JPH0149528B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil filter installed in a hydraulic circuit to clean oil.

[Conventional technology]

Injection molding machines, large machine tools, and the like are usually equipped with a hydraulic circuit for a hydraulic drive device such as a cylinder that moves a table, and a hydraulic circuit for lubricating a rotary drive unit.

The hydraulic fluid used in such hydraulic circuits is contaminated by minute foreign matter from the outside while circulating in the circuit. For this reason, an oil filter is provided in the circuit to filter and clean the hydraulic oil in order to maintain lubrication ability and preserve equipment.

As shown in Fig. 6, oil filters that have been commonly used in the past have a container A that can withstand pressure.
It has a structure in which an element C containing filter paper B wound in a roll is housed inside. A port for introducing the hydraulic oil and a port (not shown) for collecting and discharging the hydraulic oil after filtering are provided at the bottom of the container A, and the hydraulic oil circulating in the hydraulic circuit of the operating machine is continuously filtered. You can go there.

[Problem that the invention seeks to solve]

By the way, due to the filtration of the hydraulic oil, foreign matter contained in the hydraulic oil adheres to the element C, and eventually the filtering function of the filter paper B is lost. For this reason,
It is necessary to replace element C periodically.

When foreign matter adheres to the filter paper B, since the hydraulic oil flows while penetrating between the layered filter papers B from the upper end of the element C toward the lower end, the amount of adhesion is higher on the upper side of the element C. It is accompanied by a phenomenon in which there is an increase in In this case, since larger foreign particles are easier to filter, foreign particles with a diameter of, for example, 3 μm are collected on the upper side of the element C, while foreign particles with a diameter of about 0.5 μm pass through the upper side of the element C. Therefore, the diameters of the foreign particles to be collected are distributed differently in the vertical direction of the element C, and the filtering function cannot be performed satisfactorily unless small-diameter foreign particles are collected, especially on the lower side.

On the other hand, since the filter paper B of the element C is wound tightly with a uniform winding force, the density of the filter paper B is also constant in the vertical direction through which the hydraulic oil passes. For this reason,
Even if foreign matter with a large diameter can be filtered on the upper side, if the density is not sufficient on the lower side, it will not be possible to collect foreign matter with a small diameter. Such a phenomenon is remarkable when the shape of the container A is relatively deep and the path of the hydraulic oil is long.

As described above, in the element C formed by winding the filter paper B into a roll at a constant density, the upper end portion is rapidly accumulated with foreign matter, so that the interval between filter replacements becomes short. In addition, even if the filtration function is maintained, it is inevitable that the collection of small-diameter foreign substances will be insufficient, and the filter will have to be replaced more frequently to maintain the cleanliness of the hydraulic fluid. be.

Therefore, the present invention maintains the foreign matter filtering function for a long period of time and reduces the frequency of filter replacement by changing the density of the filter paper of the element in the path direction of the hydraulic oil using the pressure of the hydraulic oil. With the goal.

[Means for solving problems]

In order to achieve the above object, the present invention has a filter paper wound in a roll between an inner paper tube and an outer paper tube, which is housed in a container with its axis vertically oriented, and is actuated from the inner paper tube. In an oil filter that supplies oil upward and then discharges the inside of the filter paper downward,
A space is provided between the outer circumference of the outer paper tube and the inner wall of the container, and the inner and outer circumferential surfaces of the lower end of the outer paper tube are covered with a thin film in a hakama-like manner. opening a plurality of holes in the outer paper tube in the region;
The pressure of the hydraulic oil flowing from the inner paper tube can be transmitted to the outer peripheral surface of the film located on the inner periphery of the outer paper tube through the gap between the outer paper tube and the inner wall of the container and the hole in the outer paper tube. It is characterized by the following.

〔Example〕

Hereinafter, features of the present invention will be specifically explained with reference to embodiments shown in the drawings.

FIG. 1 is a partially cutaway front view of an oil filter showing an embodiment of the present invention.

A frame 2 for connecting and fixing the container 1 to a machine is attached to the lower part of the pressure-resistant container 1, and a lid 3 is detachably attached to the upper end of the container 1, and a hydraulic oil supply and drain is installed at the lower end. Port 4 is integrated. Inside the container 1, an element 5 made of paper wound into a roll is housed. This element 5 has an inner paper tube 6 at the center and an outer paper tube 7 on the outer periphery, and a filter paper 8 is wound between these, and the hydraulic oil flows down within this filter paper 8 from the upper end to the lower end. .

