JPH0429847Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention mainly relates to a filter for a return circuit to be disposed in a return flow path to a tank in hydraulic piping.

[Prior Art] As a filter for a return circuit that has been generally used in the past, the filter container is connected to a main body to which the primary side piping is connected, and a lower end of an opening passing through the center of the main body coaxial with the opening. A case that is attached to the main body and houses the filter element, and a cover that closes an opening on the main body for inserting and removing the filter element into the case are often used.

Among the parts constituting the container of this return circuit filter, the main body is the largest, and if it can be made smaller, weight and cost reductions can be achieved.

However, in the filter described above, since the case is attached through the opening in the main body for inserting and removing the filter element, the inner diameter of the opening needs to be larger than the outer diameter of the filter element and the outer diameter of the case. Under these constraints, the best policy is to make the wall thickness of the main body as thin as possible, and if this is made possible, the main body itself is a large-sized and heavy component, so it is possible to reduce its weight. , a significant cost reduction effect can be expected.

However, since the fluid pressure flowing from the primary pipe directly acts on the inner surface of the main body, pressure-resistant strength is required, and the main body cannot simply be made thinner.

[Problems to be Solved by the Invention] The problems to be solved by the present invention are to provide a return circuit filter whose main body can be made thin and whose filter elements can be easily replaced.

[Means for Solving the Problems] In order to solve the above problems, the return circuit filter of the present invention includes a main body having a connection port to which the primary side piping is connected, and an opening penetrating in a direction crossing the connection port; A filter comprising: a case installed below and coaxially with the opening, having a secondary fluid outlet and a filter element housed through the opening; and a cover closing an upper end of the opening on the main body. , the opening has a tapered surface that is open at the top, and the cover has a primary flow path that communicates between the connection port and the inside of the filter element, and a tapered surface that is in close contact with the tapered surface, and the cover has a flow passage that is fitted into the opening. The case includes a path forming part,
It has a secondary flow path that communicates the outer peripheral surface of the filter element with the outlet, a spring that urges the filter element upward, and a support portion for the spring, and the flow path forming lower end of the main body and the cover. It is characterized by being fluid-tightly sandwiched between the

[Function] In the return circuit filter described above, the fluid that flows in from the primary side piping flows out to the filter element through the primary side passage of the cover that communicates with the primary side piping connection port of the main body. The pressure of the primary fluid does not work except at the piping connection port. For this reason, there is no need to provide pressure resistance to the opening of the main body, which is large enough to allow insertion of the filter element, and only the cover inserted into the opening needs to have pressure resistance, making it possible to make the main body thinner. I can do it.

Also, with the piping connected to the connection port on the main unit,
The filter element can be replaced by removing the cover. In this case, a gap is created between the filter element and the opening due to the filter element moving upward due to the biasing force of the spring and the opening having a tapered surface that is open at the top. Since it can be easily held, its replacement is easy.

Furthermore, since the opening inner surface of the main body and the flow path forming part of the cover are tapered surfaces that open upward, the sealing member that seals around the primary side piping connection port will not be damaged when the cover is inserted into or removed from the opening. do not have.

[Embodiment] FIGS. 1 and 2 show an embodiment of the return circuit filter of the present invention.

In this embodiment, the filter container of the filter for the return circuit includes a main body 1 to which a pair of primary side pipes 2, 2 are connected at opposite positions, and an opening 5 passing through the center of the main body 1 at the lower end thereof coaxial with the opening. a case 3 that is attached to the main body 1 and houses a filter element 6 through the opening; and a cover 4 that closes the opening 5 on the main body 1 for inserting and removing the filter element 6 into the case 3. ing.

In the main body 1, connection ports 8, 8 for connecting a pair of primary side pipes 2, 2 provided at opposing positions
The filter corresponds to a plurality of return passages to the tank in the hydraulic system, and the flange 9 provided at the lower end of the main body is for fixing the filter itself to the tank or the like.

