JPS6231708A - Reverse-flow-filter - Google Patents

Abstract

PURPOSE:To protect a machine from foreign matters by providing a ringlike valve body for forming a check valve on the periphery of a filter outer cylinder a filter element, providing a valve body on its one end and also providing another valve body on one end of a filter element. CONSTITUTION:A valve case 22 with a built-in valve body 20 is mounted in one body with a filter outer cylinder 2 at the center outlet 21 on its one end part. A ringlike valve body 27 forming a check valve is slidably provided near a channel hole 25 located on the periphery of the filter outer cylinder 2. Meanwhile, a cylindrical filter element 11 is inserted into the filter outer cylinder 2, and a valve case 12 in which a conical trapezoid-shaped valve body 13 is arranged as a bypass valve is fitted into one end part of the filter element 11. Since foreign matters already caught can be prevented from being flowingly discharged to the upper stream side due to reverse flow, any apparatus connected to a hydraulic circuit can be protected from the foreign matters by the above mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a reverse flow filter for filtering foreign matter provided in a hydraulic circuit.

[Prior Art] For example, in a hydraulic circuit that forms a closed circuit and circulates oil, a filtration filter is provided to capture foreign matter in the oil in order to protect equipment in the hydraulic circuit.

[Problems to be Solved by the Invention] In this case, when oil flows backwards, foreign matter such as dirt trapped in the filter element flows upstream, creating the risk of harming equipment in the circuit. Therefore, conventional filters cannot be used in hydraulic circuits where oil may flow back.

Therefore, this invention has developed a reverse flow filter that prevents foreign matter such as dirt trapped in the filter element from flowing upstream even if oil flows backward in a hydraulic circuit that forms a closed circuit and circulates oil. The purpose is to obtain.

Means for Solving Problem U] In order to achieve the above object, a cylindrical filter for fluid filtration is provided in a cylindrical container, the container is connected to a fluid flow path, and a cylindrical filter is provided in the cylindrical container. In addition, a backflow valve is provided between the downstream portions of the container that opens with a low differential pressure to bypass this filter, and the filter is opened with a low differential pressure with respect to the downstream portion of the container so that fluid that has passed through the filter is provided. A non-return valve is provided integrally with the filter, and normally the fluid flows from upstream to downstream through the filter, and when the fluid flows back, the back flow valve detours the filter flow path and the fluid flows through the filter. It is configured to flow from downstream to upstream.

[Function] In this configuration, under normal conditions, the check valve opens due to fluid pressure in the forward direction, and the fluid flows through the fluid channel through the cylindrical filter for fluid filtration in the cylindrical container. Foreign matter is captured and filtered by the filter.

On the other hand, when the fluid flows back, the pressure of the fluid flowing back opens a backflow valve provided in the container that opens at a low differential pressure and bypasses the flow path passing through the filter, and the backflow fluid flows bypassing the filter. . Therefore, the foreign matter captured by the filter is prevented from floating out.

[Effects of the Invention] In this way, normally the fluid flows from upstream to downstream through the filter, and when the fluid flows backward, the filter channel is bypassed by the backflow valve to flow the fluid from downstream to upstream. When the hydraulic circuit must cause fluid to flow backwards from downstream to upstream due to the way the device is used,
This device can prevent foreign matter that has already been captured from floating out to the upstream during the backflow, and can protect the stirrer connected to the hydraulic circuit from foreign matter.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

In order to capture foreign matter in the fluid, the filter installed in the hydraulic circuit performs its function by passing the fluid from upstream to downstream during normal operation. Because of the usage pattern, when fluid must flow backwards from downstream to upstream, this device can prevent previously captured foreign matter from floating upstream and prevent equipment connected to the hydraulic circuit. can be protected from foreign objects. When fluid flows from upstream to downstream, it performs its filter function, and when fluid flows from downstream to upstream, that is, when a backflow occurs, the filter function is not inhibited. A reversible flow path is constructed.

Hereinafter, embodiments of this device will be described with reference to FIGS. 1 to 4.

FIG. 1 is a front sectional view showing the configuration of a reverse flow filter. In the figure, 1 is a reverse flow filter, and 2 is a hollow cylindrical filter outer tube constituting the reverse flow filter 1, one end of which is closed. A lid 5 is fixedly attached to the other end of the filter outer cylinder 2 with bolts 6 and is closed.