As shown in FIG. 1, the port 4 includes an inlet 9 and an outport 10 for hydraulic oil, to which are connected a supply pipe 11 and a recovery pipe 12, respectively. As shown in the sectional view of FIG. 2, the upper end of the port 4 is integrally formed with a protrusion 13 that protrudes upward at approximately the center of the container 1, and the protrusion 13 is provided with a female threaded hole 14. It is being A supply channel 15 from the import 9 is formed to communicate with the female threaded hole 14, and the female threaded hole 14 is provided with a short circuit channel 16 that penetrates the protrusion 13 in the radial direction. Further, the outport 10 communicates with the inside of the container 1 through a recovery channel 17 whose end is open at the bottom of the container 1 .

A flange 18 is provided on the circumferential surface of the protrusion 13 in which the female screw hole 14 and the short-circuit passage 16 are formed, and a punching metal 19 whose center portion is supported by the flange 18 is arranged above the short-circuit passage 16. has been done. Further, an annular projection 20 is formed on the inner wall of the container 1 to support the outer peripheral edge of the punching metal 19.
An edge 21 is provided on the upper surface of the annular projection 20 to receive the element 5 in line contact.

As shown in the sectional view of FIG. 3, the lid 3 has an opening 22 in the center thereof, and has an annular inner peripheral rib 23 on the lower surface that presses down the inner paper tube 6 and outer paper tube 7 of the element 5, respectively. And an outer peripheral rib 24 is provided protrudingly. The inner circumferential rib 23 forms a stepped portion 25 at the lower end,
This stepped portion 25 is held inserted into the inner paper tube 6. Furthermore, these inner circumferential ribs 23 and outer circumferential ribs 24 are provided with notches 23a and 24a at predetermined pitch intervals.
The hydraulic oil from inside the inner paper tube 6 can be guided to the upper end side of the filter paper 8 and also between the outer paper tube 7 and the inner wall of the container 1. Further, an annular groove 26 between the outer circumferential rib 24 and the outer circumferential surface of the lid 3 is provided with a protrusion 27 that protrudes downward over the entire circumference, and is disposed within the annular groove 26 and seals with the upper end surface of the container 1. The sealing pressure to the gasket 28 is increased.

Furthermore, by means of a fastening bolt 29 that is inserted through the opening 22 of the lid 3 and screwed into the female screw hole 14 of the protrusion 13,
The lid 3 is integrated into the container 1. This fastening bolt 2
9 is a T-shaped one with a bar 30 at the top end;
Attach the lower part of the upper end head 31 to the packing 32 and washer 3.
3 to seal the lid 3 around the opening 22.

As shown in FIG. 2, on the lower end side of this fastening bolt 29, a communication passage 34 for hydraulic oil is formed in the axial direction from the lower end. The length of this communication channel 34 is such that the upper end is above the protrusion 13 when it is screwed almost completely into the female threaded hole 14.

FIG. 4 is an exploded perspective view of the element 5,
As mentioned above, the structure is such that the roll-shaped filter paper 8 is integrated into the annular space between the inner paper tube 6 and the outer paper tube 7.

At the lower end of the outer peripheral surface of the outer paper tube 7, a stepped portion is formed on the peripheral surface around which a spacer 35, which also serves as reinforcement, is integrally wound. Further, a plurality of holes 36 are opened at regular intervals in the circumferential direction on the spacer 35, and a pair of hooks 37 for taking out the container 1 from the container 1 are attached to the upper end. Furthermore, a thin film 38 made of polypropylene or the like is integrated into the lower part of the outer paper tube 7 in the form of a hakama. This film 38 has a cylindrical shape with its lower end bent outward, and as shown in FIG. The inner piece 40 extends to a higher position than the outer piece 39. In addition, film 38
After integrating the inner paper tube 6, outer paper tube 7, and filter paper 8, a mat 41 made of a material through which hydraulic oil can penetrate is attached to the lower surface.

In the above configuration, after the element 5 is housed in the container 1, the lid 3 can be firmly fixed to the container 1 by inserting the fastening bolt 29 through the opening 22 of the lid 3 and screwing it into the female screw hole 14. At this time, the inner paper tube 6 and outer paper tube 7 of the element 5 are pressed down by the inner circumferential rib 23 and outer circumferential rib 24 on the lower surface of the lid 3, respectively, to stabilize the element 5 even against high pressure hydraulic oil. It is possible to support the Also, a seal 2 seals the upper end of the container 1 and the lower surface of the lid 3.
8 is locally pressed by a projection 27 formed in the annular groove 26 of the lid 3. Therefore, the sealing pressure of the packing 28 can be increased, and the flowing hydraulic oil will not leak out from the sealed portion between the container 1 and the lid 3.

Next, when the hydraulic oil to be filtered is sent from the supply pipe 11, the hydraulic oil flows from the supply passage 15 through the communication passage 34 in the direction of the arrow in the figure, and is discharged into the space within the inner paper tube 6 of the element 5. . After the hydraulic oil rises inside the inner paper tube 6, it enters the inside from the upper end of the filter paper 8, passes through the punching metal 19 while being filtered, and is finally discharged from the recovery channel 17 to the recovery tube 12. circulates through the machine's hydraulic circuit.

Here, at the time when the supply of hydraulic oil is started, the hydraulic oil that has reached the upper end of the container 1 not only flows into the filter paper 8 but also flows into the outer paper pipe from the plurality of notches 24a provided in the outer peripheral rib 24 of the lid 3. 7 and flows between the container 1 and the inner wall thereof. As shown in FIG. 5, this inflowing hydraulic oil causes the outer piece 3
9 deforms outward. That is, the outer piece 39
Because of the spacer 35, a gap is likely to be formed between the spacer 35 and the circumferential wall of the outer paper tube 7, and the hydraulic oil enters into this gap so that the outer piece 39 is moved into the container 1 from the state shown by the dashed line in FIG. Press toward the inner wall. Therefore, the outer piece 39 comes into close contact with the inner wall of the container 1, and prevents the hydraulic oil flowing in from above from flowing down the inner wall of the container 1 to the recovery channel 17 side. .

Simultaneously with the deformation of the outer piece 39 as described above, hydraulic oil flows into the outer paper tube 7 through the hole 36 and deforms the inner piece 4 inside.
0 and enters into the filter paper 8 from the upper edge of the inner piece 40. At this time, since a large pressure is applied to the hydraulic oil, the inner piece 40 is loaded with external pressure due to the hydraulic oil and compresses the surrounding filter paper 8 toward its center. Therefore, the filter paper 8 is deformed in diameter as shown in FIG. 5 due to the compressive force from the outside, and as a result, the density of the filter paper 8 in the area vertically surrounded by the inner piece 40 becomes higher than in the upper side. .

As mentioned above, the density of the lower part of the filter paper 8 can be set high by utilizing the pressure of the hydraulic oil from the time when the hydraulic oil is supplied into the container 1. For this reason, even when foreign matter with a small diameter passes through the filter paper 8 from top to bottom as described in the prior art section, these can be reliably filtered and collected.

In addition, the upper part of the filter paper 8 can filter foreign substances with a large diameter, and the lower part thereof can collect small-diameter foreign substances. Therefore, it is possible to efficiently filter foreign substances regardless of their size, so element 5
If you use the whole thing effectively, you can lengthen the interval between periodic replacements.

In addition, although what is shown in the drawing filters hydraulic oil using a single container 1, if the flow rate of hydraulic oil is large depending on the machine used, multiple containers 1 may be connected in parallel. and use it.

〔Effect of the invention〕

As explained above, in the oil filter of the present invention, the density of the filter paper is made larger than the upper part by compressing the lower part of the element using the pressure of the hydraulic oil. Therefore, even small foreign matter can be reliably filtered and collected, making it possible to maintain a high level of cleanliness of the hydraulic oil collected into the circuit. In addition, since the upper part of the filter paper collects large foreign substances and the lower part filters out small foreign substances,
It is possible to maintain the filtration function by effectively utilizing the entire filter paper. As a result, the effective period of use can be extended and the frequency of filter replacement can be reduced.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view of an oil filter showing an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the port section, Fig. 3 is a longitudinal sectional view of the lid section, and Fig. 4 is an exploded view of the element. FIG. 5 is an enlarged vertical sectional view showing deformation of the film at the lower end of the outer paper tube of the element, and FIG. 6 is a schematic diagram of a conventional oil filter structure. 1: Container, 3: Lid, 4: Port, 5: Element, 6: Inner paper tube, 7: Outer paper tube, 8: Filter paper, 11:
Supply pipe, 12: Recovery pipe, 13: Protrusion, 14: Female screw hole, 15: Supply channel, 16: Short circuit channel, 17:
Recovery channel, 23: Inner circumference rib, 24: Outer circumference rib, 2
9: Fastening bolt, 34: Communication channel, 35: Spacer, 36: Hole, 37: Hook, 38: Film,
39: outer piece, 40: inner piece, 41: pine.

Claims (1)

[Claims] 1 A filter paper wound in a roll between an inner paper tube and an outer paper tube is stored in a container with its axis vertically, and after supplying hydraulic oil upward from the inner paper tube, the inside of the filter paper is supplied downward. In the oil filter for discharging toward the container, a space is provided between the outer periphery of the outer paper tube and the inner wall of the container, and the inner and outer circumferential surfaces of the lower end of the outer paper tube are covered with a thin film in a hakama shape. A plurality of holes are opened in the outer paper tube in the area covered with the film, and the pressure of the hydraulic oil flowing from the inner paper tube is applied to the space between the outer paper tube and the inner wall of the container and the outside. An oil filter characterized in that the oil can be transmitted through a hole in a paper tube to the outer peripheral surface of a film located on the inner periphery of the outer paper tube.