The opening 5 vertically passes through the center of the main body 1,
In order to make it possible to insert and remove the filter element 6 and the case 3 from above, its inner diameter is made larger than the outer diameter of the filter element 6 and the outer diameter of the case 3. A step portion 11 is formed on which the upper end flange portion 12 of No. 3 is locked. A portion above the stepped portion 11 is a tapered surface that opens upward, and the connection ports 8, 8 are formed in this tapered surface portion.

The cover 4 that is attached to the opening 5 of the main body from above has a closing lid part 14 that closes the upper end of the opening 5 in the main body 1, and a flow path forming part 15 that is fitted into the tapered part of the opening 5. are doing. This flow path forming part 15 forms a T-shaped primary flow path 16 that communicates with the connection ports 8, 8 of the main body 1, and connects the lower end of the primary flow path extending downward from the center to the lower case 3. The portions of the flow path 16 facing the connection ports 8, 8 of the main body 1 are formed in a tapered shape that matches the tapered opening 5 of the main body 1, and as can be seen from FIG. The periphery of the path forming portion 15 communicates with the inside of the case 3 below. In addition, by bringing the lower end of the flow path forming portion 15 into fluid-tight contact with the filter element 6 housed in the case 3 via an O-ring 17, the primary flow path 16 is made into It communicates directly with the opening 19.

On the other hand, packings 18 are provided around the pair of openings in the primary flow path 16 in the cover 4 that communicate with the connection ports 8, 8 of the main body 1. When the passage forming portion 15 of the cover 4 having a similar tapered shape is inserted into the shaped opening 5 and finally tightened, the main body 1 and the cover 4 are brought into pressure contact.

That is, the packing 18 is attached to the main body 1, respectively.
The cover does not come into sliding contact with the inner surface of the main body 1 until it reaches around the connection ports 8, 8, and the lower end of the flow path forming portion 15 is brought into liquid-tight contact with the filter element 6 via the O-ring 17. Since a predetermined crushing margin is generated when the cover 4 is set in a predetermined position, the packing 18 on both sides can be tightened at the same time as the cover 4 is attached without damaging the packing 18. I can do it.

Flow path forming portion 15 of cover 4 formed in this way
Since the primary fluid flowing in from the connection ports 8, 8 of the main body 1 is directly communicated with the inflow opening 19 of the filter element 6, the main body 1 is connected to the connection ports 8, 8.
Since the primary side fluid pressure does not act on the inner surface except for the connecting ports 8, 8, and there is no need to provide pressure resistance to the parts other than the connecting ports 8, 8, the whole can be made relatively thin and lightweight.

On the other hand, since the primary fluid flows through the flow path forming portion 15 of the cover 4, it is necessary to have pressure resistance to withstand the primary fluid pressure. Since it is small, the wall thickness needs to be very small in terms of pressure resistance.

A stepped portion 1 formed at the lower end of the opening 5 of the cover 4
The case 3, in which the upper end flange portion 12 is locked to the case 1 via an O-ring 20, has a cylindrical shape with an opening at the lower end as an outlet port 21 for the secondary fluid, and supports the filter element 6 at its inner lower end. Bridge 22
A spring 25 that presses the filter element 6 against the lower end of the cover 4 is supported by a guide 23 disposed on the bridge 22.

The filter element 6 closes the lower end of the surrounding perforated plate 27 with an end plate 28, and has an edge frame 2 at the upper end.
9 is attached, and a filter material 30 is attached to the inner surface of the perforated plate 27.
A secondary flow path 31 is formed between the outer peripheral surface of the perforated plate 27 and the inner peripheral surface of the case 3.

The flange portion 12 of the case 3 described above is covered with a cover 4.
The mounting structure in which the step part 11 is locked via the O-ring 20 can achieve a connection using an extremely simple means with a sealing function, compared to the case where the two are connected by screws or the like. Furthermore, the filter element 6 housed in the case 3 can be replaced by simply removing the cover 4 and taking it in and out of the case 3. Moreover, since the fluid flows from the inside to the outside of the filter element 6, Since the dust is collected inside the filter element 6, the dust can be removed very easily.