In addition, at the one end of the filter outer cylinder 2, a flow passage opening 2 is provided in the center.
1, and a valve box 22 is integrally provided on the outside of this flow path port 21. The valve box 22 is provided with a flow path port 23 opposite to the flow path port 21, and a coil spring 24 is provided inside. Further, a valve body 20 having a conical shape is provided in the valve box 22, and the valve body 20 is pressed against the flow passage port 21 by a coil spring 24 to close the flow passage port 21.

Therefore, in the valve box 22, when the fluid flows out from the channel port 21 toward the channel port 23, the valve body 20 is pushed to open the channel port 21, and when the fluid flows backward, the valve body 20 is in close contact with the channel port 21. impede distribution. Reference numeral 9 designates an outflow side flange of a hydraulic circuit connected to the flow port 4a of the main body 4, and is fixed with bolts 10.

In addition, in the middle of the filter outer cylinder 2, there are 7 langes 2 on the outside.
', and a large number of passage holes 25 are bored at a predetermined pitch on the circumferential surface of the filter outer cylinder 2 near the seven flange 2' in the direction of the one end side.

Further, around the filter outer cylinder 2, a ring-shaped valve element 27 constituting a check valve is slidably provided near the flow passage hole 25 on the one end side thereof. Reference numeral 4 denotes a main body, which has a bottomed cylindrical shape with an inner diameter somewhat larger than that of the outer cylinder 2, and an oil flow port 4a is bored in the center of the bottom.

The filter outer cylinder 2 is inserted into the main body 4 with the above-mentioned one end side, and the above-mentioned flange 2- provided in the center of the filter outer cylinder 2
The two are tightly fixed by fastening with bolts 3. The upper opening of the main body 4 has a bulging portion 4b formed directly below it, and the valve body 27 is connected to this bulging portion 4.
The bulging portion 4 is pressed by the coil spring 26 disposed inside the b.
It is in contact with the end face of the inner diameter part of b and functions as a valve between this end face.

A flow passage opening is provided in a part of the side end face of the bulging portion 4b, and an inflow side flange 7 of the hydraulic circuit is attached thereto with bolts 8. Therefore, the oil in the hydraulic circuit flows from this inflow side flange 7 through the flow passage hole 25 into the filter outer cylinder 2. A cylindrical filter element 11 is inserted into the filter outer cylinder 2, and one end of the filter element 11 is in contact with the bottom of the filter outer cylinder 2, and the other end is fitted with a valve box 12. There is.

Then, this valve box 12 is pressed toward the filter element 11 side by a coil spring 14 arranged between it and the lid 5.
Fixed. The valve body 12 is a hollow cylindrical body and has flow passage ports 16,17.

Inside, there is a valve body 1 in the shape of a truncated cone that becomes a bypass valve.
3 is arranged, and this valve body 13 has a spring 15 provided inside.
The lid 5 is constantly pressed in the upper direction in the figure, and the flow path opening 1
7 is blocked. Therefore, this valve box 12
When fluid flows from the flow path port 16 toward the flow path port 16, the valve body 13 is pushed to open the flow path port 17, and when fluid flows backward, the valve body 13 comes into close contact with the flow path port 17 and obstructs the flow. Reference numeral 9 designates an outflow side flange of a hydraulic circuit connected to the flow port 4a of the main body 4, and is fixed with bolts 10.

Furthermore, arrow A on the flange 7.9 indicates the direction of inflow into the reverse flow filter 1, and arrow B indicates the direction of outflow into the reverse flow filter 1.

Further, arrows /M and B- on the flange 7.9 indicate the flow direction of the fluid with respect to the reverse flow filter 1 at the time of reverse flow.

The ring-shaped valve body (reversible flow valve) 27 having a circular trapezoidal cross section is located in the bulging portion 4b in the main body 4 and is slidably fitted on the circumferential surface of the filter outer cylinder 2. , is always biased in the direction of the outflow side flange 9 by the coil spring 26, and when the side end surface of the valve body 27 comes into contact with the bottom side edge (valve seat surface) of the bulge 4b of the main body 4, the bulge 4b The gap with the filter outer cylinder 2 is closed to prevent fluid from flowing directly from the main body 4 to the outflow side flange 9 through this gap, and when fluid flows backward from the outflow side flange 9, When the fluid pressure overcomes the spring force of the spring 26,
The valve body 27 slides on the outer peripheral surface of the filter outer cylinder 2 and closes the flow passage hole 25 of the filter outer cylinder 2 with its inner wall, thereby blocking the oil inflow path into the filter outer cylinder 2. The gap between the bulging portion 4b and the filter outer cylinder 3, which has been closed until now, is opened, and the liquid flows directly from the inflow side flange 7 through this gap.

In addition, the valve bodies 12 and 22 disposed at both ends of the filter element 11 open the valve for fluid flowing from A to B by means of a valve body 13.20 biased by a coil spring 15.24, and the filter is filtered. - Although it is designed to be able to flow out through the element 11, it acts as a check valve for flows in the B= and A' directions.

In addition, the outflow side flange 9 of the hydraulic circuit connected to the flow port 4a of the main body 4, the connection part between the flange 2' of the filter outer cylinder 2 and the main body 4, and the flow port provided in the bulge part 4b of the main body 4. The connecting portions of the hydraulic circuit with the inflow side flange 7 are sealed by providing some kind of sealing material on their mating surfaces, but this is omitted here for the sake of explanation. Further, this apparatus having the above-mentioned structure is shown in a symbol diagram as shown in FIG.

This device having such a configuration has a bulge 8I3 in the main body 4.
The ring-shaped valve body 27 having a circular trapezoidal cross section, which is slidably fitted to the circumferential surface of the filter outer cylinder 2 and is positioned at the outer circumferential surface of the filter outer cylinder 2, is always pressed against the outflow side flange 9 by the coil spring 26.
When the side end surface of the valve body 27 comes into contact with the bottom side edge (valve seat 1 to surface) of the bulging portion 4b of the main body 4, the gap between the bulging portion 4b and the filter outer cylinder 2 is reduced. is closed, and the outflow side flange 9 is directly connected to the main body 4 through this gap.
In addition, when fluid flows backward from the outflow side flange 9, when the fluid pressure overcomes the spring force of the coil spring 26, the valve body 27 closes the filter outer cylinder 2.
slides on the outer circumferential surface of the filter outer cylinder 2 and closes the flow passage hole 25 of the filter outer cylinder 2 with its inner wall, thereby blocking the oil inflow path into the filter outer cylinder 2. A gap between the bulging portion 4b and the filter outer cylinder 3 is released, and the water directly flows out from the inflow side flange 7 through this gap.

Valve box 1 arranged at both ends of filter element 11
2.22 is the valve body 13.22 biased by a spring 15.24.
The valve 20 opens the valve for fluid flowing in eight directions from A and allows the fluid to flow out through the filter element 11, but acts as a check valve for fluid flowing in one direction B- and A.

Therefore, when fluid flows in the forward direction, it passes through the plurality of flow passage holes 25, and the target foreign matter is captured by the filter element 11, passing through the valve box 2 which becomes a check valve.
2, and flows out from the outflow side flange 9 as shown by arrow B.

Since the force of the spring 24 biasing the valve body 20 is at most about 0.1 bar when converted to outflow liquid pressure, it does not cause any problem in flow path resistance.

If the filter element 11 traps more foreign matter than its capacity and the flow path resistance of the filter element 11 exceeds the allowable external pressure, there is a risk of damage. In such a situation, for example, the spring 1 should be opened at 0.2 bar.
5, when the resistance reaches 0.2 bar, the valve element 13 of the valve body 12 forming the bypass valve is activated. Therefore, the fluid that has flowed into the filter outer cylinder 2 is transferred to this valve box 12.
It flows out from the valve box 22 through the valve body 22, thereby alleviating flow path resistance.

When fluid flows backwards, the valve body 22 is closed and pressure is applied to the valve body 27. Therefore, this backflow valve body 27 is pushed up against the spring 26, and a gap is created between the main body 4 and the filter outer cylinder 2. The fluid passes through this and flows from the bulge 4b to the inflow side flange 7 without passing through the filter element 11. Therefore, there is no fear that the foreign matter trapped in the filter element 11 will be separated and floated and flow upstream.

FIG. 3 shows an example of a hydraulic circuit in which such a reverse flow filter 1 is required.

The figure shows a hydraulic circuit that is rotated (rotated) by a hydraulic motor, and the function of the reverse flow filter in this circuit will be explained.

This is a so-called H8T (H
ydro 5tatic Transmission
) This is a circuit example.

54 is called a crossover relief valve, and is a valve that releases hydraulic pressure to prevent the circuit pressure from becoming abnormally high. In this circuit, when the operating device 53 is operated, the signal (electrical or hydraulic) is given to the flow rate control device 52 as a flow rate control signal for the hydraulic pump 50, and the discharge amount of the hydraulic pump 50 is controlled to the left or right and to the left or right. change. For example, when the oil is discharged to the right circuit, the oil flow passes through the backflow valve (27 in FIG. 1) of the right reverse flow filter 1R,
The oil flows into the engine and rotates it, and the discharged oil flows into the left reverse
The flow filter 1L passes through the filter element and enters the suction side of the hydraulic pump 50.

If the signal from the operating device 53 is reversed, the flow will be reverse to that described above.

In either operation, fluid exits the hydraulic pump 50 through the left and right reverse flow filters IL.

Since it passes through the filter element of one of the reverse flow filters in 1R, foreign matter generated in the circuit is completely captured and can be prevented from damaging equipment in the circuit.

Further, since the reverse flow filter functions as explained in FIG. 1, the captured foreign matter will not float out into the hydraulic circuit again.

FIG. 4 shows an example of overuse for a hydraulic circuit using a hydraulic cylinder 61 as an actuator. In the figure, 60 is a hydraulic pump, 62 is a load, and 63 is the hydraulic pump 60.
A control valve 64 is a control device that controls the opening degree of the control valve 63.

In such a hydraulic circuit, the control valve 63 is normally opened and closed by a signal (electrical or hydraulic) from the control device 64. Then, the actuator 61 is driven upward or downward in the diagram, and the discharged oil is reverse flowed.
It passes through the steady flow path of filter 1 and returns to the tank. At this time, due to the operation of the control valve 63 and the influence of the load 62,
It may become necessary to make up the oil inlet or oil outlet lines of the actuator 61 (this is often referred to as vacuum protection). Therefore, a make-up check valve 65 is provided, and in such a circuit, oil is replenished from the reverse flow filter 1, but if there is no reverse flow filter like this device, In the conventional case, when installing the reverse flow filter 1, a normal filter is installed at the same position, and oil is injected from there. Therefore, foreign matter that was trapped in the filter floats out during this injection, causing the oil to flow out. There was a risk that it could get into the equipment in the hydraulic circuit and damage the equipment when it was driven. Therefore, it was not possible to replenish oil from the filter side, and replenishing oil was difficult.

However, by using the reverse flow filter 1 of the present invention, when the upstream side becomes a bit vacuumed,
Utilizing the foreign matter retention effect of the reverse flow filter 1, it is now possible to inject and replenish oil from the downstream side to the upstream side of this reverse flow filter 1, making oil replenishment easy. It becomes like this.

In this way, the reverse flow filter according to the present invention can exhibit the normal filter effect of trapping foreign matter during normal use, and also prevents the trapped foreign matter from floating out when the fluid flows backwards. Effects such as being able to be used in fluid circuits in which fluid flows in different directions can be obtained.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within the scope of the gist thereof.For example, in the above embodiments, the hydraulic circuit is mainly As explained above, this can be used not only for hydraulic circuits, but also for fluid circuits that use other fluids such as liquids and gases as pressure transmission media.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing one embodiment of the present invention, FIG. 2 is a symbol representation thereof, and FIGS. 3 and 4 are hydraulic circuit diagrams for explaining an example of overuse of this device. 1... Reverse filter, 2... Filter outer cylinder, 2-... Flange, 3.6.8.10...
Bolt, 4... Main body, 4a... Distribution port, 4b...
Swelling portion, 5... Lid, 7... Inflow side flange of hydraulic circuit, 9... Outflow side flange of hydraulic circuit, 11... Filter element, 12. 22... Valve box, 13 ,2
0,27... Valve body, 14,15.24.26... Coil spring, 16.17, 21, 23.25... Channel hole.

Claims (1)

[Claims] A cylindrical filter for fluid filtration is provided in a cylindrical container, and the container is connected to a fluid flow path, and the container is also provided with an opening with a low differential pressure between downstream parts to bypass this filter. The filter is provided with a backflow prevention valve that opens at a low differential pressure to the downstream part of the container and allows the fluid that has passed through the filter to pass therethrough. A reverse flow filter characterized in that normally, fluid flows from upstream to downstream through the filter, and when fluid flows backward, the filter flow path is bypassed by the backflow valve to flow the fluid from downstream to upstream. .