to remove the air contained in the liquid by using a swirling flow. However, since the swirling flow can contribute to the deterioration of the filtration performance, it is desirable to suppress the swirling flow in the vicinity of the filter medium.

In the invention described in Patent Document 1, the swirling flow in the container is suppressed as a whole, and it is not possible to generate a swirling flow in a certain part of the tank and suppress the swirling flow in another part. Therefore, even if the invention described in Patent Document 1 is applied to the filter device, there is a problem that the air contained in the liquid cannot be removed.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a filter device capable of suppressing a swirling flow in the vicinity of a filter medium while generating a swirling flow to remove air contained in a liquid. And.

In order to solve the above problems, the filter device according to the present invention includes, for example, a substantially cylindrical filter medium for filtering a liquid and a substantially cylindrical filter medium having a height lower than the height of the filter medium and abutting on the inner peripheral surface of the filter medium. A filter element having a cylinder and having substantially the same height position between the lower end of the filter medium and the lower end of the inner cylinder, and a substantially cylindrical filter case in which the filter element is provided inside. A filter case having a plurality of holes formed on its side surface, a lid member covering the upper end of the filter case, and a substantially cylindrical inflow portion covering the lower end of the filter case, which are formed in a hollow portion of the filter element. A rectifying member having an inflow portion through which a fluid flows and a rectifying member provided in a hollow portion of the inner cylinder and having a plurality of plate-shaped portions provided along a first central axis which is a central axis of the filter element. The filter element includes a member, the lower end of which is in contact with the inflow portion, and the inflow portion has a substantially cylindrical hole that opens to the upper end surface, and both ends of the side surface of the inflow portion and the side surface of the hole. A tubular portion is formed, and the hole communicates with the hollow portion of the filter element, and the tubular portion is formed inside the hole from a tangential direction at an arbitrary point on the side surface of the hole. Is caused to flow into the inflowing liquid to generate a swirling flow, and the rectifying member is provided near the lower end of the filter element.

According to the filter device according to the present invention, inside the substantially cylindrical filter case, a substantially cylindrical filter medium, a substantially cylindrical inner cylinder lower than the height of the filter medium and abutting on the inner peripheral surface of the filter medium, and a substantially cylindrical inner cylinder. A filter element having the above is provided. The inflow portion that covers the lower end of the filter case is formed with a substantially cylindrical hole that opens on the upper end surface, and the tubular portion that opens at both ends on the side surface of the inflow portion and the side surface of the hole is arbitrary on the side surface of the hole. The liquid is allowed to flow into the hole from the tangential direction at the point. As a result, a swirling flow can be generated to remove the air contained in the liquid.

Further, the positions of the lower end of the filter medium and the lower end of the inner cylinder in the height direction are substantially the same, and a plurality of hollow portions of the inner cylinder are provided along the first central axis which is the central axis of the filter element. A rectifying member having a plate-shaped portion is provided. Since the rectifying member is provided near the lower end of the filter element, the hydraulic oil that has flowed into the inflow portion passes through the space between the rectifying member and the inner cylinder and flows into the hollow portion of the filter element. As a result, the flow of the hydraulic oil is rectified into a flow in the direction along the first central axis, and the swirling flow in the vicinity of the filter medium can be suppressed. As a result, it is possible to prevent deterioration of filtration performance due to swirling flow.

Here, the tubular portion has a substantially cylindrical round hole portion that opens to the side surface and a connecting portion that connects the round hole portion and the hole, and the round hole portion is viewed in a plan view. , The central axis is provided at a position where the central axis intersects the first central axis, the connecting portion is inclined with respect to the round hole portion in a plan view, and the connecting portion is a flow path as it approaches the hole. The area may be gradually reduced. In a plan view, the central axis of the round hole portion is provided at a position where it intersects with the first central axis, and the connecting portion is tilted with respect to the round hole portion, so that the compatibility with the conventional filter device remains. , A swirling flow can be generated in the hydraulic fluid. Further, as the flow path area of the connecting portion gradually decreases as it approaches the hole, the flow velocity becomes faster, and a swirling flow is likely to occur in the hydraulic oil.