The relief valve 33 provided on the cover 4 prevents a decrease in the flow rate on the secondary side and damage to the filter element when the pressure in the primary flow path 16 increases abnormally due to clogging of the filter element 6. The valve seat 35 is for causing the primary side fluid in the flow path 16 to flow out to the surrounding secondary side. 35, the valve body 36 is pressed into contact with a spring 37 for setting the valve opening pressure, and the other end of the spring 37 is supported by a cap 38 screwed onto the cover 4, and the outlet ports 40, . . . As shown, it communicates with the secondary flow path 31 described above.

In the relief valve 33 having such a configuration, the cap 38 can be removed from the outside of the cover 4 and the spring 37 for setting the valve opening pressure and the valve body 36 can be easily taken out. Maintenance and management of the valve can be easily performed.

In the embodiment described above, the primary fluid flowing in from the connection ports 8 and 8 flows out into the filter element 6 from the primary flow path 16 formed by the flow path forming portion 15 of the cover 4, and is processed by the filter element 6. The fluid from which foreign substances have been filtered passes through the secondary flow path 31 and is discharged from the outlet 21 .

Therefore, in the main body 1, except for the connection ports 8 and 8,
Primary side fluid pressure does not work.

When the pressure in the primary flow path 16 increases abnormally due to clogging of the filter element 6, the valve body 36 of the relief valve 33 opens the valve seat 35 against the urging force of the spring 37, and the relief valve The pressure fluid that has flowed into the outlet 33 is discharged from the outlet 40, . . . to the secondary flow path 31.

When replacing the filter element 6, the cover 4 can be removed from the main body 1 while the primary pipes 2, 2 are connected to the main body 1.

When the cover 4 is removed from the main body 1, the filter element 6 moves upward due to the biasing force of the spring 25 compressed between it and the bridge 22, thereby opening the inner surface of the opening 5, which is a tapered surface with an open upper part. Since there is a gap between the filter element 6 and the filter element 6, the filter element 6 can be easily grasped, and therefore, the filter element 6 can be taken out very easily.

[Effects of the invention] According to the return circuit filter of the present invention, the primary fluid pressure flowing in from the primary piping is prevented from acting on anything other than the connection port of the main body, so the main body can be made thinner. The filter can be constructed lightweight and inexpensively.

Furthermore, since the filter element is urged upward by a spring and the opening is formed into a tapered surface that is open at the top, the filter element can be easily taken out.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the return circuit filter of the present invention, and FIG. 2 is a cross-sectional view taken along the line A--A in FIG. 1 showing the relief valve in an open state. 1...Body, 2...Primary side piping, 3...Case, 4...Cover, 5...Opening, 6...Filter element, 8...Connection port, 16...Primary side flow path, 19... Inflow opening, 21...Outflow opening, 31...
...Secondary flow path.

Claims (1)

[Claims for Utility Model Registration] A main body having a connection port to which the primary side piping is connected, and an opening penetrating through the connection port in a direction intersecting the connection port, and a main body having a connection port to which the primary side piping is connected, and a main body having a main body having a connection port to which the primary side piping is connected, and an opening penetrating through the connection port in a direction that intersects with the connection port, and a main body that is installed coaxially with the connection port below the opening, A filter comprising: a case having an outlet and a filter element housed through the opening; and a cover that closes an upper end of the opening on the main body, the opening having a tapered surface that is open at the top; The case includes a primary flow path that communicates between the opening and the inside of the filter element, and a flow path forming portion that has a tapered surface that comes into close contact with the tapered surface and is fitted into the opening, and the case has an outer circumferential surface of the filter element that It has a secondary flow path that communicates with the outlet, a spring that urges the filter element upward, and a support portion for the spring, and is liquid-tight between the main body and the lower end of the cover where the flow path is formed. being held between
A return circuit filter characterized by: