JPH0337689Y2 - - Google Patents

Description

[Detailed explanation of the invention] Industrial application field This invention is applicable to pilot circuits of construction machinery, etc.
It mainly relates to a filter device in a hydraulic circuit of a control system.

2. Description of the Related Art Hydraulic circuits in recent hydraulic drive systems have adopted remote control methods or feedback control methods for various loads, and have not only constituted complex hydraulic circuits, but also Equipment has become more compact and more precise, and in order to improve responsiveness and smooth operation, many small-diameter orifices are often installed in the circuit. Therefore, the hydraulic oil flowing through these devices and pipes must not contain any dust.If there is any dust in the hydraulic oil, it may cause problems between the components of the above equipment. This can clog gaps and orifices and cause the sliding parts to become stuck, resulting in abnormal operation and even danger.

In particular, construction machinery, which is used extensively in harsh environments with dust and muddy water flying around, and where maintenance, disassembly, and assembly of equipment and related parts cannot necessarily be carried out in a specified clean environment, are important. On the inflow side of the control system pressure oil introduced into the equipment and between each equipment, separate filters are installed specifically for that equipment to prevent dust from entering, so the number of filters is about 10 per unit. There are more and more.

To give an example, FIG. 5 is a circuit diagram showing a part of the control circuit of a remote control type hydraulic actuation system using pilot pressure. In the engine, each pump transfers hydraulic oil from tank 15 to suction strainer 1.
The pressurized oil discharged from the main pumps 11 and 12 serves as the main power source for a predetermined hydraulic operation system, and operates various actuators via hydraulic switching valves (not shown). On the other hand, the oil discharged from the pilot pump 13 passes through a line filter 24,
A relief valve 25 maintains a specified pressure and serves as a hydraulic pressure source for the control system. 16 and 17 are main pump 1
This is a servo cylinder that adjusts the amount of oil discharged from servo valves 18 and 12 according to load conditions and instruction patterns.
It acts through 9 and expands and contracts.

In addition, 26, 27, 28, and 29 are pilot valves that operate hydraulic switching valves, etc., which receive pressure oil from the pilot pump 13 as described above and generate the desired pressure regulating oil. It acts on the pilot oil chamber of the above-mentioned hydraulic switching valve, etc.

In the hydraulic circuit of the control system as described above, for the reasons mentioned above, the pressure oil supply line to each device, the filters 20, 21, 22, 23, 30, 31, 32, 33, etc. are installed between each device. is provided.

Conventionally, these filters have been mainly incorporated in joints located in the middle of control system pressure oil piping, and an example of their configuration is shown in FIG. That is, the inlet side of the flow path of the joint 34 is machined into a stepped hole, and the head of the filter material 35 made of a wire mesh machined into a hemispherical shape as shown in FIG.
A cylindrical sheet 36 as shown in FIG. 8 was driven into the stepped hole of the joint 34 together with a filter material 35, and the end surface was caulked.

Problems to be Solved by the Invention In the filter device having the conventional configuration as described above, it is difficult to install a large number of filters divided into filter material 35 and sheets 36 in the middle of the piping, and the joint 34 is difficult to install. If the fit between the stepped hole and the sheet 36 is not made very strong, the filter material 35 may fall off due to the flow of oil, or sufficient filtration may not be possible. On the other hand, if the fit is too tight, the filter material 35 may fall off when the sheet 36 is inserted. Since there are concerns such as damage to the material 35, this not only poses problems in terms of quality control but also increases costs.

Means for solving the problem In order to solve the above problems, the present invention uses the following filter. In other words, a filter element made by overlapping reinforcing wire mesh on both sides of a circular filter material is bonded or sandwiched to the inner diameter of a ring-shaped sheet to form an integrated filter, and the filter is placed in the flow path end of a joint in a circuit. The outer circumference of the filter is in contact with the inner diameter of the stepped hole of the joint, and punching is performed in several places on the circumference that appears on the end face, or a conventional retaining ring is used as an escape prevention means. Fix it with.

Function: Make a concentric stepped hole in advance at one end of the flow path of the joint used in the pilot circuit, insert the integrated filter into the stepped hole, and fix it by punching the end surface. For example, a filter device for the pilot circuit can be provided by simply assembling the joint to the pilot circuit.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a sectional view showing an embodiment of the filter device according to the present invention. In the figure, 1 is a joint for connecting pipes provided in a control circuit of a hydraulic operating system, and 2 is a filter. One end of the flow path a passing through the interior of the joint 1 forms a concentric stepped hole b having an inner diameter larger than the diameter of the flow path a. On the other hand, the filter 2 has a structure, as shown in FIG. Sheet 4 whose outer diameter is now fitted
The outer periphery of the filter element 3 is crimped and fixed at the mating surfaces of the outer ring c and the inner ring d. Therefore, the filter element 3 and the sheet 4 are integrally formed as the filter 2.