Here, the plurality of holes may be formed at positions overlapping the inner cylinder in the height direction, and air vent holes may be formed in the vicinity of the upper end of the filter case. As a result, the hydraulic oil can be filtered using the entire filter medium. In addition, the air removed from the liquid can be discharged to the outside through an air vent hole at a position higher than the liquid surface.

Here, the height of the inner cylinder may be half or less of the height of the filter medium. As a result, it is possible to suppress a decrease in filtration performance due to the inner cylinder.

According to the present invention, it is possible to suppress the swirling flow in the vicinity of the filter medium while generating a swirling flow to remove the air contained in the liquid.

It is a main part perspective view which shows the outline of the hydraulic oil tank 100 which provided the return filter 1 which is one Embodiment of this invention inside. It is a perspective view which shows the outline of the return filter 1, and is the figure which shows the state which cut in the plane along the central axis A. It is the figure which cut the inflow part 41 along the central axis A. It is the figure which cut the inflow part 41 along the line B. FIG. 5 is a sectional view taken along the line CC of the return filter 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, the return filter will be described as an example, but the present invention can be applied to various filter devices other than the return filter. Further, although the hydraulic oil will be described below as an example of the fluid, the present invention can be applied to various fluids other than the hydraulic oil.

FIG. 1 is a perspective view of a main part showing an outline of a hydraulic oil tank 100 (corresponding to a liquid tank of the present invention) in which a return filter 1 according to an embodiment of the present invention is provided.

The hydraulic oil tank 100 is installed in a work machine (for example, a hydraulic device) (not shown), and is a tank for storing hydraulic oil provided in a hydraulic circuit of hydraulic oil supplied to the hydraulic device. is there. In the hydraulic circuit, the hydraulic oil is introduced into the hydraulic oil tank 100 through the hydraulic device.

The hydraulic oil tank 100 mainly has a box-shaped tank body 101. The inside of the tank main body 101 is hollow, and the return filter 1 and the suction strainer 9 are mainly provided inside the tank main body 101.

A hole 101b into which the return filter 1 is inserted is formed in the upper surface 101a of the tank body 101. A lid member 20 (detailed later) of the return filter 1 is provided on the upper surface 101a.

A bolt insertion hole (not shown) is formed at the peripheral edge of the lid member 20. By screwing the bolt into the bolt insertion hole, the lid member 20 (that is, the return filter 1) is fastened to the tank body 101.

Further, an air breather (not shown) is provided on the upper surface 101a to filter the air entering the tank body 101 as the oil level rises and falls to prevent dust and the like from entering the hydraulic oil.

An outflow port 101d for draining the hydraulic oil in the tank body 101 to a hydraulic pump (not shown) is provided near the lower end of the tank body 101 (lower surface 101c in the present embodiment). A suction strainer 9 is provided on the upper side (+ z side) of the outlet 101d in order to prevent foreign matter from entering the hydraulic pump. The hydraulic oil stored in the hydraulic oil tank 100 is sucked into the hydraulic pump (not shown) via the suction strainer 9 and is supplied to the hydraulic device again.

The suction strainer 9 has a filter medium having a substantially cylindrical shape. The filter medium is, for example, a metal plate-shaped member having a large number of holes formed therein, and is formed into a substantially cylindrical shape by connecting both ends and rolling it into a cylindrical shape. By fitting the outlet 101d into the hollow portion of the suction strainer 9, the suction strainer 9 is positioned and fixed to the tank body 101.

An inflow pipe 102 for allowing hydraulic oil to flow into the inside of the tank body 101 is provided on the side surface 101e of the tank body 101. The inflow pipe 102 penetrates the tank body 101, and the hydraulic oil is guided to the return filter 1 via the inflow pipe 102. The hydraulic oil is filtered by the return filter 1 and stored in the hydraulic oil tank 100.

Next, the return filter 1 will be described. FIG. 2 is a perspective view showing an outline of the return filter 1, and is a view showing a state of being cut along a plane along the central axis A.

The return filter 1 mainly includes a filter case 10, a lid member 20, a filter element 30, a lower case 40, and a rectifying member 50.

The filter case 10 is a member having a substantially cylindrical shape and is made of metal. The upper end of the filter case 10 is provided on the lid member 20, and the lower end of the filter case 10 is provided on the lower case 40.

A plurality of holes 10a and 10b through which hydraulic oil passes are formed on the side surface of the filter case 10. The hole 10a is an outflow portion that communicates the space S2 between the filter case 10 and the filter element 30 and the external space S3 (see FIG. 1). The hole 10b is an air vent hole provided near the upper end of the filter case 10.

The lid member 20 is a member that covers the upper end surface of the filter case 10. The lid member 20 mainly has a first lid 21 and a second lid 22. The first lid 21 and the second lid 22 are integrated by bolts (not shown).

The first lid 21 is a plate-shaped member fixed to the upper side of the upper surface 101a (see FIG. 1), and a hole 21a is formed substantially in the center. The filter case 10 is inserted into the hole 21a.

The second lid 22 has a substantially plate-shaped flange portion 22a and convex portions 22b and 22c. The flange portion 22a is fixed to the upper side of the first lid 21. The convex portions 22b and 22c are formed so as to project downward (−z direction) from the flange portion 22a. The convex portion 22b is inserted into the inner peripheral surface of the filter case 10. As a result, the filter case 10 is sandwiched between the first lid 21 and the second lid 22. The convex portion 22c is provided on the filter element 30.

The filter element 30 is a substantially cylindrical member as a whole, and is provided inside the filter case 10. The filter element 30 mainly has an inner cylinder 31, an outer cylinder 32, a filter medium 33, and plates 34 and 35.

The inner cylinder 31 and the outer cylinder 32 are substantially hollow cylindrical members having openings at both ends. The inner cylinder 31 and the outer cylinder 32 are formed by using a material (metal or resin) having high corrosion resistance. The inner cylinder 31 is provided inside the filter medium 33, and the outer cylinder 32 is provided outside the filter medium 33.

The inner cylinder 31 covers the periphery of the rectifying member 50 (detailed later) and comes into contact with the inner peripheral surface of the filter medium 33. The lower end of the inner cylinder 31 is substantially the same as the lower end of the filter medium 33 in the height direction. The height of the inner cylinder 31 is lower than the height of the filter medium 33 (here, less than half the height of the filter medium 33). The hole 10a is formed at a position overlapping the inner cylinder 31 in the height direction (z direction).

The height of the outer cylinder 32 is substantially the same as the height of the filter medium 33. The outer cylinder 32 is formed with a large number of holes 32a through which hydraulic oil passes in substantially the entire area.

The filter medium 33 is for filtering hydraulic oil, and has a substantially cylindrical shape having a thickness in the radial direction. The filter medium 33 is formed by folding a filter paper made of synthetic resin, paper, or the like into folds, connecting both ends of the folded filter paper, and rolling the filter paper into a cylindrical shape.

A plate 34 is provided at one end of the filter medium 33 and a plate 35 is provided at the other end. The plate 34 and the plate 35 are members having a substantially disk shape or a bottomed substantially cylindrical shape, and are formed of resin or metal.

The plate 34 covers the inner cylinder 31, the outer cylinder 32, and the lower ends of the filter medium 33. The plate 34 is provided in the inflow portion 41 (detailed later). The plate 35 covers the upper ends of the outer cylinder 32 and the filter medium 33. A convex portion 22c fits into the hollow portion 35a of the plate 35. As a result, the filter element 30 is provided inside the filter case 10.

The lower case 40 is a member that allows fluid to flow into the hollow portion (space S1) of the filter element 30, and has a substantially cylindrical inflow portion 41 that covers the lower end of the filter case 10. The inflow portion 41 is formed with a substantially cylindrical hole 41b that opens in the upper end surface 41a, and a tubular portion 41d that opens at both ends on the side surface of the inflow portion 41 and the side surface of the hole 41b. The tubular portion 41d communicates the hole 41b with the external space S3.

A valve 42 is provided on the bottom surface of the substantially cylindrical hole 41b. The valve 42 opens and closes according to the difference between the pressure in the space S1 and the pressure in the external space S3. Since a known technique can be used for the valve 42, detailed description thereof will be omitted. The valve 42 is not essential.

Next, the details of the inflow unit 41 will be described. FIG. 3 is a view in which the inflow portion 41 is cut along the central axis A. FIG. 4 is a diagram in which the inflow portion 41 is cut along the line B (see FIGS. 2 and 3). Thick lines in FIGS. 3 and 4 indicate the flow of hydraulic oil.

A hole 41f into which the lower end of the filter case 10 is inserted and a hole 41g into which the plate 35 is inserted are formed on the upper end surface 41a.

The hole 41b has a small diameter portion 41e. The hole 41g is formed around the small diameter portion 41e. When the plate 35 is inserted into the hole 41g, the lower end of the filter element 30 comes into contact with the inflow portion 41, and the hole 41b and the space S1 communicate with each other.

The tubular portion 41d mainly has a substantially cylindrical round hole portion 41h that opens to the side surface 41c, and a connecting portion 41i that connects the round hole portion 41h and the hole 41b. The round hole portion 41h is an opening in which the inflow pipe 102 is provided, and is provided at a position where the central axis A1 of the round hole portion 41h intersects the central axis A in a plan view (when viewed from the z direction).

The connecting portion 41i is tilted with respect to the round hole portion 41h in a plan view. In the present embodiment, the central axis A2 of the connecting portion 41i is tilted by about 30 degrees to about 45 degrees with respect to the central axis A1 in a plan view. As a result, the hydraulic oil flows into the hole 41b from the tangential direction at an arbitrary point P on the side surface of the hole 41b, and the hydraulic oil swirls inside the hole 41b.

The flow path area of the connecting portion 41i gradually decreases as it approaches the hole 41b. Therefore, the flow velocity of the hydraulic oil when flowing into the hole 41b from the connecting portion 41i is faster than the flow velocity of the hydraulic oil flowing through the inflow pipe 102. As the flow velocity increases, a swirling flow is likely to occur in the hydraulic oil, and air bubbles are likely to collect in the center of the swirling flow.

Returning to the description of FIG. The rectifying member 50 is a member provided in the hollow portion of the filter element 30 (here, the inner cylinder 31), and rectifies the flow of hydraulic oil from a swirling flow to an upward flow.

FIG. 5 is a cross-sectional view taken along the line CC of the return filter 1. The rectifying member 50 has a plurality of plate-shaped portions 51 provided along the central axis A. In the present embodiment, the four plate-shaped portions 51 are provided so as to have a substantially cross shape in a plan view.

Since the periphery of the plate-shaped portion 51 is covered by the inner cylinder 31, the hydraulic oil flows between the inner cylinder 31 and the plate-shaped portion 51. When the hydraulic oil passes between the inner cylinder 31 and the plate-shaped portion 51, the plate-shaped portion 51 and the inner cylinder 31 are provided along the central axis A, so that the flow of the hydraulic oil flows between the inner cylinder 31 and the plate-shaped portion 51. It is rectified into a flow in the direction (here, upward) along the plate-shaped portion 51.