The outer diameter of the outer ring c of the filter 2 is such that it can be press-fitted into the stepped hole b of the joint 1.
Its thickness matches the depth of stepped hole b.

In order to install a filter device in the control circuit using the parts with the above configuration, press the filter 4 into the stepped hole b of the joint 1 in advance so that the end face of the joint 1 and the end face of the sheet 4 are on the same plane. On the plane, as shown in Figure 2, joint 1
The filter 2 is punched at multiple locations on the circumference e where the inner circumference of the stepped hole b and the outer circumference of the outer ring c of the sheet 4 are in contact with each other, or by means of escape prevention such as a retaining ring. After making sure that it does not slip out of the joint 1, the pipes may be joined using normal piping procedures. At this time, generally the filter 2 fitted into the joint 1 is assembled so as to be on the upstream side of the pipe.

Note that the filter element 3 shown in FIG. 3 is fixed by sandwiching the outer circumferential part between the outer ring c and the inner ring d of the seat 4, but in addition to this method, the seat can be constructed as a single unit and the filter element is attached to the inner diameter part of the seat 4. There are methods such as welding the outer periphery of No. 3 or press-fitting it into the inner diameter groove, but the point is that the purpose of this invention is as long as the method does not cause the filter element to fall off the seat or create a gap on the outer periphery of the filter element. can be achieved.

FIG. 4 shows a second embodiment of the present invention, in which the sheet 4 in the first embodiment is not used, and the filter element 5' is sandwiched between reinforcing wire meshes 6', 6'. 3' is the same as above, but these are crimped and sintered at the outer periphery f to form an integrated filter.Use this filter to prevent escape by punching. In this case, the depth of the stepped hole b of the joint 1 needs to match the thickness of the filter.

Effects of the invention The filter material in the filter device of this invention is protected by strong wire mesh on both sides, and its outer periphery is fixed to the inner diameter of the ring-shaped sheet, so the flow velocity in the flow path increases rapidly during use. The filter material will not be damaged or fall off due to the flow flow, and when the filter is assembled into a joint, the outer periphery of the sheet that makes up the filter should be inserted into the stepped hole provided at one end of the flow path. All you have to do is drive them together, punch the mating parts of the end faces, and assemble them into the piping.During the assembly process, you only have to handle the joint that is integrated with the filter, so the work is easy and reliable. Moreover, it costs less.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the filter device of the present invention, Figure 2 is a sectional view of the filter device of the present invention;
The drawings are a view taken in the direction of arrow A in FIG. 1, FIG. 3 is a partial sectional view showing an embodiment of the filter used in the present invention, FIG. The figure is an example of a circuit diagram showing a part of a control circuit in a hydraulic operating system, Figure 6 is a sectional view showing an example of the configuration of a conventional filter device, and Figure 7 is an external appearance of the filter material used in Figure 6. A perspective view, FIG. 8 is an external perspective view of the sheet used in FIG. 1...Joint, 2...Filter, 3,3'
...Filter element, 4...Sheet, 5,
5'...Filter material, 6,6'...Wire mesh, 20,2
1, 22, 23, 30, 31, 32, 33...filter.

Claims (1)

[Scope of claim for utility model registration] (1) A stepped hole concentric with the flow path is provided at one end of a joint flow path in a pilot circuit of a construction machine, and reinforcing wire mesh is provided on both sides of a disc-shaped filter material. A filter is constructed by integrating the stacked filter elements by joining or clamping them onto the inner diameter of a ring-shaped sheet whose outer circumference is equal to the inner diameter of the stepped hole and whose inner diameter is approximately equal to the flow path of the joint. A filter device for a pilot circuit of a construction machine, which is fitted into a stepped hole of a joint, and has means for preventing escape of the filter between the outer periphery of the filter and the inner diameter of the stepped hole of the joint. (2) Utility model registration claim 1, in which the outer periphery of the filter and the inner diameter of the stepped hole of the joint are in contact with each other and are punched at multiple points on the circumference that appear on the end face that is on the same plane. Filter device for pilot circuit of construction machinery.