The rectifying member 50 is provided near the lower end of the filter element 30. As a result, the hydraulic oil flowing into the space S1 from the hole 41b can be rectified at the earliest possible stage. Further, since the periphery of the rectifying member 50 is covered by the inner cylinder 31, the inner cylinder 31 prevents the hydraulic oil before rectification from flowing to the filter medium 33, and only the hydraulic oil after rectification is filtered by the filter medium 33. This makes it possible to prevent deterioration of filtration performance due to swirling flow.

In the present embodiment, the rectifying member 50 has four plate-shaped portions 51, but the number of plate-shaped portions 51 may be plural. Further, the shape of the plate-shaped portion 51 is not limited to the illustrated form. For example, the four plate-shaped portions 51 may be in contact with the inner cylinder 31 only, and the central portion having a substantially cross shape may be hollow.

Next, the function of the return filter 1 configured in this way will be described. The arrows in FIGS. 1 to 4 indicate the flow of hydraulic oil.

During the operation of the hydraulic system, hydraulic oil is flowing in the hydraulic circuit. As shown in FIG. 1, the hydraulic oil flows into the inflow portion 41 through the inflow pipe 102. As shown in FIG. 2, the hydraulic fluid has a high flow velocity while passing through the tubular portion 41d and swirls inside the hole 41b. As a result, the air contained in the hydraulic oil collects in the center of the vortex.

The hydraulic oil and air rise through between the rectifying member 50 and the inner cylinder 31 and flow into the space S1. The hydraulic oil is filtered by flowing from the inside to the outside of the filter medium 33, and the filtered hydraulic oil flows out to the space S2 through the holes 32a.

Since only the hydraulic oil after rectification is filtered by the filter medium 33 by the inner cylinder 31, it is possible to prevent deterioration of the filtration performance due to the swirling flow. Further, since the height of the inner cylinder 31 is less than half the height of the filter medium 33, deterioration of the filtration performance due to the inner cylinder 31 can be suppressed. Further, by forming the hole 10a at a position overlapping the inner cylinder 31 in the height direction, the hydraulic oil can be filtered using the entire filter medium 33.

The hydraulic oil after filtration flows downward in the space S2. Then, as shown in FIG. 1, it flows out from the space S2 to the external space S3 through the hole 10a which is the outflow portion. The hydraulic oil (inside the tank body 101) that has flowed out to the external space S3 flows out to the outside of the tank body 101 through the suction strainer 9 and the outlet 101d.

On the other hand, the air flowing into the space S1 floats toward the oil level L (see FIG. 1) and is discharged to the outside of the filter case 10 through the hole 10b.

According to the present embodiment, it is possible to generate a swirling flow to remove the air contained in the liquid and suppress the swirling flow in the vicinity of the filter medium to prevent deterioration of the filtration performance.

Further, according to the present embodiment, since the tubular portion 41d has a round hole portion 41h provided at a position where the central axis A1 intersects the central axis A, the tubular portion 41d remains compatible with the conventional filter device. Air can be removed from the liquid by creating a swirling flow inside the inflow section 41.

In the present embodiment, the central axis of the return filter 1 and the central axis of the suction strainer 9 coincide with each other, but the position of the suction strainer 9 is not limited to this. However, in order to reduce the size of the tank body 101 and prevent the hydraulic oil discharged from the return filter 1 from directly flowing into the suction strainer 9, the central axis of the return filter 1 and the central axis of the suction strainer 9 It is desirable to match with.

Further, in the present embodiment, the connecting portion 41i is a substantially straight pipe, and the central axis A2 is tilted by approximately 30 degrees to approximately 45 degrees with respect to the central axis A1, but the shape of the connecting portion 41i is limited to this. Absent. For example, the connecting portion may be a curved pipe. Further, the wall surface of the connecting portion may be in contact with the side surface of the hole 41b at the point P.

Further, in the present embodiment, the height of the inner cylinder 31 is less than half the height of the filter medium 33, but the height of the inner cylinder 31 may be lower than the height of the filter medium 33. However, it is desirable that the height of the inner cylinder 31 is as low as possible so as not to deteriorate the filtration performance, and is at least half the height of the filter medium 33 or less.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design changes and the like within a range not deviating from the gist of the present invention. .. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. Further, it is possible to replace a part of the configuration of the embodiment with the configuration of another embodiment, and it is possible to add, delete, replace, or the like with another configuration to the configuration of the embodiment.

Further, in the present invention, the "abbreviation" is a concept including not only the case where the identity is exactly the same but also an error or deformation to the extent that the identity is not lost. For example, "substantially orthogonal" is not limited to the case of being strictly orthogonal, and is a concept including an error of, for example, several degrees. Further, for example, in the case of simply expressing orthogonality, parallelism, coincidence, etc., not only the case of strictly orthogonality, parallelism, coincidence, etc., but also the case of substantially parallelism, substantially orthogonality, substantially coincidence, etc. are included.

Further, in the present invention, the "neighborhood" means to include a region of a certain range (which can be arbitrarily determined) near the reference position. For example, in the case of the vicinity of an edge, it is a concept indicating that it is a region of a certain range near the edge and may or may not include the edge.

1: Return filter 9: Suction strainer 10: Filter case 10a, 10b: Hole 20: Lid member 21: First lid 21a: Hole 22: Second lid 22a: Flange portion 22b, 22c: Convex portion 30: Filter element 31: Inner cylinder 32: Outer cylinder 32a: Hole 33: Filter media 34, 35: Plate 35a: Hollow part 40: Lower case 41: Inflow part 41a: Upper end surface 41b: Hole 41c: Side surface 41d: Tubular part 41e: Small diameter part 41f, 41g : Hole 41h: Round hole 41i: Connecting part 42: Valve 50: Rectifying member 51: Plate-shaped part 100: Hydraulic oil tank 101: Tank body 101a: Top surface 101b: Hole 101c: Bottom surface 101d: Outlet 101e: Side surface 102: Inflow pipe

Claims (4)

It has a substantially cylindrical filter medium for filtering a liquid and a substantially cylindrical inner cylinder which is lower than the height of the filter medium and abuts on the inner peripheral surface of the filter medium, and has a lower end of the filter medium and a lower end of the inner cylinder. The filter element, which has almost the same height position,
A filter case having a substantially cylindrical shape in which the filter element is provided, and having a plurality of holes formed on the side surfaces thereof.
A lid member that covers the upper end of the filter case and
A substantially cylindrical inflow portion that covers the lower end of the filter case, and an inflow portion that allows fluid to flow into the hollow portion of the filter element.
A rectifying member provided in the hollow portion of the inner cylinder and having a plurality of plate-shaped portions provided along the first central axis which is the central axis of the filter element.
With
The lower end of the filter element comes into contact with the inflow portion.
The inflow portion is formed with a substantially cylindrical hole that opens on the upper end surface and a tubular portion that opens at both ends on the side surface of the inflow portion and the side surface of the hole.
The hole communicates with the hollow portion of the filter element.
The tubular portion causes the liquid to flow into the hole from a tangential direction at an arbitrary point on the side surface of the hole, and causes a swirling flow in the flowing liquid.
A filter device characterized in that the rectifying member is provided near the lower end of the filter element. The filter device according to claim 1.
The tubular portion has a substantially cylindrical round hole portion that opens on the side surface, and a connecting portion that connects the round hole portion and the hole.
The round hole portion is provided at a position where the central axis intersects the first central axis in a plan view.
The connecting portion is inclined with respect to the round hole portion in a plan view.
The connecting portion is a filter device characterized in that the flow path area gradually decreases as it approaches the hole. The filter device according to claim 1 or 2.
The plurality of holes are formed at positions overlapping the inner cylinder in the height direction.
A filter device characterized in that an air vent hole is formed in the vicinity of the upper end of the filter case. The filter device according to any one of claims 1 to 3.
A filter device characterized in that the height of the inner cylinder is not more than half the height of the filter medium.

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